CN103122401B - Method for smelting low-phosphorus molten steel in converter - Google Patents
Method for smelting low-phosphorus molten steel in converter Download PDFInfo
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- CN103122401B CN103122401B CN201110369237.3A CN201110369237A CN103122401B CN 103122401 B CN103122401 B CN 103122401B CN 201110369237 A CN201110369237 A CN 201110369237A CN 103122401 B CN103122401 B CN 103122401B
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Abstract
The invention discloses a method for smelting low-phosphorus molten steel in a converter. The method comprises the following steps of: adding semisteel, adding auxiliary materials in batches, and blowing, wherein the slag generated from the auxiliary materials added in the first batch mainly comprises 33-36% by weight of CaO, 7-9% by weight of MgO, 6-8% by weight of SiO2, 6-10% by weight of Al2O3, 14-16% by weight of FeO and 4-7% by weight of MnO, the slag generated from the auxiliary materials added in the second batch mainly comprises 36-38% by weight of CaO, 8-10% by weight of MgO, 7-9% by weight of SiO2, 3-5% by weight of Al2O3, 9-13% by weight of FeO and 4-6% by weight of MnO, and the slag generated from the auxiliary materials added in the third batch mainly comprises 37-40% by weight of CaO, 9-11% by weight of MgO, 10-11% by weight of SiO2, 1-2% by weight of Al2O3, 17-19% by weight of FeO and 4-6% by weight of MnO. The method disclosed by the invention can improve the phosphorus removal effect and reduce the consumption of auxiliary materials.
Description
Technical field
The present invention relates to a kind of method of converter smelting low-phosphorus molten steel.
Background technology
Along with the increase day by day of high-quality steel demand, higher to the requirement of phosphorus content in steel.At present, the method for converter smelting Low-phosphorus Steel mainly contains double slag process and duplex practice.Double slag process is to carry rifle midway in blowing to suspend blowing, pours out after part slag, then adds the slag charge method of slag making again.Duplex practice i.e. the first dephosphorization of a block converter, and then another block converter carbon drop heats up.Employing duplex practice is smelted, organization of production difficulty, and production cost is higher.During taking molten iron as feed stock for blast furnace, the initial stage that adopts double slag process to smelt exists basicity on the low side, and the problem of temperature drift, causes dephosphorization effect not good.During taking half steel as feed stock for blast furnace, there is shortage of heat slag in the initial stage that adopts double slag process to smelt, and causing slag is slow and affect dephosphorization effect and smelting cycle.
CN1995403A discloses a kind of converter process of double slag process production high carbon low-phosphorus molten steel, this technique comprises taking high silicon high phosphorus hot metal as raw material, carry out a dephosphorization deslagging at Primary period, and control basicity of slag between 2.3-2.7, iron oxide content is 12-16 % by weight; In blowing secondary dephosphorization deslagging in mid-term, and control basicity of slag between 3.2-3.7, iron oxide content is 8-12 % by weight; At blowing later stage dephosphorization adjust molten bath terminal temperature and end point carbon again, basicity of slag is between 3.7-4.2 while finishing to control the later stage, and iron oxide content is 10-15 % by weight.Described technique has solved the dephosphorization ability that converter tapping steel with high carbon exists, the problem that terminal temperature is low.In addition, document (Sichuan metallurgical the 30th the 4th phase of volume) has carried out combined blown converter double slag process produces the process practice of Low-phosphorus Steel, points out dephosphorization and the importance of later stage rephosphorization in early stage.But the dephosphorization effect of aforesaid method is still not satisfactory.
Summary of the invention
The object of the invention is to overcome and adopt the dephosphorization effect of existing double slag process low phosphorus steel by smelting water not satisfactory and a kind of method of the converter smelting low-phosphorus molten steel with higher dephosphorization effect is provided.
The present inventor finds, although adopt the phosphorus content in the method control molten steel of three dephosphorizations in the disclosed method of CN1995403A, and, its raw material is molten iron, smelts slag system and remains CaO-SiO
2-MgO-FeO slag system, Al in slag
2o
3content is very low.And adopt method of the present invention, by oxygen blast process, add in three batches auxiliary material, and composition and the consumption of controlling auxiliary material make the composition of the slag obtaining from high-aluminum low-silicon to the progressively transition of the high silicon of low aluminium, first utilize the slagging of high-aluminum low-silicon fast, basicity is high, and temperature compares CaO-SiO
2the advantage that-MgO-FeO slag system is low, the dephosphorization effect of raising Primary period, continues residue adjustment in mid-term, mainly prevent that FeO minimizing from causing slag getting dry or splash, continuing residue adjustment in the later stage, is in order to reduce lining erosion and slag splashing, and further ensures the effect of dephosphorization and inhibition rephosphorization.
To achieve these goals, the invention provides a kind of method of converter smelting low-phosphorus molten steel, the method comprises steel raw material is added in converter, adds auxiliary material in batches, and carries out top bottom blowing, and described steel raw material is half steel, wherein,
The gross weight of the slag that the add-on of first auxiliary material and oxygen blast condition make to generate is benchmark, and the content that the chief component of slag is CaO is 33-36 % by weight, and the content of MgO is 7-9 % by weight, SiO
2content be 6-8 % by weight, Al
2o
3content be 6-10 % by weight, the content of FeO is 14-16 % by weight, the content of MnO is 4-7 % by weight; Carry out deslagging one time, and add second batch auxiliary material;
The gross weight of the slag that the add-on of second batch auxiliary material and oxygen blast condition make to generate is benchmark, and the content that the chief component of slag is CaO is 36-38 % by weight, and the content of MgO is 8-10 % by weight, SiO
2content be 7-9 % by weight, Al
2o
3content be 3-5 % by weight, the content of FeO is 9-13 % by weight, the content of MnO is 4-6 % by weight; Carry out secondary deslagging, and add the 3rd batch of auxiliary material;
The gross weight of the slag that the add-on of the 3rd batch of auxiliary material and oxygen blast condition make to generate is benchmark, and the content that the chief component of slag is CaO is 37-40 % by weight, and the content of MgO is 9-10 % by weight, SiO
2content be 10-11 % by weight, Al
2o
3content be 1-2 % by weight, the content of FeO is 17-19 % by weight, the content of MnO is 4-6 % by weight.
