CN105039634A - Dephosphorization method for converter steelmaking process - Google Patents
Dephosphorization method for converter steelmaking process Download PDFInfo
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Abstract
A dephosphorization method of a converter steelmaking process comprises the steps of slag remaining, wherein the amount of remaining slags is 35-60 kg per ton of steel; densification, wherein the remaining slags are densified, so that furnace slags cannot flow; dephosphorization, wherein waste steel and molten iron raw metal are added, different dephosphorization processes are set according to the different initial phosphorus contents in molten iron, and the target phosphorus content in molten steel is controlled to range from 0.03% to 0.05% after dephosphorization is finished; and slag discharging, wherein 40%-70% of the furnace slags are discharged after dephosphorization is finished. Decarburization is conducted according to a conventional method, the furnace slag dephosphorization effect continues to be played, and then it can be smoothly ensured that the final phosphorus content in molten steel is smaller than 0.015%. The different dephosphorization processes are set according to the different initial phosphorus contents in molten iron to produce low-phosphorous steel, so that the slag making consumption is greatly reduced, the iron loss of the dephosphorization process is reduced, and the low-cost and stable production of the low-phosphorus steel is achieved.
Description
Technical field
The present invention relates to converter steelmaking field, be specifically related to a kind of dephosphorizing method of convertor steelmaking process.
Background technology
Dephosphorization is the core missions of converter steelmaking, and dephosphorizing method main at present can be divided into conventional dephosphorization method, duplex practice and double slag process.Wherein, conventional dephosphorization method realizes dephosphorization at converter steelmaking process, and converter smelting terminates rear disposable deslagging, does not stay slag; Duplex practice refers to first dephosphorization in a converter, then molten steel is transferred to another converter decarburization, owing to adopting two same one heat steels of converter producing, although can be extremely lowly de-by phosphorus, occupy more device resource, have impact on production capacity; Double slag process is first dephosphorization in same converter, and dephosphorization terminates rear row's part slag, and then decarburization, smelts after terminating and slag can be stayed to smelt for next stove.The advantage of double slag process be take full advantage of last stove stay slag, lime and rhombspar add-on are reduced greatly, and can guarantee the production of Low-phosphorus Steel, shortcoming causes converter smelting cycle stretch-out.
In recent years, along with the increase of low-phosphorous variety steel amount, simultaneously in order to reduce the dependence to liquid iron pretreatment dephosphorizing, double slag dephosphorization is more and more paid attention to.But all do not consider in existing method that in molten iron, initial phosphorous content is on the impact of dephosphorization technology, also undeclared slag control and the temperature controlled relation of deslagging, unavoidably there will be phosphorus as initial in molten iron high, and adopt low basicity operation below and high temperature falls dephosphorized slag, rephosphorization risk can occur under this condition; Or it is high unavoidably to there will be basicity of slag control, and deslagging temperature is low, there will be the risk of deslagging difficulty under this condition.In existing converter steelmaking dephosphorization technology, the corresponding relation yet not having clear and definite deslagging temperature and basicity of slag to control, does not consider the impact of slag bubble level on deslagging yet.
Therefore, the dephosphorization of convertor steelmaking process need take into full account different initial molten iron conditions and stay Slag treatment on the impact of dephosphorization, also to consider that the technical essentials such as the phosphate capacity of slag fluidity, foaminess and slag that deslagging point relates to affect dephosphorization simultaneously, with this formulation reasonably, dephosphorization system targetedly, then be of value to and reduce costs further, reduce slag and pile up risk in stove, guarantee quality stability.
Summary of the invention
The object of the present invention is to provide a kind of dephosphorizing method of convertor steelmaking process, realize formulating different dephosphorization technologies according to initial phosphorous content different in molten iron, greatly reduce the consumption of slag material, and reduce the iron loss in dephosphorizing process, achieve the low cost quality stability of low-phosphorous variety steel.
