WO2011002094A1 - Method of desulfurization of molten iron - Google Patents

Method of desulfurization of molten iron Download PDF

Info

Publication number
WO2011002094A1
WO2011002094A1 PCT/JP2010/061366 JP2010061366W WO2011002094A1 WO 2011002094 A1 WO2011002094 A1 WO 2011002094A1 JP 2010061366 W JP2010061366 W JP 2010061366W WO 2011002094 A1 WO2011002094 A1 WO 2011002094A1
Authority
WO
WIPO (PCT)
Prior art keywords
desulfurization
hot metal
stirring blade
slag
agent
Prior art date
Application number
PCT/JP2010/061366
Other languages
French (fr)
Japanese (ja)
Inventor
菊池直樹
小泉正樹
山内崇
松田樹人
岸本康夫
岩浅麻希
中井由枝
Original Assignee
Ｊｆｅスチール株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ｊｆｅスチール株式会社 filed Critical Ｊｆｅスチール株式会社
Priority to CN201080029394.3A priority Critical patent/CN102471814B/en
Priority to BRPI1015360-8A priority patent/BRPI1015360B1/en
Priority to KR1020127001048A priority patent/KR101366720B1/en
Priority to EP10794262.5A priority patent/EP2434025B1/en
Publication of WO2011002094A1 publication Critical patent/WO2011002094A1/en

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C1/00—Refining of pig-iron; Cast iron
    • C21C1/02—Dephosphorising or desulfurising
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C1/00—Refining of pig-iron; Cast iron
    • C21C1/02—Dephosphorising or desulfurising
    • C21C1/025—Agents used for dephosphorising or desulfurising

Definitions

  • the present invention uses a mechanical stirring desulfurization apparatus equipped with a stirring blade, and a desulfurization agent via a top lance on the hot metal bath surface stirred by the stirring blade. ) Is sprayed and added to the hot metal (molten iron) for desulfurization.
  • the hot metal desulfurization treatment is generally performed using a solid desulfurization agent such as lime (CaO).
  • a lime-based desulfurization agent CaO-based desulfurization agent
  • a hot metal transfer container such as a toppedo car or hot-metal ladle using a blowing injection lance.
  • the injection desulfurization method to be added or a stirring blade (also referred to as “impeller”) is immersed in the hot metal in the hot metal conveying container, and the lime-based desulfurizing agent is added on top while stirring the hot metal with the rotating stirring blade (top addition / addition)
  • a mechanical stirring desulfurization method has been performed.
  • the particle size of the desulfurization agent to be added size in diameter
  • the desulfurization reaction efficiency will be improved.
  • the desulfurization agent is cut out (add) from the hopper, and the desulfurization agent is added to the treatment vessel from the inlet installed above the treatment vessel such as a hot metal ladle. Is common.
  • Patent Document 1 discloses that in a hot metal desulfurization method using a mechanical stirring type desulfurization apparatus, a desulfurizing agent is placed on the bath surface of the hot metal being stirred by a stirring blade via an upper blowing lance.
  • a method of performing a desulfurization process by blasting with a carrier gas has been proposed.
  • Patent Document 1 since a fine-sized desulfurization agent having excellent reactivity is added together with a carrier gas, scattering during addition is reduced, and the addition yield of the desulfurization agent is improved.
  • the fine-grain desulfurization agent has a large reaction interface area, and therefore, the desulfurization reaction is promoted, and the desulfurization rate can be remarkably improved.
  • Patent Document 1 An upper blowing lance is used to avoid aggregation of the desulfurizing agent, which is a problem when the desulfurizing agent is added from above the processing vessel, and to increase a substantial reaction interface area.
  • the powdery desulfurizing agent is sprayed on the hot metal bath surface together with the carrier gas.
  • aggregation is a phenomenon in which the added powdery desulfurizing agent coalesces in the hot metal or on the hot metal after addition and grows into a spherical shape. In order to substantially increase the reaction interface area, the aggregation is suppressed. There is a need to.
  • Patent Document 1 does not define the particle size of the desulfurizing agent, and therefore, desulfurization in which the desulfurizing agent is added at a high addition yield and aggregation of the added desulfurizing agent is prevented. It is difficult to obtain a stable treatment.
  • the hot metal may be subjected to desiliconization treatment and dephosphorization treatment before desulfurization treatment of the hot metal.
  • the desulfurization treatment is performed after removing the slag generated in the desiliconization process or the dephosphorization process in the previous process, but the slag in the previous process cannot be completely removed, and the slag in the previous process is unavoidable. Mixing and the amount of mixing vary. Since both the desiliconization process and the dephosphorization process are refining utilizing an oxidation reaction, the mixed slag has a high degree of oxidation.
  • This mixed slag is caught in the hot metal when the hot metal is stirred by the stirring blade, and is reduced by the carbon in the hot metal. Since this phenomenon is equivalent to the addition of oxygen to hot metal, it works against the desulfurization reaction, which is reductive refining. That is, the desulfurization reaction is inhibited by the mixed slag. This phenomenon has a greater effect when sprayed with a top blowing lance than when the desulfurizing agent is added on top. In the top addition method, mixed slag and desulfurizing agent (upper added flux) aggregate on the bath surface, and the mixed slag is not directly involved in the hot metal and the desulfurization reaction is difficult to be inhibited by the mixed slag. Then, there are few desulfurization agents (upper addition flux) which exist on a hot metal surface, and it is because the mixed slag is often caught as it is.
  • the present invention has been made in view of the above circumstances, and its object is to use a mechanical stirring type desulfurization apparatus equipped with a stirring blade, and a hot metal bath surface being stirred by the stirring blade via an upper blowing lance.
  • a mechanical stirring type desulfurization apparatus equipped with a stirring blade, and a hot metal bath surface being stirred by the stirring blade via an upper blowing lance.
  • desulfurization treatment of hot metal by spraying and adding desulfurizing agent it is possible to add desulfurizing agent with a high addition yield, and at the same time, it prevents aggregation of the added desulfurizing agent, which makes it stable and highly efficient
  • the present invention is to provide a hot metal desulfurization method that can be desulfurized with a hot metal.
  • the hot metal desulfurization method according to the first aspect of the present invention for solving the above problem is a hot metal desulfurization method using a mechanical stirring desulfurization apparatus, wherein the particle size is on the bath surface of the hot metal being stirred by a stirring blade.
  • a desulfurization treatment is performed by adding a lime-based desulfurizing agent of 30 to 400 ⁇ m together with a carrier gas through an upper blowing lance to perform a desulfurization treatment.
  • the upper blow lance is arranged facing downward in the vertical direction, the inner wall radius of the processing vessel containing the hot metal is D, and the radius of the stirring blade is R
  • the radius (R) of the stirring blade is expressed by the following formula (1) with respect to the inner wall radius (D) of the processing vessel.
  • the range satisfying the relationship, and the horizontal distance (A) satisfies the relationship of the following expression (2) with respect to the inner wall radius (D) and the radius (R) of the stirring blade. It is characterized by being within.
  • R ⁇ (1/2) ⁇ D (1) R ⁇ A ⁇ (1/2) ⁇ D (2)
  • D is the radius (m) of the inner wall of the processing vessel that contains the hot metal
  • R is the radius (m) of the stirring blade
  • A is the top blowing from the center of the processing vessel. The horizontal distance (m) to the center of the lance.
  • the desulfurized slag generated in the desulfurization treatment using the lime-based desulfurizing agent is added to the hot metal bath surface in advance.
  • the hot metal is stirred by the stirring blade, and then the desulfurizing agent is added.
  • the lime-based desulfurization agent having a particle size of 30 to 400 ⁇ m is added by spraying from the top blowing lance, so that it does not contain fine powder that is easily scattered, and scattering during the spraying addition Is prevented.
  • coarse particles with a small reaction interface area are not included, and the aggregation of the added desulfurizing agent is prevented, so that the desulfurization reaction interface area is increased and high-efficiency desulfurization treatment is realized stably. be able to.
  • a reduction in the desulfurizing agent basic unit and a reduction in the amount of generated slag accompanying this can be achieved, resulting in an industrially beneficial effect.
  • FIG. 1 is a schematic view of a mechanical stirring desulfurization apparatus used in the present invention.
  • FIG. 2 is a diagram showing the relationship between the particle size (horizontal axis: mm) of the lime-based desulfurizing agent and the scattering rate (vertical axis:%).
  • FIG. 3 is a diagram showing the relationship between the particle diameter of the lime-based desulfurizing agent (horizontal axis: mm) and the average diameter of the desulfurized slag (vertical axis: mm).
  • FIG. 4 is a diagram showing the relationship between the particle size (horizontal axis: mm) of the lime-based desulfurization agent and the sulfur concentration in the hot metal after treatment (vertical axis: mass%).
  • FIG. 1 shows a schematic view of a mechanical stirring type desulfurization apparatus used in the desulfurization test.
  • a hot metal ladle 2 containing hot metal 3 discharged from a blast furnace is mounted on a carriage 1 and carried into a mechanical stirring type desulfurization apparatus.
  • the mechanical stirring-type desulfurization apparatus includes a refractory stirring blade 4 that is immersed and buried in a hot metal 3 accommodated in a hot metal ladle 2 and swirls to stir the hot metal 3. It is moved up and down in a substantially vertical direction by an elevating device (not shown), and is turned around a shaft 4a as a rotating shaft by a rotating device (not shown).
  • the mechanical stirring type desulfurization apparatus is provided with an upper blowing lance 5 for adding the lime-based desulfurizing agent 7 by blowing it upward toward the hot metal 3 accommodated in the hot metal ladle 2.
  • the top blowing lance 5 is connected to a supply device including a dispenser 8 containing the powdered lime-based desulfurization agent 7 and a cutting device 9 for quantitatively cutting out from the dispenser 8. Therefore, the powdery lime-based desulfurizing agent 7 can be supplied together with the carrier gas 10 at an arbitrary timing.
  • the carrier gas 10 a reducing gas, an inert gas, or a non-oxidizing gas is used.
  • a dust collection hood (dust) 6 covering the hot metal ladle 2 is provided above the hot metal ladle 2, and exhaust gas being treated is exhausted through an exhaust duct (not shown) attached to the dust collection hood 6. Dust is sucked into a dust collector (not shown).
  • the shaft 4a and the upper blowing lance 5 of the stirring blade 4 are installed so as to penetrate the dust collection hood 6 and move up and down.
  • the particle size of the desulfurizing agent in the present invention is defined by sieving, and even if it has a spindle shape whose major axis is larger than the opening size of the sieving machine, as long as it passes through the sieving machine, It is defined as being smaller than the opening size of the sieve.
  • the lime-based desulfurizing agent 7 used was adjusted in particle size to an average particle size of ⁇ 10%.
  • a predetermined rotational speed 120 rpm
  • the installation position of the top blowing lance 5 is the horizontal distance from the center of the hot metal ladle 2 to the center of the top blowing lance 5 with the inner wall radius (inner radius) of the hot metal ladle 2 being the processing vessel being D (m).
  • Is A (m) the distance (A) is (1/2) ⁇ D, and the distance from the hot water surface of the hot metal 3 in the hot metal ladle to the tip of the top blowing lance 5 (referred to as “lance height”)
  • the position was set to 1.0 m.
  • the distance (A) was larger than the impeller radius (R) (m).
  • the upper blowing lance 5 was arranged vertically downward at this position, and nitrogen gas was used as the carrier gas.
  • the sieve As long as it passes through the divider, it is defined as being smaller than the opening size of the sieve.
  • the method for measuring the average particle size of desulfurized slag is described in P8 to P12 of “Powder Engineering Series, Volume 1, Basic Physical Properties of Powder, Editor: Powder Industry Association, Publisher: Nikkan Kogyo Shimbun”. A weighted average based on the distribution standard r (0 (number), 1 (length), 2 (area), 3 (volume)) as 1 (ie, the distribution standard as the length) The particle size was measured.
  • Fig. 2 shows the relationship between the particle size (horizontal axis: mm) of the lime-based desulfurizing agent and the scattering rate (vertical:%)
  • Fig. 3 shows the particle size of the lime-based desulfurizing agent and the average diameter of the desulfurized slag (vertical axis). : Mm).
  • the average diameter of the desulfurization slag increases as the particle diameter of the desulfurization agent increases, but the average diameter of the desulfurization slag does not become so large when the particle diameter of the desulfurization agent is 400 ⁇ m or less.
  • the scattering rate is low, but the average diameter of the desulfurization slag becomes large, and an increase in the reaction interface area cannot be expected.
  • FIG. 4 shows the relationship between the particle size of the lime-based desulfurizing agent and the sulfur concentration in the hot metal after treatment (vertical axis: mass%).
  • the particle size of the lime-based desulfurizing agent 7 in the range of 30 to 400 ⁇ m, it may be possible to perform a stable desulfurization treatment up to the low-sulfur steel region. I understood.
  • the particle size of the desulfurizing agent on the horizontal axis in FIGS. 2 to 4 indicates the average particle size of the desulfurizing agent with the particle size adjusted to an average particle size of ⁇ 10%.
  • the present invention was made based on the above test.
  • the lime-based desulfurization having a particle size of 30 to 400 ⁇ m on the bath surface of the hot metal being stirred by the stirring blade.
  • the desulfurization treatment is performed by adding the agent and the carrier gas through the top blowing lance.
  • a test for changing the installation position of the top blowing lance 5 in the radial direction of the hot metal ladle 2 using a lime-based desulfurizing agent 7 having a particle diameter of 30 to 400 ⁇ m was also carried out.
  • the radius of the stirring blade 4 is R (m)
  • the stirring blade radius (R) is equal to or less than 1/2 of the inner wall radius (D) of the hot metal ladle 2 (R ⁇ (1/2) ⁇ D).
  • the upper blowing lance 5 is vertically downward, and the lance height is constant at 1.0 m.
  • the position of the stirring blade 4 was set almost at the center of the hot metal pan 2.
  • the horizontal distance (A) from the center of the hot metal ladle 2 to the center of the upper blowing lance 5 is changed from the outer peripheral position of the stirring blade 4, that is, the radius of the stirring blade (R) to 1 / of the inner wall radius (D) of the hot metal pan 2.
  • the average value of the sulfur concentration in the hot metal after the desulfurization treatment is 0.0007% by mass (range of variation: 0.0006 to 0.001). 0015 mass%)
  • the desulfurization agent scattering rate was 5 to 10%
  • the particle size of the desulfurization slag was 5 to 10 mm, and stable and good results were obtained.
  • the vortex formed by the stirring blade 4 forms a range in which the bath surface and the flow in the bath are directed downward in the vertical direction, and the desulfurization agent 7 is added to the range by blowing upward. This is because the desulfurization reaction proceeds by being caught inside. If it is too close to the center of the hot metal ladle 2, the desulfurizing agent 7 accumulates in the co-rotating part (the part of hot metal at the same speed with impeller) around the stirring blade 4 to form a lump. On the other hand, if it is too outside, the flow on the bath surface and in the bath is upward in the vertical direction, and it takes time to get caught in the bath, and during that time, scattering and aggregation progress.
  • the upper blowing lance 5 is arranged in the vertically downward direction under the condition that the stirring blade radius (R) is within the range satisfying the relationship of the following expression (1) with respect to the inner wall radius (D) of the hot metal ladle 2.
  • R ⁇ (1/2) ⁇ D
  • R R ⁇ A ⁇ (1/2) ⁇ D
  • D is the radius (m) of the inner wall of the processing vessel that contains the hot metal
  • R is the radius (m) of the stirring blade
  • A is the top blowing from the center of the processing vessel.
  • the horizontal distance (m) to the center of the lance In operation, it is preferable to manage the scattering rate of the desulfurizing agent within a range of 40% or less and the desulfurized slag within a particle size of 14 mm or less according to the above conditions.
  • the size of the stirring blade and the processing vessel may be determined according to the intended amount of hot metal treatment (generally 250 to 350 tons) and the required degree of stirring.
  • R is preferably D / 3 or more from the viewpoint of stirring.
  • a reducing gas As the carrier gas when the lime-based desulfurizing agent 7 is blown from the top blowing lance 5, a reducing gas, an inert gas or a non-oxidizing gas is used.
  • the reducing gas include hydrocarbon gas
  • examples of the inert gas include argon gas
  • examples of the non-oxidizing gas include nitrogen gas.
  • a reducing gas is the most suitable as a carrier gas among the above gases. That is, conveyance with a reducing gas is more advantageous than other gases because it reduces the oxygen partial pressure at the reaction interface and promotes the desulfurization reaction.
  • the ideal low oxygen partial pressure at the hot metal-desulfurizing agent interface is realized.
  • any substance can be used as long as it contains lime (CaO) as a main component, in other words, contains 50% by mass or more of CaO.
  • lime CaO
  • a mixture of Al 2 O 3 , CaF 2, or the like as a hatching promoter melting agent is used.
  • dolomite CaO—MgO
  • dolomite can also be used as the lime-based desulfurizing agent 7.
  • the metal Al to be added (included when aluminum ash is used as a raw material, for example) is regarded as an active ingredient of an Al 2 O 3 source of a CaO—Al 2 O 3 -based lime-based desulfurizing agent.
  • the recovered desulfurized slag is added onto the hot metal in the hot metal ladle 2 before starting the stirring of the hot metal 3 by the stirring blade 4, and the desulfurized slag added by stirring the hot metal 3 with the stirring blade 4 is wound into the hot metal.
  • the recovered desulfurized slag is added to the hot metal 3 being stirred by the stirring blade 4 and the added desulfurized slag is wound into the hot metal. Thereafter, the addition of the lime-based desulfurizing agent 7 from the top blowing lance 5 may be started.
  • the reason for starting the addition of the lime-based desulfurization agent 7 from the top blowing lance 5 after the desulfurization slag is wound into the hot metal is that the powdery lime-based desulfurization agent 7 added from the top blowing lance 5 is efficiently put into the hot metal. This is for infiltration. That is, the added desulfurization slag is present on the hot metal bath surface for a while even when the hot metal 3 is stirred by the stirring blade 4, and in this state, the desulfurizing agent from the top blowing lance 5 is transferred to the hot metal 3. This is because it prevents the intrusion of water.
  • the time required for the added recovered slag to be caught in the hot metal varies depending on the equipment and operating conditions, but can be easily confirmed by visual observation.
  • the molten iron discharged from the blast furnace is first subjected to desiliconization treatment and / or dephosphorization treatment.
  • the slag containing iron oxide generated in the process is discharged, but it is difficult to completely discharge the slag from the container.
  • the slag containing is left. That is, slag containing iron oxide remains in the hot metal ladle 2 before the desulfurization treatment is started.
  • blast furnace slag and blast furnace cast floor desiliconization slag (desilication slag generated at blast furnace runner) flows into the hot metal ladle 2 and is brought to the desulfurization treatment process.
  • the components in the slag brought to the desulfurization process that is, iron oxide contained in the desiliconization agent and dephosphorization agent, and SiO 2 contained in the desiliconization slag, dephosphorization slag and blast furnace slag are desulfurization reaction.
  • Adversely affect That is, iron oxide is disadvantageous for the desulfurization reaction that is a reduction reaction, and SiO 2 coexists with CaO, which is the main component of the desulfurization agent, thereby reducing the basicity of the reaction site and reducing the desulfurization ability.
  • the desulfurized slag collected in advance is added to the hot metal pan before the addition of the lime-based desulfurizing agent 7 to the hot metal 3, and the added desulfurized slag is stirred with the hot metal 3 to contain the remaining iron oxide.
  • the slag or SiO 2 -containing slag is mixed with the added desulfurized slag, and the desulfurized slag adheres to the surface of the iron oxide-containing slag or SiO 2 -containing slag and is coated with the desulfurized slag.
  • the present inventors when carrying out the desulfurization treatment after the desiliconization treatment, the present inventors add the desulfurization slag collected in advance into the hot metal ladle before starting the stirring of the hot metal 3 with the stirring blade 4, It has been confirmed that desulfurized slag mainly composed of SiO 2 and mainly CaO is produced at a high iron oxide concentration.
  • the lime-based desulfurizing agent 7 having a particle size of 30 to 400 ⁇ m is added by spraying from the top blowing lance 5, so that scattering during spraying is prevented. At the same time, aggregation of the added desulfurizing agent is prevented, the desulfurization reaction interfacial area is increased, and high-efficiency desulfurization treatment is stably realized.
  • the particle size of the lime-based desulfurization agent is in the range of 20 ⁇ m or less (Comparative Example 1), in the range of 500 to 1000 ⁇ m (Comparative Example 2), in the range of 200 to 400 ⁇ m (Invention Example 1), and 30 to 100 ⁇ m.
  • Comparative Examples 1 and 2 and Invention Examples 1 and 2 the installation position of the top blowing lance is placed in a range that satisfies the above-mentioned formula (2), and desulfurization reaction is performed. The effect of the particle size of the desulfurizing agent on the flow rate was investigated.
  • Example 5 of the present invention the installation position of the top blowing lance was installed in a range satisfying the above expression (2), and the desulfurized slag collected in advance was added onto the hot metal before the stirring blades were rotated.
  • Other operating conditions other than the particle size of the lime-based desulfurizing agent and the position where the top blowing lance was installed were in accordance with Table 1. All tests were conducted with 100 charges (ch). Table 2 shows the operation conditions and the operation results.
  • Examples 6 to 9 of the present invention are d / 3 ⁇ R ⁇ d / 2 + 1/3 ⁇ (D ⁇ d) (in the symbol of the present invention, (2R) where the position of the top lance is suitable in Patent Document 1. / 3 ⁇ A ⁇ R + (1/3) ⁇ (2D ⁇ 2R), and the right side satisfies (2D) / 3 + R / 3), but R ⁇ A ⁇ (1 / 2) xD is an unsatisfactory test.
  • the desulfurization efficiency is improved as compared with Comparative Example 3 which is a conventional addition method, but in Inventive Examples 10 and 11 which are preferred ranges of the present invention, The desulfurization efficiency is remarkably improved. That is, as seen in the maximum S concentration after the treatment and the ratio of S ⁇ 0.003% by mass, Example 10 and Example 11 achieve low sulfidation with very small variations. . [Example 3]
  • the desulfurization treatment was performed under various conditions shown in Table 4, and the obtained results are also shown in Table 4.
  • the operating conditions other than those shown in Table 4 were the same as in Example 1.
  • Example 12 to 16 of the present invention in Table 4 the influence of the stirring time from when the recycled desulfurized slag (recovered slag) was charged in advance until the start of addition of the desulfurizing agent from the top blowing lance was confirmed.
  • Examples 17 to 22 of the present invention the influence of the mixed amount of Al 2 O 3 in the CaO—Al 2 O 3 -based desulfurizing agent was confirmed.
  • Examples 23 and 24 of the present invention the influence of the carrier gas of the desulfurizing agent was confirmed. did.
  • the amount of Al 2 O 3 mixed in the CaO—Al 2 O 3 desulfurizing agent is 10 to 30% (internal weight%). Was found to be particularly suitable. Further, from Invention Example 23 and Invention 24, it can be confirmed that the use of a reducing gas (propane gas (hydrocarbon gas) of Invention Example 24) as the carrier gas further improves the desulfurization efficiency. It was.
  • a reducing gas propane gas (hydrocarbon gas) of Invention Example 24
  • high-efficiency desulfurization treatment that is, treatment such that S after desulfurization treatment is, for example, 0.003% by mass
  • S after desulfurization treatment is, for example, 0.003% by mass