The present invention is by converting process, and portion-wise addition metallurgic auxiliary materials (comprising lime, high magnesium lime, composite fluxing medium, ladle slag and vanadium iron metallurgical slag), to change smelting slag system, has overcome CaO-SiO
2the deficiency of-MgO-FeO slag system semi-steel making, can significantly improve dephosphorization effect, and reduces the consumption of auxiliary material, has increased benefit.
Other features and advantages of the present invention are described in detail the embodiment part subsequently.
Embodiment
Below will be elaborated to the specific embodiment of the present invention.Should be understood that, embodiment described herein only, for description and interpretation the present invention, is not limited to the present invention.
In this specification sheets term " top bottom blowing " used refer to by oxygen rifle under the condition of top blast oxygen in converter, and make steel under the condition of bottom blowing shielding gas in converter.
In this specification sheets, term " oxygen supply intensity " used refers to the oxygen-supplying amount of the molten steel obtaining in blowing per ton in the unit time, and its unit is Nm
3/ min ton molten steel.
When term " terminal control " used refers to blow end point (oxygen blast finishes) in this specification sheets, make the chemical composition of molten steel and temperature reach that the tapping of plan steel grade requires and the control carried out simultaneously, comprise the carbon content, phosphorus content, oxygen level etc. of controlling tapping temperature and endpoint molten steel.
In this specification sheets, term used " basicity " refers to weight concentration and the acidic oxide SiO of slag neutral and alkali oxide compound CaO
2the ratio of weight concentration.
In this specification sheets term " dephosphorization rate " used refer to blow before the ratio between phosphorus content in the difference of phosphorus content and the front molten iron of blowing or half steel in endpoint molten steel after phosphorus content and blowing in half steel.
Term " half steel " used in this specification sheets can refer to the blast-melted product obtaining after desulfurization vanadium extraction.Described half steel can be for the total amount taking half steel be as benchmark, the half steel of titanium, the vanadium of 0.02-0.04 % by weight and the iron of surplus of the phosphorus of the carbon that contains 3.5-3.8 % by weight, the manganese of 0.015-0.05 % by weight, 0.06-0.09 % by weight, the sulphur of 0.002-0.03 % by weight, 0.01-0.06 % by weight.Taking the total amount of half steel as benchmark, average carbon content 3.6 % by weight of described half steel, average vanadium content 0.03 % by weight, silicone content is trace.Under preferable case, taking the total amount of half steel as benchmark, carbon, the vanadium of 0.01-0.04 % by weight and the iron of surplus that described half steel contains 3.5-3.8 % by weight.
In this specification sheets, term " rifle position " used refers to the lower-most point of shower nozzle and the distance of the interior liquid steel level of the front converter of oxygen blast of oxygen rifle.
According to the present invention, the method for described converter smelting low-phosphorus molten steel comprises steel raw material is added in converter, adds auxiliary material in batches, and carries out top bottom blowing, and described steel raw material is half steel, wherein,
The gross weight of the slag that the add-on of first auxiliary material and oxygen blast condition make to generate is benchmark, and the content that the chief component of slag is CaO is 33-36 % by weight, is preferably 35-36 % by weight; The content of MgO is 7-9 % by weight, is preferably 7-8 % by weight; SiO
2content be 6-8 % by weight, be preferably 6-7 % by weight; Al
2o
3content be 6-10 % by weight, be preferably 7-9 % by weight; The content of FeO is 14-16 % by weight, is preferably 15-16 % by weight; The content of MnO is 4-7 % by weight, is preferably 5-7 % by weight; Carry out deslagging one time, and add second batch auxiliary material;
The gross weight of the slag that the add-on of second batch auxiliary material and oxygen blast condition make to generate is benchmark, and the content that the chief component of slag is CaO is 36-38 % by weight, is preferably 37-38 % by weight; The content of MgO is 8-10 % by weight, is preferably 9-10 % by weight; SiO
2content be 7-9 % by weight, be preferably 8-9 % by weight; Al
2o
3content be 3-5 % by weight, be preferably 3-5 % by weight; The content of FeO is 9-13 % by weight, is preferably 10-12 % by weight; The content of MnO is 4-6 % by weight, is preferably 4-5 % by weight; Carry out secondary deslagging, and add the 3rd batch of auxiliary material;
The gross weight of the slag that the add-on of the 3rd batch of auxiliary material and oxygen blast condition make to generate is benchmark, and the content that the chief component of slag is CaO is 37-40 % by weight, is preferably 38-40 % by weight; The content of MgO is 9-10 % by weight, is preferably 10-11 % by weight; SiO
2content be 10-11 % by weight, be preferably 10-11 % by weight; Al
2o
3content be 1-2 % by weight, be preferably 1-2 % by weight; The content of FeO is 17-19 % by weight, is preferably 18-19 % by weight; The content of MnO is 4-6 % by weight, is preferably 5-6 % by weight.
