阅读说明：本技术 半钢炼钢转炉炉内锰矿直接合金化的方法 (Method for directly alloying manganese ore in semisteel steelmaking converter ) 是由 陈均 梁新腾 杨森祥 曾建华 于 2020-05-29 设计创作，主要内容包括：本发明公开了一种半钢炼钢转炉炉内锰矿直接合金化的方法,属于钢铁冶炼技术领域,包括以下步骤：加入造渣材料和锰矿进行一次造渣吹炼,吹炼至碳含量为0.2-0.4％时倒渣；加入造渣材料和锰矿自还原球进行二次造渣吹炼,吹炼至终点碳含量≤0.06％,钢水温度≥1680℃时出钢；所述锰矿自还原球中MnO的含量≥20wt％,MnO与还原剂的重量比为6：1～2。本发明方法采用双渣冶炼,一次造渣脱磷,二次造渣时加入锰矿自还原球进行锰矿自还原,在低碳、高温下具有较高的脱磷率和锰还原率,锰还原率达到了92％以上。(The invention discloses a method for directly alloying manganese ore in a semisteel steelmaking converter, belonging to the technical field of steel smelting and comprising the following steps: adding slagging material and manganese ore to carry out primary slagging blowing, and deslagging when the blowing is carried out until the carbon content is 0.2-0.4%; adding slagging material and manganese ore self-reduction balls to carry out secondary slagging blowing, and tapping when the carbon content is less than or equal to 0.06% and the molten steel temperature is more than or equal to 1680 ℃; the content of MnO in the manganese ore self-reduction ball is more than or equal to 20 wt%, and the weight ratio of MnO to a reducing agent is 6: 1 to 2. The method adopts double-slag smelting, the slag is firstly removed, the phosphorus is removed, the manganese ore self-reduction ball is added during the secondary slag removal to carry out the manganese ore self-reduction, the dephosphorization rate and the manganese reduction rate are higher at low carbon and high temperature, and the manganese reduction rate reaches more than 92 percent.)

1. The method for directly alloying manganese ore in the semi-steel steelmaking converter is characterized by comprising the following steps of: adding slagging material and manganese ore to carry out primary slagging blowing, and deslagging when the blowing is carried out until the carbon content is 0.2-0.4%; adding slagging material and manganese ore self-reduction balls to carry out secondary slagging blowing, and tapping when the carbon content is less than or equal to 0.06% and the molten steel temperature is more than or equal to 1680 ℃; the content of MnO in the manganese ore self-reduction ball is more than or equal to 20 wt%, and the weight ratio of MnO to a reducing agent is 6: 1 to 2.

2. The method for directly alloying manganese ore in the semi-steel steelmaking converter according to claim 1, wherein the manganese ore self-reducing pellet is composed of the following raw materials in parts by weight: manganese ore powder: reducing agent: fluxing agent: adhesive 8-9.5: 0.4-1.5: 0.15-0.2: 0.1-0.15.

3. The method for directly alloying manganese ore in the semisteel steelmaking converter according to claim 1 or 2, characterized in that the particle size of the manganese ore self-reducing pellet is 15-25 mm.

4. The method for directly alloying manganese ore in the semisteel steelmaking converter according to any one of claims 1 to 3, wherein the addition amount of manganese ore from reduction balls is 8 to 15kg/t steel.

5. The method for directly alloying manganese ore in the semisteel steelmaking converter according to any one of claims 1 to 4, wherein the addition amount of manganese ore is 1 to 3kg/t steel in one slagging blowing.

6. The method for directly alloying manganese ore in the semi-steel steelmaking converter according to claim 5, wherein the slagging materials used in the primary slagging blowing are active lime, high-magnesium lime and an acidic composite slagging agent; the adding amount of the active lime is 10-15kg/t steel, the adding amount of the high-magnesium lime is 8-13kg/t steel, and the adding amount of the acid composite slag former is subject to control the alkalinity of the slag to be 3-4.

7. The method of claim 5, wherein the top-blown lance has an oxygen supply strength of 3.0 to 4.0m at the time of primary slagging blowing³Min. t, nitrogen supply intensity of bottom-blown nitrogen gas is 0.04-0.08m³/min·t。

8. The method for directly alloying manganese ore in the semisteel steelmaking converter according to claim 5, wherein the slagging material used in the secondary slagging blowing is active lime, and the addition amount is 1-5kg/t steel.

