阅读说明：本技术 一种铝酸盐渣系及其造渣方法、冶炼方法 (Aluminate slag system and slagging method and smelting method thereof ) 是由 吕学伟 严志明 庞正德 凌家伟 蒋宇阳 徐健 游洋 游志雄 向俊一 于 2021-09-17 设计创作，主要内容包括：本发明提供了一种铝酸盐渣系及其造渣方法、冶炼方法,所述造渣方法包括控制成渣区间以获取满足要求的铝酸盐渣系,在造渣过程中,以Al-(2)O-(3)代替硅酸盐渣系中的SiO-(2)并控制Al-(2)O-(3)的含量超过SiO-(2)含量或者与SiO-(2)的含量相当,使所述铝酸盐渣系中的Al-(2)O-(3)≥20.00％,控制所述铝酸盐渣系的熔化性温度小于1450℃；控制铝酸盐渣系在温度高于1450℃时的粘度小于5.0dPa·s；控制铝酸盐渣系在温度高于1450℃时的密度为2.5～2.8g/cm～(3)；控制所述铝酸盐渣系在1450℃以上时的硫容量为2.0～8.0×10～(-4)；控制所述铝酸盐渣系在1500±20℃时的表面张力为500～540mN/m；控制炉渣的二元碱度CaO/SiO-(2)为1.5～2.00。根据本发明的铝酸盐渣系能够满足炉渣流动性能、脱硫性能及渣铁分离特性,并且能够避开高硅高铝型的高熔点物相成渣区域。(The invention provides an aluminate slag system, a slagging method and a smelting method thereof, wherein the slagging method comprises the steps of controlling a slagging interval to obtain the aluminate slag system meeting the requirements, and using Al in the slagging process 2 O 3 Replacing SiO in silicate slag system 2 And controlling Al 2 O 3 In excess of SiO 2 In an amount of or with SiO 2 The content of the aluminum oxide is equivalent to that of the aluminum oxide slag system 2 O 3 The melting temperature of the aluminate slag system is controlled to be less than 1450 ℃; controlling the viscosity of the aluminate slag system to be less than 5.0dPa & s when the temperature is higher than 1450 ℃; controlling the density of the aluminate slag system to be 2.5-2.8 g/cm when the temperature is higher than 1450 DEG C 3 (ii) a Controlling the sulfur capacity of the aluminate slag to be 2.0-8.0 x 10 at 1450 deg.C or higher ‑4 (ii) a Controlling the surface tension of the aluminate slag system to be 500-540 mN/m at 1500 +/-20 ℃; control of binary basicity of slag CaO/SiO 2 Is 1.5 to 2.00. The aluminate slag system can meet the requirements of slag flowing property and desulfurationPerformance and slag-iron separation characteristics, and can avoid a high-melting point substance phase slagging region of a high-silicon high-aluminum type.)

1. The slagging method of the aluminate slag system is characterized in that the slagging method is used for slaggingThe slag method comprises controlling the slagging interval to obtain aluminate slag system meeting the requirement, specifically, Al is used in the slagging process₂O₃Replacing SiO in silicate slag system₂And controlling Al₂O₃In excess of SiO₂In an amount of or with SiO₂The content of the aluminum oxide is equivalent to that of the aluminum oxide slag system₂O₃The melting temperature of the aluminate slag system is controlled to be less than 1450 ℃; controlling the viscosity of the aluminate slag system to be less than 5.0dPa & s when the temperature is higher than 1450 ℃; controlling the density of the aluminate slag system to be 2.5-2.8 g/cm when the temperature is higher than 1450 DEG C³(ii) a Controlling the sulfur capacity of the aluminate slag to be 2.0-8.0 x 10 at 1450 deg.C or higher^-4(ii) a Controlling the surface tension of the aluminate slag system to be 500-540 mN/m at 1500 +/-20 ℃; control of binary basicity of slag CaO/SiO₂Is 1.5 to 2.00.

2. The slagging method of aluminate slag system according to claim 1, wherein the slag comprises the following components in percentage by mass: 30.00 to 42.00 percent of CaO and Al₂O₃≥20.00％，SiO₂18.00 to 30.00 percent, 5.00 to 15.00 percent of MgO and less than 5.00 percent of other components.

3. The slagging process according to claim 1, wherein Al of the slag₂O₃/SiO₂The ratio of the ratio is 1.0 to 1.5.

4. The aluminate slag system is characterized by comprising the following components in percentage by mass:

CaO:30.00～42.00％，

Al₂O₃≥20.00％，

SiO₂:18.00～30.00％，

MgO:5.00～15.00％，

other components less than 5.00%, Al₂O₃In excess of SiO₂In an amount of or with SiO₂In equivalent content of (B), binary basicityCaO/SiO₂1.5 to 2.00;

the aluminate slag system has a melting temperature of less than 1450 deg.C, a viscosity of less than 5.0dPa · s at a temperature higher than 1450 deg.C, a density of 2.5-2.8 g/cm at a temperature higher than 1450 deg.C, and a sulfur capacity of 2.0-8.0 × 10 at a temperature higher than 1450 deg.C^-4The surface tension at 1500 ℃. + -. 20 ℃ is 500 to 540 mN/m.

5. Aluminate slag system according to claim 4, characterized in that Al₂O₃/SiO₂The ratio of the ratio is 1.0 to 1.5.

6. The aluminate slag system of claim 4, wherein the viscosity is measured by a rotating cylinder method, the fusibility temperature data of the aluminate slag system is obtained by a viscosity-temperature curve method, the sulfur content of the aluminate slag system is measured by a slag-iron equilibrium method, the density of the aluminate slag system is measured by a buoyancy method, and the surface tension of the high-alumina slag is measured by a maximum bubble method.

