阅读说明：本技术 一种转炉钢渣资源化生产的冶炼方法 (Smelting method for converter steel slag resource production ) 是由 孔祥涛 周剑波 杨昌涛 李海波 吕延春 郝宁 贾亚楠 伍从应 周德 丁宁 蓝桂年 于 2021-08-17 设计创作，主要内容包括：本发明特别涉及一种转炉钢渣资源化生产的冶炼方法,属于钢铁冶炼技术领域,方法包括：将铁水和废钢进行混合,获得冶炼铁水；将冶炼铁水进行转炉吹炼,获得脱磷铁水；其中,在转炉吹炼的结束的前0.5-1.5分钟开始进行降全铁吹炼,降全铁吹炼的供氧强度为3.2Nm～(3)/min/t-3.4Nm～(3)/min/t,降全铁吹炼的枪位高度≤1000mm,降全铁吹炼的吹炼时间至少30s；将脱磷铁水进行转炉出钢,获得炉渣和钢水；通过在冶炼的结束时,进行降全铁吹炼,使得最终炉渣的全铁含量低于15％,炉渣成分氧化镁含量小于5％；远低于正常炉渣氧化镁含量8～12％,炉渣全铁TFe含量18～20％成分区间,实现钢渣成分磁选后尾渣全部符合水泥熟料成分要求；转炉终点全铁TFe低含量,弥补了终渣MgO含量不足的问题,保证转炉炉龄18000炉以上。(The invention particularly relates to a smelting method for resource production of converter steel slag, which belongs to the technical field of steel smelting and comprises the following steps: mixing molten iron and scrap steel to obtain smelted molten iron; carrying out converter blowing on the smelted molten iron to obtain dephosphorized molten iron; wherein the reduced total iron blowing is started 0.5-1.5 minutes before the converter blowing is finished, and the oxygen supply intensity of the reduced total iron blowing is 3.2Nm 3 /min/t‑3.4Nm 3 Min/t, the height of a lance position for reducing the total iron blowing is less than or equal to 1000mm, and the blowing time for reducing the total iron blowing is at least 30 s; carrying out converter tapping on the dephosphorized molten iron to obtain slag and molten steel; by being atWhen smelting is finished, performing reduced total iron blowing to ensure that the total iron content of the final slag is lower than 15 percent and the magnesium oxide content of the slag component is lower than 5 percent; the content of magnesium oxide is far lower than that of normal slag by 8-12%, and the content of TFe in the slag is 18-20%, so that the tailings after magnetic separation of steel slag components completely meet the component requirements of cement clinker; the converter has low TFe content at the end point, makes up the problem of insufficient MgO content in the final slag, and ensures the service life of the converter to be more than 18000.)

1. A smelting method for resource production of converter steel slag is characterized by comprising the following steps:

mixing molten iron and scrap steel to obtain smelted molten iron;

carrying out converter blowing on the smelted molten iron to obtain dephosphorized molten iron; wherein the reduced total iron blowing is started 0.5-1.5 minutes before the end of the converter blowing, and the oxygen supply intensity of the reduced total iron blowing is 3.2Nm³/min/t-3.4Nm³Min/t, the height of a lance position of the reduced total iron blowing is less than or equal to 1000mm, and the blowing time of the reduced total iron blowing is at least 30s, so that the total iron content of the final slag is lower than 15%;

and carrying out converter tapping on the dephosphorized molten iron to obtain slag and molten steel.

2. The smelting method for the resource production of the converter steel slag according to claim 1, wherein the converter blowing is performed on the molten smelting iron to obtain dephosphorized molten iron, and the method specifically comprises the following steps:

carrying out first-stage blowing on the smelted molten iron, wherein the oxygen supply intensity of the first-stage blowing is 2.9Nm³/min/t-3.1Nm³Min/t, wherein the blowing time of the first stage of blowing is 1min-3 min;

performing second-stage blowing on the smelted molten iron subjected to the first-stage blowing, wherein the oxygen supply intensity of the second-stage blowing is 3.2Nm³/min/t-3.4Nm³Min/t, wherein the blowing time of the second stage of blowing is 3min-5 min; adding a slag former into the smelted molten iron while performing second-stage blowing, wherein the amount of the slag former accounts for 70-80% of the total amount of slag by weight;

in the processes of the first stage of converting and the second stage of converting, the lance position of converting is gradually reduced from 1.5m-1.7m to 1.1m-1.3 m;

carrying out third-stage blowing on the smelted molten iron subjected to the second-stage blowing, wherein the oxygen supply intensity of the third-stage blowing is 2.9Nm³/min/t-3.1Nm³Min/t, wherein the blowing time of the third stage of blowing is 2min-4 min; the gun position of the third stage blowing is 0.9-1.1 m, lime is added into the smelting molten iron while the third stage blowing is carried out, and the addition amount of the lime is 2.1-2.3 kg/ton of steel;

and carrying out reduced iron blowing on the smelted molten iron subjected to the third-stage blowing.

3. The smelting method for the resource production of the converter steel slag according to claim 2, wherein the slag former comprises the following components in percentage by mass: 85-95% of active lime and 5-15% of dolomite.

4. A smelting method for resource production of converter steel slag according to claim 3, wherein the active lime comprises the following components in percentage by mass: CaO: not less than 75%, MgO: 8-12% of SiO₂: less than or equal to 3.5 percent, less than or equal to 0.20 percent of S and less than or equal to 0.04 percent of P; wherein the sum of the CaO content and the MgO content is more than or equal to 85 percent.