For achieving the above object, technical scheme of the present invention is:
A dephosphorizing method for convertor steelmaking process, it comprises the steps:
(1) stay slag: after last stove smelting steel terminates, stay slag, stay the quantity of slag to be 35 ~ 60kg/t steel;
(2) multiviscosisty: stay slag multiviscosisty, makes slag no longer possess mobility;
(3) dephosphorization: add raw metal steel scrap and molten iron, and add lime and light dolomite slag making, and carry out slag making dephosphorization according to initial phosphorous content in molten iron, specific as follows:
As initial phosphorous content > 0.12% in molten iron, the basicity R of the dephosphorization slag mass ratio of calcium oxide and silicon-dioxide (namely in dephosphorization slag) controls to be 1.8 < R≤2.3, and dephosphorization terminates rear molten steel temperature T and controls to be 1450 DEG C of < T≤1500 DEG C;
When initial phosphorous content in molten iron is 0.09% < P≤0.12%, the basicity R of dephosphorization slag controls to be 1.6 < R≤1.8, and dephosphorization terminates rear molten steel temperature T and controls to be 1420 DEG C of < T≤1450 DEG C;
When initial phosphorous content in molten iron is 0.07% < P≤0.09%, the basicity R of dephosphorization slag controls to be 1.4 < R≤1.6, and dephosphorization terminates molten steel temperature T and controls to be 1380 DEG C of < T≤1420 DEG C;
When initial phosphorous content in molten iron is 0.05%≤P≤0.07%, the basicity R of dephosphorization slag controls to be 1.2≤R≤1.4, and dephosphorization terminates molten steel temperature T and controls to be 1340 DEG C≤T≤1380%;
Meanwhile, it is 8 ~ 12% that dephosphorization terminates content of MgO in rear dephosphorization slag, and in molten steel, target phosphorus content controls is 0.03 ~ 0.05%;
(4) deslagging
40 ~ 70% of current dephosphorization slag quality are gone after dephosphorization terminates.
Further, in step (2), described in stay the step of slag multiviscosisty to be: add viscosifying agent, its add-on is 2 ~ 4kg/ ton steel, adds rear shake converter, and viscosifying agent is mixed with staying slag, if slag no longer possesses mobility, then without the need to adding viscosifying agent again; As slag still possesses mobility, carry out second time multiviscosisty; In second time multiviscosisty, the add-on of viscosifying agent is 1 ~ 2kg/t steel, and shake converter, slag no longer possesses mobility.
In step (2), described viscosifying agent is one or both in lime, light dolomite.
In step (3), when in molten iron, silicone content is less than 0.3%, scrap ratio (in scrap ratio and raw material, steel scrap accounts for the ratio of steel scrap and molten iron gross weight) controls to be 8%≤scrap ratio < 10%; When silicone content in molten iron is 0.3%≤Si < 0.4%, it is 10%≤scrap ratio < 12% that scrap ratio controls; When silicone content in molten iron is 0.4%≤Si < 0.5%, it is 12%≤scrap ratio < 14% that scrap ratio controls; When in molten iron during silicone content >=0.5%, it is 14 ~ 16% that scrap ratio controls.
Again, in step (3), also require top blowing oxygen qi exhaustion phosphorus, oxygen flow is 2 ~ 3Nm
3/ (t steel min), oxygen rifle Altitude control is 1.6 ~ 2.2m, argon bottom-blowing composite stirring, and argon flow amount is 0.1 ~ 0.25Nm
3/ (t steel min).
In step (3), when in molten iron during initial phosphorous content > 0.09%, after oxygen blast 1 ~ 2min, add powdered iron ore, the add-on of powdered iron ore is 2 ~ 10% of slag quality, and in finishing slag, FeOx content controls 7 ~ 14%; When in molten iron during initial phosphorous content≤0.09%, without the need to adding powdered iron ore.