7. The aluminate slag system of claim 6, wherein the rotating cylinder process comprises: adopts analytical pure reagents CaO and SiO₂MgO and Al₂O₃Preparing a sample of the slag, and calibrating instrument constants with silicone oil at room temperature before viscosity testing; when the temperature of the sample is raised to the target temperature of 1420-1500 ℃, and the temperature is kept for more than 30min, measuring the viscosity of the slag, and obtaining the viscosity data of the slag;

the viscosity-temperature curve method comprises the following steps: measuring the viscosity results of the slag at different temperatures by adopting the rotating cylinder method to obtain the corresponding viscosity results at different temperatures; drawing a viscosity-temperature curve chart by adopting the viscosity under the temperature and corresponding temperature conditions, and drawing a 45-degree tangent line on the viscosity-temperature curve to obtain the temperature at a tangent point, namely the meltability temperature of the slag;

the slag-iron balance method comprises the following steps: adopts analytical pure reagents CaO and SiO₂MgO and Al₂O₃Preparing a sample of the slag for testing; root of herbaceous plantAccording to the current blast furnace process parameters, uniformly mixing a slag sample and an iron sample, placing the mixture into a graphite crucible, placing the crucible into a high-temperature furnace, heating to 1500 ℃, keeping the temperature for more than 8 hours, and ensuring that the slag sample and the iron sample are fully reacted to reach balance, wherein the iron sample is added with sulfur with a preset content; after cooling in the furnace, analyzing the sulfur content in the slag sample and the iron sample after the balance experiment, and then calculating to obtain the sulfur capacity of the slag;

the buoyancy method comprises the following steps: using analytical reagents CaO, SiO₂、MgO、Al₂O₃Preparing a sample of the furnace slag for testing, heating the sample in a high-temperature furnace to a target temperature of 1420-1500 ℃, and preserving heat for more than 30min to ensure that the components of the furnace slag and a temperature field in the furnace are balanced; completely immersing a measuring head made of metal molybdenum and hung on the mass sensor into the slag, wherein the buoyancy generated by the slag acts on the measuring head to enable the mass sensor to generate mass difference, and then calculating to obtain the density;

the maximum bubble method includes: adopts analytical pure reagents CaO and SiO₂MgO and Al₂O₃Preparing a sample of the furnace slag for testing, heating the sample in a high-temperature furnace to a target temperature of 1420-1500 ℃, and preserving heat for more than 30min to ensure that the components of the furnace slag are balanced with a temperature field in the furnace; when the test is started, suspending the capillary above the surface of the slag, controlling the air flow rate through a mass flowmeter, and recording the pressure difference value in the capillary in real time through a differential pressure sensor; after the record of the differential pressure sensor is stable, the capillary tube is slowly descended, and when the pressure is suddenly increased, the capillary tube is in contact with the liquid level of the slag; and measuring the maximum pressure at different depths and then calculating the surface tension.

8. The aluminate slag system of claim 7, wherein the iron sample is obtained by placing iron powder, carbon powder, and FeS in a graphite crucible and melting in an induction furnace in a controlled atmosphere, the controlled atmosphere being one or more of an inert atmosphere, a reducing atmosphere, and an oxidizing atmosphere.

9. A smelting method, characterized in that the smelting method comprises: the aluminate slag system is obtained by using high-alumina type iron ore or iron-containing materials containing aluminum oxide as raw materials and carrying out slagging by adopting the slagging method of any one of claims 1 to 3.

10. The smelting method according to claim 9, wherein the smelting method adopts blast furnace ironmaking, and the content of iron in the high-alumina type iron ore is less than 50 percent, Al is contained in the high-alumina type iron ore₂O₃The content is more than 6 percent, and Al₂O₃/SiO₂Up to more than 1.0.

Technical Field

The invention relates to the technical field of iron making, in particular to a slagging method of an aluminate slag system and a steel smelting process comprising the slagging method.

Background

On one hand, with the aggravation of the consumption of high-quality high-grade iron ore resources, the components of the raw materials reach the edge influencing the normal smelting of the blast furnace, and the existing blast furnace slagging system is seriously challenged. On the other hand, the high-alumina iron ore is rich in resource reserves, which account for about 1/6 of the total reserves of the iron ore in the world, and is cheap. For example, the Al in the iron ore exported from Australia currently₂O₃The content has increased and Al in iron ore₂O₃The content will continue to rise. In consideration of the factors of resources, environment, cost and the like, the high-aluminum type iron ore resource is likely to become a main raw material of the steel industry in the future. Aiming at Al in blast furnace slag caused by using high-alumina type iron ore in large quantity₂O₃The content is increased, the existing traditional silicate slag system can not meet the requirements of the physicochemical properties of slag such as viscosity, melting property, density, surface tension, sulfur capacity and the like, and the Al in the blast furnace slag follows₂O₃The increase of the content can cause the problems of the increase of the slag viscosity, the difficult separation of slag and iron, the increase of the energy consumption of a blast furnace and the like.

Disclosure of Invention

In view of the deficiencies in the prior art, it is an object of the present invention to solve one of the problems in the prior art described above. For example, an object of the present invention is to provide a method for slagging in an aluminate slag system and a smelting process using high-alumina type iron ore as a raw material and using the slagging method.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention provides a slagging method of an aluminate slag system, which comprises the step of controlling a slagging interval to obtain the aluminate slag system meeting the requirement, in particular to Al in the slagging process₂O₃Replacing SiO in silicate slag system₂And controlling Al₂O₃In excess of SiO₂In an amount of or with SiO₂The content of the aluminum oxide is equivalent to that of the aluminum oxide slag system₂O₃The melting temperature of the aluminate slag system is controlled to be less than 1450 ℃; controlling the viscosity of the aluminate slag system to be less than 5.0dPa & s when the temperature is higher than 1450 ℃; controlling the density of the aluminate slag system to be 2.5-2.8 g/cm when the temperature is higher than 1450 DEG C³(ii) a Controlling the sulfur capacity of the aluminate slag to be 2.0-8.0 x 10 at 1450 deg.C or higher^-4(ii) a Controlling the surface tension of the aluminate slag system to be 500-540 mN/m at 1500 +/-20 ℃; control of binary basicity of slag CaO/SiO₂Is 1.5 to 2.00.

