CN105039634B - A kind of dephosphorization method of convertor steelmaking process - Google Patents
A kind of dephosphorization method of convertor steelmaking process Download PDFInfo
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- CN105039634B CN105039634B CN201510535753.7A CN201510535753A CN105039634B CN 105039634 B CN105039634 B CN 105039634B CN 201510535753 A CN201510535753 A CN 201510535753A CN 105039634 B CN105039634 B CN 105039634B
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Abstract
A kind of dephosphorization method of convertor steelmaking process, it includes step：Stay slag：It is 35~60kg/ tons of steel to stay the quantity of slag；Thickening：Stay slag to be thickened, clinker is no longer possessed mobility；Dephosphorization：Steel scrap and molten iron raw metal are added, is carried out formulating different dephosphorization technologies according to initial phosphorous content different in molten iron, dephosphorization terminates target phosphorus content in rear molten steel and controlled 0.03~0.05%；Deslagging：Dephosphorization goes to the 40~70% of clinker quality after terminating.Decarburization and continue to play clinker dephosphorizing according to a conventional method again, you can smoothly ensure in final molten steel that phosphorus content is less than 0.015%.This method formulates different dephosphorization technologies to produce Low-phosphorus Steel according to initial phosphorous content difference in molten iron, substantially reduces the consumption of slag material, and reduces the iron loss in dephosphorizing process, realizes the inexpensive quality stability of Low-phosphorus Steel.
Description
Technical field
The present invention relates to pneumatic steelmaking field, and in particular to a kind of dephosphorization method of convertor steelmaking process.
Background technology
Dephosphorization is the core missions of pneumatic steelmaking, at present main dephosphorization method can be divided into conventional dephosphorization method, duplex practice with
And double slag process.Wherein, conventional dephosphorization method is the disposable deslagging after converter steelmaking process realizes that dephosphorization, converter smelting terminate, no
Stay slag；Duplex practice refers to the first dephosphorization in a converter, and molten steel then is transferred into another converter decarburization, due to being turned using two
Stove produces same one heat steel, although can be extremely lowly de- by phosphorus, but occupies more device resources, have impact on production capacity；Double slag process is
The first dephosphorization in same converter, dephosphorization terminates heel row part slag, and then decarburization again, smelting can stay slag to be used for next stove smelting after terminating
Refining.The advantage of double slag process be take full advantage of previous stove stay slag so that lime and dolomite addition are substantially reduced, and can be true
The production of Low-phosphorus Steel is protected, has the disadvantage to cause converter smelting cycle stretch-out.
In recent years, with the increase of low-phosphorous variety steel amount, while in order to reduce the dependence to liquid iron pretreatment dephosphorizing, double slags
Method dephosphorization is increasingly paid attention to.But do not consider influence of the initial phosphorous content to dephosphorization technology in molten iron in existing method, not yet
Illustrate slag control and the temperature controlled relation of deslagging, occur unavoidably as the initial phosphorus of molten iron is high, and grasped below using low alkalinity
Make and high temperature falls dephosphorized slag, can occur rephosphorization risk under the conditions of this；Or occur that basicity of slag control is high unavoidably, and deslagging temperature
It is low, the difficult risk of deslagging occurs under the conditions of this.In existing pneumatic steelmaking dephosphorization technology, also without clear and definite deslagging temperature and clinker
The corresponding relation of basicity control, influence of the clinker bubble level to deslagging is not considered yet.
Therefore, the dephosphorization of convertor steelmaking process need to take into full account different initial molten iron condition and stay Slag treatment to dephosphorization
Influence, while it is also contemplated that the technical essential pair such as phosphate capacity of slag fluidity, foaminess and clinker that deslagging point is related to
Dephosphorization influences, and so that this formulation is rational, targetedly dephosphorization system, then is beneficial to further reduce cost, reduction clinker
Risk is accumulated in stove, it is ensured that quality stability.
The content of the invention
It is an object of the invention to provide a kind of dephosphorization method of convertor steelmaking process, realize according to different initial in molten iron
Phosphorus content formulates different dephosphorization technologies, substantially reduces the consumption of slag material, and reduces the iron loss in dephosphorizing process, realizes
The inexpensive quality stability of low-phosphorous variety steel.
