CN113337673B - Preparation method of converter steelmaking efficient dephosphorization agent - Google Patents
Preparation method of converter steelmaking efficient dephosphorization agent Download PDFInfo
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- CN113337673B CN113337673B CN202110432274.8A CN202110432274A CN113337673B CN 113337673 B CN113337673 B CN 113337673B CN 202110432274 A CN202110432274 A CN 202110432274A CN 113337673 B CN113337673 B CN 113337673B
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- 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
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/064—Dephosphorising; Desulfurising
- C21C7/0645—Agents used for dephosphorising or desulfurising
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- 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
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
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- Organic Chemistry (AREA)
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- Carbon Steel Or Casting Steel Manufacturing (AREA)
- Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
Abstract
The invention discloses a preparation method of a converter steelmaking efficient dephosphorization agent, which comprises the following components: 10% of converter smelting sludge, 70% of continuous casting and steel rolling sludge, 5% of bauxite, 3% of active lime powder, 2% of calcium bentonite, 5% of calcium carbonate and 5% of a binding agent; 4. mixing the above materials with a blender, adding 3.0-3.5% water to dissolve lime, and standing for more than 10 days; in order to fully and uniformly mix a small amount of water with the raw materials, water is added, and is sprayed by a shower head, and the water pressure is 0.015-0.018 MPa; 5. fully rolling the mixed raw materials after standing by a rolling machine to increase the compactness of the raw materials; 6. and (3) pressing and forming by using a ball press machine, wherein the formed dephosphorizing agent is ellipsoidal, the maximum diameter of the dephosphorizing agent is not more than 5 cm, and the dephosphorizing agent is naturally dried in the air for more than 72 hours, collected and bagged. The method can achieve the aim of rapid dephosphorization and solve the pollution discharge problem of iron and steel enterprises.
Description
Technical Field
The invention relates to the field of ferrous metallurgy, and relates to a preparation method of a converter steelmaking efficient dephosphorization agent.
Background
For smelting high-quality steel, phosphorus in raw materials such as molten iron and scrap steel is a harmful element, so that the steel is cold-brittle and must be removed in the steelmaking production process. The steel-making and descaling method includes two methods, namely an oxidation method and a reduction method. The reduction method is usually carried out in LF reduction refining atmosphere, the product is a negative trivalent phosphorus compound, harmful gas is released in the refining process, the environment is polluted, and the reduction method is rarely used in the field of ferrous metallurgy; the oxidative dephosphorization is usually carried out by blowing oxygen into a molten iron bath in a converter or an electric furnace. The degree of phosphorus removal is limited by various conditions. The equilibrium constant Kp of dephosphorization reaction at the bath temperature of 1350 ℃ is 10 at 1650 DEG C6Thus, the dephosphorization conditions were significant at 1350 ℃. Obviously, when lime in a molten pool is melted, the alkalinity of slag and the content of FeO in slag are increased to meet the dephosphorization condition, the temperature of molten steel in the molten pool exceeds the optimal dephosphorization temperature, the dephosphorization efficiency in the early stage of converter blowing is very low, and the continuous production requirement of low-phosphorus steel cannot be met. The scale produced by the surface oxidation and falling off of the billet in the rolling process becomes iron scale, rolling oil, lubricating grease impurities and the like, and the steel rolling sludge is usually used for being mixed with sintering (blast furnace ironmaking), and the grease is slowly heated and volatilized in the sintering process to cause secondary pollution.
Disclosure of Invention
The invention aims to provide a preparation method of a converter steelmaking efficient dephosphorization agent, which can achieve the purpose of rapid dephosphorization and solve the problem of pollution discharge of steel enterprises.
