阅读说明：本技术 一种高铝铁矿粉生产烧结矿的方法 (Method for producing sintered ore from high-alumina iron ore powder ) 是由 韩凤光 邱金龙 谢朝晖 于 2019-11-21 设计创作，主要内容包括：本发明涉及一种高铝铁矿粉生产烧结矿的方法,主要解决现有技术中高铝铁矿粉烧结性能差、烧结配矿配加比例低的技术问题。本发明的技术方案为：一种高铝铁矿粉生产烧结矿的方法,包括：1)配矿,根据烧结矿的技术质量指标计算高铝铁矿粉、低铝超细铁精矿粉、赤铁矿富矿粉、烧结返矿、熔剂和固体燃料的配矿质量比例；2)配制一次混合料；3)制备高铝铁矿粉和低铝超细铁精矿粉预制料球；4)配制烧结综合混匀料；5)将烧结综合混匀料在烧结台车上进行布料,烧结综合混匀料经点火、抽风烧结过程,生产出烧结矿。本发明方法能够有效提高高铝铁矿粉的使用效率,所生产的烧结矿冶金性能优良,工艺简单,成本低。(The invention relates to a method for producing sintered ore from high-alumina iron ore powder, which mainly solves the technical problems of poor sintering performance and low proportion of added sintered ore in the prior art. The technical scheme of the invention is as follows: a method for producing sintered ore by high-alumina iron ore powder comprises the following steps: 1) ore blending, namely calculating the ore blending mass proportion of high-alumina iron ore powder, low-alumina superfine iron ore concentrate powder, hematite rich ore powder, sintering return ores, a flux and solid fuels according to the technical quality indexes of the sintering ores; 2) preparing a primary mixture; 3) preparing prefabricated material balls of high-aluminum iron ore powder and low-aluminum superfine iron concentrate powder; 4) preparing sintering comprehensive mixing materials; 5) distributing the comprehensive sintering and homogenizing material on a sintering trolley, and producing sintered ore through ignition and air draft sintering processes of the comprehensive sintering and homogenizing material. The method can effectively improve the use efficiency of the high-alumina iron ore powder, and the produced sintering ore has excellent metallurgical performance, simple process and low cost.)

1. A method for producing sintered ore by using high-alumina iron ore powder is characterized by comprising the following steps:

1) ore blending, wherein the ore blending mass proportion of the high-alumina iron ore powder, the low-alumina ultrafine iron ore concentrate powder, the hematite rich ore powder, the sintering return ores, the flux and the solid fuel is calculated according to the technical quality indexes of the sintering ores, and the sintering ore blending raw materials comprise the following components in percentage by mass: 10-20% of high-aluminum iron ore powder, 10-15% of low-aluminum superfine iron concentrate powder, 50-80% of hematite rich ore powder, 5-10% of sintered return ores, 8-15% of flux and 4-5% of solid fuel, wherein the sum of the mass percentages of the components is 100%; controlling the mass percentage of MgO in the sintered ore to be 0.8-1.6%, the mass percentage of FeO to be 7.5-8.5% and the alkalinity (CaO/SiO) of the sintered ore₂) 1.7 to 2.1; al in the high-aluminum iron ore powder₂O₃The weight percentage of the high-alumina iron ore powder is 1.5-2.5%, and the high-alumina iron ore powder with the particle size of more than or equal to 1mm accounts for more than 50% of the total mass of the high-alumina iron ore powder; al in low-aluminium superfine iron concentrate powder₂O₃The weight percentage content of the components is less than or equal to 0.4 percent;

2) preparing a primary mixture, weighing the hematite rich mineral powder, the sintering return ores, the flux and the solid fuel according to the ore blending mass proportion of the sintering ores, uniformly mixing the hematite rich mineral powder, the sintering return ores, the flux and the solid fuel by using a primary mixer, adding water in the uniform mixing process, and uniformly mixing for 5-8min to prepare a primary mixture, wherein the mass percentage of the water in the primary mixture is 6.8-7.0%; conveying the primary mixture to a mixing granulator;