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)

Abstract

Provided is a method of desulfurization of molten iron by means of a mechanical stirring type of desulfurization apparatus equipped with an impeller. The desulfurization treatment is conducted by blasting a CaO-based desulfurization agent having a particle size of 30-400 µm in diameter with a carrier gas through a top lance onto the surface of the impeller-stirred molten iron bath. Thereby, the desulfurization agent can be added at a high addition efficiency without causing aggregation of the added desulfurization agent. Thus the desulfurization can be conducted stably at a high efficiency.

Description

溶銑の脱硫方法Hot metal desulfurization method
　本発明は、攪拌羽根（ｉｍｐｅｌｌｅｒ）を備えた機械攪拌式（ｍｅｃｈａｎｉｃａｌ　ｓｔｉｒｒｉｎｇ）脱硫装置を用い、攪拌羽根によって攪拌されている溶銑浴面に上吹きランス（ｔｏｐ　ｌａｎｃｅ）を介して脱硫剤（ｄｅｓｕｌｆｕｒｉｚａｔｉｏｎ　ａｇｅｎｔ）を吹き付け添加して溶銑（ｈｏｔ　ｍｅｔａｌ（ｍｏｌｔｅｎ　ｉｒｏｎ））を脱硫する（ｄｅｓｕｌｆｕｒｉｚａｔｉｏｎ）方法に関する。 The present invention uses a mechanical stirring desulfurization apparatus equipped with a stirring blade, and a desulfurization agent via a top lance on the hot metal bath surface stirred by the stirring blade. ) Is sprayed and added to the hot metal (molten iron) for desulfurization.
　近年の低硫鋼の生産量増加に伴い、溶銑段階での効率的な脱硫処理が必須となっている。溶銑の脱硫処理は、従来から、石灰（ＣａＯ）などの固体の脱硫剤を用いる方法が一般的である。　例えば、トピードカー（ｔｏｒｐｅｄｏ　ｃａｒ）や溶銑鍋（ｈｏｔ−ｍｅｔａｌ　ｌａｄｌｅ）などの溶銑搬送容器に収容された溶銑にインジェクションランス（ｂｌｏｗｉｎｇ　ｉｎｊｅｃｔｉｏｎ　ｌａｎｃｅ）を用いて石灰系脱硫剤（ＣａＯ−ｂａｓｅｄ　ｄｅｓｕｌｆｕｒｉｚａｔｉｏｎ　ａｇｅｎｔ）を吹き込み添加するインジェクション脱硫方法や、溶銑搬送容器内の溶銑に攪拌羽根（「インペラー」とも呼ぶ）を浸漬させ、回転する攪拌羽根によって溶銑を攪拌しながら石灰系脱硫剤を上置き添加（ｔｏｐ　ａｄｄｉｔｉｏｎ／ａｄｄｉｔｉｏｎ　ｆｒｏｍ　ｔｏｐ）する機械攪拌式脱硫方法が行われてきた。 Efficient desulfurization treatment at the hot metal stage is indispensable with the recent increase in production of low-sulfur steel. Conventionally, the hot metal desulfurization treatment is generally performed using a solid desulfurization agent such as lime (CaO). For example, a lime-based desulfurization agent (CaO-based desulfurization agent) is injected into a hot metal contained in a hot metal transfer container such as a toppedo car or hot-metal ladle using a blowing injection lance. The injection desulfurization method to be added, or a stirring blade (also referred to as “impeller”) is immersed in the hot metal in the hot metal conveying container, and the lime-based desulfurizing agent is added on top while stirring the hot metal with the rotating stirring blade (top addition / addition) A mechanical stirring desulfurization method has been performed.
　この石灰系脱硫剤を用いた脱硫反応では、反応界面積（ｒｅａｃｔｉｏｎ　ｉｎｔｅｒｆａｃｉａｌ　ａｒｅａ）を増大させることが脱硫反応の効率化に効果的であり、従って、添加する脱硫剤の粒径（ｓｉｚｅ　ｉｎ　ｄｉａｍｅｔｅｒ）を細粒化すれば脱硫反応効率が向上する。　しかし、実機での機械攪拌式脱硫方法においては、ホッパーから脱硫剤を切り出し（ａｄｄ）、溶銑鍋などの処理容器の上方に設置された投入口から脱硫剤を処理容器内に上置き添加する方法が一般的である。　このような方法で細粒の脱硫剤を添加すると、飛散する脱硫剤や上昇気流で舞い上がる脱硫剤が多くなり、脱硫剤の添加歩留まりが低下し、結局、効率的な脱硫処理は得られない。 In the desulfurization reaction using this lime-based desulfurization agent, increasing the reaction interfacial area is effective for improving the efficiency of the desulfurization reaction. Therefore, the particle size of the desulfurization agent to be added (size in diameter) If slag is refined, the desulfurization reaction efficiency will be improved. However, in the mechanical stirring type desulfurization method in an actual machine, the desulfurization agent is cut out (add) from the hopper, and the desulfurization agent is added to the treatment vessel from the inlet installed above the treatment vessel such as a hot metal ladle. Is common. When a fine-grained desulfurizing agent is added by such a method, the amount of the desulfurizing agent that scatters and the desulfurizing agent that rises with the rising air flow increases, and the yield of adding the desulfurizing agent decreases, and consequently, an efficient desulfurizing treatment cannot be obtained.
　この問題を解決するべく、特許文献１には、機械攪拌式脱硫装置を用いた溶銑の脱硫方法において、攪拌羽根によって攪拌されている溶銑の浴面上に、脱硫剤を、上吹きランスを介して搬送用ガス（ｃａｒｒｉｅｒ　ｇａｓ）とともに上吹き添加（ｂｌａｓｔｉｎｇ）して脱硫処理を行う方法が提案されている。　特許文献１によれば、反応性に優れる細粒の脱硫剤を搬送用ガスとともに上吹き添加するので、添加時の飛散が少なくなり、脱硫剤の添加歩留まりが向上するとしている。　そして、細粒の脱硫剤は、反応界面積が大きく、そのため、脱硫反応が促進され、脱硫率（ｄｅｓｕｌｆｕｒｉｚａｔｉｏｎ　ｒａｔｅ）を著しく向上させることができるとしている。　また特許文献１においては上吹きされた脱硫剤を溶銑中にスムーズに分散（ｓｃａｔｔｅｒ）させる観点から、攪拌羽根の中心から脱硫剤の吹き付け位置までの水平距離Ｒについて、
　ｄ／３≦Ｒ≦ｄ／２＋１／３×（Ｄ−ｄ）
の関係を満足させる（（２）式：ただしＤは溶銑を収容する処理容器の内径（直径）、ｄは攪拌羽根の直径）ことが好ましいとしている（［００１７］~［００２０］段落）。 In order to solve this problem, Patent Document 1 discloses that in a hot metal desulfurization method using a mechanical stirring type desulfurization apparatus, a desulfurizing agent is placed on the bath surface of the hot metal being stirred by a stirring blade via an upper blowing lance. Thus, a method of performing a desulfurization process by blasting with a carrier gas has been proposed. According to Patent Document 1, since a fine-sized desulfurization agent having excellent reactivity is added together with a carrier gas, scattering during addition is reduced, and the addition yield of the desulfurization agent is improved. The fine-grain desulfurization agent has a large reaction interface area, and therefore, the desulfurization reaction is promoted, and the desulfurization rate can be remarkably improved. Further, in Patent Document 1, from the viewpoint of smoothly dispersing the sprayed desulfurizing agent in the hot metal, the horizontal distance R from the center of the stirring blade to the spraying position of the desulfurizing agent,
d / 3 ≦ R ≦ d / 2 + 1/3 × (D−d)
(Equation (2): where D is the inner diameter (diameter) of the processing vessel containing the hot metal, and d is the diameter of the stirring blade) (paragraphs [0017] to [0020]).
特開２００５−１７９６９０号公報JP 2005-179690 A
　脱硫剤の単位質量あたりの脱硫反応効率を向上させるためには、実質的な反応界面積の増加が重要である。　特許文献１では、処理容器上方から脱硫剤を上置き添加する際に問題となる脱硫剤の凝集（ａｇｇｒｅｇａｔｉｏｎ）を回避し、実質的な反応界面積を増加させるために、上吹きランスを用いて粉状脱硫剤を搬送用ガスとともに溶銑浴面上に吹き付けている。ここで、凝集とは、添加された粉状脱硫剤が添加後に溶銑中または溶銑上で合体して球状に成長する現象であり、実質的な反応界面積の増加のためには、凝集を抑制する必要がある。　凝集を抑制し、凝集径を小さくするためには、より微細な脱硫剤を添加するという方法が考えられる。　しかし一方で、上吹きランスからの吹き付け添加であっても、脱硫剤を微細化しすぎると添加歩留まりが悪化するという問題がある。 In order to improve the efficiency of the desulfurization reaction per unit mass of the desulfurizing agent, it is important to substantially increase the reaction interface area. In Patent Document 1, an upper blowing lance is used to avoid aggregation of the desulfurizing agent, which is a problem when the desulfurizing agent is added from above the processing vessel, and to increase a substantial reaction interface area. The powdery desulfurizing agent is sprayed on the hot metal bath surface together with the carrier gas. Here, aggregation is a phenomenon in which the added powdery desulfurizing agent coalesces in the hot metal or on the hot metal after addition and grows into a spherical shape. In order to substantially increase the reaction interface area, the aggregation is suppressed. There is a need to. In order to suppress aggregation and reduce the aggregation diameter, a method of adding a finer desulfurization agent is conceivable. However, on the other hand, even if it is sprayed from the top blowing lance, there is a problem that if the desulfurizing agent is made too fine, the yield of addition deteriorates.
　この観点から特許文献１を検証すれば、特許文献１は、脱硫剤の粒径を規定しておらず、従って、高い添加歩留まりで脱硫剤を添加するともに添加した脱硫剤の凝集を防止した脱硫処理を安定して得ることは、困難といわざるを得ない。 If Patent Document 1 is verified from this point of view, Patent Document 1 does not define the particle size of the desulfurizing agent, and therefore, desulfurization in which the desulfurizing agent is added at a high addition yield and aggregation of the added desulfurizing agent is prevented. It is difficult to obtain a stable treatment.
　また、溶銑の予備処理工程においては、溶銑に脱硫処理を施す前に、溶銑に対して脱珪処理、脱燐処理を行う場合がある。　この場合、前工程の脱珪処理或いは脱燐処理で生成したスラグを除去した後に脱硫処理を実施するが、前工程のスラグを完全に除去することはできず、前工程のスラグが不可避的に混入し、また、その混入量は変動する。　脱珪処理及び脱燐処理は、ともに酸化反応を利用した精錬であるので、混入したスラグは酸化度が高い。　この混入したスラグは、攪拌羽根により溶銑を攪拌した際に溶銑中に巻き込まれ、溶銑中の炭素によって還元される。　この現象は、溶銑に酸素を添加したと同等の現象であるので、還元精錬である脱硫反応に対して不利にはたらく。　つまり、混入したスラグによって脱硫反応が阻害される。　この現象は、脱硫剤の上置き添加法に比べて上吹きランスによる吹き付け添加で影響が大きい。　これは上置き添加法では混入スラグと脱硫剤（上添加フラックス）が浴面上で凝集し、混入スラグが直接溶銑に巻き込まれず混入スラグで脱硫反応が阻害され難いが、　上吹きランスによる吹き付け添加では、溶銑湯面上に存在する脱硫剤（上添加フラックス）が少なく、混入したスラグはそのまま巻き込まれることが多くなるからである。 Also, in the hot metal pretreatment process, the hot metal may be subjected to desiliconization treatment and dephosphorization treatment before desulfurization treatment of the hot metal. In this case, the desulfurization treatment is performed after removing the slag generated in the desiliconization process or the dephosphorization process in the previous process, but the slag in the previous process cannot be completely removed, and the slag in the previous process is unavoidable. Mixing and the amount of mixing vary. Since both the desiliconization process and the dephosphorization process are refining utilizing an oxidation reaction, the mixed slag has a high degree of oxidation. This mixed slag is caught in the hot metal when the hot metal is stirred by the stirring blade, and is reduced by the carbon in the hot metal. Since this phenomenon is equivalent to the addition of oxygen to hot metal, it works against the desulfurization reaction, which is reductive refining. That is, the desulfurization reaction is inhibited by the mixed slag. This phenomenon has a greater effect when sprayed with a top blowing lance than when the desulfurizing agent is added on top. In the top addition method, mixed slag and desulfurizing agent (upper added flux) aggregate on the bath surface, and the mixed slag is not directly involved in the hot metal and the desulfurization reaction is difficult to be inhibited by the mixed slag. Then, there are few desulfurization agents (upper addition flux) which exist on a hot metal surface, and it is because the mixed slag is often caught as it is.
　本発明は上記事情に鑑みてなされたもので、その目的とするところは、攪拌羽根を備えた機械攪拌式脱硫装置を用い、攪拌羽根によって攪拌されている溶銑浴面に上吹きランスを介して脱硫剤を吹き付け添加して溶銑を脱硫処理するにあたり、高い添加歩留まりで脱硫剤を添加することができると同時に、添加した脱硫剤の凝集を防止することができ、これにより、安定して高効率で脱硫することのできる、溶銑の脱硫方法を提供することである。 The present invention has been made in view of the above circumstances, and its object is to use a mechanical stirring type desulfurization apparatus equipped with a stirring blade, and a hot metal bath surface being stirred by the stirring blade via an upper blowing lance. In the desulfurization treatment of hot metal by spraying and adding desulfurizing agent, it is possible to add desulfurizing agent with a high addition yield, and at the same time, it prevents aggregation of the added desulfurizing agent, which makes it stable and highly efficient The present invention is to provide a hot metal desulfurization method that can be desulfurized with a hot metal.