In dephosphorizing method of the present invention:
Require in step of the present invention (1) that last stove smelting steel terminates rear portion fractionation slag, stays the quantity of slag to control at 35 ~ 60kg/t steel.Stay slag to be the important measures reducing lime consumption, basicity of slag that front one heat steel stays is high, through MaterialBalance Computation, stays slag 4 tons then can reduce the lime consumption of about 1 ton.But stay slag too much can be with the problem of serving, such as, strengthen staying the difficulty of slag multiviscosisty, the steelmaking process quantity of slag can be more long-pending larger, cause steelmaking process operational difficulty, the present invention finally determines to stay the quantity of slag to control at 35 ~ 60kg/t steel, has both ensured effectively to reduce lime consumption, guarantee that again the converter smelting quantity of slag is suitable, converter smelting operation is smooth.
Step (2) is prevent follow-up hot metal charging process from causing strong reaction between carbon and oxygen to the object staying slag to carry out multiviscosisty, and then causes large splash.So viscosifying agent and slag must mix by thickening, otherwise part slag may non-multiviscosisty, causes follow-up hot metal charging process generation splash.Taking to add for 1 ~ 2 time viscosifying agent is that viscosifying agent can be piled up, and multiviscosisty slag is unfavorable on the contrary, adds so can divide 2 times because once add too many, if but first time multiviscosisty slag complete, there is no need to carry out second time multiviscosisty again, add too many viscosifying agent and can cause wasting.
The present invention mainly determines according to silicone content in molten iron adding amount of scrap steel, containing molten steel of melting bath can be made after the silicon oxidation of 0.1% to heat up nearly 36 DEG C in molten iron, and scrap ratio is promoted 1%, molten steel temperature can be made to decline 12.8 DEG C, in order to ensure that dephosphorization terminates rear temperature in rationally predetermined interval, and silicone content and the impact of adding amount of scrap steel on molten steel temperature in molten iron will be made to drop to minimum, and consider the adding the impact of molten bath mix and blend and the high quantity of slag variation brought of silicone content of steel scrap, finally determine the above-mentioned corresponding relation of scrap ratio and molten iron silicon content.
In actual production, some molten iron are through pretreatment dephosphorizing, phosphorus content is lower, the then phosphorus content had is very high, and without liquid iron pretreatment dephosphorizing, produces Low-phosphorus Steel in such a situa-tion, if adopt unified technique dephosphorization, dephosphorization effect unavoidably can be caused not reach requirement, or cost is very high, or produces unstable.Step (3) is formulated corresponding dephosphorization slag making measure (be called for short and customize dephosphorization) according to initial phosphorous content difference in molten iron and is solved an above-mentioned difficult problem well, is technological core of the present invention.
First the present invention have extensively studied the relation of basicity of slag and pour point temperature, find under the condition of slag FeOx content 7 ~ 14%, shown that basicity of slag its pour point temperature 1.9,1.7,1.5,1.3 and 1.2 time is 1440,1400,1360,1330 and 1300 DEG C respectively.When the basic demand of dephosphorization is exactly deslagging, slag temperature is higher than its pour point temperature, otherwise deslagging is difficult.Simultaneously because dephosphorization also needs the regular hour, be generally 3 ~ 5min, the time is longer, then oxygen blast is more, causes temperature higher.Therefore, final selection: in molten iron during initial phosphorous content height, need longer time dephosphorization, dephosphorization terminates rear molten steel temperature can be higher, and consider that relative high alkalinity slag has greater advantages meeting on phosphor partition ratio, and yield point is higher, now select high basicity slag, and because of duration of blast slightly length, blow off temperature finally can be met a little more than its yield point, this selection is rationally also feasible in actual production.
