CN108048624A - The method that Deep Desulphurization of Hot Metal is carried out using LF stoves and spray magnesium desulfurization station - Google Patents
The method that Deep Desulphurization of Hot Metal is carried out using LF stoves and spray magnesium desulfurization station Download PDFInfo
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- CN108048624A CN108048624A CN201711318076.9A CN201711318076A CN108048624A CN 108048624 A CN108048624 A CN 108048624A CN 201711318076 A CN201711318076 A CN 201711318076A CN 108048624 A CN108048624 A CN 108048624A
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- desulfurization
- slag
- molten iron
- stoves
- station
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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
-
- 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
- C21C5/52—Manufacture of steel in electric furnaces
- C21C5/54—Processes yielding slags of special composition
-
- 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
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
Abstract
The invention belongs to iron and steel domains, and in particular to a kind of method for carrying out Deep Desulphurization of Hot Metal using LF stoves and spray magnesium desulfurization station, technical flow design are as follows：Deep Desulphurization of Hot Metal → invagination bottom blowing hot-metal bottle → LF stove heats slag making → return desulfurization station skims → and iron making enters converter.The present invention is by sending the molten iron after spray magnesium desulfurization to LF stove heat slag making, it proposes to use LF stove heated by electrodes, utilize the strong reducing property of the high temperature in heated by electrodes area, molten iron, make high basicity slag, so that desulfurizing iron product MgS enters the CaS that in slag or production is more stable, achieve the purpose that absorption and cure desulfurization product, return again to desulfurization station and skim, be then blended into converter smelting ultralow-sulfur steel.
Description
Technical field
This technology belongs to Ferrous Metallurgy molten iron preprocessing technical field, and deep desulfurization is specifically carried out to molten iron, and then is smelted
A kind of process of ultralow-sulfur steel.
Background technology
Generally in the production process of steel, sulphur must add as the harmful element for causing metal hot-short with influencing slab quality
It is more and more stringenter to the content requirement of sulphur in steel as the requirement to properties of product is higher and higher with removal.Wuhan Iron and Steel Plant one is made steel
The some ultra-low carbon steel that factory now produces can not desulfurization in refining link, it is necessary at converter tapping terminal point control [S]<0.004%, such as
Ingot iron WDT0.But molten iron is also easy to produce back sulphur after being blown magnesium powder desulfurization pretreatment, in converter smelting, due to adding
It is returned in the steel scrap, slag making materials and the molten iron residue that enter containing higher sulphur, part sulphur in molten steel, converter terminal sulphur is caused to surpass
Mark.
The content of the invention
The technical problems to be solved by the invention are in view of the deficiency of the prior art and provide a kind of using LF
The method that stove and spray magnesium desulfurization station carry out Deep Desulphurization of Hot Metal, converter tapping sulphur are stably controlled within 0.004%, iron loss of skimming
It reduces.
The present invention is to solve the problems, such as that used technical solution set forth above is：
The method for carrying out Deep Desulphurization of Hot Metal using LF stoves and spray magnesium desulfurization station, technical flow design are as follows：Deep Desulphurization of Hot Metal
→ fold into bottom blowing hot-metal bottle → LF stove heats slag making → return desulfurization station skim → iron making enters converter.
Further, the method for Deep Desulphurization of Hot Metal being carried out using LF stoves and spray magnesium desulfurization station, it is characterised in that technology controlling and process
Step is as follows：
The first step, molten iron injection magnesium powder desulfurization：Target sulphur 0.001% is skimmed clean；
Second step, spray magnesium desulfurized molten iron fold into bottom blowing hot-metal bottle, prepare into LF stove heats；
3rd step, molten iron is into LF stoves heated by electrodes, slag making, and 1300 ± 50 DEG C of temperature leaving from station, terminal slag specimen is white or Huang
Chromatic rendition slag；
4th step, LF stoves molten iron sample → skim → thermometric after returning to desulfurization station, forbid to have no sample or sulphur>0.001% converts
Enter converter.