To reach above-mentioned purpose, the technical scheme is that：
A kind of dephosphorization method of convertor steelmaking process, it comprises the following steps：
(1) slag is stayed：Previous stove steel smelting stays slag after terminating, and it is 35~60kg/t steel to stay the quantity of slag；
(2) it is thickened：Stay slag to be thickened, clinker is no longer possessed mobility；
(3) dephosphorization：Raw metal steel scrap and molten iron are added, and adds lime and light dolomite slag making, and according to molten iron
Middle initial phosphorous content carries out slag making dephosphorization, specific as follows：
As initial phosphorous content ＞ 0.12% in molten iron, the basicity R of dephosphorization clinker (calcium oxide and titanium dioxide i.e. in dephosphorization clinker
The mass ratio of silicon) control to be 1.8 ＜ R≤2.3, it is 1450 DEG C of ＜ T≤1500 DEG C that dephosphorization, which terminates rear molten steel temperature T controls,；
When in molten iron initial phosphorous content be 0.09% ＜ P≤0.12%, dephosphorization clinker basicity R control for 1.6 ＜ R≤
1.8, it is 1420 DEG C of ＜ T≤1450 DEG C that dephosphorization, which terminates rear molten steel temperature T controls,；
When in molten iron initial phosphorous content be 0.07% ＜ P≤0.09%, dephosphorization clinker basicity R control for 1.4 ＜ R≤
1.6, it is 1380 DEG C of ＜ T≤1420 DEG C that dephosphorization, which terminates molten steel temperature T controls,；
When in molten iron initial phosphorous content be 0.05%≤P≤0.07%, dephosphorization clinker basicity R control for 1.2≤R≤
1.4, it is 1340 DEG C≤T≤1380 DEG C that dephosphorization, which terminates molten steel temperature T controls,；
Meanwhile, it is that the control of target phosphorus content is 0.03 in 8~12%, molten steel that dephosphorization, which terminates in rear dephosphorization clinker content of MgO,
~0.05%；
(4) deslagging
Dephosphorization goes to the 40~70% of current dephosphorization clinker quality after terminating.
Further, it is described to stay the step of slag is thickened to be in step (2)：Thickening agent is added, its addition is 2~4kg/ tons
Converter is shaken after steel, addition, makes thickening agent with staying slag to be well mixed, if clinker no longer possesses mobility, without thickening the soup again
Agent；As clinker still possesses mobility, second of thickening of progress；The addition of thickening agent is 1~2kg/t in second of thickening
Steel, shakes converter, and clinker no longer possesses mobility.
In step (2), the thickening agent is one or both of lime, light dolomite.
In step (3), when silicone content is less than 0.3% in molten iron, scrap ratio (scrap ratio be in raw material steel scrap account for steel scrap and
The ratio of molten iron gross weight) control to be 8%≤scrap ratio ＜ 10%；When silicone content is 0.3%≤Si ＜ 0.4% in molten iron,
Scrap ratio control is 10%≤scrap ratio ＜ 12%；When silicone content is 0.4%≤Si ＜ 0.5% in molten iron, scrap ratio control
For 12%≤scrap ratio ＜ 14%；When silicone content in molten iron >=0.5%, scrap ratio control is 14~16%.
Also, in step (3), also requiring top blowing oxygen qi exhaustion phosphorus, oxygen flow is 2~3Nm3/ (t steel min), oxygen rifle height
Control as 1.6~2.2m, argon bottom-blowing composite stirring, argon flow amount is 0.1~0.25Nm3/ (t steel min).
In step (3), as initial phosphorous content ＞ 0.09% in molten iron, Iron Ore Powder, iron ore are added after 1~2min of oxygen blast
The addition of powder is the 2~10% of clinker quality, and the control of FeOx contents is 7~14% in finishing slag；When initial phosphorous content in molten iron
When≤0.09%, without adding Iron Ore Powder.