The present invention also further contemplates the relation of smelting process CO gas generating rate and basicity of slag, according to steel-making knowledge, temperature is higher, then CO bubble formation is faster, if slag surface tension force is on the low side, then easily cause slag foamed serious, thus affect deslagging process slag ladle to the acceptance of slag, also can be regarded as onesize slag ladle, to connect the weight that the high slag of air content causes connecing less, so, if deslagging temperature is high, then basicity of slag wants high, slag surface tension force is increased to reduce slag bubble level, certain slag foamed can not be too low, if but ensure that slag yield point is lower than deslagging temperature, then slag has certain foamed.Therefore, in determination molten iron of the present invention, initial phosphorous content is high, and when dephosphorization task is heavy, use high alkalinity slag, otherwise use low alkalinity slag, the corresponding relation of basicity, temperature and initial phosphorous content is described above.
Dephosphorization of the present invention terminates the rear requirement to MgO in slag, and mainly consider that dephosphorizing process temperature is very high, slag can reduce the erosion to furnace lining containing 8 ~ 12%MgO.Dephosphorization terminates rear target phosphorus content and controls 0.03 ~ 0.05%, and this is the requirement of producing Low-phosphorus Steel.If target phosphorus content is higher than 0.05%, the potentiality in dephosphorization stage can be made not play completely, follow-up dephosphorization task continues to strengthen, cause cost to increase, if target phosphorus content is lower than 0.03%, then need the longer time to carry out dephosphorization, basicity of slag requires larger, easily cause dephosphorization phases-time long, outlet temperature is too high, and slag rephosphorization risk increases.
Step (4) requires deslagging, removes 40 ~ 70% of current slag amount after dephosphorization terminates, and deslagging is the core process of dephosphorization method of the present invention.In step 3) on the basis that completes, slag has possessed good mobility and rational bubble level, now deslagging seems and is easy to, 40 ~ 70% of the amount of removing slag, then can go low alkalinity high content of phosphorus slag, if deslagging amount is more than 70%, there is the very large risk of falling molten steel, iron loss is serious, so final selected deslagging amount is 40 ~ 70% of the current quantity of slag.
In step of the present invention (3) dephosphorization, the determination of top blowing oxygen airshed is mainly considered from dephosphorization required time, if top blowing oxygen airshed is greater than 3Nm
3/ (t steel min), dephosphorization deficiency of time, may only have about 2min, is difficult to realize dephosphorization target; If but top blowing oxygen airshed is too low, then easily causes the whole converter smelting cycle elongated, affect production capacity, also affect the dynamic conditions of dephosphorizing process, so require that BOTTOM OXYGEN airshed is 2 ~ 3Nm simultaneously
3/ (t steel min), oxygen rifle height is according to oxygen blast flow set, and flow greatly then oxygen rifle height is large.The strong argon bottom-blowing of application claims, to promote dephosphorisation reaction better, but bottom blowing is also subject to the restriction of relevant bottom blowing equipment, finally requires that argon flow amount is 0.1 ~ 0.25Nm
3/ (t steel min).
Require that adding powdered iron ore makes dephosphorized slag in step (3), mainly from meeting, final slag FeOx content considers.Initial phosphorous content in molten iron is less than to the situation of 0.09%, because the dephosphorization time is relatively short, and dephosphorization to terminate rear temperature low, do not add powdered iron ore and can meet FeOx level in finishing slag yet; Initial p content is greater than to the situation of 0.09%, because the slag FeOx step-down that dephosphorization overlong time causes, adds suitable powdered iron ore and can supplement FeOx and enter slag.For the control of FeOx in finishing slag, mainly or from cost or dephosphorization require to consider, FeOx too high levels, more FeOx can enter slag ladle along with follow-up deslagging, cannot reclaim; FeOx content is too low, cannot meet the requirement of dephosphorization to oxygen level, so finishing slag FeOx content controls 7 ~ 14%.
After dephosphorizing method of the present invention completes, adopt ordinary method decarburization and continue to play slag dephosphorizing and can realize the Low-phosphorus Steel smelting requirements that phosphorus content in molten steel is less than 0.015% smoothly.
The present invention formulates different dephosphorization systems in the converter steelmaking dephosphorization stage according to initial phosphorous content difference in molten iron, realize the object with the molten iron production Low-phosphorus Steel of different initial phosphorous content, greatly reduce the add-on of slag material, and the iron loss reduced in dephosphorizing process, in final molten steel, phosphorus content controls as being less than 0.015%, achieves the low cost quality stability of low-phosphorous variety steel.