The present inventor finds, adopts in the double slag process smelting molten steel process of prior art, and during taking half steel as feed stock for blast furnace, the double-slag operation initial stage exists shortage of heat to change the problem of slag, and therefore dephosphorization effect is good and smelting cycle is long.And in the present invention, adopt and add metallurgic auxiliary materials three times, and by controlling the composition of composition, consumption and oxygen blast condition control slag of every batch of metallurgic auxiliary materials, can make when taking half steel as feed stock for blast furnace, initial smelting period realizationizations slag soon, low temperature dephosphorization effect better, stronger.
According to the present invention, described auxiliary material comprises lime, high magnesium lime, composite fluxing medium, ladle slag and vanadium iron metallurgical slag, in described metallurgic auxiliary materials, lime, high magnesium lime, the consumption of composite fluxing medium and vanadium iron metallurgical slag can be adjusted in wider scope, make to add the composition of each stage slag after auxiliary material in scope of the present invention as long as can meet the add-on of auxiliary material and oxygen blast condition, under preferable case, with respect to molten steel per ton, total consumption of described lime is 15-20 kilogram, total consumption of described high magnesium lime is 9-11 kilogram, total consumption of described composite fluxing medium is 4-6 kilogram, total consumption of described ladle slag is 4-6 kilogram, total consumption of described vanadium iron metallurgical slag is 9-12 kilogram, described composite fluxing medium is taking its gross weight as benchmark, SiO
2content be 47-50 % by weight, the content of FeO is the composite fluxing medium of 8-10 % by weight, described ladle slag is that the content of CaO is 40-55 % by weight, SiO taking its gross weight as benchmark
2content be that the content of 18-21 % by weight, FeO is the ladle slag of 1-3 % by weight, described vanadium iron metallurgical slag is taking its gross weight as benchmark, Al
2o
3content be 56-64 % by weight, the content of MgO is the vanadium iron metallurgical slag of 14-18 % by weight.
Wherein, described lime mainly contains CaO, and taking the gross weight of described lime as benchmark, the content of CaO is 85-90 % by weight.Described high magnesium lime mainly contains MgO and CaO, and taking the gross weight of described high magnesium lime as benchmark, the content of MgO is 30-40 % by weight, and the content of CaO is 48-57 % by weight.
According to the present invention, add auxiliary material in batches, and to adopt top bottom blowing be conventionally known to one of skill in the art by oxygen rifle to the method for top blast oxygen in converter, for example, can first add first auxiliary material top blast oxygen, the composition of the slag that smelting obtains reaches after requirement of the present invention, carries out deslagging one time; Then add second batch auxiliary material and continue top blast oxygen, the composition of smelting the slag obtaining reaches after requirement of the present invention, carries out secondary deslagging; Then add the 3rd batch of auxiliary material and continue top blast oxygen, until the slag obtaining reaches requirement of the present invention.
According to the present invention, the add-on of described first auxiliary material is preferably composite slag, the ladle slag of 70-75 % by weight of ladle slag total amount and the vanadium iron metallurgical slag of the 74-78 % by weight of vanadium iron metallurgical slag total amount of the 50-55 % by weight of high magnesium lime, the composite fluxing medium total amount of the 50-55 % by weight of lime, the high magnesium lime total amount of the 50-55 % by weight that comprises lime total amount.CaO, MgO, SiO in Primary period control slag
2, Al
2o
3, FeO and MnO content in scope of the present invention, can make full use of early stageization slag good, bath temperature low (bath temperature maintains 1350-1410 DEG C substantially), the dephosphorization thermodynamic condition that basicity is high, adopt top and bottom complex blowing to add strong mixing and improve dephosphorization dynamic conditions, can obtain good dephosphorization effect.
Wherein, described oxygen blast condition optimization comprises that oxygen supply intensity is 2.7-3.3Nm
3/ min ton molten steel, oxygen blow duration is 4-6 minute.Further, under preferable case, described oxygen blown method is: first with 3.1-3.3Nm
3the oxygen supply intensity oxygen blast 2-3 minute of/min ton molten steel, oxygen rifle location optimization is 1.4-1.6 rice, then with 2.7-2.8Nm
3the oxygen supply intensity oxygen blast 2-3 minute of/min ton molten steel, oxygen rifle location optimization is 1.7-1.9 rice.In employing-Gao rifle position and applicable oxygen supply intensity blow and be more conducive to control the composition of slag.
Under preferable case, in described first auxiliary material, the weight ratio of lime, high magnesium lime, composite fluxing medium, ladle slag and vanadium iron metallurgical slag is 1: (0.5-0.6): (0.25-0.35): (0.3-0.35): (0.75-0.85).
According to the present invention, the method of described deslagging can be carried out according to the method for those skilled in the art's routine, and bed drain purge also can be determined according to the situation of realization, under preferable case, after finishing blowing, carry out deslagging one time, a bed drain purge is the 70-85 % by weight that adds the total amount of the slag (rich phosphorus slag) generating after first auxiliary material oxygen blast.
According to the present invention, the add-on of described second batch auxiliary material is preferably composite fluxing medium, the ladle slag of 25-30 % by weight of ladle slag total amount and the vanadium iron metallurgical slag of the 22-26 % by weight of vanadium iron metallurgical slag total amount of the 30-35 % by weight of high magnesium lime, the composite fluxing medium total amount of the 30-35 % by weight of lime, the high magnesium lime total amount of the 30-35 % by weight that comprises lime total amount.CaO, MgO, SiO in mid-term is controlled slag in blowing
2, Al
2o
3, FeO and MnO content in scope of the present invention, and increase the content of silicon in slag, the content that simultaneously reduces aluminium in slag can further prevent the minimizing of FeO and the slag getting dry or the splash that cause.Owing to blowing mid-term, due to decarburizing reaction aggravation, in bath temperature rising and slag, FeO content reduces, dephosphorization thermodynamic condition variation, easily rephosphorization.Therefore, the operation of the deslagging after must finishing by Primary period reduces P in slag
2o
5content, simultaneously meets enough basicity and FeO content in blowing mid-term again slag making, realizes the inhibition rephosphorization in dephosphorization and blowing later stage.