　上記課題を解決するための第１の発明に係る溶銑の脱硫方法は、機械攪拌式脱硫装置を用いた溶銑の脱硫方法において、攪拌羽根によって攪拌されている溶銑の浴面上に、粒径が３０~４００μｍの石灰系脱硫剤を、上吹きランスを介して搬送用ガスとともに上吹き添加して脱硫処理を行うことを特徴とするものである。 The hot metal desulfurization method according to the first aspect of the present invention for solving the above problem is a hot metal desulfurization method using a mechanical stirring desulfurization apparatus, wherein the particle size is on the bath surface of the hot metal being stirred by a stirring blade. A desulfurization treatment is performed by adding a lime-based desulfurizing agent of 30 to 400 μm together with a carrier gas through an upper blowing lance to perform a desulfurization treatment.
　第２の発明に係る溶銑の脱硫方法は、第１の発明において、前記上吹きランスは鉛直方向下方を向いて配置され、溶銑を収容する処理容器の内壁半径をＤ、攪拌羽根の半径をＲ、処理容器の中心から前記上吹きランス中心までの水平距離をＡとしたときに、前記攪拌羽根の半径（Ｒ）が前記処理容器の内壁半径（Ｄ）に対して下記の（１）式の関係を満足する範囲内であって、且つ、前記水平距離（Ａ）が、前記内壁半径（Ｄ）及び前記攪拌羽根の半径（Ｒ）に対して下記の（２）式の関係を満足する範囲内であることを特徴とするものである。
　Ｒ≦（１／２）×Ｄ　…（１）
　Ｒ≦Ａ≦（１／２）×Ｄ　…（２）
　但し、（１）式及び（２）式において、Ｄは、溶銑を収容する処理容器の内壁半径（ｍ）、Ｒは、攪拌羽根の半径（ｍ）、Ａは、処理容器の中心から上吹きランス中心までの水平距離（ｍ）である。 In the hot metal desulfurization method according to the second invention, in the first invention, the upper blow lance is arranged facing downward in the vertical direction, the inner wall radius of the processing vessel containing the hot metal is D, and the radius of the stirring blade is R When the horizontal distance from the center of the processing vessel to the center of the upper blowing lance is A, the radius (R) of the stirring blade is expressed by the following formula (1) with respect to the inner wall radius (D) of the processing vessel. The range satisfying the relationship, and the horizontal distance (A) satisfies the relationship of the following expression (2) with respect to the inner wall radius (D) and the radius (R) of the stirring blade. It is characterized by being within.
R ≦ (1/2) × D (1)
R ≦ A ≦ (1/2) × D (2)
However, in the formulas (1) and (2), D is the radius (m) of the inner wall of the processing vessel that contains the hot metal, R is the radius (m) of the stirring blade, and A is the top blowing from the center of the processing vessel. The horizontal distance (m) to the center of the lance.
　第３の発明に係る溶銑の脱硫方法は、第１または第２の発明において、予め回収した、石灰系脱硫剤による脱硫処理にて発生した脱硫スラグを、前記溶銑の浴面上に添加した後に前記攪拌羽根によって溶銑を攪拌し、その後、前記脱硫剤を添加することを特徴とするものである。 In the hot metal desulfurization method according to the third aspect of the invention, in the first or second aspect of the invention, the desulfurized slag generated in the desulfurization treatment using the lime-based desulfurizing agent is added to the hot metal bath surface in advance. The hot metal is stirred by the stirring blade, and then the desulfurizing agent is added.
　本発明によれば、粒径を３０~４００μｍの範囲内に規定した石灰系脱硫剤を上吹きランスから吹き付けて添加するので、飛散しやすい微粉が含まれておらず、吹き付け添加時の飛散が防止される。　またこれとともに、反応界面積が小さい粗大粒が含まれておらず、しかも添加した脱硫剤の凝集が防止されるため脱硫反応界面積が増大し、高効率での脱硫処理を安定して実現することができる。　その結果、脱硫剤原単位の削減、これに伴う発生スラグ量の削減などが達成され、工業上有益な効果がもたらされる。 According to the present invention, the lime-based desulfurization agent having a particle size of 30 to 400 μm is added by spraying from the top blowing lance, so that it does not contain fine powder that is easily scattered, and scattering during the spraying addition Is prevented. Along with this, coarse particles with a small reaction interface area are not included, and the aggregation of the added desulfurizing agent is prevented, so that the desulfurization reaction interface area is increased and high-efficiency desulfurization treatment is realized stably. be able to. As a result, a reduction in the desulfurizing agent basic unit and a reduction in the amount of generated slag accompanying this can be achieved, resulting in an industrially beneficial effect.
図１は、本発明で使用した機械攪拌式脱硫装置の概略図である。FIG. 1 is a schematic view of a mechanical stirring desulfurization apparatus used in the present invention. 図２は、石灰系脱硫剤の粒径（横軸：ｍｍ）と飛散率（縦軸：％）との関係を示す図である。FIG. 2 is a diagram showing the relationship between the particle size (horizontal axis: mm) of the lime-based desulfurizing agent and the scattering rate (vertical axis:%). 図３は、石灰系脱硫剤の粒径（横軸：ｍｍ）と脱硫スラグの平均径（縦軸：ｍｍ）との関係を示す図である。FIG. 3 is a diagram showing the relationship between the particle diameter of the lime-based desulfurizing agent (horizontal axis: mm) and the average diameter of the desulfurized slag (vertical axis: mm). 図４は、石灰系脱硫剤の粒径（横軸：ｍｍ）と処理後の溶銑中硫黄濃度（縦軸：質量％）との関係を示す図である。FIG. 4 is a diagram showing the relationship between the particle size (horizontal axis: mm) of the lime-based desulfurization agent and the sulfur concentration in the hot metal after treatment (vertical axis: mass%).
　以下、本発明を詳細に説明する。 Hereinafter, the present invention will be described in detail.
　本発明者らは、機械攪拌式脱硫装置を用い、上吹きランスを介して搬送用ガスとともに石灰系脱硫剤を上吹き添加して行う溶銑の脱硫処理において、添加する脱硫剤の最適な粒径範囲を確認するべく、実機の機械攪拌式脱硫装置を用い、脱硫剤の粒径を種々変更して溶銑の脱硫試験を行った。　図１に、脱硫試験で使用した機械攪拌式脱硫装置の概略図を示す。 In the desulfurization treatment of hot metal performed by adding a lime-based desulfurization agent together with a carrier gas through a top blowing lance using a mechanical stirring type desulfurization apparatus, the present inventors set the optimum particle size of the desulfurizing agent to be added. In order to confirm the range, a hot metal desulfurization test was conducted by changing the particle size of the desulfurizing agent using a mechanical stirring desulfurization apparatus. FIG. 1 shows a schematic view of a mechanical stirring type desulfurization apparatus used in the desulfurization test.
　図１において、高炉から出銑された溶銑３を収容する溶銑鍋２が、台車（ｃａｒｒｉｎｇ　ｔｒｕｃｋ／ｃａｒｒｉｅｒ）１に搭載されて機械攪拌式脱硫装置に搬入されている。　機械攪拌式脱硫装置は、溶銑鍋２に収容された溶銑３に浸漬・埋没し、旋回して溶銑３を攪拌するための耐火物製の攪拌羽根４を備えており、この攪拌羽根４は、昇降装置（図示せず）によってほぼ鉛直方向に昇降し、且つ、回転装置（図示せず）によって軸４ａを回転軸として旋回するようになっている。　また、機械攪拌式脱硫装置には、石灰系脱硫剤７を溶銑鍋２に収容された溶銑３に向けて上吹きして添加するための上吹きランス５が設置されている。　上吹きランス５は、粉体状の石灰系脱硫剤７を収容するディスペンサー８とディスペンサー８から定量切り出すための切り出し装置（ｓｕｐｐｌｉｎｇ　ｄｅｖｉｃｅ）９とからなる供給装置と接続しており、上吹きランス５から、粉体状の石灰系脱硫剤７を搬送用ガス１０とともに任意のタイミングで供給できる構造になっている。　搬送用ガス１０としては、還元性のガス、不活性ガスまたは非酸化性のガスを使用する。　また、溶銑鍋２の上方には、溶銑鍋２を覆う集塵フード（ｄｕｓｔ　ｈｏｏｄ）６が備えられ、集塵フード６に取り付けられた排気ダクト（図示せず）を介して処理中の排ガスやダストが集塵機（図示せず）に吸引されるようになっている。　本脱硫装置の場合、攪拌羽根４の軸４ａ及び上吹きランス５は、集塵フード６を貫通し且つ上下移動が可能なように設置されている。 In FIG. 1, a hot metal ladle 2 containing hot metal 3 discharged from a blast furnace is mounted on a carriage 1 and carried into a mechanical stirring type desulfurization apparatus. The mechanical stirring-type desulfurization apparatus includes a refractory stirring blade 4 that is immersed and buried in a hot metal 3 accommodated in a hot metal ladle 2 and swirls to stir the hot metal 3. It is moved up and down in a substantially vertical direction by an elevating device (not shown), and is turned around a shaft 4a as a rotating shaft by a rotating device (not shown). Further, the mechanical stirring type desulfurization apparatus is provided with an upper blowing lance 5 for adding the lime-based desulfurizing agent 7 by blowing it upward toward the hot metal 3 accommodated in the hot metal ladle 2. The top blowing lance 5 is connected to a supply device including a dispenser 8 containing the powdered lime-based desulfurization agent 7 and a cutting device 9 for quantitatively cutting out from the dispenser 8. Therefore, the powdery lime-based desulfurizing agent 7 can be supplied together with the carrier gas 10 at an arbitrary timing. As the carrier gas 10, a reducing gas, an inert gas, or a non-oxidizing gas is used. Further, a dust collection hood (dust) 6 covering the hot metal ladle 2 is provided above the hot metal ladle 2, and exhaust gas being treated is exhausted through an exhaust duct (not shown) attached to the dust collection hood 6. Dust is sucked into a dust collector (not shown). In the case of the present desulfurization apparatus, the shaft 4a and the upper blowing lance 5 of the stirring blade 4 are installed so as to penetrate the dust collection hood 6 and move up and down.
　脱硫試験では、石灰系脱硫剤７として粒径が１０~１０００μｍの範囲のＣａＯ−２０質量％Ａｌ２Ｏ３を使用し、この石灰系脱硫剤７の飛散挙動、処理後の脱硫スラグの径、及び脱硫挙動を調査した。　表１に、脱硫処理条件を示す。尚、本発明における脱硫剤の粒径は、篩い分けによって定義されるものであり、長径が篩分器の目開き寸法よりも大きい紡錘形であっても、その篩分器を通過する限り、その篩分器の目開き寸法よりも小さいと定義する。　また、この脱硫剤の粒径を変更する脱硫試験においては、使用する石灰系脱硫剤７として、平均粒径±１０％に粒度調整したものを使用した。 In the desulfurization test, CaO-20 mass% Al 2 O 3 having a particle diameter in the range of 10 to 1000 μm is used as the lime-based desulfurizing agent 7, the scattering behavior of the lime-based desulfurizing agent 7, the diameter of the desulfurized slag after treatment, And the desulfurization behavior was investigated. Table 1 shows the desulfurization treatment conditions. Incidentally, the particle size of the desulfurizing agent in the present invention is defined by sieving, and even if it has a spindle shape whose major axis is larger than the opening size of the sieving machine, as long as it passes through the sieving machine, It is defined as being smaller than the opening size of the sieve. In the desulfurization test for changing the particle size of the desulfurizing agent, the lime-based desulfurizing agent 7 used was adjusted in particle size to an average particle size of ± 10%.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　１２８０~１３２０℃の３００トンの溶銑３を収容した溶銑鍋２を台車１に搭載し、攪拌羽根４の位置が溶銑鍋２のほぼ中心になるように、溶銑鍋２を搭載した台車１の位置を調整し、次いで、攪拌羽根４を下降させて溶銑３に浸漬させた。　攪拌羽根４が溶銑３に浸漬したならば、攪拌羽根４の旋回を開始し、所定の回転数（１２０ｒｐｍ）まで昇速した。　攪拌羽根４の回転数が所定の回転数に達したならば、切り出し装置９を起動させて、ディスペンサー８に収容された石灰系脱硫剤７を、搬送用ガスとともに溶銑３の浴面に向けて上吹きランス５から吹き付けて添加し、脱硫処理した。　この脱硫試験において、上吹きランス５の設置位置は、処理容器である溶銑鍋２の内壁半径（ｉｎｎｅｒ　ｒａｄｉｕｓ）をＤ（ｍ）、溶銑鍋２の中心から上吹きランス５の中心までの水平距離をＡ（ｍ）とすると、距離（Ａ）が（１／２）×Ｄとなり、溶銑鍋内の溶銑３の静止湯面から上吹きランス５の先端までの距離（「ランス高さ」という）が１．０ｍとなる位置とした。　なお、前記距離（Ａ）はインペラーの半径（Ｒ）（ｍ）より大であった。　そして、この位置に上吹きランス５を鉛直下方に向けて配置し、搬送用ガスとしては窒素ガスを使用した。 The position of the trolley 1 on which the hot metal ladle 2 is mounted so that the hot metal ladle 2 containing 300 tons of hot metal 3 at 1280 to 1320 ° C. is mounted on the trolley 1 and the position of the stirring blade 4 is almost the center of the hot metal ladle 2 Then, the stirring blade 4 was lowered and immersed in the hot metal 3. If the stirring blade 4 was immersed in the hot metal 3, the stirring blade 4 started to turn and increased to a predetermined rotational speed (120 rpm). When the rotational speed of the stirring blade 4 reaches a predetermined rotational speed, the cutting device 9 is started and the lime-based desulfurizing agent 7 accommodated in the dispenser 8 is directed toward the bath surface of the hot metal 3 together with the conveying gas. It added by spraying from the top blowing lance 5, and desulfurized. In this desulfurization test, the installation position of the top blowing lance 5 is the horizontal distance from the center of the hot metal ladle 2 to the center of the top blowing lance 5 with the inner wall radius (inner radius) of the hot metal ladle 2 being the processing vessel being D (m). Is A (m), the distance (A) is (1/2) × D, and the distance from the hot water surface of the hot metal 3 in the hot metal ladle to the tip of the top blowing lance 5 (referred to as “lance height”) The position was set to 1.0 m. The distance (A) was larger than the impeller radius (R) (m). Then, the upper blowing lance 5 was arranged vertically downward at this position, and nitrogen gas was used as the carrier gas.