The content of all the components of the present invention is mass content, and ratio is mass ratio.
Embodiment
Below in conjunction with embodiment, the present invention will be further described.
Embodiment 1
320t converter is implemented, and converter possesses bottom blowing ability.Concrete steps are as follows:
1) last stove smelting steel terminates rear portion fractionation slag, stays the quantity of slag 15 tons, stays slag ingredient CaO40%, SiO
211%, P
2o
53%, MgO10%, MnO3%, FeO
x25%, Al
2o
32%, other are metallic iron; No longer deslagging after institute's slag slag splashing that stays.
2) in converter, add rhombspar 500kg, lime 300kg adds up to 800kg, and material adds rear shake converter, and find that slag no longer possesses mobility, slag completes multiviscosisty.
3) hot metal composition in hot metal ladle is measured subsequently: [Si]=0.4%, [P]=0.125%, [C]=4.6%, temperature 1320 DEG C.According to silicone content, add metalliferous material molten iron 280 tons in converter, steel scrap 38 tons, scrap ratio is 12%.
4) add 5.3 tons, lime, rhombspar 1 ton, starts oxygen blast and bottom blowing stirring subsequently, top blowing oxygen airshed 900Nm
3/ min, rifle position 2m, bottom blowing flow 40Nm
3/ min, adds 2.3 tons of iron ores after oxygen blast 2min, blow off after oxygen blast 5min dephosphorization terminate, and now basicity of slag 1.95, the quantity of slag 23.4 tons, important component composition is concrete: FeOx7.4%, P
2o
53.4%, MgO9%, bath temperature is determined as 1454 DEG C, and slag yield point is determined as 1450 DEG C, and dephosphorization terminates rear molten steel [P]=0.048%, and the molten steel P content balanced with slag is 0.024%, [C]=3.1%.
5) deslagging, goes 65% of the current quantity of slag after dephosphorization terminates, also surplus 8.2 tons of slags.
6) add 4 tons of lime and 1 ton of rhombspar, continue oxygen decarburization, in carbon rejection process, continue dephosphorization, final slag basicity is 4.1, and in molten steel, P content is 0.012%, meets Low-phosphorus Steel requirement.
Embodiment 2
320t converter is implemented, and converter possesses bottom blowing ability.Concrete steps are as follows:
1) last stove smelting steel terminates rear portion fractionation slag, stays the quantity of slag 18 tons, stays slag ingredient CaO40%, SiO
210%, P
2o
53%, MgO11%, MnO3%, FeO
x24%, Al
2o
33%, other are metallic iron.No longer deslagging after institute's slag slag splashing that stays.
2) in converter, rhombspar 600kg is added, lime 200kg, add up to 800kg, after material adds, will converter be shaken, find that slag still possesses mobility, add rhombspar 300kg again, lime 100kg, adds up to 400kg, will shake converter after material adds, find that slag does not possess mobility, slag completes multiviscosisty.
3) hot metal composition in hot metal ladle is measured subsequently: [Si]=0.3%, [P]=0.102%, [C]=4.5%, temperature 1300 DEG C.According to silicone content, add metalliferous material molten iron 285 tons in converter, steel scrap 31.5 tons, scrap ratio is 10%.
4) add 1.3 tons, lime, rhombspar 0.5 ton, starts oxygen blast and bottom blowing stirring subsequently, top blowing oxygen airshed 800Nm
3/ min, rifle position 1.9m, bottom blowing flow 35Nm
3/ min, adds 0.9 ton of iron ore after oxygen blast 1min, blow off after oxygen blast 4.2min dephosphorization terminate, and now basicity of slag 1.75, the quantity of slag 19.3 tons, important component composition is concrete: FeOx8%, P
2o
53.6%, MgO10%, bath temperature is determined as 1420 DEG C, and slag yield point is determined as 1380 DEG C, and dephosphorization terminates rear molten steel [P]=0.05%, and in the molten steel balanced with slag, P content is 0.028%, [C]=3.44%.