9. The method of claim 5, wherein the top-blown lance has an oxygen supply strength of 2.0 to 3.0m during the secondary slagging blowing³Min. t, nitrogen supply intensity of bottom-blown nitrogen gas is 0.1-0.2m³/min·t。

10. The method for directly alloying manganese ore in the semisteel steelmaking converter according to claim 5, wherein the reducing agent in the manganese ore self-reduction pellet is selected from more than one of anthracite, coke or aluminum, the fluxing agent is selected from fluorite powder and/or aluminum oxide, and the adhesive is water glass; preferably, the reducing agent is selected from anthracite and the fluxing agent is selected from fluorite powder.

Technical Field

The invention belongs to the technical field of steel smelting, and particularly relates to a method for directly alloying manganese ore in a semi-steel steelmaking converter.

Background

In the steel-making production, manganese is an essential alloying element, and has important effects on improving the quality of steel and the performance of the steel. At present, most iron and steel enterprises perform manganese alloying operation on molten steel by adding ferromanganese alloy in the tapping process or refining process. The manganese series alloy is mainly made of rich manganese ore, which is a high energy consumption and high pollution process, and has high manufacturing cost and great environmental pollution. Therefore, many steel enterprises explore the direct manganese ore alloying process to reduce the alloying cost of the converter.

CN105838843A discloses a technology for applying manganese ore direct alloying to converter steelmaking, the converter steelmaking technology adopts a one-time carbon drawing method, the FeO content of the final slag is 13% -15%, the average smelting period is 12.3min, manganese alloy ore is added into the converter in batches within 4 min-10 min after the start of converter steelmaking, the adding amount of the manganese alloy ore in each converter is as follows: 10-14 kg/ton steel, end point carbon content: c is more than or equal to 0.08 percent; the end point temperature is 1650-1680 ℃, the residual manganese content at the end point is increased by 0.16-0.20 percent, wherein the manganese element content in the manganese alloy ore is at least 44.2 percent by weight. The application is the same as a general manganese ore alloying process, the requirement on TMn in manganese ore is high, the end point molten steel carbon content C is generally required to be more than or equal to 0.08%, and the end point temperature is as low as possible, because the recovery rate of manganese in manganese ore can be obviously reduced when the end point molten steel carbon content is too low or too high, and when the end point molten steel carbon content is reduced, the reaction rate of reduction reaction [ C ] + (MnO) ([ Mn ] + CO) in the manganese ore furnace is obviously reduced under the influence of the activity of carbon [ C ] in molten steel and the mass transfer rate thereof, so that the recovery rate of manganese is lower.

CN110527786A discloses a method for direct alloying steelmaking of converter manganese ore, which adopts a converter double-slag smelting method, adds a slagging material to carry out primary slagging blowing, pulls carbon to release slag after earlier stage dephosphorization, then carries out secondary slagging blowing, adds the slagging material, a temperature raising agent and manganese ore to carry out alloying in the secondary slagging blowing process, and the blowing is carried out until the end point molten steel temperature is 1640 plus 1670 ℃, and tapping is carried out. According to the method, the manganese content of the molten steel at the end point is increased by adding the temperature raising agent, but the temperature raising agent is directly added into a converter, so that part of the temperature raising agent is lost; meanwhile, in order to ensure the manganese content of the end-point molten steel, the carbon content C of the end-point molten steel is required to be more than or equal to 0.08%, and if the carbon content of the end-point molten steel is too low, the manganese recovery rate is also low.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the existing direct manganese ore alloying process has low end point carbon content, high end point molten steel temperature and low manganese recovery rate.

The technical scheme for solving the technical problems comprises the following steps: the method for directly alloying manganese ore in the semi-steel steelmaking converter comprises the following steps: adding slagging material and manganese ore to carry out primary slagging blowing, and deslagging when the blowing is carried out until the carbon content is 0.2-0.4%; adding slagging material and manganese ore self-reduction balls to carry out secondary slagging blowing, and tapping when the carbon content is less than or equal to 0.06% and the molten steel temperature is more than or equal to 1680 ℃; the content of MnO in the manganese ore self-reduction ball is more than or equal to 20 wt%, and the weight ratio of MnO to a reducing agent is 6: 1 to 2.