According to an exemplary embodiment of the slagging method of an aluminate slag system of the present invention, the slag may have a composition, in mass percent, of: 30.00 to 42.00 percent of CaO and Al₂O₃≥20.00％，SiO₂18.00 to 30.00 percent, 5.00 to 15.00 percent of MgO and less than 5.00 percent of other components.

According to an exemplary embodiment of the slagging process of an aluminate slag system according to the present invention, the Al of the slag₂O₃/SiO₂The ratio of the ratio may be 1.0 to 1.5.

The invention also provides an aluminate slag system, which comprises the following components in percentage by mass: 30.00 to 42.00 percent of CaO and Al₂O₃≥20.00％，SiO₂:18.00～30.00％，5.00-15.00% of MgO, less than 5.00% of other components, and Al₂O₃In excess of SiO₂In an amount of or with SiO₂Has equivalent content of CaO/SiO in binary alkalinity₂1.5 to 2.00; the aluminate slag system has a melting temperature of less than 1450 deg.C, a viscosity of less than 5.0dPa · s at a temperature higher than 1450 deg.C, a density of 2.5-2.8 g/cm at a temperature higher than 1450 deg.C, and a sulfur capacity of 2.0-8.0 × 10 at a temperature higher than 1450 deg.C^-4The surface tension at 1500 ℃. + -. 20 ℃ is 500 to 540 mN/m.

According to an exemplary embodiment of the aluminate slag system of the present invention, Al₂O₃/SiO₂The ratio of the ratio may be 1.0 to 1.5.

According to an exemplary embodiment of the aluminate slag system of the present invention, the viscosity may be measured using a rotating cylinder method, the fusibility temperature data of the aluminate slag system may be obtained using a viscosity-temperature curve method, the sulfur content of the aluminate slag system may be measured using a slag-iron equilibrium method, the density of the aluminate slag system may be measured using a buoyancy method, and the surface tension of the high-alumina slag may be measured using a maximum bubble method.

According to an exemplary embodiment of the aluminate slag system of the present invention, the rotating cylinder process may comprise: adopts analytical pure reagents CaO and SiO₂MgO and Al₂O₃Preparing a sample of the slag, and calibrating instrument constants with silicone oil at room temperature before viscosity testing; and when the temperature of the sample is raised to the target temperature of 1420-1500 ℃, keeping the temperature for more than 30min, starting to measure the viscosity of the slag, and obtaining the viscosity data of the slag.

According to an exemplary embodiment of the aluminate slag system of the present invention, the viscosity temperature profile method may comprise: measuring the viscosity results of the slag at different temperatures by adopting the rotating cylinder method to obtain the corresponding viscosity results at different temperatures; and drawing a viscosity-temperature curve chart by adopting the viscosity under the temperature and the corresponding temperature condition, and drawing a 45-degree tangent line on the viscosity-temperature curve to obtain the temperature at the tangent point, namely the meltability temperature of the slag.

An exemplary embodiment of an aluminate slag system according to the present inventionThe slag-iron balance method may include: adopts analytical pure reagents CaO and SiO₂MgO and Al₂O₃Preparing a sample of the slag for testing; according to the current blast furnace process parameters, uniformly mixing a slag sample and an iron sample, placing the mixture into a graphite crucible, placing the crucible into a high-temperature furnace, heating to 1500 ℃, keeping the temperature for more than 8 hours, and ensuring that the slag sample and the iron sample are fully reacted to reach balance, wherein sulfur with a preset content is added into the iron sample; after cooling in the furnace, analyzing the sulfur content in the slag sample and the iron sample after the balance experiment, and then calculating to obtain the sulfur capacity of the slag;

according to an exemplary embodiment of the aluminate slag system of the present invention, the buoyancy process may comprise: using analytical reagents CaO, SiO₂、MgO、Al₂O₃Preparing a sample of the furnace slag for testing, heating the sample in a high-temperature furnace to a target temperature of 1420-1500 ℃, and preserving heat for more than 30min to ensure that the components of the furnace slag and a temperature field in the furnace are balanced; and completely immersing a measuring head made of metal molybdenum and hung on the mass sensor into the slag, wherein the buoyancy generated by the slag acts on the measuring head to cause the mass sensor to generate mass difference, and then calculating to obtain the density.

According to an exemplary embodiment of the aluminate slag system of the present invention, the maximum bubble method may comprise: adopts analytical pure reagents CaO and SiO₂MgO and Al₂O₃Preparing a sample of the furnace slag for testing, heating the sample in a high-temperature furnace to a target temperature of 1420-1500 ℃, and preserving heat for more than 30min to ensure that the components of the furnace slag are balanced with a temperature field in the furnace; when the test is started, suspending the capillary above the surface of the slag, controlling the air flow rate through a mass flowmeter, and recording the pressure difference value in the capillary in real time through a differential pressure sensor; after the record of the differential pressure sensor is stable, the capillary tube is slowly descended, and when the pressure is suddenly increased, the capillary tube is in contact with the liquid level of the slag; and measuring the maximum pressure at different depths and then calculating the surface tension.

According to an exemplary embodiment of the aluminate slag system of the present invention, the iron sample is obtained by placing iron powder, carbon powder and FeS in a graphite crucible and melting in an induction furnace of controlled atmosphere, which is one or more of inert atmosphere, reducing atmosphere and oxidizing atmosphere.