The technical scheme of the invention is as follows: a preparation method of a converter steelmaking efficient dephosphorization agent comprises the following steps: converter smelting OG mud, continuous casting and steel rolling sludge, calcium bentonite, calcium carbonate, active lime powder, bauxite and a binding agent; the method is characterized in that: [1]OG mud is smelted in a converter, and the OG mud comprises the following main components in percentage by mass: CaO 8-15%, SiO23 to 6% of Al2O32-5%, FeO 0.5-2%, TFe 50-53%, S less than or equal to 0.08%; [2]And (3) continuous casting and steel rolling sludge deposition: iron scale produced in the continuous casting process, and the steel rolling process mainly comprises the steps of heating a plate blank, rolling the iron scale produced in the dephosphorization process and rolling oil, wherein the TFe content of the iron scale is about 70 percent; the TFe content in the sludge generated in the continuous casting process and the steel rolling process is 65 percent; [3]The bonding agent comprises the following components: MgCl216-18.5% of MgSO4Content 8% CaSO41.0% of CaCl25.0-8.0% of NaCl, 5.5% of KCl and 3.0-3.8% of silicate; the dephosphorizing agent is prepared by the following method: 1. collecting materials, namely collecting converter smelting sludge, and sludge containing iron scales generated in a steel rolling process and a continuous casting process; 2. naturally drying the continuous casting sludge, the steel rolling sludge and the converter smelting sludge; 3. the mass percentage of the ingredients is as follows: 10% of converter smelting sludge, 70% of continuous casting and steel rolling sludge, 5% of bauxite, 3% of active lime powder, 2% of calcium bentonite, 5% of calcium carbonate and 5% of a binding agent; 4. mixing the above materials with a blender, adding 3.0-3.5% water to dissolve lime, and standing for more than 10 days; in order to fully and uniformly mix a small amount of water with the raw materials, water is added, and is sprayed by a shower head, and the water pressure is 0.015-0.018 MPa; 5. the mixed raw materials after standing are fully rolled by a rolling machine, so that the compactness of the raw materials is improved; 6. and (3) pressing and forming by using a ball press machine, wherein the formed dephosphorizing agent is ellipsoidal, the maximum diameter of the dephosphorizing agent is not more than 5 cm, and the dephosphorizing agent is naturally dried in the air for more than 72 hours, collected and bagged.
FeO and Fe in converter steelmaking slag2O3The content is the necessary condition for promoting lime dissolution and rapid slagging dephosphorization in the early smelting stage. Usually, oxygen is blown into the interface of slag and steel in the converter molten bath (lance position is usually called high-tension)The iron in the molten iron is oxidized into Fe2O3And FeO (iron oxide in the slag is usually expressed by FeO), the iron oxide in the slag reacts with CaO to generate calcium ferrite, thereby promoting the quick dissolution of lime particles by layer stripping, and when the FeO content in the slag is more than 11 percent, the dephosphorization capability of the slag is enhanced, the dephosphorization reaction speed is accelerated, and the aim of quick dephosphorization can be achieved.
Therefore, the low-melting-point iron oxide is added in the initial stage of converter blowing, thereby not only reducing the blowing oxidation of iron in molten iron, but also promoting lime to be rapidly melted and melted in a molten pool, and being an ideal high-efficiency dephosphorization method.
Converter steelmaking dry dedusting ash, wet dedusting OG mud (containing a large amount of ferric oxide and a small amount of ferrous oxide), and iron scale or sludge (mainly containing iron oxide) generated in continuous casting and steel rolling processes are processed and used as a cosolvent and a coolant for converter steelmaking and are put into the steelmaking production process again. The slagging agent can promote rapid slagging and slagging in the initial smelting stage, and is beneficial to rapid dephosphorization in the early smelting stage. At the same time, Fe in sludge and dust2O3Part of FeO is reduced into Fe in the steel-making process, and the other part exists in the slag in the form of FeO to replace the oxidation of Fe in the molten iron, thereby improving the yield of the molten iron and achieving the purpose of reducing the steel-making cost of the converter. The product can replace the existing slagging material, has low price and considerable economic benefit, and solves the problem of sewage discharge and treatment of enterprises.