3) preparing prefabricated material balls of high-aluminum iron ore powder and low-aluminum superfine iron ore concentrate powder, and adding the high-aluminum iron ore powder, the low-aluminum superfine iron ore concentrate powder, bentonite and water into a disc pelletizer to carry out mixed pelletizing; the high-aluminum iron ore powder and low-aluminum superfine iron ore concentrate powder prefabricated material balls comprise the following components in percentage by mass: 95.5-97.8% of high-alumina iron ore powder, 0.2-1.5% of low-alumina superfine iron concentrate powder, 0.0-3.0% of bentonite and 2.0-3.0% of water;

4) preparing a sintering comprehensive mixed material, adding the primary mixed material mixed by the primary mixer, the high-aluminum iron ore powder and the low-aluminum ultra-fine iron ore concentrate powder prefabricated material balls into a granulator for further mixing granulation, and controlling the moisture according to given moisture parameters; mixing for 5-8min to obtain sintered mixed material;

5) distributing the sintering mixture on a sintering trolley, controlling the thickness of a material layer of the sintering mixture to be 700-1000 mm, producing sintered ore by igniting and exhausting the sintering comprehensive mixture, and controlling the exhaust negative pressure to be 12-16kPa and the ignition temperature to be 1150-1250 ℃ in the sintering process.

2. The method of claim 1, wherein the particle size of the sinter mix is 1-3 mm.

3. The method for producing the sintered ore from the high-alumina iron ore powder as claimed in claim 1, wherein the grain size of the sintered return ore is less than or equal to 5 mm.

4. The method for producing sintered ore from high-alumina iron ore powder according to claim 1, wherein the solid fuel is any one of coke powder, anthracite powder or a mixture of coke powder and anthracite powder; the mass percentage of C in the solid fuel is 77-85%; the solid fuel with the grain diameter less than or equal to 3mm accounts for more than 90 percent of the total mass proportion of the solid fuel.

5. The method for producing the sinter as claimed in claim 1, wherein the flux includes quicklime 41-45 wt%, limestone powder 33-36 wt%, dolomite powder 22-24 wt%; the flux with the grain diameter less than or equal to 3mm accounts for more than 90 percent of the total mass proportion of the flux; the mass percentage of CaO in the quicklime is 80-90%; the mass percentage of CaO in the limestone powder is 50-53%; the dolomite powder comprises 19-22% by mass of MgO and 29-33% by mass of CaO.

Technical Field

The invention relates to a method for producing sintered ore, in particular to a method for producing sintered ore from high-alumina iron ore powder, and specifically relates to Al in the high-alumina iron ore powder₂O₃The weight percentage content of the iron-making raw material is more than or equal to 1.5 percent, and belongs to the technical field of production of sintered ores of iron-making raw materials.

Background

With the gradual depletion of high-quality iron ore resources, steel enterprises have to face the practical situation of using inferior ores. The high-alumina iron ore powder in the poor-quality ore has high iron grade and low price, but the high-alumina content of the high-alumina iron ore powder limits the addition proportion in sintering.

In sintering, the iron ore with the aluminum oxide content exceeding 1.5 percent is generally classified as high-alumina iron ore powder, and the iron ore with the aluminum oxide content exceeding 2.5 percent is generally classified as ultrahigh-alumina iron ore powder.

The aluminum oxide has a high melting point, so that the generation of a sintering liquid phase is not facilitated, and the sintering product quality is not adversely affected. Meanwhile, alumina in the raw materials easily causes deterioration of low-temperature reduction degradation index of the sintered ore, and finally influences the air permeability of the blast furnace. In addition, the increase of the alumina content in the sintered ore causes the increase of the amount of blast furnace slag, thereby causing some problems such as the increase of coke ratio, the increase of molten iron cost, and the like. Because the sintering performance of the high-alumina iron ore powder is poor, the proportion of the high-alumina iron ore powder in the sintering process is generally limited.