5. The smelting method for resource production of converter steel slag according to claim 3, wherein the dolomite comprises the following components in percentage by mass: CaO: not less than 50%, MgO: not less than 35 percent of SiO₂：≤3％。

6. The smelting method for resource production of converter steel slag according to claim 1, wherein the dephosphorized molten iron is subjected to converter tapping to obtain slag and molten steel, the temperature of the tapped molten steel is 1650-1670 ℃, and the carbon content of the tapped molten steel is 0.03-0.08%.

7. The smelting method for resource production of converter steel slag according to claim 1, wherein the converter tapping is performed on the dephosphorized molten iron to obtain slag and molten steel, and specifically comprises the following steps:

purging nitrogen gas from the dephosphorized molten iron, wherein the gun position for purging the nitrogen gas is 5000-7000 mm, and the time for purging the nitrogen gas is 2-4 s; and then carrying out slag pouring and furnace shaking operation to obtain slag and molten steel.

8. The smelting method for the resource production of the converter steel slag according to claim 7, wherein the deslagging and furnace shaking operation specifically comprises:

the furnace body is tilted to the position of 77-82 degrees and kept for 4-6 s, and then the furnace is shaken to the position of 84-85 degrees.

9. The smelting method for the resource production of the converter steel slag according to claim 1, wherein molten iron and scrap steel are mixed to obtain smelted molten iron, and the molten iron comprises the following components in percentage by mass: c: 4.20% -6.80%, Si: 0.30% -0.70%; mn: 0.30% -0.70%; p: 0.12% -0.15%; s: 0.02% -0.07%; ti: 0.10% -0.50%; cr: 0.10 to 0.20 percent, and the balance of Fe and inevitable impurities.

10. The smelting method for the resource production of the converter steel slag according to claim 1, wherein the molten iron and the scrap steel are mixed to obtain the smelted molten iron, and the content of the scrap steel is more than 19% by weight.

Technical Field

The invention belongs to the technical field of steel smelting, and particularly relates to a smelting method for resource production of converter steel slag.

Background

In the process of steelmaking of the converter, dolomite, light-burned dolomite, magnesium calcium lime and other raw materials containing magnesia are added for slagging and protecting a furnace lining. One is to increase the content of magnesium oxide in the slag, which is beneficial to the dissolution of lime and the participation of early slagging in decarburization and dephosphorization reactions. Along with the temperature rise of the molten pool, the magnesium oxide participates in slagging reaction and can generate substances such as the forsterite and the like which are beneficial to smelting. Secondly, along with the smelting and the continuous addition of lime slag materials, the MgO content in the slag reaches a saturated state, and when the blowing is carried out to the end point, the solubility of MgO in the slag is reduced to 8 percent after the alkalinity of the slag exceeds 3.0. When the MgO content in the slag exceeds the solubility, part of the dissolved MgO is separated out in a crystalline state, so that the decarburization, dephosphorization and furnace lining protection of the converter can be met to the maximum extent, and the development of the slag splashing furnace protection process after the smelting is finished is realized. In order to increase the viscosity of the slag and reduce the physical erosion corrosion of the slag on a furnace lining, the content of magnesium oxide in the ideal slag is 8-14%.

The raw materials and smelting process of different steel plants are different, the chemical components of the converter steel slag fluctuate, but the main chemical components are basically CaO and SiO₂、Al₂O₃、FeO、Fe₂O₃、MnO、MgO、P₂O₅And metallic Fe, etc. At present, the converter steel slag is mainly applied as cement clinker, and the composition comparison of the converter steel slag and the cement clinker is shown in the following table:

material	CaO	SiO2	A12O3	Fe2O3	FeO	MgO	P2O5
								Steel slag	40-50	10-15	1-5	2-9	10-20	8-12	1-8
Cement clinker	63-67	21-24	4-7	2-4	Trace amount of	<5	Trace amount of

Compared with silicate cement clinker, the chemical composition of the steel slag has the characteristics of high iron oxide, high phosphorus, low silicon and low aluminum. The main chemical compositions of the silicate clinker and the steel slag are compared. The content of MgO in the chemical components in the converter steel slag is generally 8-12%, and exceeds the upper limit index of the content of MgO limited by Portland cement, which is less than 5%, so that the aim is to limit the reaction of free magnesium oxide (f-MgO) and water to generate magnesium hydroxide Mg (OH)₂Result inThe volume expands 148%, resulting in volume cracking of the concrete article. The chemical components and mineral compositions of the steel slag are very similar to those of silicate cement clinker, and CaO and SiO in the chemical compositions₂FeO and Fe₂O₃The sum of the contents is more than 85 percent, and the steel slag is used for replacing partial raw material to produce the cement clinker, thereby not only reducing the consumption of limestone and iron correction raw materials in the cement production, but also reducing CO₂And (4) discharging gas.