The raw materials comprise: converter smelting OG mud, continuous casting and steel rolling sludge (continuous casting and steel rolling iron scale) and calcium bentonite. Converter sludge (OG sludge): the wet dedusting product for converter steelmaking comprises the following components in percentage by mass: CaO 8-15%, SiO23 to 6% of Al2O32-5%, FeO 0.5-2%, TFe 50-53%, S less than or equal to 0.08%; and (3) continuous casting and steel rolling sludge deposition: mainly comprises iron scale, rolling oil and the like generated in the processes of heating, rolling and dephosphorization of a plate blank. The main components are FeO and Fe2O3、Fe3O4Iron scale (FeO, Fe) of steel-making continuous casting billet2O3、Fe3O4) The TFe content is about 70 percent; continuous castingThe TFe content in the sludge generated in the process and the steel rolling process is 65 percent, the melting point is low, and the early slagging dephosphorization is facilitated (for example, the FeO melting point is 1369 ℃). The scale deposition (scale produced in the process of billet continuous casting and steel rolling) of steel enterprises is about 2 percent of the steel yield, and if the bulk scale is taken as a cooling fluxing agent, the density of the scale is 4.5-5.0g/cm3The loose iron scale with light weight is easy to be pumped away in the dust removing process. Most of the added dephosphorization materials directly enter the dedusting flue, so that the dephosphorization effect is not achieved, and the material consumption and the load of dedusting equipment are increased. Therefore, the method is the most effective method for utilizing the solid waste resources by adding the pellets into a converter steelmaking furnace after pelletizing according to a certain proportion.
The use of the dephosphorizing agent is compared with the prior art: the dephosphorizing agent produced by the method is subjected to industrial tests in the converter smelting process and is produced through molten iron desulphurization pretreatment, converter smelting, LF refining, RH refining and continuous casting.
The test is divided into 2 groups, No. 1-5 is the first group, No. 6-10 is the second group.
In the first group, no dephosphorizing agent is added in No. 1 to No. 5, and the rest slag materials are 5 tons of lime and 1.2 tons of dolomite in each furnace; 500Kg of coolant (the granulated steel after hot disintegration of converter slag, which contains 90% of iron) is added in the smelting process of the converter.
And in the second group, adding a dephosphorizing agent into No. 6 to No. 10 of the converter for 1 minute after the lance oxygen is ignited in the converter, and adding 500Kg of dephosphorizing agent into the converter at the later smelting stage (for cooling). The rest slag charge is lime of 4 tons per furnace and dolomite of 1.2 tons per furnace steel.
And comparing the dephosphorization rate of the converter, the blowing time of the converter and the smelting period of the converter.
In the first group, the dephosphorization rate of the converter is 89.34-90.65%, the average dephosphorization rate is 90.7%, the blowing time of the converter is 15.5-17.5 min, and the smelting period of the converter is 42-43 min.
And in the second group, a dephosphorizing agent is added at the early stage and the later stage of the converter smelting (dephosphorization is added at the later stage to be used as a cooling agent), the dephosphorization rate is 94.20-95.65%, and the average dephosphorization rate is 95.2%
The consumption of steel materials can be obviously reduced, and the average consumption is reduced by 15.38Kg per ton of steel; the smelting period is reduced to 37.3 minutes per furnace from the average 42.8 minutes (per furnace steel) of the original process, the smelting time of a converter of each furnace steel is reduced by 5.5 minutes on average, the main method is that the blowing time is shortened, and the components and temperature accuracy are improved because the converter blowing can rapidly dephosphorize, so that the direct steel tapping (without sampling and analyzing the components) can be realized after the converter blowing is finished, the time can be saved by more than 5 minutes, three furnaces can be produced for each converter every day, and the production efficiency is greatly improved.
Controlling the components of the converter final slag: CaO content 42-46%, SiO215-18.5% of P2O51.5-3.2% of Al2O3The content is 2.0-4.5%; MgO content of 4.5-10%, binary basicity (CaO/SiO)2(R)) is controlled to be 2.4-3.0, the MnO content is 3.0-6.3%, and the iron oxide Fe in the slag2O3The content is 16-23%.