　所定量（７ｋｇ／溶銑トン）の石灰系脱硫剤７を添加完了し、そして、所定時間（１５分間）の攪拌が行われたなら、攪拌羽根４の回転を停止させた。　攪拌羽根４の旋回が停止したなら、攪拌羽根４を上昇させ、溶銑鍋２の上方に待機させた。生成した脱硫スラグが浮上して溶銑表面を覆い、静止した状態で溶銑３の脱硫処理が終了する。 When the addition of a predetermined amount (7 kg / ton of hot metal) of the lime-based desulfurizing agent 7 was completed and stirring was performed for a predetermined time (15 minutes), the rotation of the stirring blade 4 was stopped. When the swirling of the stirring blade 4 was stopped, the stirring blade 4 was lifted and placed on standby above the hot metal ladle 2. The generated desulfurization slag rises and covers the hot metal surface, and the desulfurization process of the hot metal 3 is completed in a stationary state.
　この脱硫処理終了後、溶銑３からサンプルを採取して溶銑の硫黄含有量を調査するとともに、溶銑上に浮遊する脱硫スラグを１０ｋｇ採取し、粒径分布測定により、脱硫スラグの平均径を算出した。　また、脱硫処理中に上記集塵機のフィルターに捕捉された石灰系脱硫剤７の量を測定し、脱硫剤の添加量に対する比率（百分率）を飛散率（ｓｃａｔｔｅｒ　ｒａｔｉｏ）として評価した。　尚、脱硫スラグの粒径は、前述した脱硫剤の粒径と同様に、篩い分けによって定義されるものであり、長径が篩分器の目開き寸法よりも大きい紡錘形であっても、その篩分器を通過する限り、その篩分器の目開き寸法よりも小さいと定義する。　また、脱硫スラグの平均粒径測定方法は、「粉体工学叢書、第１巻、粉体の基礎物性、編者：粉体工業会、発行所：日刊工業新聞社」のＰ８~Ｐ１２に記載される方法に基づき、分布の基準ｒ（０（個数）、１（長さ）、２（面積）、３（体積）のいずれか）を１として（すなわち分布の基準を長さとして）重み付き平均粒子径を測定した。 After completion of this desulfurization treatment, a sample was taken from the hot metal 3 to investigate the sulfur content of the hot metal, and 10 kg of desulfurized slag floating on the hot metal was sampled, and the average diameter of the desulfurized slag was calculated by particle size distribution measurement. . In addition, the amount of the lime-based desulfurizing agent 7 captured by the filter of the dust collector during the desulfurization treatment was measured, and the ratio (percentage) with respect to the added amount of the desulfurizing agent was evaluated as a scattering ratio. The particle size of the desulfurized slag is defined by sieving in the same manner as the particle size of the desulfurizing agent described above. Even if the major axis has a spindle shape larger than the mesh size of the sieve, the sieve As long as it passes through the divider, it is defined as being smaller than the opening size of the sieve. The method for measuring the average particle size of desulfurized slag is described in P8 to P12 of “Powder Engineering Series, Volume 1, Basic Physical Properties of Powder, Editor: Powder Industry Association, Publisher: Nikkan Kogyo Shimbun”. A weighted average based on the distribution standard r (0 (number), 1 (length), 2 (area), 3 (volume)) as 1 (ie, the distribution standard as the length) The particle size was measured.
　図２に、石灰系脱硫剤の粒径（横軸：ｍｍ）と飛散率（縦：％）との関係を、図３に、石灰系脱硫剤の粒径と脱硫スラグの平均径（縦軸：ｍｍ）との関係を示す。　図２及び図３からも明らかなように、脱硫剤の粒径が３０μｍ未満の場合、飛散率は急激に上昇し、８０％以上に達する。　一方、脱硫剤の粒径が大きくなるほど脱硫スラグの平均径は大きくなるが、脱硫剤の粒径が４００μｍ以下の範囲では、脱硫スラグの平均径は余り大きくはならない。　脱硫剤の粒径が４００μｍを超える範囲では、飛散率は低いが脱硫スラグの平均径が大きくなり、反応界面積の増加は期待できない。 Fig. 2 shows the relationship between the particle size (horizontal axis: mm) of the lime-based desulfurizing agent and the scattering rate (vertical:%), and Fig. 3 shows the particle size of the lime-based desulfurizing agent and the average diameter of the desulfurized slag (vertical axis). : Mm). As is clear from FIGS. 2 and 3, when the particle size of the desulfurizing agent is less than 30 μm, the scattering rate increases rapidly and reaches 80% or more. On the other hand, the average diameter of the desulfurization slag increases as the particle diameter of the desulfurization agent increases, but the average diameter of the desulfurization slag does not become so large when the particle diameter of the desulfurization agent is 400 μm or less. In the range where the particle size of the desulfurization agent exceeds 400 μm, the scattering rate is low, but the average diameter of the desulfurization slag becomes large, and an increase in the reaction interface area cannot be expected.
　図４に、石灰系脱硫剤の粒径と処理後の溶銑中硫黄濃度（縦軸：質量％）との関係を示す。　飛散率及び脱硫スラグの平均径から予測されるように、石灰系脱硫剤７の粒径を３０~４００μｍの範囲内とすることで、低硫鋼域まで安定した脱硫処理が可能とあることが分かった。　尚、図２~４の横軸の脱硫剤粒径は、粒度を平均粒径±１０％の範囲に調整した脱硫剤の平均粒径を示している。 FIG. 4 shows the relationship between the particle size of the lime-based desulfurizing agent and the sulfur concentration in the hot metal after treatment (vertical axis: mass%). As predicted from the scattering rate and the average diameter of the desulfurized slag, by making the particle size of the lime-based desulfurizing agent 7 in the range of 30 to 400 μm, it may be possible to perform a stable desulfurization treatment up to the low-sulfur steel region. I understood. Note that the particle size of the desulfurizing agent on the horizontal axis in FIGS. 2 to 4 indicates the average particle size of the desulfurizing agent with the particle size adjusted to an average particle size of ± 10%.
　本発明は上記試験に基づきなされたもので、機械攪拌式脱硫装置を用いた溶銑の脱硫方法において、攪拌羽根によって攪拌されている溶銑の浴面上に、粒径が３０~４００μｍの石灰系脱硫剤を、上吹きランスを介して搬送用ガスとともに上吹き添加して脱硫処理を行うことを特徴とする。 The present invention was made based on the above test. In the hot metal desulfurization method using the mechanical stirring desulfurization apparatus, the lime-based desulfurization having a particle size of 30 to 400 μm on the bath surface of the hot metal being stirred by the stirring blade. The desulfurization treatment is performed by adding the agent and the carrier gas through the top blowing lance.
　また更に、粒径が３０~４００μｍの範囲内の石灰系脱硫剤７を使用して、上吹きランス５の溶銑鍋２の半径方向での設置位置を変更する試験も実施した。　この場合、攪拌羽根４の半径をＲ（ｍ）とすると、攪拌羽根半径（Ｒ）は溶銑鍋２の内壁半径（Ｄ）の１／２以下（Ｒ≦（１／２）×Ｄ）であり、また、上吹きランス５は鉛直方向下向きであり、ランス高さは１．０ｍの一定とした。　攪拌羽根４の位置は溶銑鍋２のほぼ中心位置に設置した。 Furthermore, a test for changing the installation position of the top blowing lance 5 in the radial direction of the hot metal ladle 2 using a lime-based desulfurizing agent 7 having a particle diameter of 30 to 400 μm was also carried out. In this case, if the radius of the stirring blade 4 is R (m), the stirring blade radius (R) is equal to or less than 1/2 of the inner wall radius (D) of the hot metal ladle 2 (R ≦ (1/2) × D). Further, the upper blowing lance 5 is vertically downward, and the lance height is constant at 1.0 m. The position of the stirring blade 4 was set almost at the center of the hot metal pan 2.
　その結果、溶銑鍋２の中心から上吹きランス５の中心までの水平距離（Ａ）を、攪拌羽根４の外周位置つまり攪拌羽根半径（Ｒ）から溶銑鍋２の内壁半径（Ｄ）の１／２までの範囲とした場合（Ｒ≦Ａ≦（１／２）×Ｄ）に、脱硫処理後の溶銑中硫黄濃度の平均値が０．０００７質量％（ばらつきの範囲：０．０００６~０．００１５質量％）、脱硫剤の飛散率が５~１０％、脱硫スラグの粒径が５~１０ｍｍとなり、安定して良好な結果が得られた。 As a result, the horizontal distance (A) from the center of the hot metal ladle 2 to the center of the upper blowing lance 5 is changed from the outer peripheral position of the stirring blade 4, that is, the radius of the stirring blade (R) to 1 / of the inner wall radius (D) of the hot metal pan 2. 2 (R ≦ A ≦ (1/2) × D), the average value of the sulfur concentration in the hot metal after the desulfurization treatment is 0.0007% by mass (range of variation: 0.0006 to 0.001). 0015 mass%), the desulfurization agent scattering rate was 5 to 10%, and the particle size of the desulfurization slag was 5 to 10 mm, and stable and good results were obtained.
　上吹きランス５の設置位置が、この好適範囲よりも溶銑鍋２の中心側（溶銑鍋の中心から攪拌羽根４の外周位置未満、０≦Ａ＜Ｒ）の場合には、添加位置近傍で巨大な脱硫剤の塊が形成され、脱硫スラグの粒径が過大となると共に、脱硫剤が攪拌羽根４の軸４ａに付着して脱硫反応が悪化した。　一方、好適範囲よりも外側の場合（（１／２）×Ｄ＜Ａ≦Ｄ）には、外側になるほど脱硫剤の飛散率が高くなり、且つ、脱硫スラグの粒径が大きくなった。 When the installation position of the top lance 5 is closer to the center side of the hot metal ladle 2 than this preferred range (less than the outer peripheral position of the stirring blade 4 from the center of the hot metal ladle, 0 ≦ A <R), it is huge near the addition position. The desulfurization agent lump was formed, the particle size of the desulfurization slag became excessive, and the desulfurization agent adhered to the shaft 4a of the stirring blade 4 to deteriorate the desulfurization reaction. On the other hand, when it was outside the preferred range ((1/2) × D <A ≦ D), the desulfurization agent scattering rate increased and the particle size of the desulfurized slag increased toward the outside.
　これは、攪拌羽根４で形成される渦流によって浴面及び浴内での流れが鉛直方向下向きとなる範囲が形成され、この範囲に脱硫剤７を上吹き添加することで、脱硫剤７が浴内に巻き込まれて脱硫反応が進行することによる。　溶銑鍋２の中心に近すぎる場合には、攪拌羽根４の周囲に在る共回り部（ｔｈｅ　ｐａｒｔ　ｏｆ　ｈｏｔ　ｍｅｔａｌ　ｗｈｉｃｈ　ｒｏｔａｔｅｓ　ａｔ　ｔｈｅ　ｓａｍｅ　ｓｐｅｅｄ　ｗｉｔｈ　ｉｍｐｅｌｌｅｒ）に脱硫剤７が蓄積して塊を形成し、一方、外側すぎる場合には、浴面及び浴内での流れが鉛直方向上向きであり、浴内に巻き込まれるまでに時間を費やし、その間に飛散、凝集が進行するからである。 This is because the vortex formed by the stirring blade 4 forms a range in which the bath surface and the flow in the bath are directed downward in the vertical direction, and the desulfurization agent 7 is added to the range by blowing upward. This is because the desulfurization reaction proceeds by being caught inside. If it is too close to the center of the hot metal ladle 2, the desulfurizing agent 7 accumulates in the co-rotating part (the part of hot metal at the same speed with impeller) around the stirring blade 4 to form a lump. On the other hand, if it is too outside, the flow on the bath surface and in the bath is upward in the vertical direction, and it takes time to get caught in the bath, and during that time, scattering and aggregation progress.
　即ち、攪拌羽根半径（Ｒ）が溶銑鍋２の内壁半径（Ｄ）に対して下記の（１）式の関係を満足する範囲内である条件下において、上吹きランス５を鉛直下向き方向に配置したときには、上吹きランス５の設置位置を、下記の（２）式の関係を満足する範囲とするときに、高い脱硫率が得られることが分かった。
　Ｒ≦（１／２）×Ｄ　…（１）
　Ｒ≦Ａ≦（１／２）×Ｄ　…（２）
　但し、（１）式及び（２）式において、Ｄは、溶銑を収容する処理容器の内壁半径（ｍ）、Ｒは、攪拌羽根の半径（ｍ）、Ａは、処理容器の中心から上吹きランス中心までの水平距離（ｍ）である。
　操業においては上記条件等により、脱硫剤の飛散率を４０％以下、脱硫スラグを粒径１４ｍｍ以下の範囲にそれぞれ管理することが好ましい。　なお、攪拌羽根４（および回転軸）を処理容器の中心に位置させることは必須ではなく、偏心させても攪拌に問題は無い。
　また、攪拌羽根や処理容器のサイズは、目的とする溶銑処理量（一般に２５０~３５０トン）および必要とされる攪拌の程度に応じて決定すればよい。　目安としえては、Ｒは攪拌の観点からＤ／３以上であることが好ましい。 That is, the upper blowing lance 5 is arranged in the vertically downward direction under the condition that the stirring blade radius (R) is within the range satisfying the relationship of the following expression (1) with respect to the inner wall radius (D) of the hot metal ladle 2. When it did, it turned out that a high desulfurization rate is acquired when the installation position of the top blowing lance 5 is made into the range which satisfies the relationship of following (2) Formula.