Although the application of the steel slag is wide, the development and the application of the steel slag recycling technology achieve certain achievement. However, in general, the utilization rate of steel slag in China is not high, most of the steel slag is used as a cement admixture, and a plurality of restriction factors exist when the steel slag is stably and reliably applied, and the following problems mainly exist:

1. poor volume stability: the content of chemical component MgO in the converter steel slag is generally 8-14 percent and exceeds the chemical index (MgO) limited by Portland cement<5%). Whether these MgO constituents are present in the form of periclase, what effect they have on the stability of the cement? In addition, the steel slag contains (f-CaO) which is often more than 4.5%, and the (f-CaO) may cause volume instability, and how do the factors which may cause poor cement stability affect the cement stability? The MgO component in the steel slag is mainly in solid solution with FeO and MnO to form an RO phase with an MgO matrix. The existing form of MgO is related to the alkalinity of the steel slag, and the influence on the volume stability of the steel slag is different. MgO in the low-alkalinity steel slag mainly exists in forsterite and magnesian rose pyroxene. At higher basicity, the MgO component in the steel slag exists in the form of the current RO phase in a free state, and mainly exists in the form of a solid solution of MgO, FeO and MnO. The scholars believe that the RO phase does not undergo hydration and expansion, nor does it promote hydration under high temperature and pressure conditions. The phyllogoxin considers that the cement is divided into two RO phases according to a hydration activity factor Km which is MgO/(MnO + FeO), and the Km is more than 1, belongs to a periclase solid solution, and influences the pressure steaming stability of the cement; the cement with Km less than 1 belongs to a wustite solid solution, and the pressure steaming stability of the cement is not influenced. Hounich considers that the MgO component of the steel slag exists in the form of RO phase, no periclase exists, and the RO phase is stable when the molar ratio of FeO, MnO and MgO in the RO phase is 1:1 and 0.5:1And (4) phasing. At present, the main reason for the expansion of the steel slag is recognized at home and abroad to be Ca (OH) formed by hydration of (f-CaO)₂Thereby, the effect is achieved. The (f-CaO) in the steel slag has slow hydration rate, generally the (f-CaO) hydration rate begins after the gelled mineral system is hardened, and Ca (OH) generated by the hydration₂The volume expansion rate is 97.9%, which causes the sample to expand and crack, namely the volume stability of the building is poor.

2. The steel slag has poor grindability: the steel slag contains mineral composition similar to that of silicate cement clinker, such as B ore (beta-C)₂S), A ore (C)₃S) (very low content, only small amount present at very fast cooling conditions. Calcium aluminoferrite, calcium ferrite (C2F), free CaO (f-CaO), etc., which make the steel slag cementitious. The steel slag also contains RO phase (divalent metal oxide continuous solid solution with MgO and FeO as main components) and Ca (OH) generated in the cooling weathering process₂With CaCO₃The low alkalinity steel slag also contains inactive minerals such as olivine, magnesian roselle and the like. The main reasons for the hardness of steel slag and the difficulty in crushing and grinding are that part of the mineral composition in the steel slag has high hardness and high forming temperature. Hou Guihua considers that the grindability of steel slag minerals is greatly different, and RO phase and Ca phase₂(Al，Fe)₂O₅The grindability is poor, the grindability of the ore A and the ore B is better, and the grindability is better than that of slag. Therefore, the steel slag can not be crushed by a hammer crusher during processing, and the existing solution mainly adopts the reaction and pulverization in the process of hot braising treatment, so that the grindability of the steel slag can be greatly improved; the rod mill has less over-crushing and selective crushing function, can discharge and remove iron in time, and is the core of steel slag processing.

3. Low hydration activity: the steel slag has low content of active minerals, and has the same active minerals as the silicate cement clinker. The steel slag contains tricalcium silicate (abbreviated as C) of early active mineral₃S) and tricalcium aluminate (abbreviated to C)₃A) The content of the slag is far lower than that of cement clinker, and silicate minerals and iron aluminate minerals with hydration activity in the steel slag are only 40-60%; and C formed in a high-temperature molten state₃S has compact structure and hydration speed lower than C in clinker₃S; meanwhile, the steel slag also contains RO phase, magrose pyroxene, olivine and the like, and almost no glue is generatedA mineral that is a setting mineral. The steel slag contains about 20-30% of RO phase, so that the relative content of active minerals is reduced. Therefore, although steel slag has a gelation property, the early gelation property is far lower than that of portland cement clinker.

The iron and steel industry is an important basic industry of national economy, and along with the development and the improvement of vitality level of the iron and steel industry, the problems of resources, energy consumption and waste discharge are increasingly serious. According to the data of the China Association for the application of waste steel, in 2018, the production amount of steel slag in China reaches 1.21 hundred million tons, and the comprehensive utilization rate of the steel slag is only about 30 percent. From the beginning of the last 90 years to the end of 2018, the accumulated stockpiling amount of the steel slag tailings in China exceeds 18 hundred million tons, and the occupied area is more than 20 mu of ten thousand. The stacking of the solid wastes not only occupies the land, but also brings environmental pollution and ecological damage, and the metallurgy industry of China faces serious challenges of resources and environment. In order to fully utilize solid waste resources, improve the utilization rate and comprehensive management of the steel slag, increase economic benefits, improve the environmental level, protect the requirements of ecological environment and ensure that the steel slag treatment meets the principle of less investment, fast output, more slag steel consumption and maximum benefits. The main tasks at present are: actively promotes the deep research, the graded utilization, the high-quality and high-grade use and the large-scale utilization of the steel slag and the tailings. Advanced popularization technology, low energy consumption, large slag consumption and high added value, and comprehensively realizes zero discharge of the steel slag.

Disclosure of Invention

In view of the above problems, the present invention has been made to provide a smelting method for resource production of converter steel slag that overcomes or at least partially solves the above problems.