According to the method for directly alloying the manganese ore in the semi-steel steelmaking converter, the manganese ore self-reduction ball is composed of the following raw materials in parts by weight: manganese ore powder: reducing agent: fluxing agent: adhesive 8-9.5: 0.4-1.5: 0.15-0.2: 0.1-0.15.

In the method for directly alloying the manganese ore in the semi-steel steelmaking converter, the particle size of the manganese ore self-reduction ball is 15-25 mm.

In the method for directly alloying the manganese ore in the semi-steel steelmaking converter, the addition amount of the manganese ore self-reduction ball is 8-15kg/t steel.

According to the method for directly alloying the manganese ore in the semi-steel steelmaking converter, the addition amount of the manganese ore is 1-3kg/t steel during one-time slagging blowing.

In the method for directly alloying manganese ore in the semi-steel steelmaking converter, the slagging material used in primary slagging blowing is active lime, high-magnesium lime and an acidic composite slagging agent; the adding amount of the active lime is 10-15kg/t steel, the adding amount of the high-magnesium lime is 8-13kg/t steel, and the adding amount of the acid composite slag former is subject to control the alkalinity of the slag to be 3-4.

Wherein, in the method for directly alloying manganese ore in the semi-steel steelmaking converter, the oxygen supply intensity of the top blowing lance is 3.0-4.0m during primary slagging blowing³Min. t, nitrogen supply intensity of bottom-blown nitrogen gas is 0.04-0.08m³/min·t。

In the method for directly alloying manganese ore in the semi-steel steelmaking converter, the slagging material used in the secondary slagging blowing is active lime, and the addition amount is 1-5kg/t steel.

Wherein, in the method for directly alloying manganese ore in the semi-steel steelmaking converter, the oxygen supply intensity of the top blowing lance is 2.0-3.0m during the secondary slagging blowing³Min. t, nitrogen supply intensity of bottom-blown nitrogen gas is 0.1-0.2m³/min·t。

In the method for directly alloying the manganese ore in the semi-steel steelmaking converter, the reducing agent in the manganese ore self-reduction ball is selected from more than one of anthracite, coke or aluminum, the fluxing agent is selected from fluorite powder and/or aluminum oxide, and the adhesive is water glass; preferably, the reducing agent is selected from anthracite and the fluxing agent is selected from fluorite powder.

Compared with the prior art, the invention has the beneficial effects that:

the method adopts double-slag smelting, the slag is firstly removed, the phosphorus is removed, the manganese ore self-reduction ball is added during the secondary slag removal to carry out the manganese ore self-reduction, the dephosphorization rate and the manganese reduction rate are higher at low carbon and high temperature, and the manganese reduction rate reaches more than 92 percent.

Detailed Description

Specifically, the method for directly alloying manganese ore in the semi-steel steelmaking converter comprises the following steps: adding slagging material and manganese ore to carry out primary slagging blowing, and deslagging when the blowing is carried out until the carbon content is 0.2-0.4%; adding slagging material and manganese ore self-reduction balls to carry out secondary slagging blowing, and tapping when the carbon content is less than or equal to 0.06% and the molten steel temperature is more than or equal to 1680 ℃; the content of MnO in the manganese ore self-reduction ball is more than or equal to 20 wt%, and the weight ratio of MnO to a reducing agent is 6: 1 to 2.

The manganese ore self-reduction ball is adopted, and reduction is carried out by consuming a reducing agent (carbon) carried by the manganese ore self-reduction ball when the end point molten steel carbon content is lower, so that the influence of the molten steel carbon on the reduction rate is remarkably reduced, and the reduction rate of manganese is further improved.

The main purpose of requiring the MnO content in the manganese ore self-reduction balls to be more than or equal to 20 percent is to reduce the addition amount of the self-reduction balls as far as possible on the premise of improving the end-point molten steel manganese, and if the MnO content in the self-reduction balls is too low, the addition amount is very large, so that converter smelting is influenced, and the method is not economical.