Aiming at improving the sintering performance of the high-alumina iron ore powder and increasing the proportion, a great deal of research work is carried out by sintering workers for the purpose of improving the sintering performance of the high-alumina iron ore powder and the proportion, and certain effects are achieved, but the sintering performance of the sintered ore is difficult to effectively improve.

Chinese patent application publication No. CN104694681A discloses a blast furnace smelting method for high-alumina ore, which comprises the steps of determining regulation and control thresholds of Al2O3/SiO2, CaO/SiO2, charging grade, coke thermal state intensity and blast kinetic energy according to a quadratic fitting regression analysis prediction interval by using 'ore blending, charging ore, coke and blast' as basic acquisition parameters, and then adjusting the proportion of sintered ore according to the regulation and control thresholds to ensure stable and smooth operation of a blast furnace. The method mainly separates and feeds the high-alumina iron ore powder into the furnace by screening the high-alumina iron ore powder with different grain sizes, cannot effectively improve the metallurgical performance of the sintered ore, and is irrelevant to the sintering process.

The application publication number is CN109439820A, which discloses a blast furnace smelting raw material and a smelting method thereof, mainly provides a high-aluminum low-magnesium boron-containing blast furnace smelting raw material and a method for carrying out high-aluminum low-magnesium boron-containing blast furnace smelting by using the furnace burden, and belongs to the technical field of blast furnace ore blending.

The Chinese patent application with the application publication number of CN106399608A discloses a method for improving the efficiency of smelting high-alumina iron ore by a blast furnace by utilizing high-reactivity coke, which belongs to the technology in the coking field and is not suitable for the sintering technology of common iron concentrate powder.

In the prior art, because the high-alumina iron ore powder has poor sintering performance, the use proportion of the high-alumina iron ore powder is limited in order to ensure the metallurgical performance of the sintered ore.

Disclosure of Invention

The invention aims to provide a method for producing sintered ore from high-alumina iron ore powder, which mainly solves the technical problems of poor sintering performance and low proportion of added sintered ore in the prior art.

The invention adopts the technical scheme that the method for producing the sinter from the high-alumina iron ore powder comprises the following steps:

1) ore blending, wherein the ore blending mass proportion of the high-alumina iron ore powder, the low-alumina ultrafine iron ore concentrate powder, the hematite rich ore powder, the sintering return ores, the flux and the solid fuel is calculated according to the technical quality indexes of the sintering ores, and the sintering ore blending raw materials comprise the following components in percentage by mass: 10-20% of high-aluminum iron ore powder, 10-15% of low-aluminum superfine iron concentrate powder, 50-80% of hematite rich ore powder, 5-10% of sintered return ores, 8-15% of flux and 4-5% of solid fuel, wherein the sum of the mass percentages of the components is 100%; controlling the mass percentage of MgO in the sintered ore to be 0.8-1.6%, the mass percentage of FeO to be 7.5-8.5% and the alkalinity (CaO/SiO) of the sintered ore₂) 1.7 to 2.1;

2) preparing a primary mixture, weighing the hematite rich mineral powder, the sintering return ores, the flux and the solid fuel according to the ore blending mass proportion of the sintering ores, uniformly mixing the hematite rich mineral powder, the sintering return ores, the flux and the solid fuel by using a primary mixer, adding water in the uniform mixing process, and uniformly mixing for 5-8min to prepare a primary mixture, wherein the mass percentage of the water in the primary mixture is 6.8-7.0%; conveying the primary mixture to a mixing granulator;

3) preparing prefabricated material balls of high-aluminum iron ore powder and low-aluminum superfine iron ore concentrate powder, and adding the high-aluminum ore, the low-aluminum superfine iron ore concentrate powder, bentonite and water into a disc pelletizer to carry out mixed pelletizing; the high-aluminum iron ore powder and low-aluminum superfine iron ore concentrate powder prefabricated material balls comprise the following components in percentage by mass: 95.5-97.8% of high-alumina iron ore powder, 0.2-1.5% of low-alumina superfine iron concentrate powder, 0.0-3.0% of bentonite and 2.0-3.0% of water;