In the dephosphorization method of the present invention：
Require that previous stove steel smelting terminates rear portion fractionation slag in step (1) of the present invention, stay quantity of slag control in 35~60kg/t
Steel.It is to reduce the important measures of lime consumption to stay slag, and preceding one heat steel stays basicity of slag high, by MaterialBalance Computation, stays 4 tons of slag
About 1 ton of lime consumption can then be reduced.But stay slag excessively to bring some problems, such as, the difficulty for staying slag to be thickened increased,
The steelmaking process quantity of slag can be more long-pending bigger, causes steelmaking process operating difficulties, the present invention is final determine to stay quantity of slag control 35~
60kg/t steel, had both ensured effectively to reduce lime consumption, also ensured that the converter smelting quantity of slag is suitable, converter smelting operation is smooth.
Step (2) to staying the purpose that slag is thickened to be to prevent follow-up hot metal charging process from triggering strong reaction between carbon and oxygen, and then
Cause big splash.So, densification must mix thickening agent and clinker, and otherwise part slag may be thickened, after causing
Splash occurs for continuous hot metal charging process.It is that thickening agent can be accumulated, thick on the contrary because once plus too many to take 1~2 addition thickening agent
Change clinker unfavorable, add so can divide 2 times, but if thickening clinker has been completed for the first time, it is not necessary that carry out again thick for the second time
Change, plus too many thickening agent can cause to waste.
The present invention is mainly determined to adding amount of scrap steel according to silicone content in molten iron, is aoxidized in molten iron containing 0.1% silicon
After may be such that molten steel of melting bath heating it is nearly 36 DEG C, and by scrap ratio lifted 1%, can make molten steel temperature decline 12.8 DEG C, in order to ensure
Dephosphorization terminates rear temperature in rationally predetermined interval, and make it that silicone content and adding amount of scrap steel are to molten steel temperature in molten iron
Influence is preferably minimized, and the quantity of slag change that the influence that is mixed to molten bath of addition in view of steel scrap and silicone content height are brought
It is dynamic, the final above-mentioned corresponding relation for determining scrap ratio and molten iron silicon content.
In actual production, some molten iron pass through pretreatment dephosphorizing, and phosphorus content is relatively low, and the then phosphorus content having is very high, and not
By liquid iron pretreatment dephosphorizing, Low-phosphorus Steel is produced in such a situa-tion, if using unified technique dephosphorization, can cause unavoidably
Dephosphorization effect does not reach requirement, or cost is very high, or produces unstable.Step (3) is made according to initial phosphorous content difference in molten iron
Fixed corresponding dephosphorization slag making measure (referred to as customizing dephosphorization) solves above-mentioned problem well, is the technological core of the present invention.
The present invention have extensively studied the relation of basicity of slag and pour point temperature first, discovery clinker FeOx contents 7~
Under conditions of 14%, drawn basicity of slag its pour point temperature at 1.9,1.7,1.5,1.3 and 1.2 be 1440 respectively,
1400th, 1360,1330 and 1300 DEG C.Slag temperature is higher than its pour point temperature when the basic demand of dephosphorization is exactly deslagging, no
Then deslagging is difficult.Simultaneously because dephosphorization also needs regular hour, usually 3~5min, the time is longer, then oxygen blast is more, causes
Temperature is higher.Therefore, final choice：For initial phosphorous content in molten iron it is high when, it is necessary to which longer time dephosphorization, dephosphorization terminates rear steel
Liquid temperature degree can be higher, and considers that relative high alkalinity clinker has greater advantages meeting on phosphor partition ratio, and pour point is higher, now
High basicity slag is selected, and because duration of blast is slightly longer, can finally meet blow off temperature and be slightly above its pour point, this selection is in reality
It is rationally also feasible in production.
The present invention also further contemplates the relation of smelting process CO gas generating rates and basicity of slag, is known according to steel-making
Know, temperature is higher, then CO bubble formations are faster, if slag surface tension force is relatively low, be easily caused clinker foamed seriously, from
And receiving of the deslagging process slag ladle to clinker is influenceed, it also is understood as an equal amount of slag ladle and connects the high clinker of air content causing to connect
Weight it is less, so, if deslagging temperature is high, basicity of slag will height so that the increase of slag surface tension force is to reduce clinker
Bubble level, certain clinker foamed can not be too low, but as long as ensureing that clinker pour point is less than deslagging temperature, then clinker has
Certain foamed.Therefore, present invention determine that initial phosphorous content is high in molten iron, during dephosphorization task weight, high alkalinity clinker is used, otherwise use
Low alkalinity clinker, the corresponding relation of basicity, temperature and initial phosphorous content is as described above.