The embodiment of the invention provides a smelting method for resource production of converter steel slag, which comprises the following steps:

mixing molten iron and scrap steel to obtain smelted molten iron;

carrying out converter blowing on the smelted molten iron to obtain dephosphorized molten iron; wherein the reduced total iron blowing is started 0.5-1.5 minutes before the end of the converter blowing, and the oxygen supply intensity of the reduced total iron blowing is 3.2Nm³/min/t-3.4Nm³Min/t, the height of the lance position for reducing the total iron blowing is less than or equal to 1000mm, the blow time of the reduced total iron blow being at least 30s, so that the total iron content of the final slag is less than 15%;

and carrying out converter tapping on the dephosphorized molten iron to obtain slag and molten steel.

Optionally, the converter blowing is performed on the smelted molten iron to obtain dephosphorized molten iron, and the converter blowing specifically includes:

carrying out first-stage blowing on the smelted molten iron, wherein the oxygen supply intensity of the first-stage blowing is 2.9Nm³/min/t-3.1Nm³Min/t, wherein the blowing time of the first stage of blowing is 1min-3 min;

performing second-stage blowing on the smelted molten iron subjected to the first-stage blowing, wherein the oxygen supply intensity of the second-stage blowing is 3.2Nm³/min/t-3.4Nm³Min/t, wherein the blowing time of the second stage of blowing is 3min-5 min; adding a slag former into the smelted molten iron while performing second-stage blowing, wherein the amount of the slag former accounts for 70-80% of the total amount of slag by weight;

in the processes of the first stage of converting and the second stage of converting, the lance position of converting is gradually reduced from 1.5m-1.7m to 1.1m-1.3 m;

carrying out third-stage blowing on the smelted molten iron subjected to the second-stage blowing, wherein the oxygen supply intensity of the third-stage blowing is 2.9Nm³/min/t-3.1Nm³Min/t, wherein the blowing time of the third stage of blowing is 2min-4 min; the gun position of the third stage blowing is 0.9-1.1 m, lime is added into the smelting molten iron while the third stage blowing is carried out, and the addition amount of the lime is 2.1-2.3 kg/ton of steel;

and carrying out reduced iron blowing on the smelted molten iron subjected to the third-stage blowing.

Optionally, the slag former comprises the following components in percentage by mass: 85-95% of active lime and 5-15% of dolomite.

Optionally, the active lime comprises the following components in percentage by mass: CaO: not less than 75%, MgO: 8-12% of SiO₂: less than or equal to 3.5 percent, less than or equal to 0.20 percent of S and less than or equal to 0.04 percent of P; wherein the sum of the CaO content and the MgO content is more than or equal to 85 percent.

Alternatively to this, the first and second parts may,the dolomite comprises the following components in percentage by mass: CaO: not less than 50%, MgO: not less than 35 percent of SiO₂：≤3％。

Optionally, the dephosphorized molten iron is subjected to converter tapping to obtain slag and molten steel, the temperature of the tapped molten steel is 1650-1670 ℃, and the carbon content of the tapped molten steel is 0.03-0.08%.

Optionally, the converter tapping is performed on the dephosphorized molten iron to obtain slag and molten steel, and the converter tapping specifically includes:

purging nitrogen gas from the dephosphorized molten iron, wherein the gun position for purging the nitrogen gas is 5000-7000 mm, and the time for purging the nitrogen gas is 2-4 s; and then carrying out slag pouring and furnace shaking operation to obtain slag and molten steel.

Optionally, the deslagging and furnace shaking operation specifically includes:

the furnace body is tilted to the position of 77-82 degrees and kept for 4-6 s, and then the furnace is shaken to the position of 84-85 degrees.

Optionally, mix molten iron and scrap steel, obtain and smelt in the molten iron, the composition of molten iron includes by mass fraction: c: 4.20% -6.80%, Si: 0.30% -0.70%; mn: 0.30% -0.70%; p: 0.12% -0.15%; s: 0.02% -0.07%; ti: 0.10% -0.50%; cr: 0.10 to 0.20 percent, and the balance of Fe and inevitable impurities.

Optionally, the molten iron and the scrap steel are mixed to obtain the smelting molten iron, wherein the content of the scrap steel is more than 19% by weight.

One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

the smelting method for the resource production of the converter steel slag provided by the embodiment of the invention comprises the following steps: mixing molten iron and scrap steel to obtain smelted molten iron; carrying out converter blowing on the smelted molten iron to obtain dephosphorized molten iron; wherein the reduced total iron blowing is started 0.5-1.5 minutes before the end of the converter blowing, and the oxygen supply intensity of the reduced total iron blowing is 3.2Nm³/min/t-3.4Nm³Min/t, the height of the lance position of the reduced iron converting is less than or equal to 1000mm, and the converting time of the reduced iron converting is at least 30s, so that the final converting is realizedThe total iron content of the slag is lower than 15%; carrying out converter tapping on the dephosphorized molten iron to obtain slag and molten steel; reducing total iron and blowing at the end of smelting to ensure that the total iron content of the final slag is lower than 15 percent and the magnesium oxide content of the slag component is lower than 5 percent; the content of magnesium oxide is far lower than that of normal slag by 8-12%, and the content of TFe in the slag is 18-20%, so that the tailings after magnetic separation of steel slag components completely meet the component requirements of cement clinker; the converter terminal full-iron TFe low-content control strategy makes up the problem of insufficient MgO content in the final slag, ensures that the slag has high viscosity, takes dicalcium silicate and tricalcium silicate as main phases in a slag splashing layer, ensures that the slag splashes, sticks and resists corrosion, and ensures that the converter is more than 18000.

The foregoing description is only an overview of the technical solutions of the present invention, and the embodiments of the present invention are described below in order to make the technical means of the present invention more clearly understood and to make the above and other objects, features, and advantages of the present invention more clearly understandable.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.