4) preparing a sintering comprehensive mixed material, adding the primary mixed material mixed by the primary mixer, the high-aluminum iron ore powder and the low-aluminum ultra-fine iron ore concentrate powder prefabricated material balls into a granulator for further mixing granulation, and controlling the moisture according to given moisture parameters; mixing for 5-8min to obtain sintered mixed material;

5) distributing the sintering mixture on a sintering trolley, controlling the thickness of a material layer of the sintering mixture to be 700-1000 mm, producing sintered ore by igniting and exhausting the sintering comprehensive mixture, and controlling the exhaust negative pressure to be 12-16kPa and the ignition temperature to be 1150-1250 ℃ in the sintering process.

Further, in the step 3), the content of the whole aluminum oxide is reduced to an acceptable level under the neutralization of the low-aluminum ore by the high-aluminum iron ore powder; the high-alumina iron ore powder is used as a pellet core due to the coarse particles, and low-alumina ultrafine concentrate is adhered to the high-alumina iron ore powder, so that the pellets grow continuously under the action of a binder and water.

Al in the high-aluminum iron ore powder₂O₃The weight percentage of the high-alumina iron ore powder is 1.5-2.5%, the high-alumina iron ore powder with the particle size of more than or equal to 1mm accounts for more than 50% of the total mass of the high-alumina iron ore powder, and the main mineral is hematite or goethite.

Al in the low-aluminum superfine iron concentrate powder₂O₃The weight percentage content of the low-aluminum superfine iron concentrate powder is less than or equal to 0.4 percent, the grain diameter of the low-aluminum superfine iron concentrate powder is less than or equal to 80 mu m, and the main mineral is magnetite concentrate.

The grain size of the sintered return ores is less than or equal to 5 mm.

The solid fuel is any one of coke powder, anthracite powder or a mixture of the coke powder and the anthracite powder; the mass percentage of C in the solid fuel is 77-85%; the solid fuel with the grain diameter less than or equal to 3mm accounts for more than 90 percent of the total mass proportion of the solid fuel.

The flux comprises 41-45% of quicklime, 33-36% of limestone powder and 22-24% of dolomite powder by mass; the flux with the grain diameter less than or equal to 3mm accounts for more than 90 percent of the total mass proportion of the flux; the mass percentage of CaO in the quicklime is 80-90%; the mass percentage of CaO in the limestone powder is 50-53%; the dolomite powder comprises 19-22% by mass of MgO and 29-33% by mass of CaO.

The method of the invention is based on the following research findings of the applicant:

the aluminum oxide in the iron ore is not beneficial to the generation of a sintering liquid phase, thereby having adverse effect on the sintering product quality. The alumina easily causes the deterioration of the low-temperature reduction degradation index of the sinter, and finally influences the air permeability of the blast furnace. In addition, the increase of the alumina content in the sintered ore causes the increase of the amount of blast furnace slag, thereby causing some problems such as the increase of coke ratio, the increase of molten iron cost, and the like. Because the sintering performance of the high-alumina iron ore powder is poor, the proportion of the high-alumina iron ore powder in the sintering process is generally limited.

Meanwhile, the amount of aluminum oxide contained in the ultrafine iron concentrate is often small, and Al is common₂O₃The content is less than or equal to 0.4 percent, and the iron content is higher. Because the finer particles can reduce the air permeability of a sintering material layer in sintering and influence the sintering yield, the superfine fine powder is difficult to process in the sintering process and the price is lower relative to rich mineral powder.

The invention effectively combines the two raw materials together, can improve the sintering performance of the high-alumina iron ore powder, improves the utilization efficiency of the superfine fine powder ore, does not change the content of aluminum oxide in the sintered ore and reduces the sintering cost, and achieves multiple purposes.

The invention can not only improve the use ratio of the high-alumina iron ore powder and the superfine fine ore powder and improve the grade of the sintering ore, but also further improve the sintering performance and reduce the sintering cost. Meanwhile, the technology has positive significance for improving the utilization rate of the high-aluminum iron ore powder and the low-aluminum superfine powder.