Wherein, the first step carries out injection magnesium powder desulfurization process to entering factory's molten iron.According to the sample before desulfurizing iron into
Point, relevant parameter is set, and highest priority sulphur 0.001%, after being blown, the molten iron sample that takes that treated synchronously carries out work of skimming
Industry, dry slag agent 30-100kg is thrown after skimming more than 80%, and (about 110-120 tons of a stove molten iron throws dry slag agent 30- per stove molten iron
100kg), until removing clean.
Blast-melted slag fusion temperature belongs to lower melting-point slag system between 1300-1400 DEG C, and adding in lime can improve
The fusing point of slag makes slag become glutinous, under conditions of heating measures are not taken, anyway adjusts slag composition, be difficult to reach rush
The effect for melting lime, and 2600 DEG C are may be up in heated by electrodes area temperature, the lime of addition can very fast slagging, slag variation
Route is as shown in Figure 1, slag system is turned from a-quadrant in figure (blast-melted slag) to B area (slag fusing point is at 2200-2400 DEG C or so)
Become.And phosphorus content is high in molten iron, reproducibility is strong, and good high alkalinity reducing slag is just formd in heating process.
The first step treated molten iron is hung up, is blended into special hot-metal bottle by second step.To ensure hot-metal bottle in LF stoves and taking off
Sulphur station can be general, carries out relevant treatment to hot-metal bottle in advance, and ventilative facility, buggy ladle, the resistance to material of hot-metal bottle slag line are transformed
And optimization.
Hot-metal bottle adds bottom blowing function, and desulfurization product and bubble are close to each other during BOTTOM ARGON BLOWING, collide, product is in gas
Bubble surface oscillation either slides to exist along bubble surface adsorbs or departs from two kinds of possibility by bubble, and suitable Air Bubble Size can
To accelerate the ascent rate of desulfurization product and aggregation probability, LF stoves process period has the sufficiently long time to allow production in 25min or so
Object floats.
3rd step, molten iron connect argon gas into after LF stoves, and to promote the heat exchange of heating process, buggy ladle is beaten to heating
Position heating using high tap position arc stream slugging, when molten iron temperature rises to 1300 ± 50 DEG C, observes slag condition, terminal slag specimen is white
Or yellow reducing slag can terminate the operation of LF stoves, desulfurization station is returned in preparation.
Since in heating process, slag basicity is high, in heated by electrodes area there is substantial amounts of [Ca] in attachment, in 2200 DEG C of item
Under part, reaction CaO+MgS=MgO+CaS can be promoted to occur to the right, form more stable CaS, it is several that sulphur is bessemerized back in reduction
Rate.
4th step, LF stoves molten iron sample → skim → thermometric after returning to desulfurization station, forbid to have no sample or sulphur>0.001% converts
Enter converter.
The central scope of the present invention：It, must in order to improve ultralow-sulfur steel tapping sulphur qualification ratio on the basis of existing equipment
It must solve the problems, such as that injection magnesium powder desulfurization production ultralow-sulfur steel is maximum：Molten iron pure magnesium desulfuration slag is dilute, how to remove clean.
According to the result and MaterialBalance Computation of each process procedure sample examination ω [S], it can be deduced that converter it is various enter
Stove material brings the weight proportion of sulphur into, and under low-sulfur steel production model, molten iron slag accounts for raw material and brings molten steel sulphur ratio into
Maximum brings sulphur weight into as 3.34kg, proportion 43.5%.
In the case where being blown pure magnesium technique, [Mg] and the reaction of Salmon-Saxl that are dissolved in molten iron generate solid-state MgS, and particle is tiny, largely
It floats after MgS aggregations, the floating of desulfurization product follows Stockes formula：
ν-desulfurization product ascent rate, m/s in formula；G-acceleration of gravity, 9.18m/s；
The viscosity of η-molten iron, Pas； ρ1、ρ2- molten iron and desulfurization product density, kgm-3
R-sorbent particle radius, m；K-apparent rate constant.