Wherein, described oxygen blast condition optimization comprises that oxygen supply intensity is 2.7-2.8Nm
3/ min ton molten steel, oxygen blow duration is 6-8 minute.Under preferable case, oxygen rifle position is 1.7-1.9 rice.Adopt high rifle position and applicable oxygen supply intensity to blow and be more conducive to control the composition of slag.
Under preferable case, in described second batch auxiliary material, the weight ratio of lime, high magnesium lime, composite fluxing medium, ladle slag and vanadium iron metallurgical slag is 1: (0.5-0.65): (0.25-0.35): (0.15-0.25): (0.3-0.45).
According to the present invention, the method of described deslagging can be carried out according to the method for those skilled in the art's routine, and bed drain purge also can be determined according to the situation of realization, under preferable case, after finishing blowing, carry out secondary deslagging, secondary bed drain purge is the 30-40 % by weight that adds the total amount of the slag (rich phosphorus slag) generating after second batch auxiliary material oxygen blast.
According to the present invention, the add-on of described the 3rd batch of auxiliary material is preferably the composite fluxing medium of the 10-20 % by weight of high magnesium lime, the composite fluxing medium total amount of the 10-20 % by weight of lime, the high magnesium lime total amount of the 10-20 % by weight that comprises lime total amount.CaO, MgO, SiO in controlling slag in the blowing later stage
2, Al
2o
3, FeO and MnO content in scope of the present invention, and further increase the content of silicon in slag, the content that reduces the content of aluminium in slag simultaneously and increase FeO contributes to further dephosphorization and suppresses rephosphorization, more favourable to slag splashing technique.
Wherein, described oxygen blast condition optimization comprises that oxygen supply intensity is 2.7-2.8Nm
3/ min ton molten steel, oxygen blow duration is 2-3 minute.Further, under preferable case, described oxygen blown method is: first with 2.7-2.8Nm
3the oxygen supply intensity oxygen blast 1-1.5 minute of/min ton molten steel, oxygen rifle location optimization is 1.4-1.6 rice, and 40-60 second before tapping, oxygen rifle location optimization is lower than 1 meter, and oxygen blow duration is 1-1.5 minute.Adopt high-low rifle position and applicable oxygen supply intensity to blow and be more conducive to control the composition of slag.
Under preferable case, in described the 3rd batch of auxiliary material, the weight ratio of lime, high magnesium lime and composite fluxing medium is 1: (0.35-0.8): (0.2-0.4).
In the present invention, the plurality of raw materials in every a collection of auxiliary material can add respectively also can evenly mix and add afterwards, can continous way add also and can add by intermittent type.
In the present invention, the conventional method of bessemerizing that described converter top bottom blowing method is known to the skilled person.Preferably, described converter top bottom blowing is top blast oxygen, bottom blowing shielding gas, and according to the present invention, the intensity of bottom blowing shielding gas can be 0.015-0.045Nm
3/ ton molten steel min.For example, can for example,, at Primary period bottom blowing inactive gas (nitrogen), switch to bottom blowing rare gas element (for example argon gas) in the blowing later stage.Described shielding gas is rare gas element and/or nitrogen.
Under preferable case, after adding the 3rd batch of auxiliary material smelting to finish, molten steel is tapped in ladle, and in tapping process, carry out the deoxidation step that well known to a person skilled in the art such as pre-alloyed, and slag is stayed in converter, carry out slag splashing, that is, can adopt rifle position to carry out nitrogen blowing lower than 1 meter.
According to the present invention, in the process of bessemerizing, make slag (high silicon, low aluminium) transition from high-aluminum low-silicon to existing converter slag by add metallurgic auxiliary materials and control oxygen blast condition in batches, be mainly to utilize the slagging of high-aluminum low-silicon fast, basicity is high, and temperature compares CaO-SiO
2the advantage that-MgO-FeO slag system is low, the dephosphorization effect of raising Primary period.Residue adjustment in mid-term is mainly to prevent that FeO minimizing from causing slag getting dry or splash, later stage-residue adjustment is mainly to reduce lining erosion and slag splashing, and reaches further dephosphorization and suppress rephosphorization.
The present invention completes whole converting process on a block converter, make high-aluminum low-silicon slag by adding first metallurgic auxiliary materials early stage, greatly bring into play the characteristic of this class slag, improve the dephosphorization effect in early stage, then deslagging can be removed rich phosphorus slag, and second batch is added in continuation and the 3rd batch of metallurgic auxiliary materials made the further dephosphorization of new slag and suppressed rephosphorization, can make the phosphorus content in molten steel be controlled in 0.015 % by weight, can also reduce the blowing cycle simultaneously, and reduce quickened lime, the consumption of high magnesium lime, realize ladle slag simultaneously, the recycle of vanadium iron metallurgical slag, alleviate environmental stress, reach the object of cost efficiency.
According to method provided by the invention, described oxygen blown process and add the process of auxiliary material to realize automatic control by computer.
More than describe the preferred embodiment of the present invention in detail; but the present invention is not limited to the detail in above-mentioned embodiment, within the scope of technical conceive of the present invention; can carry out multiple simple variant to technical scheme of the present invention, these simple variant all belong to protection scope of the present invention.
It should be noted that in addition, each concrete technical characterictic described in above-mentioned embodiment, in reconcilable situation, can combine by any suitable mode, for fear of unnecessary repetition, the present invention is to the explanation no longer separately of various possible array modes.