5) deslagging, goes 60% of the current quantity of slag after dephosphorization terminates, also surplus 7.8 tons of slags.
6) add 3.5 tons of lime and 1 ton of rhombspar, continue oxygen decarburization, continue dephosphorization at carbon rejection process, final slag basicity 3.8, P content 0.010% in molten steel, meets the requirement of low P steel.
Embodiment 3
320t converter is implemented, and converter possesses bottom blowing ability.Concrete steps are as follows:
1) last stove smelting steel terminates rear portion fractionation slag, stays the quantity of slag 12 tons, stays slag ingredient CaO40%, SiO
211%, P
2o
53.1%, MgO9%, MnO3%, FeO
x24%, Al
2o
33%, other are metallic iron.No longer deslagging after institute's slag slag splashing that stays.
2) in converter, add rhombspar 500kg, lime 200kg, add up to 700kg, will shake converter after material adds, find that slag does not possess mobility, slag completes multiviscosisty.
3) hot metal composition in hot metal ladle is measured subsequently: [Si]=0.45%, [P]=0.082%, [C]=4.5%, temperature 1310 DEG C.According to silicone content, add metalliferous material molten iron 275 tons in converter, steel scrap 41.1 tons, scrap ratio is 13%.
4) add 4.5 tons, lime, rhombspar 1.9 tons, starts oxygen blast and bottom blowing stirring subsequently, top blowing oxygen airshed 830Nm
3/ min, rifle position 1.9m, bottom blowing flow 45Nm
3blow off after/min. oxygen blast 3.6min dephosphorization terminate, and now basicity of slag 1.58, the quantity of slag 21.6 tons, important component composition is concrete: FeOx7.5%, P
2o
52.6%, MgO9%, bath temperature is determined as 1390 DEG C, and slag yield point is determined as 1370 DEG C, and dephosphorization terminates rear molten steel [P]=0.045%, and the molten steel P content balanced with slag is 0.02%, [C]=3.66%.
5) deslagging, goes 40% of the current quantity of slag after dephosphorization terminates, also surplus 12 tons of slags.
6) add 5.0 tons of lime and 1 ton of rhombspar, continue oxygen decarburization, continue dephosphorization at carbon rejection process, final slag basicity 4.1, molten steel P content 0.008%, meets the requirement of low P steel.
Embodiment 4
320t converter is implemented, and converter possesses bottom blowing ability.Concrete steps are as follows:
1) last stove smelting steel terminates rear portion fractionation slag, stays the quantity of slag 17 tons, stays slag ingredient CaO42%, SiO
211%, P
2o
53.0%, MgO9%, MnO3%, FeO
x25%, Al
2o
33%, other are metallic iron.No longer deslagging after institute's slag slag splashing that stays.
2) in converter, add rhombspar 700kg, lime 300kg, add up to 1000kg, will shake converter after material adds, find that slag does not possess mobility, slag completes multiviscosisty.
3) hot metal composition in hot metal ladle is measured subsequently: [Si]=0.41%, [P]=0.062%, [C]=4.5%, temperature 1300 DEG C.According to silicone content, add metalliferous material molten iron 280 tons in converter, steel scrap 38.1 tons, scrap ratio is 12%.
4) add 1 ton, lime, rhombspar 0.8 ton, starts oxygen blast and bottom blowing stirring subsequently, top blowing oxygen airshed 800Nm
3/ min, rifle position 1.9m, bottom blowing flow 45Nm
3blow off after/min. oxygen blast 3.3min dephosphorization terminate, and now basicity of slag 1.35, the quantity of slag 19.5 tons, important component composition is concrete: FeOx9.6%, P
2o
52.8%, MgO9%, bath temperature is determined as 1360 DEG C, and slag yield point is determined as 1330 DEG C, and dephosphorization terminates rear molten steel [P]=0.038%, and the P content balanced with slag is 0.019%, [C]=3.71%.