Requirement to MgO in clinker after dephosphorization of the present invention terminates, mainly considers that dephosphorizing process temperature is very high, clinker contains 8
~12%MgO can reduce the erosion to furnace lining.Dephosphorization terminates rear target phosphorus content control 0.03~0.05%, and this is to low-phosphorous
The requirement of steel production.If target phosphorus content is higher than 0.05%, the potentiality in dephosphorization stage can be caused not play completely, follow-up dephosphorization
Task continues to increase, and causes cost to increase, if target phosphorus content is less than 0.03%, takes longer for coming dephosphorization, clinker
Basicity requires bigger, is easily caused that dephosphorization phases-time is long, final temperature is too high, the increase of clinker rephosphorization risk.
Step (4) requires that the 40~70% of current slag amount are gone in deslagging, dephosphorization after terminating, and deslagging is dephosphorization method of the present invention
Core process.In step 3) complete on the basis of, clinker possesses good mobility and rational bubble level, now
Deslagging, which seems, to be easy to, and goes to the 40~70% of the quantity of slag, then can be fallen low alkalinity high content of phosphorus slag, if deslagging amount exceedes
70%, there is the very big risk of falling molten steel, iron loss is serious, so, final selected deslagging amount is the 40~70% of the current quantity of slag.
What is considered from dephosphorization required time is mainly to the determination of top blast oxygen flow in step (3) dephosphorization of the present invention,
If top blast oxygen flow is more than 3Nm3/ (t steel min), the dephosphorization time is not enough, may there was only 2min or so, is difficult to realize de-
Phosphorus target；But if top blast oxygen flow is too low, then it is elongated to be easily caused the whole converter smelting cycle, influences production capacity, while
The dynamic conditions of dephosphorizing process is influenceed, it requires bottom blowing oxygen flow is 2~3Nm3/ (t steel min), oxygen rifle height root
According to oxygen blast flow set, then oxygen rifle is highly big greatly for flow.The strong argon bottom-blowing of application claims, it is anti-to advantageously promote dephosphorization
Should, but bottom blowing, also by the restriction of related bottom blowing equipment, it is 0.1~0.25Nm finally to require argon flow amount3/ (t steel min).
Require that adding Iron Ore Powder makes dephosphorized slag, mainly considers from final slag FeOx contents are met in step (3).
When initial phosphorous content in molten iron is less than 0.09%, because the dephosphorization time is relatively short, and to terminate rear temperature low for dephosphorization, no
Plus Iron Ore Powder can also meet FeOx levels in finishing slag；When initial p content is more than 0.09%, because dephosphorization overlong time
The clinker FeOx step-downs of initiation, plus appropriate Iron Ore Powder can supplement FeOx and enter slag.For the control of FeOx in finishing slag, it is main or from
Cost or dephosphorization requirement consider, and FeOx too high levels, more FeOx can enter slag ladle with follow-up deslagging, it is impossible to return
Receive；FeOx contents are too low, it is impossible to meet requirement of the dephosphorization to oxygen content, so, finishing slag FeOx contents are controlled 7~14%.
After the completion of dephosphorization method of the present invention, using conventional method decarburization and continue play clinker dephosphorizing can be suitable
Profit realizes Low-phosphorus Steel smelting requirements of the phosphorus content less than 0.015% in molten steel.
The present invention formulates different dephosphorization systems in the pneumatic steelmaking dephosphorization stage according to initial phosphorous content difference in molten iron, real
Now with the purpose of the molten iron production Low-phosphorus Steels of different initial phosphorous contents, the addition of slag material is substantially reduced, and reduce dephosphorization mistake
Phosphorus content control is that the stable metaplasia of low cost of low-phosphorous variety steel is realized less than 0.015% in iron loss in journey, final molten steel
Production.