R ≦ (1/2) × D (1)
R ≦ A ≦ (1/2) × D (2)
However, in the formulas (1) and (2), D is the radius (m) of the inner wall of the processing vessel that contains the hot metal, R is the radius (m) of the stirring blade, and A is the top blowing from the center of the processing vessel. The horizontal distance (m) to the center of the lance.
In operation, it is preferable to manage the scattering rate of the desulfurizing agent within a range of 40% or less and the desulfurized slag within a particle size of 14 mm or less according to the above conditions. In addition, it is not essential to position the stirring blade 4 (and the rotation shaft) at the center of the processing container, and there is no problem in stirring even if it is decentered.
Further, the size of the stirring blade and the processing vessel may be determined according to the intended amount of hot metal treatment (generally 250 to 350 tons) and the required degree of stirring. As a guide, R is preferably D / 3 or more from the viewpoint of stirring.
　上吹きランス５から石灰系脱硫剤７を吹き込む際の搬送用ガスとしては、還元性のガス、不活性ガスまたは非酸化性のガスを使用する。　還元性のガスとしては炭化水素ガスなどが挙げられ、不活性ガスとしてはアルゴンガスなどが挙げられ、また、非酸化性ガスとしては窒素ガスなどが挙げられる。　溶銑の脱硫反応は還元反応であるので、上記のガスの中では還元性ガスが搬送用ガスとして最適である。　つまり、還元性ガスによる搬送は、反応界面での酸素分圧を低下させて脱硫反応を促進させるので、他のガスに比べて有利である。　特に、微細な粉状脱硫剤が溶銑に浸入する条件では理想的な溶銑−脱硫剤界面での低酸素分圧化が実現される。 As the carrier gas when the lime-based desulfurizing agent 7 is blown from the top blowing lance 5, a reducing gas, an inert gas or a non-oxidizing gas is used. Examples of the reducing gas include hydrocarbon gas, examples of the inert gas include argon gas, and examples of the non-oxidizing gas include nitrogen gas. Since the hot metal desulfurization reaction is a reduction reaction, a reducing gas is the most suitable as a carrier gas among the above gases. That is, conveyance with a reducing gas is more advantageous than other gases because it reduces the oxygen partial pressure at the reaction interface and promotes the desulfurization reaction. Especially, under the condition that a fine powdery desulfurizing agent enters the hot metal, the ideal low oxygen partial pressure at the hot metal-desulfurizing agent interface is realized.
　石灰系脱硫剤７としては、石灰（ＣａＯ）を主成分とするもの、換言すれば、ＣａＯを５０質量％以上含有するものであればどのような物質であっても使用可能である。　具体的には、生石灰（ｂｕｒｎｅｄ　ｌｉｍｅ）や石灰石（ｌｉｍｅｓｔｏｎｅ）などを単独で使用しても、これらにＡｌ２Ｏ３やＣａＦ２などを滓化促進剤（ｔｈｅ　ａｇｅｎｔ　ｗｈｉｃｈ　ｐｒｏｍｏｔｅ　ｍｅｌｔｉｎｇ）として混合したもの、更には、ドロマイト（ＣａＯ−ＭｇＯ）（ｄｏｌｏｍｉｔｅ）なども石灰系脱硫剤７として使用可能である。　しかし例えばＣａＯ−Ａｌ２Ｏ３系（残部不純物５質量％以下）の石灰系脱硫剤でＡｌ２Ｏ３の比率を増加すると、液相の生成量が増加するが、過剰な液相生成は粉状脱粒剤の凝集を促進し、反応界面積の低下につながることから得策でない。　つまり、ＣａＯ−Ａｌ２Ｏ３脱硫剤において、Ａｌ２Ｏ３の比率に適正な領域が存在することが調査により分かった。　ここで、添加する金属Ａｌ（例えばアルミ灰を原料とした場合に含まれる）はＣａＯ−Ａｌ２Ｏ３質の石灰系脱硫剤のＡｌ２Ｏ３源の有効成分とみなす。 As the lime-based desulfurizing agent 7, any substance can be used as long as it contains lime (CaO) as a main component, in other words, contains 50% by mass or more of CaO. Specifically, even when burned lime or limestone is used alone, a mixture of Al 2 O 3 , CaF 2, or the like as a hatching promoter melting agent is used. Furthermore, dolomite (CaO—MgO) (dolomite) can also be used as the lime-based desulfurizing agent 7. However, for example, when the ratio of Al 2 O 3 is increased with a CaO—Al 2 O 3 -based lime-based desulfurization agent (the remaining impurities are 5% by mass or less), the amount of liquid phase generated increases, but excessive liquid phase generation is reduced to powder. It is not a good idea because it promotes agglomeration of the granular degranulating agent and leads to a reduction in the reaction interface area. That is, it has been found by investigation that an appropriate region exists in the ratio of Al 2 O 3 in the CaO—Al 2 O 3 desulfurization agent. Here, the metal Al to be added (included when aluminum ash is used as a raw material, for example) is regarded as an active ingredient of an Al 2 O 3 source of a CaO—Al 2 O 3 -based lime-based desulfurizing agent.
　本発明においては、当該脱硫処理よりも以前に実施した、石灰系脱硫剤を用いた脱硫処理にて発生した脱硫スラグを予め回収しておくことが好ましい。　そして、この回収した脱硫スラグを攪拌羽根４による溶銑３の攪拌開始前に、溶銑鍋２の溶銑上に添加し、攪拌羽根４によって溶銑３を攪拌して添加した脱硫スラグを溶銑中に巻込ませるか、或いは、撹拌羽根４によって撹拌されている溶銑３に、回収した脱硫スラグを上置き添加し、添加した脱硫スラグを溶銑中に巻込ませる。　その後、上吹きランス５からの石灰系脱硫剤７の添加を開始すればよい。　脱硫スラグを溶銑中に巻込ませた後に上吹きランス５からの石灰系脱硫剤７の添加を開始する理由は、上吹きランス５から添加する粉状の石灰系脱硫剤７を効率良く溶銑中に浸入させるためである。　つまり、添加した脱硫スラグは、溶銑３が撹拌羽根４による撹拌状態であっても暫くの期間、溶銑浴面上に存在しており、この状態では上吹きランス５からの脱硫剤の溶銑３への浸入を妨害するからである。　添加した回収スラグが溶銑内に巻き込まれるまでの所要時間は設備や操業条件により異なるが、目視観察などで容易に確認することができる。 In the present invention, it is preferable to collect in advance the desulfurization slag generated in the desulfurization treatment using the lime-based desulfurization agent performed before the desulfurization treatment. Then, the recovered desulfurized slag is added onto the hot metal in the hot metal ladle 2 before starting the stirring of the hot metal 3 by the stirring blade 4, and the desulfurized slag added by stirring the hot metal 3 with the stirring blade 4 is wound into the hot metal. Alternatively, the recovered desulfurized slag is added to the hot metal 3 being stirred by the stirring blade 4 and the added desulfurized slag is wound into the hot metal. Thereafter, the addition of the lime-based desulfurizing agent 7 from the top blowing lance 5 may be started. The reason for starting the addition of the lime-based desulfurization agent 7 from the top blowing lance 5 after the desulfurization slag is wound into the hot metal is that the powdery lime-based desulfurization agent 7 added from the top blowing lance 5 is efficiently put into the hot metal. This is for infiltration. That is, the added desulfurization slag is present on the hot metal bath surface for a while even when the hot metal 3 is stirred by the stirring blade 4, and in this state, the desulfurizing agent from the top blowing lance 5 is transferred to the hot metal 3. This is because it prevents the intrusion of water. The time required for the added recovered slag to be caught in the hot metal varies depending on the equipment and operating conditions, but can be easily confirmed by visual observation.
　高炉から出銑された溶銑には、最初に脱珪処理および／または脱燐処理が施されることが一般的である。　これら脱珪処理および／または脱燐処理の処理後には当該処理工程にて発生した酸化鉄を含有するスラグは排出されるが、スラグを完全に収容容器から排出することは困難であり、酸化鉄を含有するスラグが残留する。　つまり、脱硫処理を開始する前に溶銑鍋２には、酸化鉄を含有するスラグが残留している。
　また、脱硫処理工程が第１工程の場合でも、高炉スラグや高炉鋳床脱珪スラグ（ｄｅｓｉｌｉｃｏｎｉｚａｔｉｏｎ　ｓｌａｇ　ｇｅｎｅｒａｔｅｄ　ａｔ　ｂｌａｓｔ　ｆｕｒｎａｃｅ　ｒｕｎｎｅｒ）が溶銑鍋２に流入し、脱硫処理工程に持ち来たされる。　この場合、脱硫処理工程に持ち来たされるスラグ中の成分、すなわち脱珪剤及び脱燐剤に含まれる酸化鉄や、脱珪スラグ、脱燐スラグ、高炉スラグに含まれるＳｉＯ２が脱硫反応に悪影響を及ぼす。
　即ち、酸化鉄は還元反応である脱硫反応に不利であり、またＳｉＯ２は脱硫剤の主成分であるＣａＯと共存することで、反応サイトの塩基性低下を招き脱硫能を低下させる。 In general, the molten iron discharged from the blast furnace is first subjected to desiliconization treatment and / or dephosphorization treatment. After the desiliconization process and / or the dephosphorization process, the slag containing iron oxide generated in the process is discharged, but it is difficult to completely discharge the slag from the container. The slag containing is left. That is, slag containing iron oxide remains in the hot metal ladle 2 before the desulfurization treatment is started.
Even when the desulfurization treatment process is the first process, blast furnace slag and blast furnace cast floor desiliconization slag (desilication slag generated at blast furnace runner) flows into the hot metal ladle 2 and is brought to the desulfurization treatment process. In this case, the components in the slag brought to the desulfurization process, that is, iron oxide contained in the desiliconization agent and dephosphorization agent, and SiO 2 contained in the desiliconization slag, dephosphorization slag and blast furnace slag are desulfurization reaction. Adversely affect.
That is, iron oxide is disadvantageous for the desulfurization reaction that is a reduction reaction, and SiO 2 coexists with CaO, which is the main component of the desulfurization agent, thereby reducing the basicity of the reaction site and reducing the desulfurization ability.
　このような場合に、予め回収した脱硫スラグを、石灰系脱硫剤７の溶銑３への添加前に溶銑鍋内に添加し、添加した脱硫スラグを溶銑３と攪拌することで残留した酸化鉄含有スラグ或いはＳｉＯ２含有スラグは添加した脱硫スラグと混じり合い、酸化鉄含有スラグ或いはＳｉＯ２含有スラグの表面に脱硫スラグが付着し、脱硫スラグによって被覆されたような形態となる。　このような形態になると、溶銑中に巻き込まれても、外周は高融点の脱硫スラグで囲まれていることから、酸化鉄含有スラグ或いはＳｉＯ２含有スラグは溶銑３と直接接触せず、酸化鉄含有スラグ及びＳｉＯ２含有スラグの脱硫反応への悪影響が防止される。 In such a case, the desulfurized slag collected in advance is added to the hot metal pan before the addition of the lime-based desulfurizing agent 7 to the hot metal 3, and the added desulfurized slag is stirred with the hot metal 3 to contain the remaining iron oxide. The slag or SiO 2 -containing slag is mixed with the added desulfurized slag, and the desulfurized slag adheres to the surface of the iron oxide-containing slag or SiO 2 -containing slag and is coated with the desulfurized slag. If it becomes such a form, even if it is caught in hot metal, since the outer periphery is surrounded by high-melting-point desulfurization slag, iron oxide-containing slag or SiO 2 -containing slag is not in direct contact with hot metal 3 and iron oxide adverse effect on the desulfurization reaction containing slag and SiO 2 containing slag is prevented.
　即ち、予め回収した脱硫スラグを添加することにより、残留する酸化鉄含有スラグからの溶銑３への酸素の供給が防止され、或いは、残留するＳｉＯ２含有スラグによる反応サイトの塩基性低下が防止されるので、残留するスラグによって還元反応である脱硫反応が阻害されることを未然に防止することができる。
　特に、上吹きランス５により脱硫剤を浴面に投射する場合には脱硫スラグの添加効果がより顕著になる。
　尚、本発明者らは、脱珪処理後に脱硫処理を実施する場合に、予め回収した脱硫スラグを攪拌羽根４による溶銑３の攪拌開始前に溶銑鍋内に添加することで、中心部は、酸化鉄濃度が高くＳｉＯ２を主体とし、その周囲は、ＣａＯを主体とする脱硫スラグが生成されることを確認している。 That is, by adding the previously recovered desulfurized slag, the supply of oxygen from the remaining iron oxide-containing slag to the hot metal 3 is prevented, or the basic deterioration of the reaction site due to the remaining SiO 2 -containing slag is prevented. Therefore, it can prevent beforehand that the desulfurization reaction which is a reduction reaction is inhibited by the residual slag.
In particular, when the desulfurizing agent is projected onto the bath surface by the top blowing lance 5, the effect of adding desulfurized slag becomes more remarkable.
In addition, when carrying out the desulfurization treatment after the desiliconization treatment, the present inventors add the desulfurization slag collected in advance into the hot metal ladle before starting the stirring of the hot metal 3 with the stirring blade 4, It has been confirmed that desulfurized slag mainly composed of SiO 2 and mainly CaO is produced at a high iron oxide concentration.
