Comprehensive treatment method for vanadium-containing steel slag

Abstract

The invention relates to the technical field of comprehensive utilization of metallurgical solid wastes, in particular to a comprehensive treatment method of vanadium-containing steel slag, which comprises the following steps: adding the ground vanadium-containing steel slag into an acid leaching solution for leaching reaction, and carrying out solid-liquid separation on the reacted mixture to obtain tailings rich in metal elements and a solution rich in calcium ions; cO2 gas is introduced into the solution rich in calcium ions for a mineralization reaction, and calcium carbonate precipitates are obtained; a tempering agent and a reducing agent are added into the tailings rich in metal elements, pelletizing, drying and smelting are conducted in sequence, and vanadium-containing pig iron is obtained; wherein the step S2 and the step S3 are not limited in sequence. The comprehensive treatment method for the vanadium-containing steel slag shows remarkable beneficial technical effects in the aspects of improving the recovery rate of metal elements, reducing the treatment cost and realizing maximum utilization of resources, so that environmental pollution is reduced, and sustainable utilization of the resources and sustainable development of economy are promoted.

Description

Technical Field

[0001] The invention relates to the technical field of comprehensive utilization of metallurgical solid waste, and in particular to a comprehensive treatment method for vanadium-containing steel slag. Background Art

[0002] In current industrial production, especially in the field of steel manufacturing, steel mills in Sichuan, Yunnan, Ma'anshan, Anhui, and Chengde, Hebei widely use vanadium-titanium magnetite as the main raw material for blast furnace smelting. The smelting process of this ore not only produces a large amount of steel products, but also generates a byproduct containing rich resources - vanadium-containing steel slag. Vanadium-containing steel slag not only contains 1% to 4% V2O5, but also is rich in other valuable metal elements such as Fe (iron), V (vanadium), and Mn (manganese). The effective extraction and recycling of these elements are of great significance to improving resource utilization efficiency and promoting the development of a circular economy.

[0003] However, with the acceleration of the global industrialization process, CO2 emissions have increased dramatically, causing serious environmental problems, especially aggravating the greenhouse effect, posing a severe challenge to the global climate system. In this context, exploring and implementing effective CO2 emission reduction and fixation technologies has become a focus of widespread concern in the international community. As an innovative environmental governance method, CO2 mineral carbonation fixation technology can effectively capture and store CO2 in the atmosphere by converting CO2 into a stable carbonate form, providing a feasible solution to mitigate global warming.

[0004] It is worth noting that the CaO (calcium oxide) content in vanadium-containing steel slag is as high as 30% to 45%, making it a highly potential carbon fixation raw material. Using CaO in steel slag and CO2 for carbonation reaction can not only greatly improve the resource utilization rate of steel slag and reduce the pressure of waste accumulation on the environment, but also generate calcium carbonate products with wide application value, such as building materials, plastic fillers, papermaking fillers, etc., thus achieving dual benefits of economy and environmental protection.

[0005] Further research shows that calcium ions in steel slag have a high dissolution rate under acidic conditions, which facilitates the pretreatment of steel slag and the subsequent CO2 absorption process. By optimizing the reaction conditions, such as adjusting the pH value, temperature, pressure and other parameters of the solution, the reaction rate of CO2 and CaO in steel slag can be significantly increased, and the formation of carbonation products can be accelerated. Therefore, the use of vanadium-containing steel slag for mineral carbonation fixation of CO2 can not only effectively solve the problem of solid waste treatment generated by the steel industry, but also serve as an innovative means of carbon emission reduction, which has far-reaching significance for promoting green and low-carbon development and achieving sustainable development goals.

[0006] In view of this, the present invention is proposed. Summary of the invention

[0007] The purpose of the present invention is to provide a comprehensive treatment method for vanadium-containing steel slag, which can convert calcium resources in steel slag into calcium carbonate products with high added value, while enriching metal elements, thereby realizing the green conversion of waste into resources.

[0008] The present invention provides a comprehensive treatment method for vanadium-containing steel slag, comprising the following steps:

[0009] S1, adding the ground vanadium-containing steel slag into an acidic leaching solution for leaching reaction, and separating the mixture after the reaction into solid and liquid to obtain tailings rich in metal elements and a solution rich in calcium ions;

[0010] S2, introducing CO2 gas into the solution rich in calcium ions to carry out a mineralization reaction to obtain calcium carbonate precipitation;

[0011] S3, adding a conditioning agent and a reducing agent to the tailings rich in metal elements, and successively performing pelletizing, drying and smelting to obtain vanadium-containing pig iron;

[0012] There is no order restriction for step S2 and step S3, and the mass ratio of the tailings rich in metal elements to the conditioning agent and the reducing agent is 10:(0.3-0.7):(0.8-1.2), and preferably 10:0.5:1.