In addition, also can carry out arbitrary combination between various embodiment of the present invention, as long as it is without prejudice to thought of the present invention, it should be considered as content disclosed in this invention equally.
Below will describe the present invention by embodiment.
In following examples, described auxiliary material contains lime, high magnesium lime, composite fluxing medium, ladle slag and vanadium iron metallurgical slag; In lime, the content of CaO is 90 % by weight; In high magnesium lime, the content of MgO is 40 % by weight, and the content of CaO is 57 % by weight; SiO in composite fluxing medium
2content be 48 % by weight, FeO content is 8 % by weight; In ladle slag, the content of CaO is 50 % by weight, SiO
2content be that the content of 20 % by weight, FeO is 2 % by weight; Al in vanadium iron metallurgical slag
2o
3content be 60 % by weight, the content of MgO is 16 % by weight.
In following examples, the measuring method of described slag composition is xrf analysis method, the content of Ca, Mg, Si, Al, Fe, Mn, P, S, V, Ti in Main Analysis slag.
Embodiment 1
The present embodiment is for illustrating the method for converter smelting low-phosphorus molten steel provided by the invention.
Half steel after 120 tons of vanadium extractions is added in converter and smelted, wherein the composition of half steel and charging temperature are as shown in table 1 below, then in converter, add auxiliary material and be blown into wherein oxygen, the gross weight of the auxiliary material that adds (lime, high magnesium lime, composite slag and containing aluminium slag charge) is as shown in table 2, the relation that adds corresponding blowing oxygen quantity when adding auxiliary material of auxiliary material as:
Add first auxiliary material top blast oxygen, described first auxiliary material comprises composite fluxing medium, the ladle slag of 75 % by weight of ladle slag total amount and the vanadium iron metallurgical slag of 78 % by weight of vanadium iron metallurgical slag total amount of 54 % by weight of high magnesium lime, the composite fluxing medium total amount of 53 % by weight of lime, the high magnesium lime total amount of 55 % by weight of lime total amount, oxygen blast condition comprises that starting rifle position is 1.4 meters, and first with 3.1Nm
3the oxygen supply intensity oxygen blast of/min ton molten steel 3 minutes, then carries rifle position to 1.7 meters, then with 2.7Nm
3the oxygen supply intensity oxygen blast of/min ton molten steel 3 minutes; And bottom blowing nitrogen always, nitrogen air supply intensity is 2.5Nm
3/ min ton molten steel; The rich phosphorus slag of pouring out slag gross weight 80 % by weight after molten steel Primary period finishes, bath temperature is controlled at 1350-1410 DEG C, taking the gross weight of slag as benchmark, described slag consist of CaO:36 % by weight, MgO:8 % by weight, SiO
2: 7 % by weight, Al
2o
3: 8 % by weight, FeO:16 % by weight, MnO:7 % by weight;
Add second batch auxiliary material top blast oxygen, described second batch auxiliary material comprises the vanadium iron metallurgical slag of composite fluxing medium, the ladle slag of ladle slag total amount 25 % by weight and 22 % by weight of vanadium iron metallurgical slag total amount of 33 % by weight of high magnesium lime, the composite fluxing medium total amount of 33 % by weight of lime, the high magnesium lime total amount of 35 % by weight of lime total amount, and oxygen blast condition comprises that oxygen supply intensity is 2.7Nm
3/ min ton molten steel, oxygen blow duration is 7 minutes, rifle position is 1.7 meters; And bottom blowing nitrogen always, nitrogen air supply intensity is 3Nm
3/ min ton molten steel; The rich phosphorus slag of slag gross weight 30 % by weight is poured out in blowing mid-term after finishing, taking the gross weight of slag as benchmark, described slag consist of CaO:38 % by weight, MgO:10 % by weight, SiO
2: 8 % by weight, Al
2o
3: 3 % by weight, FeO:11 % by weight, MnO:6 % by weight;
Add the 3rd batch of auxiliary material top blast oxygen, described the 3rd batch of auxiliary material comprises the composite fluxing medium of 13 % by weight of high magnesium lime, the composite fluxing medium total amount of 14 % by weight of lime, the high magnesium lime total amount of 10 % by weight of lime total amount, oxygen blast condition comprises that starting rifle position is 1.7 meters, and with 2.7Nm
3the oxygen supply intensity oxygen blast of/min ton molten steel 2 minutes, and bottom blowing nitrogen always, nitrogen air supply intensity is 2.8Nm
3/ min ton molten steel; Blowing is after the later stage finishes, taking the gross weight of slag as benchmark, described slag consist of CaO:40 % by weight, MgO:10 % by weight, SiO
2: 11 % by weight, Al
2o
3: 2 % by weight, FeO:19 % by weight, MnO:7 % by weight;
To obtain molten steel and tap, and to having gone out the slag staying after steel, adopting rifle position to be less than 1 meter of nitrogen blowing, the air supply intensity of nitrogen is 2.7Nm
3/ min ton molten steel, carries out slag splashing, and the time is controlled at 30 seconds, ensures slag splashing effect.
Composition and the tapping temperature of tapping molten steel are as shown in table 3, and the weight of tapping is 130 tons, and the steel of refining is the steel of U75V steel grade.