The content of all the components of the present invention is mass content, and ratio is mass ratio.
Embodiment
With reference to embodiment, the present invention will be further described.
Embodiment 1
Implement in 320t converters, converter possesses bottom blowing ability.Comprise the following steps that：
1) previous stove steel smelting terminates rear portion fractionation slag, stays 15 tons of the quantity of slag, stays slag ingredient CaO 40%, SiO211%,
P2O53%, MgO 10%, MnO 3%, FeOx25%, Al2O32%, other are metallic iron；After stayed slag slag splashing no longer
Deslagging.
2) dolomite 500kg is added into converter, lime 300kg adds up to 800kg, material to shake converter after adding, found
Clinker no longer possesses mobility, and clinker completes thickening.
3) hot metal composition in ladle is then determined：[Si]=0.4%, [P]=0.125%, [C]=4.6%, temperature
1320℃.According to silicone content, 280 tons of addition metalliferous material molten iron, 38 tons of steel scrap into converter, scrap ratio is 12%.
4) 5.3 tons of lime is added, 1 ton of dolomite then begins to oxygen blast and bottom blowing stirring, top blast oxygen flow 900Nm3/
Min, rifle position 2m, bottom blowing flow 40Nm3Blow off and dephosphorization knot after 2.3 tons of iron ores, oxygen blast 5min are added after/min, oxygen blast 2min
Beam, now basicity of slag 1.95,23.4 tons of the quantity of slag, important component composition is specific：FeOx 7.4%, P2O53.4%, MgO 9%,
Bath temperature is determined as 1454 DEG C, and clinker pour point is determined as 1450 DEG C, and dephosphorization terminates rear molten steel [P]=0.048%, with clinker
The molten steel P content of balance is 0.024%, [C]=3.1%.
5) deslagging, dephosphorization removes the 65% of the current quantity of slag after terminating, also remain 8.2 tons of slags.
6) 4 tons of lime and 1 ton of dolomite are added, continues oxygen decarburization, continues dephosphorization, final slag alkali in decarbonizing process
Spend for 4.1, P content is 0.012% in molten steel, meets Low-phosphorus Steel requirement.
Embodiment 2
Implement in 320t converters, converter possesses bottom blowing ability.Comprise the following steps that：
1) previous stove steel smelting terminates rear portion fractionation slag, stays 18 tons of the quantity of slag, stays slag ingredient CaO 40%, SiO210%,
P2O53%, MgO 11%, MnO 3%, FeOx24%, Al2O33%, other are metallic iron.After stayed slag slag splashing no longer
Deslagging.
2) dolomite 600kg, lime 200kg are added into converter, adds up to 800kg, material to shake converter after adding, sends out
Existing clinker still possesses mobility, adds dolomite 300kg, lime 100kg, adds up to 400kg, material to be shaken after adding and turns
Stove, it is found that clinker does not possess mobility, clinker completes thickening.
3) hot metal composition in ladle is then determined：[Si]=0.3%, [P]=0.102%, [C]=4.5%, temperature
1300℃.According to silicone content, 285 tons of addition metalliferous material molten iron, 31.5 tons of steel scrap into converter, scrap ratio is 10%.
4) 1.3 tons of lime is added, 0.5 ton of dolomite then begins to oxygen blast and bottom blowing stirring, top blast oxygen flow
800Nm3/ min, rifle position 1.9m, bottom blowing flow 35Nm3Stop after adding 0.9 ton of iron ore, oxygen blast 4.2min after/min, oxygen blast 1min
Blow and dephosphorization terminates, now basicity of slag 1.75,19.3 tons of the quantity of slag, important component composition is specific：FeOx 8%, P2O53.6%,
MgO 10%, bath temperature is determined as 1420 DEG C, and clinker pour point is determined as 1380 DEG C, dephosphorization terminate rear molten steel [P]=
P content is 0.028%, [C]=3.44% in 0.05%, with the molten steel of clinker balance.
5) deslagging, dephosphorization removes the 60% of the current quantity of slag after terminating, also remain 7.8 tons of slags.