In order to achieve the purposes of improving the use proportion of the superfine iron fine powder of the high-alumina iron ore powder, effectively improving the sintering performance of the high-alumina iron ore powder and ensuring and even improving the iron grade and the quality of the sintered ore, the invention mainly adopts the following technical scheme.

The method can effectively solve the problem that the addition proportion of the high-alumina iron ore powder is limited in sintering due to high alumina content, not only can improve the addition proportion of the high-alumina iron ore powder and improve the metallurgical performance of the high-alumina iron ore powder, but also can improve the sintered iron grade and the quality of sintered ore.

Compared with the prior art, the invention has the following positive effects: 1. the use proportion of the high-alumina iron ore powder is improved, and the ore cost of the sinter is reduced. The high-alumina iron ore powder has high alumina content, and thus has adverse effect on sintering performance, so that the high-alumina iron ore powder has relatively low price. The invention effectively solves the technical problem caused by adding high-alumina iron ore powder in a high proportion in the sintering process. In the sintering process, the proportion of the high-alumina iron ore powder is increased, and the cost of the sintered ore is relatively reduced; the use problem of two kinds of ores which are difficult to treat in the market is effectively solved by matching and using the low-aluminum concentrate powder, the two kinds of ores are subjected to complementary balance of aluminum oxide content, and the problems of poor air permeability and reduced capacity of sintering ores caused by using the concentrate powder are effectively solved by a pelletizing method. 2. The iron grade is improved. The iron grade of the fine ore is generally higher, and the iron grade of the sinter is improved to a certain extent by matching with the high-alumina iron ore powder. 3. Effectively solves the problem of high low-temperature reduction degradation index caused by high content of aluminum oxide in the sintering ore. By carrying out pelletizing and pelletizing in combination with the low-aluminum concentrate ore, on one hand, the content of aluminum oxide in the sinter ore can be controlled within an acceptable range; on the other hand, after the total aluminum oxide of the sintered ore is reduced, the low-temperature reduction degradation index can be improved. 4. The quality of the sinter is improved. Because the low-aluminum superfine fine iron powder is magnetite and is wrapped outside the pellet, the magnetite is oxidized in the sintering process to release heat, and thus the finished product rate of the sintered ore is improved. The finished product rate of the sinter is improved, the repeated manufacture is avoided, and the production cost is greatly reduced; the sintered ore manufactured by the method has good sintered ore quality and metallurgical performance. 5. The invention has the advantages of easy implementation, obvious effect and low implementation cost.

Detailed Description

The present invention will be further illustrated by the following specific examples, which are to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever.

A method for producing sintered ore by using high-alumina iron ore powder comprises the following steps:

1) ore blending, wherein the ore blending mass proportion of the high-alumina iron ore powder, the low-alumina ultrafine iron ore concentrate powder, the hematite rich ore powder, the sintering return ores, the flux and the solid fuel is calculated according to the technical quality indexes of the sintering ores, and the sintering ore blending raw materials comprise the following components in percentage by mass: 10-20% of high-aluminum iron ore powder, 10-15% of low-aluminum superfine iron concentrate powder, 50-80% of hematite rich ore powder, 5-10% of sintered return ores, 8-15% of flux and 4-5% of solid fuel, wherein the sum of the mass percentages of the components is 100%; controlling the mass percentage of MgO in the sintered ore to be 0.8-1.6%, the mass percentage of FeO to be 7.5-8.5% and the alkalinity (CaO/SiO) of the sintered ore₂) 1.7 to 2.1;

2) preparing a primary mixture, weighing the hematite rich mineral powder, the sintering return ores, the flux and the solid fuel according to the ore blending mass proportion of the sintering ores, uniformly mixing the hematite rich mineral powder, the sintering return ores, the flux and the solid fuel by using a primary mixer, adding water in the uniform mixing process, and uniformly mixing for 5-8min to prepare a primary mixture, wherein the mass percentage of the water in the primary mixture is 6.8-7.0%; conveying the primary mixture to a mixing granulator;