Table 1
| C | Si | Mn | P | S | V | Ti | Fe | Charging temperature (DEG C) | |
| Half composition of steel (% by weight) | 3.6 | Trace | 0.02 | 0.08 | 0.02 | 0.03 | 0.01 | Surplus | 1320 |
Table 2
| Auxiliary material | Lime (kg) | High magnesium lime (kg) | Ladle slag (kg) | Composite fluxing medium (kg) | Vanadium titanium metallurgical slag (kg) |
| Add total amount | 2360 | 1320 | 560 | 660 | 1300 |
Table 3
In this convertor steelmaking process, there is not the phenomenon of spitting and getting dry, in molten steel, phosphorus content is lower than 0.015 % by weight, and dephosphorization rate is more than 90%; And, start to form the slag that covers molten steel 3 minutes from oxygen blast, shorten 0.5 minute than conventional method for making steel.
Embodiment 2
The present embodiment is for illustrating the method for converter smelting low-phosphorus molten steel provided by the invention.
Half steel after 120 tons of vanadium extractions is added in converter and smelted, wherein the composition of half steel and charging temperature are as shown in table 4 below, then in converter, add auxiliary material and be blown into wherein oxygen, the gross weight of the auxiliary material that adds (lime, high magnesium lime, composite slag and containing aluminium slag charge) is as shown in table 5, the relation that adds corresponding blowing oxygen quantity when adding auxiliary material of auxiliary material as:
Add first auxiliary material top blast oxygen, described first auxiliary material comprises lime, the high magnesium lime of 52 % by weight of high magnesium lime total amount and the composite slag of 53 % by weight of composite slag total amount of 51 % by weight of lime total amount, the vanadium iron metallurgical slag of 74 % by weight of the ladle slag of 70 % by weight of ladle slag total amount and vanadium iron metallurgical slag total amount, oxygen blast condition comprises that starting rifle position is 1.6 meters, and first with 3.3Nm
3the oxygen supply intensity oxygen blast of/min ton molten steel 3.5 minutes, then carries rifle position to 1.9 meters, then with 2.8Nm
3the oxygen supply intensity oxygen blast of/min ton molten steel 2.5 minutes; And bottom blowing nitrogen always, nitrogen air supply intensity is 2.5Nm
3/ min ton molten steel; The rich phosphorus slag of pouring out slag gross weight 75% after molten steel Primary period finishes, bath temperature is controlled at 1350-1410 DEG C, taking the gross weight of slag as benchmark, described slag consist of CaO:33 % by weight, MgO:7 % by weight, SiO
2: 6 % by weight, Al
2o
3: 9 % by weight, FeO:15 % by weight, MnO:6 % by weight;
Add second batch auxiliary material top blast oxygen, described second batch auxiliary material comprises the high magnesium lime of 32 % by weight of lime, the high magnesium lime total amount of 33 % by weight of lime total amount, the vanadium iron metallurgical slag of 26 % by weight of the composite fluxing medium of 31 % by weight of composite fluxing medium total amount, the ladle slag of ladle slag total amount 30 % by weight and vanadium iron metallurgical slag total amount, oxygen blast condition comprises that oxygen supply intensity is 2.8Nm
3/ min ton molten steel, oxygen blow duration is 6 minutes, rifle position is 1.9 meters; And bottom blowing nitrogen always, nitrogen air supply intensity is 3Nm
3/ min ton molten steel; The rich phosphorus slag of slag gross weight 35% is poured out in blowing mid-term after finishing, taking the gross weight of slag as benchmark, described slag consist of CaO:35 % by weight, MgO:10 % by weight, SiO
2: 7 % by weight, Al
2o
3: 3 % by weight, FeO:10 % by weight, MnO:6 % by weight;
Add the 3rd batch of auxiliary material top blast oxygen, described the 3rd batch of auxiliary material comprises lime, the high magnesium lime of 16 % by weight of high magnesium lime total amount and the composite slag of 16 % by weight of composite slag total amount of 16 % by weight of lime total amount, oxygen blast condition comprises that starting rifle position is 1.9 meters, and first with 2.8Nm
3the oxygen supply intensity oxygen blast of/min ton molten steel 2 minutes, and bottom blowing nitrogen always, nitrogen air supply intensity is 2.8Nm
3/ min ton molten steel; After the molten steel blowing later stage finishes, taking the gross weight of slag as benchmark, described slag consist of CaO:37 % by weight, MgO:9 % by weight, SiO
2: 10 % by weight, Al
2o
3: 2 % by weight, FeO:17 % by weight, MnO:6 % by weight;
To obtain molten steel and tap, and to having gone out the slag staying after steel, adopting rifle position to be less than 1 meter of nitrogen blowing, the air supply intensity of nitrogen is 2.8Nm
3/ min ton molten steel, carries out slag splashing, and the time is controlled at 30 seconds, ensures slag splashing effect.
Composition and the tapping temperature of tapping molten steel are as shown in table 6, and the weight of tapping is 130 tons, and the steel of refining is the steel of U75V steel grade.
Table 4
| C | Si | Mn | P | S | V | Ti | Fe | Charging temperature (DEG C) | |
| Half composition of steel (% by weight) | 3.6 | Trace | 0.02 | 0.08 | 0.02 | 0.03 | 0.01 | Surplus | 1320 |
Table 5
| Auxiliary material | Lime (kg) | High magnesium lime (kg) | Ladle slag (kg) | Composite fluxing medium (kg) | Vanadium titanium metallurgical slag (kg) |
| Add total amount | 2200 | 1180 | 550 | 640 | 1260 |
Table 6
In this convertor steelmaking process, there is not the phenomenon of spitting and getting dry, in molten steel, P content is lower than 0.015 % by weight, and dephosphorization rate is 90%; And, from adding converter, described half steel forms the slag that covers molten steel after 3 minutes, shorten 0.5 minute than conventional method for making steel.
Embodiment 3
The present embodiment is for illustrating the method for converter smelting low-phosphorus molten steel provided by the invention.