6) 3.5 tons of lime and 1 ton of dolomite are added, continue oxygen decarburization, dephosphorization, final slag alkali are continued in decarbonizing process
P content 0.010% in degree 3.8, molten steel, meets low P steel requirement.
Embodiment 3
Implement in 320t converters, converter possesses bottom blowing ability.Comprise the following steps that：
1) previous stove steel smelting terminates rear portion fractionation slag, stays 12 tons of the quantity of slag, stays slag ingredient CaO 40%, SiO211%,
P2O53.1%, MgO 9%, MnO 3%, FeOx24%, Al2O33%, other are metallic iron.After stayed slag slag splashing not
Deslagging again.
2) dolomite 500kg, lime 200kg are added into converter, adds up to 700kg, material to shake converter after adding, sends out
Existing clinker does not possess mobility, and clinker completes thickening.
3) hot metal composition in ladle is then determined：[Si]=0.45%, [P]=0.082%, [C]=4.5%, temperature
1310℃.According to silicone content, 275 tons of addition metalliferous material molten iron, 41.1 tons of steel scrap into converter, scrap ratio is 13%.
4) 4.5 tons of lime is added, 1.9 tons of dolomite then begins to oxygen blast and bottom blowing stirring, top blast oxygen flow
830Nm3/ min, rifle position 1.9m, bottom blowing flow 45Nm3Simultaneously dephosphorization terminates blow off after/min. oxygen blast 3.6min, now basicity of slag
1.58,21.6 tons of the quantity of slag, important component composition is specific：FeOx 7.5%, P2O52.6%, MgO 9%, bath temperature is determined as
1390 DEG C, clinker pour point is determined as 1370 DEG C, and dephosphorization terminates rear molten steel [P]=0.045%, and the molten steel P balanced with clinker contains
Measure as 0.02%, [C]=3.66%.
5) deslagging, dephosphorization removes the 40% of the current quantity of slag after terminating, also remain 12 tons of slags.
6) 5.0 tons of lime and 1 ton of dolomite are added, continue oxygen decarburization, dephosphorization, final slag alkali are continued in decarbonizing process
Degree 4.1, molten steel P content 0.008% meets low P steel requirement.
Embodiment 4
Implement in 320t converters, converter possesses bottom blowing ability.Comprise the following steps that：
1) previous stove steel smelting terminates rear portion fractionation slag, stays 17 tons of the quantity of slag, stays slag ingredient CaO 42%, SiO211%,
P2O53.0%, MgO 9%, MnO 3%, FeOx25%, Al2O33%, other are metallic iron.After stayed slag slag splashing not
Deslagging again.
2) dolomite 700kg, lime 300kg are added into converter, adds up to 1000kg, material to shake converter after adding,
It was found that clinker does not possess mobility, clinker completes thickening.
3) hot metal composition in ladle is then determined：[Si]=0.41%, [P]=0.062%, [C]=4.5%, temperature
1300℃.According to silicone content, 280 tons of addition metalliferous material molten iron, 38.1 tons of steel scrap into converter, scrap ratio is 12%.
4) 1 ton of lime is added, 0.8 ton of dolomite then begins to oxygen blast and bottom blowing stirring, top blast oxygen flow 800Nm3/
Min, rifle position 1.9m, bottom blowing flow 45Nm3Simultaneously dephosphorization terminates blow off after/min. oxygen blast 3.3min, now basicity of slag 1.35, slag
19.5 tons of amount, important component composition is specific：FeOx 9.6%, P2O52.8%, MgO 9%, bath temperature is determined as 1360 DEG C,
Clinker pour point is determined as 1330 DEG C, and dephosphorization terminates rear molten steel [P]=0.038%, is 0.019% with the P content that clinker is balanced,
[C]=3.71%.
5) deslagging, dephosphorization removes the 50% of the current quantity of slag after terminating, also remain 9.8 tons of slags.
6) 4.5 tons of lime and 1 ton of dolomite are added, continue oxygen decarburization, dephosphorization, final slag alkali are continued in decarbonizing process
Degree 3.5, molten steel P content 0.009% meets low P steel requirement.