[0013] The present invention adds an acidic leaching solution to vanadium-containing steel slag, wherein the content of CaO in the steel slag is about 40%, and the calcium ions in the steel slag are dissolved after acid leaching, and the content can be reduced to 20%. The mixture obtained by the leaching reaction is separated by solid and liquid to obtain tailings rich in metal elements and a solution rich in calcium ions, wherein CO2 gas is introduced into the solution rich in calcium ions for mineralization reaction, which can not only slow down the greenhouse effect, but also neutralize the solid waste residue, and the generated calcium carbonate precipitation has a wide range of uses; and the proportion of metal elements in the tailings rich in metal elements is significantly increased, and a tempering agent and a reducing agent are added thereto, and vanadium-containing pig iron can be obtained by successively pelletizing, drying and smelting. Therefore, the present invention not only realizes the effective utilization of calcium resources, but also enriches metal elements, realizes the green conversion of waste to resources, and opens up a new way for solid waste treatment in the steel industry.

[0014] As a preferred embodiment of the present technical solution, the conditioning agent is a material rich in silicon and / or aluminum. The conditioning agent is mainly used to adjust the slag composition in the tailings smelting process to facilitate the reduction and separation of metals, and the material rich in silicon and / or aluminum can react with the metal oxides in the tailings to generate corresponding silicates and aluminates, which can act as fluxing and reduction aids in the smelting process.

[0015] Specifically, the conditioning agent includes any one or more of silicon dioxide, aluminum oxide, aluminosilicate minerals, calcium silicate, calcium aluminate, and industrial waste rich in silicon and / or aluminum. The above substances can effectively adjust the composition and properties of the tailings to facilitate the reduction of metals and the fluidity of the tailings, thereby facilitating the reduction and separation of metals.

[0016] As a preferred embodiment of the present technical solution, the reducing agent includes any one or more of coke, coal, charcoal and carbon monoxide to reduce the metal oxides to metal elements, thereby realizing the recovery and refining of the metals.

[0017] As a preferred embodiment of the present invention, the acidic leaching solution is an acetic acid solution or a hydrochloric acid solution.

[0018] The concentration of the acetic acid solution is 0.05-0.5 mol / L, and preferably 0.2-0.4 mol / L, and the mass ratio of the acetic acid solution to the vanadium-containing steel slag is (5-60):1, and preferably (20-40):1;

[0019] The concentration of the hydrochloric acid solution is 0.03-0.2 mol / L, and preferably 0.1-0.2 mol / L. The mass ratio of the hydrochloric acid solution to the vanadium-containing steel slag is (5-60):1, and preferably (30-60):1.

[0020] As a preferred embodiment of the present technical solution, the leaching reaction temperature is 20-30°C and the time is 1-3h. During the leaching reaction, stirring and the like can be used to fully carry out the reaction so that the calcium element in the vanadium-containing steel slag enters the solution in the form of calcium ions.

[0021] The present invention effectively improves the dissolution rate of calcium in vanadium-containing steel slag by optimizing the acid solution system and leaching conditions, and provides higher-grade raw materials for subsequent metal refining.

[0022] As a preferred embodiment of the present technical solution, during the mineralization reaction, the temperature of the mineralization reaction is controlled to be 20-100°C, the flow rate of CO2 gas introduction is 5-10L / min, and the pressure of the reaction system is 150-200bar.

[0023] As a preferred embodiment of the present technical solution, during the smelting, the temperature is controlled to be 1600-1700°C and the time is 90-120 minutes.

[0024] As a preferred embodiment of the present technical solution, the particle size of the ground vanadium-containing steel slag is less than or equal to 200 μm, so as to increase the contact area between the acid solution and the vanadium-containing steel slag during the acid leaching process and improve the leaching efficiency.

[0025] As a preferred embodiment of the present technical solution, the content of V2O5 in the vanadium-containing steel slag is 1.0-1.8%, and the content of TFe is 20-25%.