Half steel after 120 tons of vanadium extractions is added in converter and smelted, wherein the composition of half steel and charging temperature are as shown in table 7 below, then in converter, add auxiliary material and be blown into wherein oxygen, the gross weight of the auxiliary material that adds (lime, high magnesium lime, composite slag and containing aluminium slag charge) is as shown in table 8, the relation that adds corresponding blowing oxygen quantity when adding auxiliary material of auxiliary material as:
Add first auxiliary material top blast oxygen, described first auxiliary material comprises lime, the high magnesium lime of 55 % by weight of high magnesium lime total amount and the composite slag of 51 % by weight of composite slag total amount of 53 % by weight of lime total amount, the vanadium iron metallurgical slag of 76 % by weight of the ladle slag of 73 % by weight of ladle slag total amount and vanadium iron metallurgical slag total amount, oxygen blast condition comprises that starting rifle position is 1.5 meters, and first with 3.2Nm
3the oxygen supply intensity oxygen blast of/min ton molten steel 3 minutes, then carries rifle position to 1.8 meters, then with 2.8Nm
3the oxygen supply intensity oxygen blast of/min ton molten steel 3 minutes; And bottom blowing nitrogen always, nitrogen air supply intensity is 3Nm
3/ min ton molten steel; The rich phosphorus slag of pouring out slag gross weight 80% after molten steel Primary period finishes, bath temperature is controlled at 1350-1410 DEG C, taking the gross weight of slag as benchmark, described slag consist of CaO:35 % by weight, MgO:8 % by weight, SiO
2: 7 % by weight, Al
2o
3: 7 % by weight, FeO:15 % by weight, MnO:7 % by weight;
Add second batch auxiliary material top blast oxygen, described second batch auxiliary material comprises lime, the high magnesium lime of 34 % by weight of high magnesium lime total amount and the composite slag of 35 % by weight of composite slag total amount of 31 % by weight of lime total amount, ladle slag total amount, the vanadium iron metallurgical slag of 24 % by weight of the ladle slag of 27 % by weight and vanadium iron metallurgical slag total amount, oxygen blast condition comprises that oxygen supply intensity is 2.8Nm
3/ min ton molten steel, oxygen blow duration is 8 minutes, rifle position is 1.8 meters; And bottom blowing nitrogen always, nitrogen air supply intensity is 3Nm
3/ min ton molten steel; The rich phosphorus slag of slag gross weight 30% is poured out in blowing mid-term after finishing, taking the gross weight of slag as benchmark, described slag consist of CaO:36 % by weight, MgO:8 % by weight, SiO
2: 8 % by weight, Al
2o
3: 3 % by weight, FeO:11 % by weight, MnO:6 % by weight;
Add the 3rd batch of auxiliary material top blast oxygen, described the 3rd batch of auxiliary material comprises lime, the high magnesium lime of 11 % by weight of high magnesium lime total amount and the composite slag of 14 % by weight of composite slag total amount of 16 % by weight of lime total amount, oxygen blast condition comprises that starting rifle position is 1.8 meters, and first with 2.7Nm
3the oxygen supply intensity oxygen blast of/min ton molten steel 2 minutes, and bottom blowing nitrogen always, nitrogen air supply intensity is 2.9Nm
3/ min ton molten steel; After the molten steel blowing later stage finishes, taking the gross weight of slag as benchmark, described slag consist of CaO:38 % by weight, MgO:10 % by weight, SiO
2: 10 % by weight, Al
2o
3: 2 % by weight, FeO:19 % by weight, MnO:5 % by weight;
To obtain molten steel and tap, and to having gone out the slag staying after steel, adopting rifle position to be less than 1 meter of nitrogen blowing, the air supply intensity of nitrogen is 2.8Nm
3/ min ton molten steel, carries out slag splashing, and the time is controlled at 30 seconds, ensures slag splashing effect.
Composition and the tapping temperature of tapping molten steel are as shown in table 9, and the weight of tapping is 130 tons, and the steel of refining is the steel of U75V steel grade.
Table 7
| C | Si | Mn | P | S | V | Ti | Fe | Charging temperature (DEG C) | |
| Half composition of steel (% by weight) | 3.6 | Trace | 0.02 | 0.08 | 0.02 | 0.03 | 0.01 | Surplus | 1320 |
Table 8
| Auxiliary material | Lime (kg) | High magnesium lime (kg) | Ladle slag (kg) | Composite fluxing medium (kg) | Vanadium titanium metallurgical slag (kg) |
| Add total amount | 2290 | 1260 | 555 | 655 | 1290 |
Table 9
In this convertor steelmaking process, there is not the phenomenon of spitting and getting dry, in molten steel, P content is lower than 0.015 % by weight, and dephosphorization rate is 90%; And, from adding converter, described half steel forms the slag that covers molten steel after 3 minutes, shorten 0.5 minute than conventional method for making steel.