　以上説明したように、本発明によれば、粒径を３０~４００μｍの範囲内に規定した石灰系脱硫剤７を上吹きランス５から吹き付けて添加するので、吹き付け添加時の飛散が防止されるとともに、添加した脱硫剤の凝集が防止されて脱硫反応界面積が増大し、高効率での脱硫処理が安定して実現される。 As described above, according to the present invention, the lime-based desulfurizing agent 7 having a particle size of 30 to 400 μm is added by spraying from the top blowing lance 5, so that scattering during spraying is prevented. At the same time, aggregation of the added desulfurizing agent is prevented, the desulfurization reaction interfacial area is increased, and high-efficiency desulfurization treatment is stably realized.
　［実施例１］ [Example 1]
　図１に示す機械攪拌式脱硫装置を用い、石灰系脱硫剤としてＣａＯ−２０質量％Ａｌ２Ｏ３を使用して（脱硫剤添加量：７ｋｇ／溶銑トン）溶銑の脱硫処理を行った結果を示す。石灰系脱硫剤の搬送用ガスとしては窒素ガスを使用した。　使用した攪拌羽根は４枚の羽根を有し、羽根に傾斜のないものである。　攪拌羽根の位置は溶銑鍋のほぼ中心とした。 Using the mechanical stirring type desulfurization apparatus shown in FIG. 1, the result of desulfurization treatment of hot metal using CaO-20 mass% Al 2 O 3 as the lime-based desulfurization agent (addition amount of desulfurization agent: 7 kg / ton of hot metal) Show. Nitrogen gas was used as the carrier gas for the lime-based desulfurization agent. The stirring blade used has four blades, and the blades are not inclined. The position of the stirring blade was approximately the center of the hot metal pan.
　操業条件としては、石灰系脱硫剤の粒径を、２０μｍ以下の範囲（比較例１）、５００~１０００μｍの範囲（比較例２）、２００~４００μｍの範囲（本発明例１）及び３０~１００μｍの範囲（本発明例２~５）の４水準とし、比較例１、２及び本発明例１、２では上吹きランスの設置位置を上記の（２）式を満たす範囲に配置し、脱硫反応に及ぼす脱硫剤の粒径の影響を調査した。　本発明例３、４では、上吹きランスを上記の（２）式を満たさない範囲に設置し、脱硫反応に及ぼす上吹きランスの設置位置の影響を調査した。また、本発明例５では、上吹きランスの設置位置を上記の（２）式を満たす範囲に設置し、且つ予め回収した脱硫スラグを攪拌羽根の回転前に溶銑上に添加した。　石灰系脱硫剤の粒径及び上吹きランスの設置位置以外のその他の操業条件は、表１に準じた。　何れの試験も１００チャージ（ｃｈ）実施した。操業条件及び操業結果を表２に示す。 As operating conditions, the particle size of the lime-based desulfurization agent is in the range of 20 μm or less (Comparative Example 1), in the range of 500 to 1000 μm (Comparative Example 2), in the range of 200 to 400 μm (Invention Example 1), and 30 to 100 μm. In Comparative Examples 1 and 2 and Invention Examples 1 and 2, the installation position of the top blowing lance is placed in a range that satisfies the above-mentioned formula (2), and desulfurization reaction is performed. The effect of the particle size of the desulfurizing agent on the flow rate was investigated. In Invention Examples 3 and 4, the top blowing lance was installed in a range not satisfying the above formula (2), and the influence of the installation position of the top blowing lance on the desulfurization reaction was investigated. In addition, in Example 5 of the present invention, the installation position of the top blowing lance was installed in a range satisfying the above expression (2), and the desulfurized slag collected in advance was added onto the hot metal before the stirring blades were rotated. Other operating conditions other than the particle size of the lime-based desulfurizing agent and the position where the top blowing lance was installed were in accordance with Table 1. All tests were conducted with 100 charges (ch). Table 2 shows the operation conditions and the operation results.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表２に示すように、比較例１及び比較例２に比べ、本発明例１及び本発明例２では脱硫処理後の溶銑の平均硫黄濃度が低下した。　また、上吹きランスの設置位置を好適な範囲以外とした本発明例３及び本発明例４と、上吹きランスの設置位置が好適な範囲である本発明例２とを比較すると、本発明例２での脱硫効率（ｄｅｓｕｌｆｕｒｉｚａｔｉｏｎ　ｅｆｆｉｃｉｅｎｃｙ）が高いことが分かった。　また更に、脱硫スラグをリサイクル使用した本発明例５では、脱硫処理後の溶銑の平均硫黄濃度が更に低下し、しかもばらつきが小さくなることが確認できた。
　［実施例２］ As shown in Table 2, compared with Comparative Example 1 and Comparative Example 2, in Invention Example 1 and Invention Example 2, the average sulfur concentration of the hot metal after the desulfurization treatment decreased. Further, the present invention example 3 and the present invention example 4 in which the installation position of the top blowing lance is outside the preferred range and the present invention example 2 in which the installation position of the top blowing lance is in a suitable range are compared. It was found that the desulfurization efficiency at 2 was high. Furthermore, in Invention Example 5 in which desulfurized slag was recycled, it was confirmed that the average sulfur concentration of the hot metal after the desulfurization treatment was further reduced and the variation was reduced.
[Example 2]
　前記の特許文献１においては、脱硫剤の溶銑中への分散の観点から、上吹きランスの設置位置につき検討している。　そこで本発明において好適な上吹きランス設置位置との関係を確認するために、表３に示す諸条件で、脱硫処理を行った。　表３に示された以外の操業条件は実施例１と同様とした。　何れの試験も１００チャージ実施した。 In the above-mentioned Patent Document 1, the installation position of the top blowing lance is examined from the viewpoint of dispersion of the desulfurizing agent in the molten iron. Therefore, desulfurization treatment was performed under various conditions shown in Table 3 in order to confirm the relationship with the preferred position of the top blowing lance in the present invention. The operating conditions other than those shown in Table 3 were the same as in Example 1. All tests were conducted with 100 charges.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　本発明例６~９は、上吹きランスの位置が特許文献１で好適とする、ｄ／３≦Ｒ≦ｄ／２＋１／３×（Ｄ−ｄ）（本発明の記号で表すと（２Ｒ）／３≦Ａ≦Ｒ＋（１／３）×（２Ｄ−２Ｒ）で、右辺は（２Ｄ）／３＋Ｒ／３と整理される）を満足するが、本発明が好適とするＲ≦Ａ≦（１／２）×Ｄは満足しない試験である。　本発明例６~９では、従来の上置き添加法である比較例３に比べると、脱硫効率が改善されているが、本発明の好適範囲である本発明例１０および本発明例１１ではさらに格段に脱硫効率が改善されている。すなわち、処理後の最高Ｓ濃度およびＳ＜０．００３質量％となる比率にみられるように、本発明例１０および本発明例１１では非常に小さいばらつきにて低硫化することが実現されている。
　［実施例３］ Examples 6 to 9 of the present invention are d / 3 ≦ R ≦ d / 2 + 1/3 × (D−d) (in the symbol of the present invention, (2R) where the position of the top lance is suitable in Patent Document 1. / 3 ≦ A ≦ R + (1/3) × (2D−2R), and the right side satisfies (2D) / 3 + R / 3), but R ≦ A ≦ (1 / 2) xD is an unsatisfactory test. In Inventive Examples 6 to 9, the desulfurization efficiency is improved as compared with Comparative Example 3 which is a conventional addition method, but in Inventive Examples 10 and 11 which are preferred ranges of the present invention, The desulfurization efficiency is remarkably improved. That is, as seen in the maximum S concentration after the treatment and the ratio of S <0.003% by mass, Example 10 and Example 11 achieve low sulfidation with very small variations. .
[Example 3]
　表４に示す諸条件で、脱硫処理を行い、得られた結果も表４に合わせ示した。　表４に示された以外の操業条件は実施例１と同様とした。　ここで表４の本発明例１２~１６においては、リサイクルされた脱硫スラグ（回収スラグ）を予め投入してから、上吹きランスからの脱硫剤添加の開始までの攪拌時間の影響を確認した。　また本発明例１７~２２においては、ＣａＯ−Ａｌ２Ｏ３系脱硫剤におけるＡｌ２Ｏ３混合量の影響を確認し、本発明例２３および２４においては、脱硫剤の搬送ガスの影響を確認した。 The desulfurization treatment was performed under various conditions shown in Table 4, and the obtained results are also shown in Table 4. The operating conditions other than those shown in Table 4 were the same as in Example 1. Here, in Examples 12 to 16 of the present invention in Table 4, the influence of the stirring time from when the recycled desulfurized slag (recovered slag) was charged in advance until the start of addition of the desulfurizing agent from the top blowing lance was confirmed. In Examples 17 to 22 of the present invention, the influence of the mixed amount of Al 2 O 3 in the CaO—Al 2 O 3 -based desulfurizing agent was confirmed. In Examples 23 and 24 of the present invention, the influence of the carrier gas of the desulfurizing agent was confirmed. did.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
　本実施例で用いた脱硫装置においては、添加した脱硫スラグ（回収スラグ）が溶銑内に巻き込まれるまでに１分程度掛かることを確認しているが、本発明例１２~１６においては、攪拌時間を２分間および３分間とした本発明例１５および本発明例１６で脱硫効率がとくに良好であった。　なお、４分以上攪拌した本発明例１３、１４で脱硫効率が低下したが、これは同一攪拌時間で脱硫剤添加後の時間が十分確保できないためと考えられる。したがって本機械攪拌式脱硫装置では３分以下の攪拌時間がとくに好適であった。 In the desulfurization apparatus used in this example, it was confirmed that it took about 1 minute for the added desulfurization slag (recovered slag) to be caught in the hot metal, but in Examples 12 to 16 of the present invention, the stirring time was The desulfurization efficiency was particularly good in Invention Example 15 and Invention Example 16 in which the sample was kept for 2 minutes and 3 minutes. In addition, although the desulfurization efficiency fell in this invention example 13 and 14 stirred for 4 minutes or more, it is thought that this is because the time after addition of a desulfurization agent cannot fully be secured in the same stirring time. Therefore, the stirring time of 3 minutes or less was particularly suitable in this mechanical stirring type desulfurization apparatus.
　また、本発明例１７~２２から、本実施例で用いた機械攪拌式脱硫装置においては、ＣａＯ−Ａｌ２Ｏ３脱硫剤におけるＡｌ２Ｏ３混合量は１０~３０％（内掛重量％）がとくに好適であることが分かった。　また、本発明例２３および本発明２４から、搬送用ガスとして還元性のガス（本発明例２４のプロパンガス（炭化水素系ガス））を用いると、脱硫効率がさらに改善されることが確認できた。
　なお、上記実施例で使用した以外の周知の脱硫剤、搬送ガスにおいてもとくに問題なく本発明の効果が得られることを確認したが、発明効果の観点からは、脱硫剤としてＣａＯ−Ａｌ２Ｏ３系脱硫剤を使用することが有利であった。 In addition, from Examples 17 to 22 of the present invention, in the mechanical stirring type desulfurization apparatus used in this example, the amount of Al 2 O 3 mixed in the CaO—Al 2 O 3 desulfurizing agent is 10 to 30% (internal weight%). Was found to be particularly suitable. Further, from Invention Example 23 and Invention 24, it can be confirmed that the use of a reducing gas (propane gas (hydrocarbon gas) of Invention Example 24) as the carrier gas further improves the desulfurization efficiency. It was.
Incidentally, known desulfurizing agent other than those used in the above embodiment, it was confirmed that the effect of the present invention without particular problems in the transportation gas is obtained, in terms of the invention effects, CaO-Al 2 O as a desulfurizing agent It was advantageous to use a 3 system desulfurizing agent.
　本発明によれば、高効率での脱硫処理、すなわち脱硫処理後Ｓを例えば０．００３質量％とするような処理を、結果のばらつきを抑制し安定して実現することができる。　その結果、脱硫剤原単位の削減や、これに伴う発生スラグ量の削減などが達成され、工業上有益な効果がもたらされる。 According to the present invention, high-efficiency desulfurization treatment, that is, treatment such that S after desulfurization treatment is, for example, 0.003% by mass can be stably realized while suppressing variation in results. As a result, a reduction in the desulfurization unit basic unit and a reduction in the amount of generated slag associated therewith are achieved, and an industrially beneficial effect is brought about.
　１　台車
　２　溶銑鍋（処理容器）
　３　溶銑
　４　攪拌羽根
　４ａ　回転羽根の軸
　５　上吹きランス
　６　集塵フード
　７　石灰系脱硫剤
　８　ディスペンサー
　９　切り出し装置
　１０　搬送用ガス
　Ａ　処理容器の中心から上吹きランスの中心までの水平距離
　Ｒ　攪拌羽根の半径
　Ｄ　処理容器の内壁半径 1 cart 2 hot metal ladle (processing container)
3 Hot metal 4 Stirring blade 4a Shaft of rotating blade 5 Top blowing lance 6 Dust collection hood 7 Lime-based desulfurizing agent 8 Dispenser 9 Cutting device 10 Transport gas A Horizontal distance from center of processing vessel to center of top blowing lance R Stirring blade Radius D Inner wall radius of processing vessel