In yet another aspect, the present invention provides a smelting process, comprising: the aluminate slag system is obtained by using high-alumina iron ore or iron-containing materials containing aluminum oxide as raw materials and carrying out slagging by adopting the slagging method.

According to an exemplary embodiment of the smelting method of the present invention, the smelting method may employ blast furnace iron making. The content of iron in the high-aluminum iron ore is lower than 50 percent, and Al is contained in the high-aluminum iron ore₂O₃The content is more than 6 percent, and Al₂O₃/SiO₂Up to more than 1.0.

Compared with the prior art, the method for smelting iron by utilizing the high-aluminum slag system has the beneficial effects that:

1) the invention can meet the requirements of the smooth operation of the blast furnace on the flow property of the slag, the desulfurization property and the slag-iron separation, and has great significance for the large-scale application of high-aluminum type iron ore resources to blast furnace iron making.

2) The high-aluminum slag system slag can avoid a high-silicon high-aluminum type high-melting point matter phase slagging region, and the physicochemical property of the high-aluminum slag system slag not only meets the smooth running requirement of a blast furnace, but also is even superior to that of the traditional silicate slag system.

3) The method determines a new slagging interval suitable for blast furnace operation in the high-aluminum slag system, has feasibility in both slag-iron separation and molten iron quality analysis, and can provide theoretical support for expanding the range of novel blast furnace raw materials in the future.

4) The invention can increase the usage amount of low-cost high-aluminum iron ore resources and reduce the cost of blast furnace charging raw materials, thereby reducing the blast furnace iron-making cost.

Drawings

The above and other objects and features of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings, in which:

fig. 1 shows a thermodynamic phase diagram of slag obtained by a slagging process of an aluminate slag system according to an exemplary embodiment of the present invention.

Description of reference numerals:

100-slagging interval of common blast furnace, 200-slagging interval of aluminate system.

Detailed Description

Hereinafter, the slagging method of the aluminate slag system and the smelting process using the high-alumina type iron ore as a raw material and adopting the slagging method according to the present invention will be described in detail with reference to the accompanying drawings and exemplary embodiments. In the present invention, the percentage data referred to generally refer to the mass percentage content.

The invention provides an aluminate slag system slagging process suitable for blast furnace iron making of high-alumina iron ore resources, which is characterized in that blast furnace slagging is carried out by utilizing the idea of replacing silicon with aluminum, a slagging interval is determined in the aluminate slag system, and the slagging interval can be suitable for the blast furnace iron making process of the high-alumina iron ore resources.

Specifically, the invention provides a slagging method of an aluminate slag system, which comprises the step of controlling a slagging interval to obtain the aluminate slag system meeting the requirement, specifically, Al is used in the slagging process₂O₃Replacing SiO in silicate slag system₂And controlling Al₂O₃In excess of SiO₂In an amount of or with SiO₂The content of the aluminum oxide is equivalent to that of the aluminum oxide slag system₂O₃The melting temperature of the aluminate slag system is controlled to be less than 1450 ℃; controlling the viscosity of the aluminate slag system to be less than 5.0dPa & s when the temperature is higher than 1450 ℃; controlling the density of the aluminate slag system to be 2.5-2.8 g/cm when the temperature is higher than 1450 DEG C³(ii) a Controlling the sulfur capacity of the aluminate slag to be 2.0-8.0 x 10 at 1450 deg.C or higher (e.g. 1450-1500 deg.C)^-4(ii) a Controlling the surface tension of the aluminate slag system to be 500-540 mN/m at 1500 +/-20 ℃; control of binary basicity of slag CaO/SiO₂Is 1.5 to 2.00.

Fig. 1 is a diagram of a liquid phase region of slag, in which,represents a liquidus at 1500 ℃;is the liquidus at 1450 ℃. The liquid phase area is in the liquidus line, and the slag with the components in the liquid phase area at 1450 ℃ or 1500 ℃ can be completely melted into liquid state. Blast furnace smelting requires that slagging is carried out in a liquid phase region, otherwise, slag is not melted, and blast furnace smelting cannot be smoothly carried out.

As shown in FIG. 1, the thermodynamic phase diagram of slag is found for CaO-SiO₂-Al₂O₃The MgO system with Al₂O₃The slag with increasing content can separate out high-melting-point phase in a high-aluminum high-silicon area, so that the problems of increased viscosity of the slag, difficult separation of the slag from molten iron, weakened desulphurization capability and increased energy consumption of a blast furnace are caused, and the problems are directly related to the viscosity, melting temperature, sulfur capacity and surface tension of the slag.

The invention avoids the high-melting point material phase slagging region of high aluminum and high silicon and finds a high aluminum slag system slagging region. The viscosity of the aluminate slag system in the slagging interval is less than 5.0dPa.s when the temperature is higher than 450 ℃; the melting temperature is less than 1450 ℃, and the melting temperature of the aluminate slag system can be reduced in the slagging interval to reduce smelting energy consumption.

The desulfurization performance of the slag is quantified by the sulfur capacity of the slag, and the sulfur capacity of the aluminate slag system is 2.0-8.0 multiplied by 10 at 1450 DEG C^-4And (3) a range. The desulfurization performance of the slag is improved under the aluminate slag system, S in the molten iron can be better removed, and the aim of improving the quality of the molten iron is fulfilled.

The slag-iron separation characteristics of the slagging interval comprise slag density and surface tension, the surface tension of the aluminate slag system according to the invention is in the range of 500-550 mN/m at 1500 ℃, and the density of the aluminate slag system is in the range of 2.5-2.8 g/cm at temperatures above 1450 ℃³And (3) a range.