Fig. 1 is a flow chart of a method provided by an embodiment of the invention.

Detailed Description

The present invention will be described in detail below with reference to specific embodiments and examples, and the advantages and various effects of the present invention will be more clearly apparent therefrom. It will be understood by those skilled in the art that these specific embodiments and examples are for the purpose of illustrating the invention and are not to be construed as limiting the invention.

Throughout the specification, unless otherwise specifically noted, terms used herein should be understood as having meanings as commonly used in the art. Accordingly, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. If there is a conflict, the present specification will control.

Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.

In order to solve the technical problems, the general idea of the embodiment of the application is as follows:

according to a typical embodiment of the invention, the invention provides a control method for the resource production of converter slag, which is suitable for the requirement that the phosphorus and sulfur of steel grade are less than 0.045%; the converter adopts a single slag operation method, and the dephosphorization rate is more than 85 percent; the converter loading is produced in a mode of 80% molten iron and 20% scrap steel. Generally, the present invention can be realized with a scrap content of 19% or more.

A first part: converter slagging operation (Selective slag remaining + Single slag operation)

(1) Slag TiO according to end point₂The content is different, the single slag and selective slag remaining operation process is adopted to control the TiO of the converter final slag₂The content is below 5%. In the first stage (0-3 min) of converter smelting, the speed is 3.0Nm³Blowing at an oxygen supply intensity of/min/t, and in the second stage (2-6 min)3.3Nm³Blowing at the oxygen supply intensity of/min/t; adding active lime (90%) and dolomite (10%) into the converter, wherein the slag former accounts for 70-80% of the total slag amount, and stirring by adopting the maximum bottom blowing flow.

The reason why the slag former accounts for 70-80% of the total slag amount is that the slag amount is enough to realize good dephosphorization, the rest slag former is added in the later operation of controlling slag rephosphorization, and if the adverse effect of too small addition amount in the step is that the effect of inhibiting slag rephosphorization cannot be realized.

The oxygen lance hard blowing process in the first stage is combined with the large oxygen supply flow in the second stage, so that the dephosphorization rate is improved, and the smelting efficiency is improved; in the early stage, the hard blowing operation is adopted, so that the desiliconization time of molten iron can be shortened by 1-2 minutes, and the high ferric oxide and the physical heat of the previous furnace are added, so that the slag is activated, and the dephosphorization and titanium removal capability of the slag is improved.

The steel slag can be fully contacted by adopting larger bottom blowing flow, and good dynamic conditions are provided for dephosphorization.

As an alternative embodiment, the active lime active ingredient: CaO + MgO is more than or equal to 85 percent; SiO 2₂Less than or equal to 3.5 percent; s is less than or equal to 0.20 percent; p is less than or equal to 0.04 percent; wherein CaO is more than or equal to 75 percent, and MgO is 8-12 percent; CaO of light-burned dolomite is more than or equal to 50 percent, MgO is more than or equal to 35 percent, and SiO is₂Less than or equal to 3 percent, and the particle size range is as follows: 5-40 mm.

(2) And the blowing gun position is gradually reduced and controlled according to 1.6-1.2 m, the molten iron desiliconization time is shortened, the heating efficiency of the oxygen gun is improved, and the kinetic and thermodynamic conditions for dephosphorization are created in advance. The decarbonized furnace slag is recycled, the characteristics of high FeO content in the slag are fully exerted, the utilization efficiency of the furnace slag at the early stage is improved, most of phosphorus is removed at the early stage of smelting, and the addition amount of slagging materials at the middle and later stages is reduced.

(3) In the third stage of converter blowing, 3.0Nm (6-13 min)³Blowing with oxygen supply intensity of/min/t, and adding a small amount of the rest lime within 80-90% of the total blowing oxygen consumption; a smaller bottom blowing flow is adopted; the lance position of the oxygen lance is controlled according to 1.1-0.9 m, and the terminal lance pressure time is controlled according to 90-120 seconds.

(4) After the converter blowing is finished, the converter is shaken to pour slag, measure the temperature and sample;

(5) the converter is ready for tapping.

A second part: slag-iron separation operation in tapping

(1) And (4) terminal furnace reversing operation: the temperature is controlled according to 1650-1670 ℃, the carbon content of the tapped steel is controlled according to 0.03-0.08%, the terminal gun pressing time is more than or equal to 90 seconds, and the gun pressing position is less than or equal to 1000 mm.

(2) Slag foaming was controlled using a foam inhibitor down-converter. The end point oxygen supply intensity is improved from 3.0Nm³The/min/t is increased to 3.3Nm³Pressing the gun for 30 seconds per min/t, and adding 50kg of light-burned dolomite for manual slag pressing in the process of turning down the furnace. Blowing the slag at 6500-7500 mm height by nitrogen for 5-8 seconds, and turning the furnace, wherein N is used for lifting the furnace₂And blowing and overturning the liquid level of the pressed steel.

And the slag pressing operation after smelting can promote the separation of iron beads on the interface of steel and slag as soon as possible.

The oxygen supply intensity at the end point is adjusted from 3.0Nm³The/min/t is increased to 3.3Nm³And the total iron content of the slag can be lower than 15% by pressing the gun for 30 seconds per min/t, and the service life of the furnace can be ensured not to be shortened under the condition that the content of magnesium oxide is reduced and the slag meets the requirement of cement.