3) preparing prefabricated material balls of high-aluminum iron ore powder and low-aluminum superfine iron ore concentrate powder, and adding the high-aluminum iron ore powder, the low-aluminum superfine iron ore concentrate powder, bentonite and water into a disc pelletizer to carry out mixed pelletizing; the high-aluminum iron ore powder and low-aluminum superfine iron ore concentrate powder prefabricated material balls comprise the following components in percentage by mass: 95.5-97.8% of high-alumina iron ore powder, 0.2-1.5% of low-alumina superfine iron concentrate powder, 0.0-3.0% of bentonite and 2.0-3.0% of water;

4) preparing a sintering comprehensive mixed material, adding the primary mixed material mixed by the primary mixer, the high-aluminum iron ore powder and the low-aluminum ultra-fine iron ore concentrate powder prefabricated material balls into a granulator for further mixing granulation, and controlling the moisture according to given moisture parameters; mixing for 5-8min to obtain sintered mixed material;

5) distributing the sintering mixture on a sintering trolley, controlling the thickness of a material layer of the sintering mixture to be 700-1000 mm, producing sintered ore by igniting and exhausting the sintering comprehensive mixture, and controlling the exhaust negative pressure to be 12-16kPa and the ignition temperature to be 1150-1250 ℃ in the sintering process.

Example 1 of the invention uses Al in high-alumina iron ore powder₂O₃The content of (B) is 1.5% by weight.

Ore blending, namely calculating the ore blending mass proportion of high-alumina iron ore powder, low-alumina superfine iron ore concentrate powder, hematite rich ore powder, sintering return ores, a flux and solid fuels according to the technical quality indexes of the sintering ores; in the sintering raw materials, the weight percentage content of MgO is 1.4%, and the alkalinity of sintering ore is 1.95;

preparing a primary mixture, wherein the raw material ratio is as follows: 15% of Australia Yangtze ore, 23% of Brazilian Callas ore, 5% of Tomba ore, 9.5% of return ores, 4.5% of solid fuel and 13% of the sum of the mass of quick lime, dolomite and limestone; mixing all raw fuels according to a proportioning condition, adding the raw fuels into a primary mixer for uniformly mixing, and then feeding the materials into a granulator for pelletizing and granulating;

granulating and pelletizing high-alumina iron ore powder and low-alumina ore, and adding 10% of high-alumina iron ore powder A, 15% of low-alumina superfine powder and 2% of bentonite into a powerful mixer for powerful mixing for 2 min; the mixed raw materials and 3% of water are added into a disc pelletizer to pelletize. After the high-alumina iron ore powder is pelletized, the air permeability of a sinter bed is greatly improved;

preparing a sintering comprehensive mixing material, adding pellets produced by a disc pelletizer into a granulator to be converged with the materials of a primary mixer; water was added to the mix to a moisture content of 6.8%.

And after the granulation is finished, conveying the belt to an ore tank and distributing materials by using a trolley. After the cloth is distributed, air draft ignition is carried out, and the ignition temperature is 1150 ℃.

By detecting the finished sintered ore obtained by the method, the iron grade of the sintered ore is improved to 58.4 percent from the original 58.2 percent, the drum strength is improved to 83.56 percent from 83.33 percent, the yield is improved to 70.54 percent from 69.52 percent, the content of the aluminum oxide in the sintered ore is still unchanged from the original, and the ore blending cost of the sintered ore is reduced by 2.1 yuan/t. Meanwhile, the metallurgical performance of the sintered ore is also improved, and the low-temperature reduction degradation rate RDI +3.15 mm% is improved from the original 56.84% to 59.22%. The performance index of the sintered ore is shown in table 1.

TABLE 1 Performance index of sintered ore of example 1 of the present invention

In addition to the above embodiments, the present invention may have other embodiments. All technical solutions formed by adopting equivalent substitutions or equivalent transformations fall within the protection scope of the claims of the present invention.