Claims (9)
1. a method for converter smelting low-phosphorus molten steel, the method comprises steel raw material is added in converter, adds auxiliary material in batches, and carries out top bottom blowing, described steel raw material is half steel, it is characterized in that,
The gross weight of the slag that the add-on of first auxiliary material and oxygen blast condition make to generate is benchmark, and the content that the chief component of slag is CaO is 33-36 % by weight, and the content of MgO is 7-9 % by weight, SiO
2content be 6-8 % by weight, Al
2o
3content be 6-10 % by weight, the content of FeO is 14-16 % by weight, the content of MnO is 4-7 % by weight; Carry out deslagging one time, and add second batch auxiliary material;
The gross weight of the slag that the add-on of second batch auxiliary material and oxygen blast condition make to generate is benchmark, and the content that the chief component of slag is CaO is 36-38 % by weight, and the content of MgO is 8-10 % by weight, SiO
2content be 7-9 % by weight, Al
2o
3content be 3-5 % by weight, the content of FeO is 9-13 % by weight, the content of MnO is 4-6 % by weight; Carry out secondary deslagging, and add the 3rd batch of auxiliary material;
The gross weight of the slag that the add-on of the 3rd batch of auxiliary material and oxygen blast condition make to generate is benchmark, and the content that the chief component of slag is CaO is 37-40 % by weight, and the content of MgO is 9-10 % by weight, SiO
2content be 10-11 % by weight, Al
2o
3content be 1-2 % by weight, the content of FeO is 17-19 % by weight, the content of MnO is 4-6 % by weight;
Described auxiliary material comprises lime, high magnesium lime, composite fluxing medium, ladle slag and vanadium iron metallurgical slag;
Described first auxiliary material comprises composite fluxing medium, the ladle slag of 70-75 % by weight of ladle slag total amount and the vanadium iron metallurgical slag of the 74-78 % by weight of vanadium iron metallurgical slag total amount of the 50-55 % by weight of high magnesium lime, the composite fluxing medium total amount of the 50-55 % by weight of lime, the high magnesium lime total amount of the 50-55 % by weight of lime total amount; Described oxygen blast condition comprises that oxygen supply intensity is 2.7-3.3Nm
3/ min ton molten steel, oxygen blow duration is 4-6 minute;
Described second batch auxiliary material comprises composite fluxing medium, the ladle slag of 25-30 % by weight of ladle slag total amount and the vanadium iron metallurgical slag of the 22-26 % by weight of vanadium iron metallurgical slag total amount of the 30-35 % by weight of high magnesium lime, the composite fluxing medium total amount of the 30-35 % by weight of lime, the high magnesium lime total amount of the 30-35 % by weight of lime total amount; Oxygen blast condition comprises that oxygen supply intensity is 2.7-2.8Nm
3/ min ton molten steel, oxygen blow duration is 6-8 minute;
Described the 3rd batch of auxiliary material comprises the composite fluxing medium of the 10-20 % by weight of high magnesium lime, the composite fluxing medium total amount of the 10-20 % by weight of lime, the high magnesium lime total amount of the 10-20 % by weight of lime total amount, and oxygen blast condition comprises that oxygen supply intensity is 2.7-2.8Nm
3/ min ton molten steel, oxygen blow duration is 2-3 minute.
2. method according to claim 1, wherein, with respect to molten steel per ton, total consumption of described lime is 15-20 kilogram, total consumption of described high magnesium lime is 9-11 kilogram, total consumption of described composite fluxing medium is 4-6 kilogram, and total consumption of described ladle slag is 4-6 kilogram, and total consumption of described vanadium iron metallurgical slag is 9-12 kilogram; Described composite fluxing medium is taking its gross weight as benchmark, SiO
2content be 47-50 % by weight, the content of FeO is the composite fluxing medium of 8-10 % by weight; Described ladle slag is that the content of CaO is 40-55 % by weight, SiO taking its gross weight as benchmark
2content be 18-21 % by weight, the content of FeO is the ladle slag of 1-3 % by weight; Described vanadium iron metallurgical slag is taking its gross weight as benchmark, Al
2o
3content be 56-64 % by weight, the content of MgO is the vanadium iron metallurgical slag of 14-18 % by weight.
3. method according to claim 1, wherein, in described first auxiliary material, the weight ratio of lime, high magnesium lime, composite fluxing medium, ladle slag and vanadium iron metallurgical slag is 1:(0.5-0.6): (0.25-0.35): (0.3-0.35): (0.75-0.85).
4. method according to claim 1 and 2, wherein, a bed drain purge is the 70-85 % by weight that adds the slag total amount generating after first auxiliary material oxygen blast.
5. method according to claim 1, wherein, in described second batch auxiliary material, the weight ratio of lime, high magnesium lime, composite fluxing medium, ladle slag and vanadium iron metallurgical slag is 1:(0.5-0.65): (0.25-0.35): (0.15-0.25): (0.3-0.45).
6. method according to claim 1 and 2, wherein, secondary bed drain purge is the 30-40 % by weight that adds the total amount of the slag generating after second batch auxiliary material oxygen blast.
7. method according to claim 1, wherein, in described the 3rd batch of auxiliary material, the weight ratio of lime, high magnesium lime and composite fluxing medium is 1:(0.35-0.8): (0.2-0.4).
8. method according to claim 1, wherein, it is 0.08-0.14 % by weight that the condition of blow end point control makes carbon content of molten steel, converter terminal temperature is 1670 DEG C-1685 DEG C.
9. method according to claim 1, wherein, taking the gross weight of described half steel as benchmark, titanium, the vanadium of 0.02-0.04 % by weight and the iron of surplus of the phosphorus of the carbon that described half steel contains 3.5-3.8 % by weight, the manganese of 0.015-0.05 % by weight, 0.06-0.09 % by weight, the sulphur of 0.002-0.03 % by weight, 0.01-0.06 % by weight.
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| CN104060018B (en) * | 2014-03-05 | 2016-01-06 | 攀钢集团攀枝花钢铁研究院有限公司 | A kind of method of low phosphorus steel by smelting semisteel |
| CN106884067A (en) * | 2016-12-25 | 2017-06-23 | 秦皇岛首秦金属材料有限公司 | A kind of converter operating method of high phosphorus hot metal low phosphorus steel by smelting |
| CN111850241B (en) * | 2020-07-23 | 2021-10-19 | 芜湖县天海耐火炉料有限公司 | Sintered synthetic slag and preparation method thereof |
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