The compositions of the test steel smelted products are shown in Table 1.
TABLE 1 test Steel smelt Components
The dephosphorizing agent produced by the method is widely used in steel-making production, is suitable for converter smelting of high-phosphorus molten iron, and can be used as a coolant for matching use under the condition of insufficient scrap steel resources.
Application effect, resource utilization: converter sludge and continuous casting steel rolling sludge are wastes in metallurgical production, and are processed into a dephosphorizing agent, and oxides containing metallic iron and other effective components are utilized, so that the slagging and dephosphorizing efficiency is improved, the consumption of steel materials is reduced, the cost of the dephosphorizing agent per ton is 350 yuan per ton, and the adding amount per ton of steel is 30 kg; meanwhile, the consumption of steel materials can be reduced by 15.38kg, the price of the produced steel billet is calculated by 2500 yuan/ton, the price of the active lime is 520 yuan/ton per ton, and the weight of steel in each furnace is calculated by 125 tons. Per ton of steel yields benefits: the method has the advantages that (2500/1000) multiplied by 15.38- (300/1000 × 30 ═ 29.45 yuan, the annual steel yield is calculated by 600 million tons, the steel and iron material consumption is reduced, and the economic benefit of 1.767 million yuan can be created, because the smelting period is shortened, the yield can be increased by more than 13 million tons every year.
Detailed Description
A preparation method of a converter steelmaking efficient dephosphorization agent comprises the following steps: converter smelting OG mud, continuous casting and steel rolling sludge, calcium bentonite, calcium carbonate, active lime powder, bauxite and a binding agent; [1]OG mud is smelted in a converter, and the OG mud comprises the following main components in percentage by mass: CaO 8-15%, SiO23 to 6% of Al2O32-5%, FeO 0.5-2%, TFe 50-53%, S less than or equal to 0.08%; [2]And (3) continuous casting and steel rolling sludge settling: iron scale produced in the continuous casting process, and the steel rolling process mainly comprises the steps of heating a plate blank, rolling the iron scale produced in the dephosphorization process and rolling oil, wherein the TFe content of the iron scale is about 70 percent; the TFe content in the sludge generated in the continuous casting process and the steel rolling process is 65 percent; [3]The bonding agent comprises the following components: MgCl216-18.5% of MgSO4Content 8%, CaSO41.0% of CaCl25.0-8.0% of NaCl, 5.5% of KCl and 3.0-3.8% of silicate; the dephosphorizing agent is prepared by the following method: 1. collecting materials, namely collecting converter smelting sludge, and sludge containing iron scales generated in a steel rolling process and a continuous casting process; 2. naturally drying the continuous casting sludge, the steel rolling sludge and the converter smelting sludge; 3. the mass percentage of the ingredients is as follows: 10% of converter smelting sludge, 70% of continuous casting and steel rolling sludge, 5% of bauxite, 3% of active lime powder and calcium base2% of bentonite, 5% of calcium carbonate and 5% of a binding agent; 4. mixing the above materials with a blender, adding 3.0-3.5% water to dissolve lime, and standing for more than 10 days; in order to fully and uniformly mix a small amount of water with the raw materials, water is added, and is sprayed by a shower head, and the water pressure is 0.015-0.018 MPa; 5. fully rolling the mixed raw materials after standing by a rolling machine to increase the compactness of the raw materials; 6. and (3) pressing and forming by using a ball press machine, wherein the formed dephosphorizing agent is ellipsoidal, the maximum diameter of the dephosphorizing agent is not more than 5 cm, and the dephosphorizing agent is naturally dried in the air for more than 72 hours, collected and bagged.