Claims (6)
1. a kind of dephosphorization method of convertor steelmaking process, it is characterised in that it comprises the following steps：
1) slag is stayed
Previous stove steel smelting stays slag after terminating, and it is 35~60kg/t steel to stay the quantity of slag；
2) it is thickened
Stay slag to be thickened, clinker is no longer possessed mobility；
3) dephosphorization
Steel scrap and molten iron are added, and adds lime and light dolomite slag making, and slag making is carried out according to initial phosphorous content in molten iron
Dephosphorization, it is specific as follows：
When the mass ratio of calcium oxide and silica in initial phosphorous content ＞ 0.12% in molten iron, dephosphorization clinker is basicity R controls
For 1.8 ＜ R≤2.3, it is 1450 DEG C of ＜ T≤1500 DEG C that dephosphorization, which terminates rear molten steel temperature T controls,；
When initial phosphorous content is 0.09% ＜ P≤0.12% in molten iron, the basicity R controls of dephosphorization clinker are 1.6 ＜ R≤1.8, are taken off
It is 1420 DEG C of ＜ T≤1450 DEG C that phosphorus, which terminates rear molten steel temperature T controls,；
When initial phosphorous content is 0.07% ＜ P≤0.09% in molten iron, the basicity R controls of dephosphorization clinker are 1.4 ＜ R≤1.6, are taken off
It is 1380 DEG C of ＜ T≤1420 DEG C that phosphorus, which terminates molten steel temperature T controls,；
When initial phosphorous content is 0.05%≤P≤0.07% in molten iron, the basicity R controls of dephosphorization clinker are 1.2≤R≤1.4, are taken off
It is 1340 DEG C≤T≤1380 DEG C that phosphorus, which terminates molten steel temperature T controls,；
It is that target phosphorus content is 0.03~0.05% in 8~12%, molten steel that dephosphorization, which terminates in rear clinker content of MgO,；
4) deslagging
Dephosphorization goes to the 40~70% of current clinker quality after terminating.
2. the dephosphorization method of convertor steelmaking process according to claim 1, it is characterised in that step 2) in, it is described to stay slag
The step of thickening is：Thickening agent is added, its addition is 2~4kg/ tons of steel, shakes converter, thickening agent is mixed with clinker
Even, such as clinker no longer possesses mobility, then without the agent that thickens the soup again；As clinker still possesses mobility, second of thickening of progress；The
The addition of thickening agent is 1~2kg/t steel in secondary thickening, shakes converter, and clinker no longer possesses mobility.
3. the dephosphorization method of convertor steelmaking process according to claim 2, it is characterised in that step 2) in, the thickening
Agent is one or both of lime, light dolomite.
4. the dephosphorization method of convertor steelmaking process according to claim 1, it is characterised in that step 3) in, when in molten iron
During silicone content ＜ 0.3%, it is 8%≤scrap ratio ＜ that scrap ratio, which is that steel scrap accounts for steel scrap and the ratio control of molten iron gross weight in raw material,
10%；When silicone content is 0.3%≤Si ＜ 0.4% in molten iron, scrap ratio control is 10%≤scrap ratio ＜ 12%；Work as molten iron
When middle silicone content is 0.4%≤Si ＜ 0.5%, scrap ratio control is 12%≤scrap ratio ＜ 14%；When silicone content in molten iron >=
When 0.5%, scrap ratio control is 14~16%.
5. the dephosphorization method of convertor steelmaking process according to claim 1, it is characterised in that step 3) in, in addition to top
Oxygen blast qi exhaustion phosphorus, oxygen flow is 2~3Nm3/ (t steel min), oxygen rifle highly controls to be 1.6~2.2m；Argon bottom-blowing is combined
Stirring, argon flow amount is 0.1~0.25Nm3/ (t steel min).
6. the dephosphorization method of convertor steelmaking process according to claim 1, it is characterised in that step 3) in, when in molten iron
During initial phosphorous content ＞ 0.09%, add Iron Ore Powder after 1~2min of oxygen blast, the addition of Iron Ore Powder for clinker quality 2~
10%, the control of FeOx contents is 7~14% in finishing slag.
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