Claims (3)

  1. 　機械攪拌式脱硫装置を用いた溶銑の脱硫方法において、攪拌羽根によって攪拌されている溶銑の浴面上に、粒径が３０~４００μｍの石灰系脱硫剤を、上吹きランスを介して搬送用ガスとともに上吹き添加して脱硫処理を行う、溶銑の脱硫方法。 In a hot metal desulfurization method using a mechanical stirring desulfurization apparatus, a lime-based desulfurization agent having a particle size of 30 to 400 μm is conveyed on the bath surface of the hot metal being stirred by a stirring blade through a top blowing lance. A hot metal desulfurization method in which the desulfurization treatment is performed by top blowing.
  2. 　前記上吹きランスは鉛直方向下方を向いて配置され、溶銑を収容する処理容器の内壁半径をＤ、攪拌羽根の半径をＲ、処理容器の中心から前記上吹きランス中心までの水平距離をＡとしたときに、前記攪拌羽根の半径（Ｒ）が前記処理容器の内壁半径（Ｄ）に対して下記の（１）式の関係を満足する範囲内であって、且つ、前記水平距離（Ａ）が、前記内壁半径（Ｄ）及び前記攪拌羽根の半径（Ｒ）に対して下記の（２）式の関係を満足する範囲内である、請求項１に記載の溶銑の脱硫方法。
    　Ｒ≦（１／２）×Ｄ　…（１）
    　Ｒ≦Ａ≦（１／２）×Ｄ　…（２）
    　但し、（１）式及び（２）式において、Ｄは、溶銑を収容する処理容器の内壁半径（ｍ）、Ｒは、攪拌羽根の半径（ｍ）、Ａは、処理容器の中心から上吹きランス中心までの水平距離（ｍ）である。     The upper blowing lance is arranged vertically downward, the inner wall radius of the processing vessel containing hot metal is D, the radius of the stirring blade is R, and the horizontal distance from the center of the processing vessel to the center of the upper blowing lance is A. The radius (R) of the stirring blade is within a range satisfying the relationship of the following expression (1) with respect to the inner wall radius (D) of the processing vessel, and the horizontal distance (A) The hot metal desulfurization method according to claim 1, wherein is within a range satisfying a relationship of the following expression (2) with respect to the inner wall radius (D) and the radius (R) of the stirring blade.
    R ≦ (1/2) × D (1)
    R ≦ A ≦ (1/2) × D (2)
    However, in the formulas (1) and (2), D is the radius (m) of the inner wall of the processing vessel that contains the hot metal, R is the radius (m) of the stirring blade, and A is the top blowing from the center of the processing vessel. The horizontal distance (m) to the center of the lance.
  3. 　予め回収した、石灰系脱硫剤による脱硫処理にて発生した脱硫スラグを、前記溶銑の浴面上に添加した後に前記攪拌羽根によって溶銑を攪拌し、その後、前記脱硫剤を添加する、請求項１または請求項２に記載の溶銑の脱硫方法。 The desulfurization slag generated in the desulfurization treatment with a lime-based desulfurization agent, which has been collected in advance, is added to the hot metal bath surface, the hot metal is stirred with the stirring blade, and then the desulfurization agent is added. Alternatively, the hot metal desulfurization method according to claim 2.
PCT/JP2010/061366 2009-06-30 2010-06-29 Method of desulfurization of molten iron WO2011002094A1 (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
CN201080029394.3A CN102471814B (en) 2009-06-30 2010-06-29 The sulfur method of molten iron
BRPI1015360-8A BRPI1015360B1 (en) 2009-06-30 2010-06-29 METHOD FOR DESULFURATION OF HOT METAL
KR1020127001048A KR101366720B1 (en) 2009-06-30 2010-06-29 Method of desulfurization of molten iron
EP10794262.5A EP2434025B1 (en) 2009-06-30 2010-06-29 Method of desulfurization of molten iron