Claims (1)
1. A preparation method of a converter steelmaking efficient dephosphorization agent comprises the following steps: converter smelting OG mud, continuous casting and steel rolling sludge, calcium bentonite, calcium carbonate, active lime powder, bauxite and a binding agent; the method is characterized in that: [1]OG mud is smelted in a converter, and the OG mud comprises the following main components in percentage by mass: CaO 8-15%, SiO23 to 6% of Al2O32-5%, FeO 0.5-2%, TFe 50-53%, S less than or equal to 0.08%; [2]And (3) continuous casting and steel rolling sludge deposition: iron scale produced in the continuous casting process, and the steel rolling process mainly comprises the steps of heating a plate blank, rolling the iron scale produced in the dephosphorization process and rolling oil, wherein the TFe content of the iron scale is about 70 percent; the TFe content in the sludge generated in the continuous casting process and the steel rolling process is 65 percent; [3]The bonding agent comprises the following components: MgCl216-18.5% of MgSO4Content 8% CaSO41.0% of CaCl25.0-8.0% of NaCl, 5.5% of KCl and 3.0-3.8% of silicate; the dephosphorizing agent is prepared by the following method: 1. collecting materials, namely collecting converter smelting sludge, and sludge containing iron scales generated in a steel rolling process and a continuous casting process; 2. naturally drying the continuous casting sludge, the steel rolling sludge and the converter smelting sludge; 3. the mass percentage of the ingredients is as follows: 10% of converter smelting sludge, 70% of continuous casting and steel rolling sludge, 5% of bauxite, 3% of active lime powder, 2% of calcium bentonite, 5% of calcium carbonate and 5% of a binding agent; 4. mixing the above materials with a blender, adding 3.0-3.5% water to dissolve lime, and standing for more than 10 days; in order to ensure that a small amount of water and raw materials are fully mixedUniformly mixing, adding water, and sprinkling water by using a shower head, wherein the water pressure is 0.015-0.018 MPa; 5. the mixed raw materials after standing are fully rolled by a rolling machine, so that the compactness of the raw materials is improved; 6. and (3) pressing and forming by using a ball press machine, wherein the formed dephosphorizing agent is ellipsoidal, the maximum diameter of the dephosphorizing agent is not more than 5 cm, and the dephosphorizing agent is naturally dried in the air for more than 72 hours, collected and bagged.
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| JP3940280B2 (en) * | 2001-09-27 | 2007-07-04 | 新日本製鐵株式会社 | How to remove hot metal |
| KR100514775B1 (en) * | 2002-11-13 | 2005-09-13 | 주식회사 한테크 | Method for producing dephosphorization agent and iron oxide pigment using electrostatic precipitator dust obtained from oxygen converter |
| JP5087905B2 (en) * | 2005-11-09 | 2012-12-05 | Ｊｆｅスチール株式会社 | Hot metal dephosphorization method |
| CN101560586B (en) * | 2009-04-23 | 2012-03-14 | 重庆大学 | Compound dephosphorization agent with converter slag as raw material and preparing method thereof |
| CN103725877B (en) * | 2013-12-26 | 2016-08-17 | 南阳汉冶特钢有限公司 | A kind of method that pneumatic steelmaking dust circulation utilizes |
| CN107557517A (en) * | 2017-08-07 | 2018-01-09 | 河钢股份有限公司承德分公司 | A kind of method using converter dust-removing ash auxiliary semi-steel making dephosphorization early stage |
| CN108165704A (en) * | 2017-12-19 | 2018-06-15 | 北京科技大学 | A kind of vanadium extraction half steel extra furnace dephosphorization Dephosphorising flux and its preparation method and application |
| CN108486315B (en) * | 2018-05-21 | 2020-05-26 | 武汉科技大学 | Molten iron dephosphorization and desulfurization agent using converter steelmaking fly ash as base material and preparation method thereof |
| CN109252014B (en) * | 2018-10-09 | 2020-09-29 | 敬业钢铁有限公司 | Desulphurization dephosphorization process in molten iron pretreatment process |
| CN111944946B (en) * | 2020-08-17 | 2021-03-23 | 河北蓝海智投环保科技有限公司 | Dedusting ash cold pressing block and preparation method and application thereof |
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