[0026] The comprehensive treatment method of vanadium-containing steel slag of the present invention has at least the following beneficial effects:

[0027] 1. The present invention uses an acidic leaching solution to treat vanadium-containing steel slag, which can effectively dissolve calcium ions in the vanadium-containing steel slag, thereby improving the quality of the tailings rich in metal elements, providing higher quality raw materials for the subsequent metal refining process, not only improving the refining efficiency, but also reducing the energy consumption and chemical use required in the refining process, and further reducing the processing cost;

[0028] 2. The present invention can convert calcium resources in steel slag into calcium carbonate products with high added value by introducing CO2 gas into a solution rich in calcium ions for mineralization reaction, which not only realizes the effective utilization of resources but also provides an additional source of product income for the market;

[0029] 3. The present invention reduces unnecessary acid consumption, thereby reducing costs; in addition, due to the increased recovery rate of metal elements, the metal content in the tailings is reduced, which reduces the material consumption required for subsequent treatment. At the same time, due to the increase in the content of metal elements in the solution, the concentration of pollutants in the wastewater is correspondingly reduced, making the wastewater treatment process simpler and less costly;

[0030] 4. The comprehensive treatment method of vanadium-containing steel slag of the present invention has shown significant beneficial technical effects in improving the recovery rate of metal elements, reducing treatment costs and maximizing resource utilization, which not only helps to reduce environmental pollution, but also promotes the sustainable utilization of resources and sustainable economic development. DETAILED DESCRIPTION

[0031] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0032] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form also includes the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this description, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0033] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Example 1

[0035] S1. Grind vanadium-containing steel slag (V2O5 content of 1.26%, TFe content of 20%) using a ball mill to a particle size of ≤150 μm; prepare an acetic acid solution with a concentration of 0.15 mol / L; add vanadium-containing steel slag powder to the acetic acid solution at 25°C, stir well to react for 1.5 hours, filter the solution, and obtain tailings rich in metal elements and a solution rich in calcium ions, wherein the mass ratio of the acetic acid solution to the vanadium-containing steel slag powder is 40:1;

[0036] Testing showed that the V2O5 content in the metal-element-rich tailings increased from 1.26% to 2.14%, and the TFe grade increased from 20% to 27%.

[0037] S2. Continuously introduce CO2 gas into the calcium ion-rich solution for 20 minutes to carry out a mineralization reaction to obtain calcium carbonate precipitation, wherein the temperature of the mineralization reaction is 60° C., the flow rate of CO2 gas introduction is 5 L / min, and the pressure of the reaction system is 150 bar;

[0038] S3. The tailings rich in iron and vanadium metal elements after filtration are mixed with industrial waste (SiO2: 40-60%, Al2O3: 10-20%) and coke powder, and then added into a pelletizing machine for pelletizing and drying. Then, the mixture is added into a smelting furnace and heated to 1650°C for 100 minutes. The melt is poured out to obtain vanadium-containing pig iron with a vanadium content of 2.4%.

[0039] Example 2

[0040] S1. Grind vanadium-containing steel slag (V2O5 content of 1.26%, TFe content of 20%) using a ball mill to a particle size of ≤200 μm; prepare an acetic acid solution with a concentration of 0.5 mol / L; add vanadium-containing steel slag powder to the acetic acid solution at 25°C, stir well to react for 2 hours, filter the solution, and obtain tailings rich in metal elements and a solution rich in calcium ions, wherein the mass ratio of the acetic acid solution to the vanadium-containing steel slag powder is 10:1;

[0041] The results showed that the V2O5 content in the tailings rich in metal elements increased from 1.26% to 2.31%, and the TFe grade increased from 20% to 28%.

[0042] S2. Continuously introduce CO2 gas into the calcium ion-rich solution for 30 minutes to carry out a mineralization reaction to obtain calcium carbonate precipitation, wherein the temperature of the mineralization reaction is 80° C., the flow rate of CO2 gas introduction is 3 L / min, and the pressure of the reaction system is 150 bar;

[0043] S3. The tailings rich in iron and vanadium metal elements after filtration are mixed with industrial waste (SiO2: 40%-60%, Al2O3: 10%-20%) and coke powder, and then added into a pelletizing machine for pelletizing and drying. Then, the mixture is added into a smelting furnace and heated to 1700°C for 90 minutes. The melt is poured out to obtain vanadium-containing pig iron with a vanadium content of 2.5%.

[0044] Example 3

[0045] S1. Grind vanadium-containing steel slag (V2O5 content of 1.26%, TFe content of 20%) using a ball mill to a particle size of ≤150 μm; prepare an acetic acid solution with a concentration of 0.05 mol / L; add vanadium-containing steel slag powder to the acetic acid solution at 25°C, stir well to react for 3 hours, filter the solution, and obtain tailings rich in metal elements and a solution rich in calcium ions, wherein the mass ratio of the acetic acid solution to the vanadium-containing steel slag powder is 60:1;

[0046] The results showed that the V2O5 content in the tailings rich in metal elements increased from 1.26% to 2.12%, and the TFe grade increased from 20% to 25%.