5) deslagging, goes 50% of the current quantity of slag after dephosphorization terminates, also surplus 9.8 tons of slags.
6) add 4.5 tons of lime and 1 ton of rhombspar, continue oxygen decarburization, continue dephosphorization at carbon rejection process, final slag basicity 3.5, molten steel P content 0.009%, meets the requirement of low P steel.
Claims (6)
1. a dephosphorizing method for convertor steelmaking process, is characterized in that, it comprises the steps:
1) slag is stayed
Stay slag after last stove smelting steel terminates, stay the quantity of slag to be 35 ~ 60kg/t steel;
2) multiviscosisty
Stay slag multiviscosisty, make slag no longer possess mobility;
3) dephosphorization
Add steel scrap and molten iron, and add lime and light dolomite slag making, and carry out slag making dephosphorization according to initial phosphorous content in molten iron, specific as follows:
As initial phosphorous content > 0.12% in molten iron, in dephosphorization slag, the mass ratio of calcium oxide and silicon-dioxide and basicity R control to be 1.8 < R≤2.3, and dephosphorization terminates rear molten steel temperature T and controls to be 1450 DEG C of < T≤1500 DEG C;
When initial phosphorous content in molten iron is 0.09% < P≤0.12%, the basicity R of dephosphorization slag controls to be 1.6 < R≤1.8, and dephosphorization terminates rear molten steel temperature T and controls to be 1420 DEG C of < T≤1450 DEG C;
When initial phosphorous content in molten iron is 0.07% < P≤0.09%, the basicity R of dephosphorization slag controls to be 1.4 < R≤1.6, and dephosphorization terminates molten steel temperature T and controls to be 1380 DEG C of < T≤1420 DEG C;
When initial phosphorous content in molten iron is 0.05%≤P≤0.07%, the basicity R of dephosphorization slag controls to be 1.2≤R≤1.4, and dephosphorization terminates molten steel temperature T and controls to be 1340 DEG C≤T≤1380%;
It is 8 ~ 12% that dephosphorization terminates content of MgO in rear slag, and in molten steel, target phosphorus content is 0.03 ~ 0.05%;
4) deslagging
40 ~ 70% of current slag quality are gone after dephosphorization terminates.
2. the dephosphorizing method of convertor steelmaking process according to claim 1, it is characterized in that, step 2) in, the described step of slag multiviscosisty of staying is: add viscosifying agent, its add-on is 2 ~ 4kg/ ton steel, and shake converter, makes viscosifying agent mix with slag, as slag no longer possesses mobility, then without the need to adding viscosifying agent again; As slag still possesses mobility, carry out second time multiviscosisty; In second time multiviscosisty, the add-on of viscosifying agent is 1 ~ 2kg/t steel, and shake converter, slag no longer possesses mobility.
3. the dephosphorizing method of convertor steelmaking process according to claim 2, is characterized in that, step 2) in, described viscosifying agent is one or both in lime, light dolomite.
4. the dephosphorizing method of convertor steelmaking process according to claim 1, it is characterized in that, step 3) in, when in molten iron during silicone content < 0.3%, in scrap ratio and raw material, steel scrap accounts for the ratio control of steel scrap and molten iron gross weight is 8%≤scrap ratio < 10%; When silicone content in molten iron is 0.3%≤Si < 0.4%, it is 10%≤scrap ratio < 12% that scrap ratio controls; When silicone content in molten iron is 0.4%≤Si < 0.5%, it is 12%≤scrap ratio < 14% that scrap ratio controls; When in molten iron during silicone content >=0.5%, it is 14 ~ 16% that scrap ratio controls.