(3) The slag pouring and furnace shaking operation process comprises the following steps: tilting the furnace body to a position of 75-84 degrees after the slag pouring is started, keeping the angle for 4-6 seconds, then slowly shaking the furnace to a position of 84-86 degrees, and pouring out the high-content P as soon as possible₂O₅、TiO₂Slag of (2), TiO controlling converter final slag₂The content is kept below 5%.

(4) After the scrap steel is added, the furnace is shaken backwards to 315 degrees, the amount of pig iron stuck to the surface of the converter slag is reduced, and the molten steel is turned over due to splashing of iron blocks.

According to the method provided by the embodiment of the invention, the oxygen lance hard blowing process in the first stage is combined with the large oxygen supply flow in the second stage, so that the dephosphorization rate is improved, and the smelting efficiency is improved; the hard blowing operation is adopted in the early stage, so that the desiliconization time of molten iron can be shortened by 1-2 minutes, and the high ferric oxide and the physical heat of the previous furnace are added, so that the slag is activated, and the dephosphorization and titanium removal capability of the slag is improved; the steel slag can be fully contacted by adopting larger bottom blowing flow, and good dynamic conditions are provided for dephosphorization; and the slag pressing operation after smelting promotes the separation of iron beads on the interface of steel and slag as soon as possible. The content of magnesium oxide in the converter slag component produced by the method is less than 5%, and the content of TFe (total iron in the slag) is less than 15%; the content of magnesium oxide is far lower than that of normal slag by 8-12%, and the content of TFe in the slag is 18-20%, so that the tailings after magnetic separation of steel slag components completely meet the component requirements of cement clinker; the converter terminal full-iron TFe low-content control strategy makes up the problem of insufficient MgO content in the final slag, ensures that the slag has high viscosity, takes dicalcium silicate and tricalcium silicate as main phases in a slag splashing layer, ensures that the slag splashes, sticks and resists corrosion, and ensures that the converter is more than 18000.

The smelting method for the converter steel slag resource production of the present application will be described in detail below with reference to examples, comparative examples and experimental data.

Example 1

The smelting method for the resource production of the converter steel slag provided by the embodiment comprises the following steps:

the molten iron condition is as follows: c: 4.20 percent; si: 0.30 percent; mn: 0.36 percent; p: 0.12 percent; s: 0.02 percent; ti: 0.20 percent; cr: 0.10 percent; v: 0.07 percent; temperature: 1360 ℃.

A converter charging system: 62.5 tons of molten iron and 14.5 tons of scrap steel, wherein the ratio of the scrap steel is 19 percent.

And (3) converter operation: the first stage uses 3.1Nm³Blowing with the oxygen supply intensity of/min/t, wherein the blowing gun position is 1.6 meters, the process gun position is 1.6-0.9 meters, and the time is 0-3 minutes. 3200kg of lime (40 kg/ton steel) and 150kg of lightly calcined dolomite (2 kg/ton steel) are added into the converter within 1 minute after the start of blowing, and the flow rate of bottom-blown nitrogen is 0.1Nm³Min/t; the lance position in the process is 1.6 meters, and 200kg of lime (2.2 kg/ton steel) is added into the converter after 10 minutes of blowing; the lance position in the process is 1.0 meter, the time is 11-13 minutes, and the oxygen supply intensity in one minute before blowing is finished is 3.1Nm³The/min/t is increased to 3.3Nm³At/min/t, 50 light burned dolomite was added at 12 minutes and 30 seconds.

And (3) furnace reversing operation: when the lance is lifted and the slag is poured to 6000mm, the oxygen lance is blown by nitrogen for 3 seconds and then poured into the furnace, and N is used₂Blowing and overturning the liquid level of the pressed steel; tilting the furnace body to a 77-degree position after the slag pouring is started, keeping for 4 seconds, then slowly shaking the furnace to a 84-degree position, and pouring out the high-content TiO as soon as possible₂The total amount of the 1/2 slag is used as the slag.

At the converter tapping end point: c: 0.056%, Mn: 0.091%, P: 0.019% and a temperature of 1650 ℃.

Example 2

The smelting method for the resource production of the converter steel slag provided by the embodiment comprises the following steps:

the molten iron condition is as follows: c: 5.26 percent; si: 0.45 percent; mn: 0.46 percent; p: 0.145 percent; s: 0.012%; ti: 0.15 percent; cr: 0.12 percent; v: 0.06 percent; temperature: 1375 deg.C.

A converter charging system: 58.5 tons of molten iron and 16.5 tons of scrap steel, wherein the ratio of the scrap steel is as follows: 22 percent.

And (3) converter operation: the first stage uses 3.1Nm³/min/And (t) blowing with the oxygen supply intensity, wherein the blowing gun position is 1.6 meters, the process gun position is 1.6-0.9 meters, and the time is 0-3 minutes. 2400kg of lime (40 kg/ton steel) +250kg of light-burned dolomite (4 kg/ton steel) were added to the converter within 1 minute after the start of blowing, and the flow of nitrogen under bottom-blown was 0.1Nm³Min/t; the lance position in the process is 1.6 meters, the time is 3-6 minutes, and 500kg of coke is added into the converter after blowing is started for 4 minutes; the lance position in the process is 1.2 meters, the time is 6-10 minutes, and 200kg of lime (3 kg/ton steel) is added into the converter after 10 minutes of blowing; the lance position in the process is 0.9 meter, the time is 11-13 minutes, and the oxygen supply intensity in one minute before blowing is finished is 3.1Nm³The/min/t is increased to 3.3Nm³At 12 minutes and 28 seconds, 50kg of light burned dolomite was added/min/t.