[0047] S2. Continuously introduce CO2 gas into the calcium ion-rich solution for 30 minutes to carry out a mineralization reaction to obtain calcium carbonate precipitation, wherein the temperature of the mineralization reaction is 60° C., the flow rate of CO2 gas introduction is 5 L / min, and the pressure of the reaction system is 150 bar;

[0048] S3. The tailings rich in iron and vanadium metal elements after filtration are mixed with industrial waste (SiO2: 40%-60%, Al2O3: 10%-20%) and charcoal, and then added into a pelletizing machine for pelletizing and drying. Then, the mixture is added into a smelting furnace and heated to 1600°C for 120 minutes. The melt is poured out to obtain vanadium-containing pig iron with a vanadium content of 2.3%.

[0049] Example 4

[0050] S1. Grind vanadium-containing steel slag (V2O5 content of 1.26%, TFe content of 20%) using a ball mill to a particle size of ≤150 μm; prepare a hydrochloric acid solution with a concentration of 0.1 mol / L; add the vanadium-containing steel slag powder to the hydrochloric acid solution at 25°C, stir well to react for 2 hours, filter the solution, and obtain tailings rich in metal elements and a solution rich in calcium ions, wherein the mass ratio of the hydrochloric acid solution to the vanadium-containing steel slag powder is 40:1;

[0051] The results showed that the V2O5 content in the tailings rich in metal elements increased from 1.26% to 2.20%, and the TFe grade increased from 20% to 26.5%.

[0052] S2. Continuously introduce CO2 gas into the calcium ion-rich solution for 25 minutes to carry out a mineralization reaction to obtain calcium carbonate precipitation, wherein the temperature of the mineralization reaction is 60° C., the flow rate of CO2 gas introduction is 5 L / min, and the pressure of the reaction system is 150 bar;

[0053] S3. The tailings rich in iron and vanadium metal elements after filtration are mixed with industrial waste (SiO2: 40%-60%, Al2O3: 10%-20%) and coke powder, and then added into a pelletizing machine for pelletizing and drying. Then, the mixture is added into a smelting furnace and heated to 1650°C for 100 minutes. The melt is poured out to obtain vanadium-containing pig iron with a vanadium content of 2.5%.

[0054] Example 5

[0055] S1. Grind vanadium-containing steel slag (V2O5 content of 1.26%, TFe content of 20%) using a ball mill to a particle size of ≤150 μm; prepare a hydrochloric acid solution with a concentration of 0.2 mol / L; add the vanadium-containing steel slag powder to the hydrochloric acid solution at 25°C, stir and react for 1.5 hours, filter the solution, and obtain tailings rich in metal elements and a solution rich in calcium ions, wherein the mass ratio of the hydrochloric acid solution to the vanadium-containing steel slag powder is 10:1;

[0056] The results showed that the V2O5 content in the tailings rich in metal elements increased from 1.26% to 2.30%, and the TFe grade increased from 20% to 27.4%.

[0057] S2. Continuously introduce CO2 gas into the calcium ion-rich solution for 30 minutes to carry out a mineralization reaction to obtain calcium carbonate precipitation, wherein the temperature of the mineralization reaction is 60° C., the flow rate of CO2 gas introduction is 5 L / min, and the pressure of the reaction system is 150 bar;

[0058] S3. The tailings rich in iron and vanadium metal elements after filtration are mixed with industrial waste (SiO2: 40%-60%, Al2O3: 10%-20%) and coke powder, and then added into a pelletizing machine for pelletizing and drying. Then, the mixture is added into a smelting furnace and heated to 1700°C for 90 minutes. The melt is poured out to obtain vanadium-containing pig iron with a vanadium content of 2.5%.

[0059] Example 6

[0060] S1. Grind vanadium-containing steel slag (V2O5 content of 1.26%, TFe content of 20%) using a ball mill to a particle size of ≤150 μm; prepare a hydrochloric acid solution with a concentration of 0.05 mol / L; add the vanadium-containing steel slag powder to the hydrochloric acid solution at 25°C, stir and react for 3 hours, filter the solution, and obtain tailings rich in metal elements and a solution rich in calcium ions, wherein the mass ratio of the hydrochloric acid solution to the vanadium-containing steel slag powder is 60:1;

[0061] The results showed that the V2O5 content in the tailings rich in metal elements increased from 1.26% to 2.32%, and the TFe grade increased from 20% to 27.2%.