The slagging method of the aluminate slag system is different from the traditional silicate slag system slagging, and is mainly embodied in Al in the slag of the aluminate slag system₂O₃The content exceeds SiO₂The contents or the contents are equivalent. Al in traditional silicate slag system slag₂O₃The content is less than 16.00 percent; however according to the presentAl in aluminate slag system of the invention₂O₃The content exceeds 20.00%.

Wherein, the slag comprises the following components by mass percent: 30.00 to 42.00 percent of CaO and Al₂O₃≥20.00％，SiO₂18.00 to 30.00 percent, 5.00 to 15.00 percent of MgO and less than 5.00 percent of other components.

For example, the slag may have the following composition in mass percent: 30.00 to 39.50 percent of CaO and Al₂O₃≥20.00％，SiO₂18.00 to 30.00 percent, 5.00 to 6.95.00 percent of MgO and less than 5.00 percent of other components.

Al in slag in slagging zone₂O₃/SiO₂The ratio of the ratio may be 1.0 to 1.5. For example, Al₂O₃/SiO₂The mass fraction percentage can be 1.08, and correspondingly, Al in the slag₂O₃The content may be 26.00% SiO₂The content may be 24.00%; al (Al)₂O₃/SiO₂The mass fraction percentage can be 1.27, corresponding to Al in the slag₂O₃The content may be 28.00% SiO₂The content may be 22.00%; al (Al)₂O₃/SiO₂The mass fraction percentage can be 1.50, corresponding to Al in the slag₂O₃The content may be 30.00% SiO₂The content may be 20.00%.

Binary basicity (CaO/SiO) of slag in slagging zone₂) Can be in the range of 1.5 to 2.00. For example, the binary basicity (CaO/SiO) of the slag in the slagging compartment₂) Can be 1.67, and the content of CaO in the corresponding slag can be 40.00 percent and SiO₂The content may be 24.00%; binary basicity (CaO/SiO) of slag in slagging zone₂) May be 1.82, corresponding to a CaO content of 40.00% in the slag, SiO₂The content may be 22.00%; binary basicity (CaO/SiO) of slag in slagging zone₂) Can be 2.00, and the corresponding CaO content in the slag can be 40.00 percent and SiO₂The content may be 20.00%.

The slag system viscosity of the aluminate slag system is lower than 5.0dPa.s from the aspect of slag-iron separation; a meltability temperature of less than 1450 ℃; the aluminum isThe surface tension of the acid salt slag system is larger than that of the traditional slag system, and the density can be in the range of 2.50-2.80 g/cm³The method is beneficial to slag-iron separation and meets the requirement of the blast furnace on slag-iron separation.

From the investigation of the desulfurization capability of the slag, compared with the traditional slag, the aluminate slag system has higher sulfur capacity, and under the condition that the fluidity of the slag has no obvious difference (namely, the dynamic condition of the slag desulfurization has no obvious change), the thermodynamic condition of the slag desulfurization is improved, the slag can be promoted to absorb harmful elements S in molten iron, and the requirement of blast furnace smelting on the desulfurization capability of the blast furnace slag is met.

According to the invention, Al is increased during the slagging process of a blast furnace₂O₃The content is reduced simultaneously₂And (4) realizing slagging by replacing silicon with aluminum. The slagging method is suitable for the blast furnace ironmaking process of the high-aluminum iron ore resource, and the 'aluminum substituted silicon' is equal-mass substitution instead of equimolar substitution for fitting production.

The scheme of replacing silicon with aluminum for slagging can be applied to the blast furnace smelting slagging process, and is further applied to the blast furnace ironmaking process of high-aluminum iron ore resources. However, the present invention is not limited thereto, and is also applicable to non-blast furnace smelting processes.

The method aims to solve the problems of viscosity increase of the slag, difficult slag-iron separation, reduction of desulfurization capacity and increase of slag energy consumption. In another aspect of the present invention, there is provided a smelting process, comprising: the aluminate slag system is obtained by using high-alumina iron ore or iron-containing materials containing aluminum oxide as raw materials and carrying out slagging by adopting the slagging method.

The smelting method can be a steel smelting method, and is suitable for the process of using the high-aluminum iron ore for smelting steel in a blast furnace or a non-blast furnace, so that the high-aluminum iron ore resources comprise Al-containing Al such as blast furnace dust removal ash and the like₂O₃The metallurgical solid waste is efficiently utilized, and the energy-saving emission-reducing and metallurgical green development of the blast furnace is promoted.

In one exemplary embodiment, a steel making process includes the steps of:

high-aluminium iron ore is sent into a blast furnace for smelting, and the smelting temperature interval is controlledThe temperature is higher than 1450 ℃, and high-aluminum slag system and iron are obtained after the temperature is stably raised. Among them, the high-alumina type iron ore is a typical complex and difficult-to-handle iron ore, and the iron grade in the ore is low (generally less than 50%), Al₂O₃High content (generally more than 6 percent), high ratio of aluminum to silicon, and can reach more than 1.0 (Al under the conventional condition)₂O₃/SiO₂＜1)。

In the smelting process, Al in the high-aluminum slag system₂O₃/SiO₂The mass fraction percentage of the catalyst can be controlled to be 1.0-1.5, and the catalyst has binary alkalinity (CaO/SiO)₂) Can be controlled to be 1.5 to 2.00, and the viscosity of the generated high-aluminum slag system can be controlled to be less than 5.0dPa.s, and the density can be controlled to be 2.5 to 2.8g/cm³The surface tension can be in the range of 500 to 540mN/m, and the sulfur capacity can be in the range of 2.0 to 8.0 x 10^-4. The melting temperature of the high-aluminum slag system can be controlled to be less than 1450 ℃.