5. the dephosphorizing method of convertor steelmaking process according to claim 1, is characterized in that, step 3) in, also comprise top blowing oxygen qi exhaustion phosphorus, oxygen flow is 2 ~ 3Nm
3/ (t steel min), oxygen rifle Altitude control is 1.6 ~ 2.2m; Argon bottom-blowing composite stirring, argon flow amount is 0.1 ~ 0.25Nm
3/ (t steel min).
6. the dephosphorizing method of convertor steelmaking process according to claim 1, it is characterized in that, step 3) in, when in molten iron during initial phosphorous content > 0.09%, powdered iron ore is added after oxygen blast 1 ~ 2min, the add-on of powdered iron ore is 2 ~ 10% of slag quality, and in finishing slag, FeOx content controls 7 ~ 14%.
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| CN201510535753.7A CN105039634B (en) | 2015-08-27 | 2015-08-27 | A kind of dephosphorization method of convertor steelmaking process |
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| CN201510535753.7A CN105039634B (en) | 2015-08-27 | 2015-08-27 | A kind of dephosphorization method of convertor steelmaking process |
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| CN105039634B CN105039634B (en) | 2017-10-31 |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN105821177A (en) * | 2016-05-03 | 2016-08-03 | 首钢京唐钢铁联合有限责任公司 | Full-tri-de technological method for converter and method for reducing total slag amount |
| CN106048129A (en) * | 2016-07-11 | 2016-10-26 | 湖南华菱涟源钢铁有限公司 | Converter high-carbon low-phosphorous end-point control metallurgy method under condition of phosphorous molten iron in blast furnace |
| CN112547290A (en) * | 2020-11-20 | 2021-03-26 | 攀枝花钢城集团有限公司 | Preparation method of fine-grained low-phosphorus steel slag |
| CN115125350A (en) * | 2021-03-29 | 2022-09-30 | 宝山钢铁股份有限公司 | Method and system for accurately controlling converter slag remaining amount |
| CN115261546A (en) * | 2021-04-30 | 2022-11-01 | 宝山钢铁股份有限公司 | Method, system, apparatus and medium for determining the most economical scrap ratio in converter steelmaking |
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| CN102776314A (en) * | 2012-07-24 | 2012-11-14 | 钢铁研究总院 | Smelting method of ultra-low phosphorus steel |
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| CN101314805A (en) * | 2007-05-31 | 2008-12-03 | 上海梅山钢铁股份有限公司 | High-efficiency dephosphorization smelting method for medium phosphor hot metal revolving furnace |
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105821177A (en) * | 2016-05-03 | 2016-08-03 | 首钢京唐钢铁联合有限责任公司 | Full-tri-de technological method for converter and method for reducing total slag amount |
| CN106048129A (en) * | 2016-07-11 | 2016-10-26 | 湖南华菱涟源钢铁有限公司 | Converter high-carbon low-phosphorous end-point control metallurgy method under condition of phosphorous molten iron in blast furnace |
| CN106048129B (en) * | 2016-07-11 | 2017-10-10 | 湖南华菱涟源钢铁有限公司 | Converter high-carbon low-phosphorus terminal point control metallurgical method under a kind of phosphorus high ferro water condition |
| CN112547290A (en) * | 2020-11-20 | 2021-03-26 | 攀枝花钢城集团有限公司 | Preparation method of fine-grained low-phosphorus steel slag |
| CN115125350A (en) * | 2021-03-29 | 2022-09-30 | 宝山钢铁股份有限公司 | Method and system for accurately controlling converter slag remaining amount |
| CN115125350B (en) * | 2021-03-29 | 2023-09-12 | 宝山钢铁股份有限公司 | Precise control method and system for slag remaining amount of converter |
| CN115261546A (en) * | 2021-04-30 | 2022-11-01 | 宝山钢铁股份有限公司 | Method, system, apparatus and medium for determining the most economical scrap ratio in converter steelmaking |
| CN115261546B (en) * | 2021-04-30 | 2024-05-14 | 宝山钢铁股份有限公司 | Determination method, system, equipment and medium for most economical scrap ratio in converter steelmaking |
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