Sorbent particle ascent rate is directly proportional to the quadratic power of its radius size, compared with CaO fimily desulfurizing agents, CaO's
Granularity is in 0.2-1.0mm or so, and the desulfurization product of Mg bubbles is such as without considering aggregation, 100 μm of individual particle list amount diameter 80-
[1], the diameter of CaO particles is 8-50 times of pure magnesium desulfuration product, therefore the ascent rate of pure magnesium desulfuration product is much smaller than CaO systems
Desulfurizing agent.This is also one of the reason for pre- desulphurization control tapping sulphur of lime is stablized.
Secondly, reaction in magnesium desulfurization category iron liquid, desulfurization degree is deeper, and [S] concentration is lower in molten iron, and desulfurization product is more difficult to gather
Collection nucleation, in the case of the similary distance that floats, floating interval of floating dock is longer, and the lime desulfurization category top of the slag reacts, in reaction product
It is floating apart from short, surface slag need to only be taken off to the clean purpose that can reach stability contorting element sulphur.
In order to solve the problems, such as to exclude spray magnesium desulfurization product, it is necessary to when optimizing quantity and the addition of desulfurization station lime slag making
Machine plays the desulphurizing ability of CaO, makes high alkalinity slag, dilutes and adsorbs magnesium desulfurization product, in terms of floating is promoted, takes and prolong
The long calmness time solves.In current desulphurization plant, the problem using CaO maximums is that lime fusing point is high (2580 DEG C),
Even if the fluxing agents such as addition CaF are not easy to melt, and without lime device is blown, therefore, after the present invention will be by that will spray magnesium desulfurization
Molten iron is sent to LF stove heat slag making, proposes, using LF stove heated by electrodes, to utilize the strong reduction of the high temperature in heated by electrodes area, molten iron
Property, make high basicity slag so that desulfurizing iron product MgS enters the CaS that in slag or production is more stable, reaches absorption and cures desulfurization
The purpose of product returns again to desulfurization station and skims, is then blended into converter smelting ultralow-sulfur steel.
Compared to the prior art, the beneficial effects of the invention are as follows：
1) converter tapping sulphur is stably controlled within 0.004%, and the more traditional injection pure magnesium desulfuration technique of chance of success carries
It is high by 29.6%；
2) crust through LF stoves treated the molten iron top of the slag, be easy to be removed, iron loss of skimming reduces；
3) since molten iron reproducibility itself is strong, desulfurization thermodynamic condition is easily formed after LF slag making, reaches and makes white slag suction
The purpose of attached desulfurization product.
Description of the drawings
Fig. 1 is molten iron into slag composition and variation of melting point before and after LF stove slag making.
Fig. 2 is the clinker appearance after furnaceman's LF sequence.
Specific embodiment
For a better understanding of the present invention, with reference to the embodiment content that the present invention is furture elucidated, but the present invention is not
It is limited only to the following examples.
Embodiment
Certain steel mill implements technical solution of the present invention, and by this technique productions, 128 stove ultralow-sulfur steels, flow are molten iron
Deep desulfurization → invagination bottom blowing hot-metal bottle → LF stoves slag making → return desulfurization station skims → and iron making enters converter.Specific embodiment controls
Divide four steps：
The first step carries out injection magnesium powder desulfurization process to entering factory's molten iron.According to the sample constituents before desulfurizing iron, set
Relevant parameter, highest priority sulphur 0.001%, after being blown, the molten iron sample that takes that treated synchronously carries out operation of skimming, skims
Dry slag agent (main component CaO) 50kg (about 115 tons of a stove molten iron throws dry slag agent by stove) is thrown after more than 90%, until removing dry
Only；
The first step treated molten iron is hung up, is blended into special hot-metal bottle by second step.To ensure hot-metal bottle in LF stoves and taking off
Sulphur station can be general, carries out relevant treatment to special hot-metal bottle in advance, and ventilative facility, buggy ladle, the resistance to material of hot-metal bottle slag line are carried out
Transformation and optimization；
3rd step, molten iron use LF stove heated by electrodes into after LF stoves, connect argon gas, so that the heat for promoting heating process is handed over
It changes, buggy ladle is beaten to the heating of heating position, using high tap position arc stream slugging, when molten iron temperature rises to 1300 ± 20 DEG C, observes slag
Condition, terminal slag specimen can terminate the operation of LF stoves for white or yellow reducing slag, and desulfurization station is returned in preparation；
4th step, LF stoves molten iron sample → skim → thermometric after returning to desulfurization station, forbid to have no sample or sulphur>0.001% converts
Enter converter.