The mass percentage of the main components of the high-alumina slag system can be controlled to be 30.00-42.00% of CaO and Al₂O₃:20.00～32.00％，SiO₂:18.00～30.00％，MgO:5.00～15.00％。

According to the invention, the physicochemical properties of the slag can also be obtained by using appropriate measurement methods, for example, the viscosity of the high-alumina slag is measured by using a rotating cylinder method, the melting temperature data of the high-alumina slag is obtained by using a viscosity-temperature curve method, the sulfur content of the slag is measured by using a slag-iron balance method, the density of the high-alumina slag is measured by using a buoyancy method, and the surface tension of the high-alumina slag is measured by using a maximum bubble method. The specific implementation conditions are as follows:

(1) obtaining slag viscosity data

The viscosity can be measured by a rotating cylinder method, and specifically, the method can comprise the following steps: using analytical reagent (CaO, SiO)₂、MgO、Al₂O₃) Preparing a sample of the slag for testing and calibrating the instrument constants with three silicone oils of 0.96 poise, 4.92 poise and 9.80 poise at room temperature before viscosity testing; and when the temperature of the sample is raised to the target temperature of 1420-1500 ℃, keeping the temperature for a certain time (for example, more than 30 minutes), starting to measure the viscosity of the slag, and acquiring the viscosity data of the slag.

To ensure the reliability of the experimental results, multiple (e.g., three) replicates were performed.

(2) Obtaining slag meltability temperature data

The method can adopt a viscosity-temperature curve method to obtain the meltability temperature data of the aluminate slag system, and specifically comprises the following steps: measuring the viscosity results of the slag at different temperatures by adopting the rotating cylinder method to obtain the corresponding viscosity results at different temperatures; and drawing a viscosity-temperature curve chart by adopting the viscosity under the temperature and the corresponding temperature condition, and taking the tangent point temperature value of a tangent line of 45 degrees as the meltability temperature.

(3) Obtaining sulfur capacity data

The sulfur content of the aluminate slag system can be measured by adopting a slag-iron balance method, and the method specifically comprises the following steps: adopts analytical pure reagents CaO and SiO₂MgO and Al₂O-disposition test samples of the slag; based on the blast furnace smelting field data of the vanadium titano-magnetite, a slag sample and an iron sample can be uniformly mixed according to a certain mass ratio (for example, the slag-iron ratio can be 0.25-0.5, namely 100g of pig iron and 25-50 g of slag) and then placed in a graphite crucible, the crucible is placed in a high-temperature furnace, the temperature is raised to 1500 ℃, the constant temperature is kept for more than 8 hours, the sufficient reaction of the slag sample and the iron sample is ensured to tend to balance, wherein the iron sample is added with a predetermined content of sulfur, and the sulfur content in the iron sample can be 0.46-0.60%; and after cooling in the furnace, analyzing the sulfur content in the slag sample and the iron sample, and calculating and obtaining the sulfur capacity.

The iron sample can be obtained by placing iron powder, carbon powder and FeS in a graphite crucible and melting in an induction furnace with a controllable atmosphere. The controllable atmosphere is one or more of inert atmosphere, reducing atmosphere and oxidizing atmosphere.

(4) Obtaining slag density data

The density of the aluminate slag system can be measured by adopting a buoyancy method, and the method specifically comprises the following steps: using analytical reagent (containing CaO and SiO)₂、MgO、Al₂O₃) Preparing a sample of the furnace slag for testing, heating the sample in a high-temperature furnace to a target temperature of 1420-1500 ℃, and preserving heat for more than 30min to ensure that the components of the furnace slag and a temperature field in the furnace are balanced;

and completely immersing the molybdenum measuring head hung on the mass sensor into the slag, wherein the buoyancy generated by the slag acts on the measuring head to cause the mass difference of the mass sensor, and then calculating to obtain the density.

(5) Obtaining surface tension data

The method for measuring the surface tension of the high-alumina slag by adopting the maximum bubble method specifically comprises the following steps:

adopts analytical pure reagents CaO and SiO₂MgO and Al₂O, preparing a sample of the furnace slag for testing, heating the sample in a high-temperature furnace to a target temperature of 1420-1500 ℃, and preserving heat for more than 30min to ensure that the components of the furnace slag are balanced with a temperature field in the furnace; when the experiment is started, suspending the capillary above the surface of the slag, controlling the air flow rate through a mass flowmeter, recording the pressure difference value in the capillary in real time through a differential pressure sensor, and controlling the air flow rate to be about 10 bubbles per minute; after the record of the differential pressure sensor is stable, the capillary tube is slowly descended, and when the pressure is increased in magnitude, the capillary tube is in contact with the liquid level of the slag; the maximum pressure at different depths is determined taking into account the melt surface disturbance phenomena, and the surface tension is then calculated.

To ensure the reliability of the experimental results, multiple (e.g., three) replicates were performed.

The aluminate slag system according to the exemplary embodiment of the present invention proposes a new slagging interval based on the aluminate slag system based on the measurement result of the physicochemical property of the slag: (30-42 wt.%) CaO- (20-32 wt.%) Al₂O₃-(18～30wt.％)SiO₂- (5-15 wt.%) MgO, combined with the requirements of blast furnace operation, predicts the physicochemical properties of the slag, and discusses the feasibility of aluminate slagging intervals from the aspects of slag-iron separation and pig iron S content.

Wherein, the slag viscosity is measured by adopting a rotating cylinder method, and the method comprises the following steps: test samples were prepared with analytically pure reagents and instrument constants were calibrated with three silicone oils of 0.96 poise, 4.92 poise and 9.80 poise at room temperature prior to viscosity testing. And when the sample is heated to the target temperature and is kept warm for a certain time, measuring the viscosity of the slag to obtain the viscosity data of the slag. In order to ensure the reliability of the experimental results, repeated experiments are carried out for a plurality of times.