And (3) furnace reversing operation: when the height of the lance is 6500mm and the slag is poured, the oxygen lance is blown by nitrogen for 4 seconds and then poured, and N is used₂Blowing and overturning the liquid level of the pressed steel; tilting the furnace body to a 75-degree position after the slag pouring is started, keeping for 4 seconds, then slowly shaking the furnace to a 84-degree position, and pouring out the high-content TiO as soon as possible₂The total amount of the 1/2 slag is used as the slag.

At the converter tapping end point: c: 0.045%, Mn: 0.136%, P: 0.022 percent and the temperature is 1660 ℃.

Example 3

The smelting method for the resource production of the converter steel slag provided by the embodiment comprises the following steps:

the molten iron condition is as follows: c: 6.20 percent; si: 0.57 percent; mn: 0.61%; p: 0.14 percent; s: 0.06 percent; ti: 0.12 percent; cr: 0.13 percent; v: 0.06 percent; temperature: 1366 ℃.

A converter charging system: 58.5 tons of molten iron and 16.5 tons of scrap steel, and the ratio of the scrap steel is 22 percent.

And (3) converter operation: the first stage uses 3.1Nm³Blowing with the oxygen supply intensity of/min/t, wherein the blowing gun position is 1.6 meters, the process gun position is 1.6-0.90 meters, and the time is 0-3 minutes. 3120kg of lime (40 kg/ton steel) were added to the converter within 1 minute after the start of the blowing, and the flow rate of the nitrogen under bottom-blowing was 0.1Nm³Min/t; the lance position in the process is 1.6 meters, the time is 3-6 minutes, and 200kg of lime (3 kg/ton steel) is added into the converter 4 minutes after blowing; the lance position in the process is 1.0 meter, the time is 11-13 minutes, and the oxygen supply intensity in one minute before blowing is finished is 3.1Nm³The/min/t is increased to 3.3Nm³At/min/t, 50kg of light-burned dolomite was added at 12 minutes and 35 seconds.

And (3) furnace reversing operation: when the lance is lifted and the slag is poured to 6600mm height, the oxygen lance is blown by nitrogen for 7 seconds and then poured into the furnace, and N is used₂Blowing and overturning the liquid level of the pressed steel; tilting the furnace body to a 75-degree position after the slag pouring is started, keeping for 4 seconds, then slowly shaking the furnace to a 84-degree position, and pouring out the high-content TiO as soon as possible₂The total amount of the 1/2 slag is used as the slag.

At the converter tapping end point: c: 0.055%, Mn: 0.128%, P: 0.028%, temperature 1665 ℃.

Example 4

The smelting method for the resource production of the converter steel slag provided by the embodiment comprises the following steps:

the molten iron condition is as follows: c: 6.80 percent; si: 0.70 percent; mn: 0.66 percent; p: 0.15 percent; s: 0.07 percent; ti: 0.16 percent; cr: 0.14 percent; v: 0.07 percent; temperature: 1340 deg.c.

A converter charging system: 60.2 tons of molten iron and 15.9 tons of scrap steel, wherein the ratio of the scrap steel is 21 percent.

And (3) converter operation: the first stage uses 3.1Nm³Blowing with the oxygen supply intensity of/min/t, wherein the blowing gun position is 1.6 meters, the process gun position is 1.6-0.90 meters, and the time is 0-3 minutes. After the start of the blowing, 3.1 tons of lime (41 kg/ton of steel) were added to the converter within 1 minute, and the nitrogen flow was 0.1Nm³Min/t; the lance position in the process is 1.6 meters, the time is 3-6 minutes, and 0.2 ton of lime (1.5 kg/ton of steel) and 600kg of coke are added into the converter 4 minutes after blowing; the lance position in the process is 1.0 meter, the time is 11-13 minutes, and the oxygen supply intensity in one minute before blowing is finished is 3.1Nm³The/min/t is increased to 3.3Nm³At/min/t, 50kg of light-burned dolomite was added at 12 minutes and 30 seconds.

And (3) furnace reversing operation: when the lance is lifted and the slag is poured to the height of 7000mm, the oxygen lance is blown by nitrogen for 8 seconds and then is poured out, and N is used₂Blowing and overturning the liquid level of the pressed steel; tilting the furnace body to a 75-degree position after the slag pouring is started, keeping for 3 seconds, then slowly shaking the furnace to a 84-degree position, and pouring out the high-content TiO as soon as possible₂The total amount of the 2/3 slag is used as the slag.

At the converter tapping end point: c: 0.035%, Mn: 0.152%, P: 0.027%, temperature 1670 ℃.

Comparative example 1

The smelting method provided by the comparative example comprises the following steps:

the molten iron condition is as follows: c: 6.20 percent; si: 0.57 percent; mn: 0.61%; p: 0.14 percent; s: 0.06 percent; ti: 0.12 percent; cr: 0.13 percent; v: 0.06 percent; temperature: 1366 ℃.

A converter charging system: 58.5 tons of molten iron and 16.5 tons of scrap steel, and the ratio of the scrap steel is 22 percent.

And (3) converter operation: the first stage uses 3.1Nm³Blowing with the oxygen supply intensity of/min/t, wherein the blowing gun position is 1.6 meters, the process gun position is 1.6-0.90 meters, and the time is 0-3 minutes. 3120kg of lime (40 kg/ton steel) were added to the converter within 1 minute after the start of the blowing, and the flow rate of the nitrogen under bottom-blowing was 0.1Nm³Min/t; the lance position in the process is 1.6 meters, the time is 3-6 minutes, and 200kg of lime (3 kg/ton steel) is added into the converter 4 minutes after blowing; the gun position in the process is 1.0 meter, the time is 11-13 minutes, and 50kg of light-burned dolomite is added when the time is 12 minutes and 35 seconds.