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
JP2009155148 2009-06-30
JP2009-155148 2009-06-30
JP2009294022 2009-12-25
JP2009-294022 2009-12-25
JP2010-147015 2010-06-29
JP2010147015A JP5195833B2 (en) 2009-06-30 2010-06-29 Hot metal desulfurization method

Publications (1)

Publication Number Publication Date
WO2011002094A1 true WO2011002094A1 (en) 2011-01-06

Family

ID=43411162

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2010/061366 WO2011002094A1 (en) 2009-06-30 2010-06-29 Method of desulfurization of molten iron

Country Status (6)

Country Link
EP (1) EP2434025B1 (en)
JP (1) JP5195833B2 (en)
KR (1) KR101366720B1 (en)
CN (1) CN102471814B (en)
BR (1) BRPI1015360B1 (en)
WO (1) WO2011002094A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108486307A (en) * 2018-04-17 2018-09-04 中冶南方工程技术有限公司 A kind of converter dust-removing gray iron recovery system and method based on KR desulfurization station

Families Citing this family (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5668641B2 (en) * 2011-08-22 2015-02-12 Ｊｆｅスチール株式会社 Hot metal desulfurization method
JP6237293B2 (en) * 2014-02-06 2017-11-29 新日鐵住金株式会社 Hot metal desulfurization treatment method
KR101597263B1 (en) 2014-04-04 2016-02-24 주식회사 포스코 Processing apparatus for molten metal and the method thereof
KR101602835B1 (en) 2014-05-26 2016-03-11 주식회사 포스코 Processing apparatus for molten metal and the method thereof
CN104928440B (en) * 2015-07-20 2017-05-10 上海信孚环保技术工程有限公司 Hot metal desulphurization device capable of saving desulfurizing agents and application thereof
JP6369516B2 (en) * 2015-10-05 2018-08-08 Ｊｆｅスチール株式会社 Mechanical stirring type hot metal desulfurization method
JP6402762B2 (en) * 2015-10-05 2018-10-10 Ｊｆｅスチール株式会社 Desulfurization agent, mechanical stirring type hot metal desulfurization method and method
EP3572534B1 (en) * 2017-01-19 2021-04-28 JFE Steel Corporation Desulfurization processing method of molten steel, and desulfurization agent
KR102034264B1 (en) * 2018-08-03 2019-10-17 주식회사 포스코 Apparatus for processing hot metal and method for processing hot metal
JP6726437B1 (en) * 2020-05-29 2020-07-22 ダイヤモンドエンジニアリング株式会社 Mechanical stirring type desulfurization system
CN111979375B (en) * 2020-08-19 2022-04-29 武汉钢铁有限公司 Molten iron KR stirring mixing characteristic quantitative characterization method and intelligent desulfurization method

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001288507A (en) * 2000-04-04 2001-10-19 Nkk Corp Method for producing low phosphorus molten iron
JP2005179690A (en) 2003-12-16 2005-07-07 Jfe Steel Kk Method for desulfurizing molten pig iron
JP2009079261A (en) * 2007-09-26 2009-04-16 Jfe Steel Kk Method for desulfurizing molten pig iron

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5938566A (en) * 1982-08-25 1984-03-02 松下電器産業株式会社 Refrigerator
BR9814479A (en) * 1997-12-26 2000-10-10 Nippon Kokan Kk "method for refining cast iron and method for reducing castings for the production of cast iron"
JP2006241502A (en) * 2005-03-02 2006-09-14 Nippon Steel Corp Desulfurizing agent for molten iron and method for desulfurizing molten iron
JP5045031B2 (en) * 2006-08-25 2012-10-10 Ｊｆｅスチール株式会社 Hot metal desulfurization agent and desulfurization treatment method
JP5101988B2 (en) * 2007-10-26 2012-12-19 新日鐵住金株式会社 Molten metal desulfurization agent

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001288507A (en) * 2000-04-04 2001-10-19 Nkk Corp Method for producing low phosphorus molten iron
JP2005179690A (en) 2003-12-16 2005-07-07 Jfe Steel Kk Method for desulfurizing molten pig iron
JP2009079261A (en) * 2007-09-26 2009-04-16 Jfe Steel Kk Method for desulfurizing molten pig iron

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
"Huntai no Kiso Bussei", vol. 1, THE NIKKAN KOGYO SHIMBUN, LTD., article "Huntai Kougaku Sousho", pages: 8 - 12
See also references of EP2434025A4

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108486307A (en) * 2018-04-17 2018-09-04 中冶南方工程技术有限公司 A kind of converter dust-removing gray iron recovery system and method based on KR desulfurization station

Also Published As

Publication number Publication date
CN102471814A (en) 2012-05-23
JP2011149087A (en) 2011-08-04
CN102471814B (en) 2016-06-15
EP2434025B1 (en) 2018-03-21
KR20120026623A (en) 2012-03-19
KR101366720B1 (en) 2014-02-24
BRPI1015360B1 (en) 2021-10-26
BRPI1015360A2 (en) 2016-05-10
EP2434025A4 (en) 2016-12-14
JP5195833B2 (en) 2013-05-15
EP2434025A1 (en) 2012-03-28

Similar Documents

Publication Publication Date Title
JP5195833B2 (en) Hot metal desulfurization method
JP5194678B2 (en) Hot metal desulfurization method
JP4845078B2 (en) Hot metal desulfurization method
JP5045031B2 (en) Hot metal desulfurization agent and desulfurization treatment method
JP5195737B2 (en) Hot metal desulfurization method
JP5177170B2 (en) Hot metal desulfurization method
JP4715369B2 (en) Hot metal desulfurization treatment method
JP2007247045A (en) Method for desulfurizing molten iron
JP5066923B2 (en) Hot metal desulfurization treatment method
JP5458499B2 (en) Hot metal desulfurization treatment method
JP5401938B2 (en) Hot metal desulfurization method
JP5446300B2 (en) Hot metal desulfurization treatment method
JP5906664B2 (en) Hot metal desulfurization method
JP4984928B2 (en) Hot metal desulfurization method
JP6156598B2 (en) Desulfurizing agent, hot metal desulfurization method, and hot metal manufacturing method
JP6238019B2 (en) Hot metal desulfurization method with less recuperation
JP2019189893A (en) Method for desulfurizing molten iron
JP6416634B2 (en) Desiliconization and desulfurization methods in hot metal ladle
JP5418248B2 (en) Hot metal desulfurization method
JP5609081B2 (en) Hot metal desulfurization method
JP2013129861A (en) Method of desulfurizing molten iron
JP6649639B2 (en) Method of adding desulfurizing agent into hot metal processing vessel and method of refining hot metal
JP2018172719A (en) Desulfurization method of molten pig iron
JP2006336036A (en) Method for desulfurizing molten iron
JP2001064715A (en) Desulfurizing agent for molten iron and using method thereof

Legal Events

Date Code Title Description
WWE Wipo information: entry into national phase

Ref document number: 201080029394.3

Country of ref document: CN

121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 10794262

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 2546/MUMNP/2011

Country of ref document: IN

WWE Wipo information: entry into national phase

Ref document number: 2010794262

Country of ref document: EP

NENP Non-entry into the national phase

Ref country code: DE

ENP Entry into the national phase

Ref document number: 20127001048

Country of ref document: KR

Kind code of ref document: A

REG Reference to national code

Ref country code: BR

Ref legal event code: B01A

Ref document number: PI1015360

Country of ref document: BR

ENP Entry into the national phase

Ref document number: PI1015360

Country of ref document: BR

Kind code of ref document: A2

Effective date: 20111229