Obtaining the data of the meltability temperature of the slag by adopting a viscosity-temperature curve method, and the method comprises the following steps: and preparing a test sample by adopting an analytically pure reagent, and measuring the viscosity results of the slag at different temperatures to obtain a series of corresponding viscosity results at different temperatures. And then, plotting the viscosity-temperature result to obtain a viscosity-temperature curve, and taking a tangent point temperature value of a tangent line of 45 degrees as meltability temperature data.

The method for measuring the sulfur content of the furnace slag by adopting a slag-iron balance method comprises the following steps: an analytical reagent is adopted to prepare a test sample, iron samples for experiments are iron powder, carbon powder and FeS, the iron samples are melted in an induction furnace with controllable atmosphere through a graphite crucible, and the sulfur content of the prepared iron sample is 0.462%. Uniformly mixing a slag sample and an iron sample according to a slag-iron ratio of 0.36(100g of molten iron and 36g of slag), placing the mixture into a graphite crucible, placing the crucible into a high-temperature furnace, heating to 1500 ℃, keeping the temperature for 8 hours, and ensuring that the two are fully reacted and tend to balance. And then cooling the test sample in the furnace, analyzing the sulfur content in the slag sample and the iron sample, and calculating and obtaining the sulfur capacity of the slag.

The method for measuring the slag density by adopting a buoyancy method comprises the following steps: and preparing a test sample by adopting an analytically pure reagent, heating the sample in a high-temperature furnace to a target temperature, and preserving the temperature for 30min to ensure that the components of the slag and a temperature field in the furnace are balanced. And a molybdenum measuring head hung on the mass sensor is completely immersed in the slag, the buoyancy generated by the slag acts on the measuring head to enable the mass sensor to generate a mass difference, and then the slag density data is obtained through calculation. And in order to ensure the reliability of the experimental result, repeated experiments are carried out for a plurality of times (three times).

The method for measuring the surface tension of the slag by adopting a maximum bubble method comprises the following steps: and preparing a test sample by adopting an analytically pure reagent, heating the sample in a high-temperature furnace to a target temperature, and preserving the temperature for 30min to ensure that the components of the slag and a temperature field in the furnace are balanced. When an experiment is started, suspending a capillary above the surface of slag, controlling the air flow rate through a mass flowmeter, and recording the pressure difference value in the capillary in real time through a differential pressure sensor; the air flow rate was controlled at about 10 bubbles per minute. After the record of the differential pressure sensor is stable, the capillary is slowly descended, and when the pressure is suddenly increased, the capillary is in contact with the slag liquid level. And (4) considering the melt surface disturbance phenomenon, measuring the maximum pressure at different depths in an experiment, and then calculating to obtain the surface tension data of the molten slag. And in order to ensure the reliability of the experimental result, repeated experiments are carried out for a plurality of times (three times).

The invention also provides an aluminate slag system slagging interval which is different from the traditional silicate slag system slagging interval. The slagging interval is Al in the aluminate slag system slagging interval₂O₃With SiO₂The content percentage is equivalent to or even exceeds SiO₂Different from the traditional silicate slag system slagging interval.

In an exemplary embodiment, the aluminate slag system may have a composition, in mass percent: 30.00 to 42.00 percent of CaO and Al₂O₃≥20.00％，SiO₂18.00 to 30.00 percent of MgO, 5.00 to 15.00 percent of MgO, less than 5.00 percent of other components, and binary alkalinity CaO/SiO₂Is 1.5 to 2.00. The aluminate slag system has a melting temperature of less than 1450 deg.C, a viscosity of less than 5.0dPa · s at a temperature higher than 1450 deg.C, a density of 2.5-2.8 g/cm at a temperature higher than 1450 deg.C, and a sulfur capacity of 2.0-8.0 × 10 at a temperature higher than 1450 deg.C^-4The surface tension at 1500 ℃. + -. 20 ℃ is 500 to 540 mN/m.

In order to better understand the above exemplary embodiments of the present invention, a method for smelting iron using a high-alumina slag system is described below with reference to specific examples.

Example 1

In the high-alumina slag system provided by the invention, a group of slag is taken, and the specific components of the group of slag comprise 40.50% of CaO and Al₂O₃:32.00％，SiO₂:18.00％，MgO:9.50％，Al₂O₃/SiO₂The mass fraction percentage is 1.78. The viscosity of the slag is 4.0-7.0 dPas, and the requirement of blast furnace iron making on the viscosity of the slag below 10 dPas is met; the melting temperature of the slag is lower than 1440 ℃ (the ideal range is about 1300-1450 ℃); the sulfur capacity of the slag was 3.5X 10^-4～7.5×10^-4(desirable range is 1.0X 10^-4～3.0×10^-3Nearby); the density of the slag is 2.55-2.65 g/cm³The range (the density of the conventional slag is 2.5-2.7 multiplied by 10)^-3Nearby); the surface tension of the slag is within the range of 510-540 mN/m (the surface tension of the conventional slag is within the range of 500-600 mN/m), and all properties of the slag meet the smelting requirements of the blast furnace.

Example 2

The high-alumina slag system comprises 41.00 percent of CaO and Al₂O₃:29.00％，SiO₂:19.00％，MgO:11.00％，Al₂O₃/SiO₂The mass fraction percentage is 1.53. The viscosity of the slag is 6.65-8.0 dPas; the melting temperature of the slag is lower than 1440 ℃; the sulfur capacity of the slag is about 1.36X 10^-4(ii) a The density of the slag was 2.76g/cm³Nearby; the surface tension of the slag was about 560mN/m, and each slag property was in a suitable range.