And (3) furnace reversing operation: when the lance is lifted and the slag is poured to 6600mm height, the oxygen lance is blown by nitrogen for 7 seconds and then poured into the furnace, and N is used₂Blowing and overturning the liquid level of the pressed steel; tilting the furnace body to a 75-degree position after the slag pouring is started, keeping for 4 seconds, then slowly shaking the furnace to a 84-degree position, and pouring out the high-content TiO as soon as possible₂The total amount of the 1/2 slag is used as the slag.

At the converter tapping end point: c: 0.055%, Mn: 0.128%, P: 0.028%, temperature 1665 ℃.

Comparative example 2

The smelting method for the resource production of the converter steel slag provided by the embodiment comprises the following steps:

the molten iron condition is as follows: c: 6.20 percent; si: 0.57 percent; mn: 0.61%; p: 0.14 percent; s: 0.06 percent; ti: 0.12 percent; cr: 0.13 percent; v: 0.06 percent; temperature: 1366 ℃.

A converter charging system: 58.5 tons of molten iron and 16.5 tons of scrap steel, and the ratio of the scrap steel is 22 percent.

And (3) converter operation: the first stage uses 3.1Nm³Blowing with the oxygen supply intensity of/min/t, wherein the blowing gun position is 1.6 meters, the process gun position is 1.6-0.90 meters, and the time is 0-3 minutes. Within 1 minute after blowing3120kg of lime (40 kg/ton steel) were added to the converter, and the flow of nitrogen was 0.1Nm³Min/t; the lance position in the process is 1.6 meters, the time is 3-6 minutes, and 200kg of lime (3 kg/ton steel) is added into the converter 4 minutes after blowing; the lance position in the process is 1.0 meter, the time is 11-13 minutes, and the oxygen supply intensity in two minutes before blowing is finished is 3.1Nm³The/min/t is increased to 3.3Nm³At/min/t, 50kg of light-burned dolomite was added at 12 minutes and 35 seconds.

And (3) furnace reversing operation: when the lance is lifted and the slag is poured to 6600mm height, the oxygen lance is blown by nitrogen for 7 seconds and then poured into the furnace, and N is used₂Blowing and overturning the liquid level of the pressed steel; tilting the furnace body to a 75-degree position after the slag pouring is started, keeping for 4 seconds, then slowly shaking the furnace to a 84-degree position, and pouring out the high-content TiO as soon as possible₂The total amount of the 1/2 slag is used as the slag.

At the converter tapping end point: c: 0.055%, Mn: 0.128%, P: 0.028%, temperature 1665 ℃.

Related experiments:

the converter slags obtained in examples 1 to 4 and comparative examples 1 to 2 were examined and the results are shown in the following table.

From the above table, the content of magnesium oxide in the slag component obtained by smelting by the method provided by the invention is less than 5%, and the content of TFe in the slag is less than 15%; the content of magnesium oxide in the slag is far lower than that in the range of normal slag with the components of 8-12% and the content of TFe in the slag with the components of 18-20%, so that the tailings after the magnetic separation of the components of the steel slag completely meet the component requirements of cement clinker, and meanwhile, the content of TFe in the converter terminal total iron is low, so that the problem of insufficient MgO content in the terminal slag is solved, and the service life of the converter is more than 18000.

One or more technical solutions in the embodiments of the present invention at least have the following technical effects or advantages:

(1) according to the method provided by the embodiment of the invention, the oxygen lance hard blowing process in the first stage is combined with the large oxygen supply flow in the second stage, so that the dephosphorization rate is improved, and the smelting efficiency is improved; the hard blowing operation is adopted in the early stage, so that the desiliconization time of molten iron can be shortened by 1-2 minutes, and the high ferric oxide and the physical heat of the previous furnace are added, so that the slag is activated, and the dephosphorization and titanium removal capability of the slag is improved;

(2) the method provided by the embodiment of the invention adopts larger bottom blowing flow, so that the steel slag can be fully contacted, and good dynamic conditions are provided for dephosphorization;

(3) according to the method provided by the embodiment of the invention, the slag pressing operation is carried out after smelting is finished, so that the separation of iron beads on the interface of steel and slag is promoted as soon as possible;

(4) the content of magnesium oxide in the converter slag component produced by the method provided by the embodiment of the invention is less than 5%, and the content of TFe in the slag is less than 15%; the content of magnesium oxide is far lower than that of normal slag by 8-12%, and the content of TFe in the slag is 18-20%, so that the tailings after magnetic separation of steel slag components completely meet the component requirements of cement clinker; the converter terminal full-iron TFe low-content control strategy makes up the problem of insufficient MgO content in the final slag, ensures that the slag has high viscosity, takes dicalcium silicate and tricalcium silicate as main phases in a slag splashing layer, ensures that the slag is splashed, adhered and resistant to corrosion, and ensures that the converter is more than 18000;

(5) the method provided by the embodiment of the invention changes the oxygen supply intensity from 3.0Nm at the final stage of blowing³The/min/t is increased to 3.3Nm³And the total iron content of the slag can be lower than 15% by pressing the gun for 30 seconds per min/t, and the service life of the furnace can be ensured not to be shortened under the condition that the content of magnesium oxide is reduced and the slag meets the requirement of cement.

Finally, it should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.