The weight ratio of MnO in the manganese ore self-reduction ball to the reducing agent is 6: 1-2 times, the manganese reduction rate is high and economic; this is because, in this ratio range, it can be ensured that MnO in the manganese ore self-reducing pellet is completely reduced by the reducing agent, and the amount of the reducing agent is not excessive.

The addition amount of the manganese ore self-reduction balls is too small to improve the effect of molten steel manganese at the end point, and the addition amount of the manganese ore self-reduction balls is too large to cause the temperature drop in the converter to be too large and influence the normal smelting of the converter, so the addition amount of the manganese ore self-reduction balls is 8-15kg/t steel.

The particle size of the manganese ore self-reduction ball used in the invention is 15-25mm, and the particle size can ensure that the reduction ball is positioned between molten steel and steel slag after being added into a converter, thereby being beneficial to promoting the manganese reduction reaction. The manganese ore can float on the surface of the steel slag from the reduction ball with the particle size of less than 15mm, so that good melting and reaction effects can not be achieved, and the reduction rate of manganese is reduced; when the particle size is larger than 25mm, the manganese ore self-reduction balls are added from the storage bin to break through steel slag and enter molten steel, so that carbon in the manganese ore self-reduction balls enters the molten steel, the effect of reducing manganese is not achieved, and the manganese reduction rate is reduced.

Preparation of manganese ore self-reduction balls: manganese ore powder with the granularity of less than 200 meshes, a reducing agent, a fluxing agent and a bonding agent are mixed according to the proportion of 8-9.5: 0.4-1.5: 0.15-0.2: mixing at a ratio of 0.1-0.15, pressing into balls, and oven drying.

During primary slagging, manganese ore is added mainly for promoting earlier-stage slagging dephosphorization, and then the MnO content in the slag is increased to improve the manganese reduction rate; if the addition amount of the manganese ore is too small, the effect of promoting slagging and dephosphorization is not achieved; if the addition amount of the manganese ore is too large, slag is over-activated, and splashing accidents are easy to happen. Therefore, the addition amount of the manganese ore is 1-3kg/t steel during primary slagging.

The purpose of reducing the gas supply intensity of the oxygen lance after secondary slagging is to ensure the tapping temperature and carbon, simultaneously reduce the impact depth of oxygen jet flow as much as possible, reduce the burning loss of a reducing agent in a self-reduction ball and improve the reduction rate.

The purpose of improving the bottom blowing gas supply strength after secondary slagging is to enhance the dynamic conditions of the reduction reaction, promote the mass transfer between steel and slag and improve the reduction rate.

The manganese ore comprises the following components in percentage by weight: TMn: 26% -40%, TFe: 6% -9% of SiO₂: 12% -19%, CaO: 11 to 15 percent of the total weight of the alloy, less than or equal to 0.050 percent of P, less than or equal to 0.30 percent of S and the balance of impurities.

In the invention, the active lime, the high-magnesium lime and the acidic composite slagging agent are auxiliary materials commonly used in steelmaking in the field. The active lime mainly contains CaO, and the content of CaO is 85-90 wt% based on the total weight of the active lime. The high-magnesium lime mainly contains MgO and CaO, and the content of the MgO is 30-40 wt% and the content of the CaO is 48-55 wt% based on the total weight of the high-magnesium lime. SiO in the acidic composite slagging agent₂The content is 40-70 wt%, and SiO in the acidic composite slagging agent is preferably₂40-60 wt.% of iron oxide (Fe)₂O₃And FeO) 15 to 20 wt%, CaO 10 to 15 wt%, MgO 3 to 9 wt%, and the balance of small amounts of impurities.

The conventional reducing agent, fluxing agent and adhesive are all suitable for the manganese ore self-reduction balls, but anthracite is most suitable to be used as the reducing agent in view of economy and reduction effect. The reducing agents used in the following examples are all anthracite, and the content of C in the anthracite is more than or equal to 90 wt%; the fluxing agent is fluorite powder; the adhesive is water glass.

The following examples are provided to further illustrate the embodiments of the present invention and are not intended to limit the scope of the present invention.