Example 3

Taking a group of furnace slag which is not in the high-alumina slag system range provided by the invention, wherein the composition percentage of the furnace slag is that CaO accounts for 45.00 percent, and Al accounts for₂O₃:34.00％，SiO₂:16.00％，MgO:5.00％，Al₂O₃/SiO₂The mass fraction percentage is 0.47. The viscosity of the slag is 30.8 dPas, which is far beyond the proper viscosity range of the slag; the sulfur capacity of the slag was 5.23X 10^-6Too low a value, too weak slag desulfurization ability; in summary, this slag, which is not within the scope of the high-alumina slag system proposed by the present invention, does not meet blast furnace ironmaking requirements.

The above-described respective physicochemical properties of the slag in examples 1 to 3 were measured by the following measurement methods:

(1) obtaining slag viscosity data

Measuring the viscosity of the slag by a rotating cylinder method: test samples were prepared with analytically pure reagents and instrument constants were calibrated with three silicone oils of 0.96 poise, 4.92 poise and 9.80 poise at room temperature prior to viscosity testing. And when the sample is heated to the target temperature and is kept warm for a certain time, measuring the viscosity of the slag to obtain the viscosity data of the slag. And in order to ensure the reliability of the experimental result, repeated experiments are carried out for a plurality of times (three times).

(2) Obtaining slag meltability temperature data

Obtaining slag meltability temperature data by adopting a viscosity-temperature curve method: and preparing a test sample by adopting an analytically pure reagent, and measuring the viscosity results of the slag at different temperatures to obtain a series of corresponding viscosity results at different temperatures. And then, plotting the viscosity-temperature result to obtain a viscosity-temperature curve, and taking a tangent point temperature value of a tangent line of 45 degrees as meltability temperature data.

(3) Obtaining sulfur capacity data

Measuring the sulfur content of the slag by a slag-iron balance method: an analytical reagent is adopted to prepare a test sample, iron samples for experiments are iron powder, carbon powder and FeS, the iron samples are melted in an induction furnace with controllable atmosphere through a graphite crucible, and the sulfur content of the prepared iron sample is 0.462%. Uniformly mixing a slag sample and an iron sample according to a slag-iron ratio of 0.36(100g of pig iron and 36g of slag), placing the mixture into a graphite crucible, placing the crucible into a high-temperature furnace, heating to 1500 ℃, keeping the temperature for 8 hours, and ensuring that the two are fully reacted and tend to balance. And then cooling the test sample in the furnace, analyzing the sulfur content in the slag sample and the iron sample, and calculating and obtaining the sulfur capacity of the slag.

(4) Obtaining slag density data

Measuring the slag density by a buoyancy method: and preparing a test sample by adopting an analytically pure reagent, heating the sample in a high-temperature furnace to a target temperature, and preserving the temperature for 30min to ensure that the components of the slag and a temperature field in the furnace are balanced. And a molybdenum measuring head hung on the mass sensor is completely immersed in the slag, the buoyancy generated by the slag acts on the measuring head to enable the mass sensor to generate a mass difference, and then the slag density data is obtained through calculation. And in order to ensure the reliability of the experimental result, repeated experiments are carried out for a plurality of times (three times).

(5) Obtaining surface tension data

The maximum bubble method measures the slag surface tension: and preparing a test sample by adopting an analytically pure reagent, heating the sample in a high-temperature furnace to a target temperature, and preserving the temperature for 30min to ensure that the components of the slag and a temperature field in the furnace are balanced. When an experiment is started, suspending a capillary above the surface of slag, controlling the air flow rate through a mass flowmeter, and recording the pressure difference value in the capillary in real time through a differential pressure sensor; the air flow rate was controlled at about 10 bubbles per minute. After the record of the differential pressure sensor is stable, the capillary is slowly descended, and when the pressure is suddenly increased, the capillary is in contact with the slag liquid level. And (4) considering the melt surface disturbance phenomenon, measuring the maximum pressure at different depths in an experiment, and then calculating to obtain the surface tension data of the molten slag. And in order to ensure the reliability of the experimental result, repeated experiments are carried out for a plurality of times (three times).

It can be seen that as the Al/Si ratio increases, the slag viscosity tends to decrease first and then increase, and at high Al₂O₃When the slag viscosity is less than 5 dPa.s (20.00-32.00%), the melting temperature of the blast furnace slag is increased and then decreased along with the increase of the ratio of aluminum to silicon, and the melting temperature is reduced when the Al content is high₂O₃(20.00-32.00%) melting temperature is lower than 1500 ℃, and the requirement of blast furnace smooth operation on slag fluidity is met. With Al₂O₃Instead of SiO₂The sulfur capacity of the slag is slightly increased, and the desulfurization capability of the slag is improved. The surface tension of the slag is increased along with the increase of the ratio of aluminum to silicon, which is beneficial to the separation of slag and iron.

The novel high-aluminum iron ore is suitable for being used in a blast furnace iron-making slag system (30-42 wt.%) CaO- (20-32 wt.%) Al₂O₃-(18～30wt.％)SiO₂- (5-15 wt.%) MgO, Al in blast furnace slag composition₂O₃When the mass fraction of the slag exceeds 20.00 percent, a new slag forming interval exists, the physical and chemical properties of the blast furnace slag, such as viscosity, melting temperature, sulfur capacity, surface tension and the like, all meet the requirements of normal blast furnace smelting on the performance of the slag, and part of parameters are even superior to those of the traditional silicate slag system.

From the investigation of the desulfurization capacity of the slag, compared with the traditional slag, the aluminate slag system has higher sulfur capacity, no obvious difference in slag flowability and improved thermodynamic conditions although the desulfurization kinetic conditions are not obviously changed, which shows that the capacity of the slag system for absorbing harmful elements S is enhanced, and the requirement of the blast furnace slag on the desulfurization capacity is met.

Although the present disclosure has been described above in connection with exemplary embodiments and the accompanying drawings, it will be apparent to those of ordinary skill in the art that various modifications may be made to the above-described embodiments without departing from the spirit and scope of the claims.