[0062] S2. Continuously introduce CO2 gas into the calcium ion-rich solution for 30 minutes to carry out a mineralization reaction to obtain calcium carbonate precipitation, wherein the temperature of the mineralization reaction is 60° C., the flow rate of CO2 gas introduction is 5 L / min, and the pressure of the reaction system is 150 bar;

[0063] S3. The tailings rich in iron and vanadium metal elements after filtration are mixed with industrial waste (SiO2: 40%-60%, Al2O3: 10%-20%) and coke powder, and then added into a pelletizing machine for pelletizing and drying. Then, the mixture is added into a smelting furnace and heated to 1600°C for 120 minutes. The melt is poured out to obtain vanadium-containing pig iron with a vanadium content of 2.45%.

[0064] Comparative Example 1

[0065] This comparative example is substantially the same as Example 1, except that citric acid is used instead of the acetic acid solution in Example 1.

[0066] The vanadium content of the vanadium-containing pig iron finally obtained in this comparative example did not change significantly, which may be because citric acid cannot effectively dissolve the calcium element in the vanadium-containing steel slag, so high-grade metal smelting raw materials cannot be obtained.

[0067] Comparative Example 2

[0068] This comparative example is substantially the same as Example 1, except that no solid waste is added.

[0069] The vanadium content of the vanadium-containing pig iron finally obtained in this comparative example is 2.05%, which may be because no tempering agent is added, and the reduction and separation of the metal are limited.

[0070] In summary, the present invention not only realizes the effective utilization of calcium resources, but also enriches metal elements, realizes the green transformation of waste into resources, and opens up a new path for solid waste treatment in the steel industry.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A comprehensive treatment method for vanadium-containing steel slag, characterized in that: The following steps are involved: S1, adding the ground vanadium-containing steel slag into an acidic leaching solution for leaching reaction, and separating the mixture after the reaction into solid and liquid to obtain tailings rich in metal elements and a solution rich in calcium ions; S2, introducing CO2 gas into the solution rich in calcium ions to carry out a mineralization reaction to obtain calcium carbonate precipitation; S3, adding a conditioning agent and a reducing agent to the tailings rich in metal elements, and successively performing pelletizing, drying and smelting to obtain vanadium-containing pig iron; There is no order restriction for step S2 and step S3, and the mass ratio of the tailings rich in metal elements to the conditioning agent and the reducing agent is 10:(0.3-0.7):(0.8-1.2).

2. The comprehensive treatment method of vanadium-containing steel slag according to claim 1, characterized in that: The conditioning agent is a material rich in silicon and / or aluminum.

3. The comprehensive treatment method of vanadium-containing steel slag according to claim 1, characterized in that: The conditioning agent includes any one or more of silicon dioxide, aluminum oxide, aluminosilicate minerals, calcium silicate, calcium aluminate and industrial waste rich in silicon and / or aluminum.

4. The comprehensive treatment method of vanadium-containing steel slag according to claim 1, characterized in that: The reducing agent includes any one or more of coke, coal, charcoal and carbon monoxide.

5. The comprehensive treatment method of vanadium-containing steel slag according to claim 1, characterized in that: The acidic leaching solution is an acetic acid solution or a hydrochloric acid solution, The concentration of the acetic acid solution is 0.05-0.5 mol / L, and the mass ratio of the acetic acid solution to the vanadium-containing steel slag is (5-60):1; The concentration of the hydrochloric acid solution is 0.03-0.2 mol / L, and the mass ratio of the hydrochloric acid solution to the vanadium-containing steel slag is (5-60):

1.

6. The comprehensive treatment method of vanadium-containing steel slag according to claim 1, characterized in that: The leaching reaction temperature is 20-30°C and the time is 1-3h.

7. The comprehensive treatment method of vanadium-containing steel slag according to claim 1, characterized in that: During the mineralization reaction, the temperature of the mineralization reaction is controlled to be 20-100° C., the flow rate of CO2 gas is 5-10 L / min, and the pressure of the reaction system is 150-200 bar.

8. The comprehensive treatment method of vanadium-containing steel slag according to claim 1, characterized in that: During the smelting, the temperature is controlled to be 1600-1700° C. and the time is 90-120 minutes.

9. The comprehensive treatment method of vanadium-containing steel slag according to claim 1, characterized in that: The particle size of the ground vanadium-containing steel slag is less than or equal to 200 μm.

10. The comprehensive treatment method of vanadium-containing steel slag according to claim 1, characterized in that: The content of V2O5 in the vanadium-containing steel slag is 1.0-1.8%, and the content of TFe is 20-25%.