The present embodiment carries out above-mentioned technique, and all-the-way tracking Sulfur Content in Hot Iron ingredient is relatively stablized, and does not occur sulfur content fluctuation
Situation, ratio of the converter terminal sulphur less than 0.005% reach 97.6%, and the ratio for reaching internally controlling requirement (sulphur≤0.004%) reaches
88.3%, more former technique reaches the ratio 58.7% of internally controlling requirement (sulphur≤0.004%), improves 29.6%.
During LF stove heats, molten iron slag is relatively easy to form reproducibility white slag, table 1 be clinker after LF stove slag making into
Divide, MnO+FeO contents 1.32% in slag, basicity 4.65, meet the condition of desulfurization.Fig. 2 be furnaceman's LF sequence after slag specimen outside
It sees, during returning to desulfurization station and skimming, it is found that the molten iron surface slag after heating easily cools down caking, it, can convenient for removing
It is skimmed with realizing without iron.
Slag composition after 1 LF stove slag making of table
The above is only the preferred embodiment of the present invention, it is noted that is come for those of ordinary skill in the art
It says, without departing from the concept of the premise of the invention, several modifications and variations can also be made, these belong to the present invention's
Protection domain.
Claims (3)
1. the method that Deep Desulphurization of Hot Metal is carried out using LF stoves and spray magnesium desulfurization station, it is characterised in that technological process is as follows：Molten iron is deep
Desulfurization → invagination bottom blowing hot-metal bottle → LF stoves heated by electrodes slag making → return desulfurization station skims → and iron making enters converter.
2. the method that Deep Desulphurization of Hot Metal is carried out using LF stoves and spray magnesium desulfurization station, it is characterised in that technology controlling and process step is as follows：
The first step, molten iron injection magnesium powder desulfurization：Target sulphur 0.001% is skimmed clean；
Second step, spray magnesium desulfurized molten iron fold into bottom blowing hot-metal bottle, prepare into LF stove heats；
3rd step, molten iron is into LF stoves heated by electrodes, slag making, 1300 ± 50 DEG C of temperature leaving from station, terminal slag specimen for white or yellow also
Former slag；
4th step, LF stoves molten iron sample → skim → thermometric after returning to desulfurization station, forbid to have no sample or sulphur>0.001% be blended into turn
Stove.
3. the method according to claim 2 that Deep Desulphurization of Hot Metal is carried out using LF stoves and spray magnesium desulfurization station, it is characterised in that
In the first step, injection magnesium powder desulfurization process is carried out to entering factory's molten iron, the molten iron sample that takes that treated synchronously carries out operation of skimming,
Dry slag agent 30-100kg is thrown after skimming more than 80%, until removing clean.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711318076.9A CN108048624A (en) | 2017-12-12 | 2017-12-12 | The method that Deep Desulphurization of Hot Metal is carried out using LF stoves and spray magnesium desulfurization station |
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| CN201711318076.9A CN108048624A (en) | 2017-12-12 | 2017-12-12 | The method that Deep Desulphurization of Hot Metal is carried out using LF stoves and spray magnesium desulfurization station |
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| CN108048624A true CN108048624A (en) | 2018-05-18 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113604631A (en) * | 2021-07-16 | 2021-11-05 | 武汉钢铁有限公司 | Method for inhibiting refining resulfurization of low-sulfur steel in LF furnace |
-
2017
- 2017-12-12 CN CN201711318076.9A patent/CN108048624A/en active Pending
Non-Patent Citations (1)
| Title |
|---|
| 廖扬标 等: ""铁水进LF炉造渣深脱硫工艺实践"", 《武钢技术》 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113604631A (en) * | 2021-07-16 | 2021-11-05 | 武汉钢铁有限公司 | Method for inhibiting refining resulfurization of low-sulfur steel in LF furnace |
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Application publication date: 20180518 |