Method for preparing high-quality hollow sphere from copper smelting waste residues

Abstract

The invention provides a method for preparing a high-quality hollow sphere from copper smelting waste residues, and relates to the technical field of secondary resource reutilization in the non-ferrous metallurgy industry. The preparation method of the high-quality hollow sphere comprises the steps that the copper smelting waste residues serve as basic raw materials, a proper amount of S is added, mixing is conducted to prepare a mixture, a ball mill is used for conducting grinding treatment on the mixture, and the high-quality hollow sphere is obtained; powder is obtained; preparing the powder into a hollow sphere through a plasma torch; an airflow screening machine is used for screening the hollow spheres; and under the protection of inert gas, the screened hollow sphere is subjected to high-temperature roasting, so that the content of toxic elements in the hollow sphere is reduced, and the high-quality hollow sphere which meets the national standard and can be industrially applied is obtained. The whole preparation process is simple, the content of toxic element As in the hollow sphere can be greatly reduced, and the prepared hollow sphere becomes a product capable of being directly applied industrially.

Description

Technical Field

[0001] The invention relates to the field of secondary resource recycling in nonferrous metallurgical industry, and specifically to a method for preparing high-quality hollow spheres by utilizing copper smelting waste slag. Background Art

[0002] At present, copper smelting enterprises mostly use pyrometallurgical smelting technology to produce copper, which will produce a large amount of copper smelting waste slag. The accumulation of a large amount of copper smelting waste slag not only occupies land resources, but also pollutes soil and water resources. Copper smelting waste slag is rich in many valuable metal elements such as Cu, Fe, Zn, Pb, Ni, etc. At present, the utilization rate of Cu in copper smelting waste slag is less than 12%, and the utilization rate of Fe is less than 1%. The development of copper smelting waste slag recycling technology can bring a lot of economic benefits, save the cost of importing mineral resources, and alleviate environmental pressure. Therefore, research on the resource utilization of copper smelting waste slag is urgent.

[0003] Hollow spheres have the advantages of large specific surface area, low density, easy dispersion, and controllable morphology. They are widely used in sewage purification, chemical catalysts, catalyst carriers, nanoreactors, drug sustained release and other fields. If hollow spheres are prepared from copper smelting waste slag, their recycling rate can be significantly improved. Patent CN110204352A provides a method for preparing magnetic hollow ceramic microspheres from copper slag tailings, which uses a flame spray gun to melt-spray copper slag tailings mixed with various auxiliary materials (such as lime and magnesium oxide powder) to form hollow spheres, but this preparation method has the following two shortcomings: (1) The powder forming by flame spraying is highly dependent on the flame temperature and the auxiliary materials added to reduce the melting point of the waste slag tailings. Maintaining a high temperature is the key factor in achieving powder forming. However, the temperature limit of the flame spray gun is about 3000℃. The upper limit of the flame temperature and the addition of auxiliary materials make the composition and forming control measures of the hollow spheres relatively limited; (2) It is difficult to significantly remove the toxic element As during the hollow sphere molding process. The subsequent application of the powder requires a large amount of economic and technological investment to eliminate the impact of the toxic element As. Summary of the invention

[0004] In order to address the deficiencies in the prior art, the present invention provides a method for preparing high-quality hollow spheres using copper smelting waste slag. The preparation process is simple and can significantly reduce the content of toxic element As in the hollow spheres, so that the prepared hollow spheres become products that meet national standards and can be directly applied in industrial applications.

[0005] In order to achieve the above object, the specific scheme adopted by the present invention is: A method for preparing high-quality hollow spheres using copper smelting waste slag mainly comprises the following steps: Step 1: using copper smelting waste slag as the basic raw material, adding an appropriate amount of S, mixing to form a mixture, and grinding the mixture with a ball mill to obtain a powder; Step 2: Forming the powder into a hollow sphere by a plasma spray gun; Step 3: Using an airflow screening machine to screen the hollow spheres; Step 4: Under the protection of inert gas, the hollow spheres obtained by screening are calcined at high temperature to reduce the content of the toxic element As in the hollow spheres.

[0006] Furthermore, the copper smelting waste slag comprises the following components in percentage by mass: Fe2O3 54%, SiO2 29%, CaO 3%, Al2O3 3%, ZnO≤3%, Na4SiO4≤2%, and MgO≤1.5%.

[0007] Furthermore, in step 1, the amount of S added is 1-5% of the amount of copper smelting waste slag.

[0008] Furthermore, in step 1, the particle size of the obtained powder is 20-100 μm.

[0009] Furthermore, in step 2, the specific parameters for preparing hollow spheres are: using argon and hydrogen as working gases, the argon pressure is 5-20MPa, the argon flow rate is 60-120L / min, the hydrogen pressure is 10-15MPa, and the hydrogen flow rate is 10-20L / min; the current is 280-680A; the voltage is 90-160V; the powder feeding rate is 1-10kg / min; and the plasma spray melting temperature is 8000-10000℃.

[0010] Furthermore, in step 2, the hollow spheres are collected with liquid nitrogen at a collection distance of 100-500 mm; and the tail gas generated during the preparation process is filtered through a bag dust collector.

[0011] Furthermore, the hollow spheres obtained by screening in step three have a particle size of 20-60 μm and a wall thickness of 0.2-3 μm.

[0012] Furthermore, in step 4, the hollow spheres are calcined at a temperature of 600-750° C. for 2-10 hours under argon protection, and the tail gas generated during the high-temperature calcination process is filtered through a bag filter.

[0013] Beneficial effects: 1) The present invention converts copper smelting waste slag into high-quality hollow sphere products that can be directly applied in industry, which can realize the comprehensive resource utilization of solid waste and create new economic value; 2) The present invention prepares hollow spheres by plasma spray gun, which can generate higher temperature, so that the substances in the powder can be quickly melted into spheres; 3) The rapid and efficient heating of plasma can produce a higher vapor pressure after the powder is melted, and the higher vapor pressure makes the molten powder form hollow spheres during the flight process; 4) The added S can react with As to generate AsS, and under high temperature conditions, AsS can be quickly volatilized to achieve the purpose of removing As. The right amount of S combined with a higher plasma temperature can quickly volatilize and remove the toxic element As in the powder, and combined with high-temperature roasting, the content of the toxic element As in the hollow sphere can be greatly reduced, making the hollow sphere a product that can be directly applied in industry; 5) The present invention realizes the secondary resource recycling of copper smelting waste slag, and the process is simple and easy to be mass-produced and applied. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is the SEM image of the product prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0015] The present invention provides a method for preparing high-quality hollow spheres by using copper smelting waste slag, the steps of which are: Step 1: using copper smelting waste slag as a basic raw material, adding S accounting for 1-5% of the copper smelting waste slag content, mixing to form a mixture, and grinding the mixture with a ball mill to obtain a powder with a particle size of 20-100 μm; Step 2: The powder is made into hollow spheres by a plasma spray gun, and the hollow spheres are collected by liquid nitrogen. The tail gas generated during the preparation of the hollow spheres is filtered by a bag dust collector; Step 3: The collected hollow spheres are sieved by an airflow sieving machine to collect hollow spheres with a particle size of 20-60 μm and a wall thickness of 0.2-3 μm; Step 4: calcining the collected hollow spheres under the protection of an inert gas (such as argon) at a temperature of 600-750°C for 2-10 hours to further remove the toxic element As in the hollow spheres, thereby obtaining high-quality hollow spheres. The tail gas generated during the high-temperature calcination process is filtered through a bag filter; Step 5: Return the recovered As-containing substances to the white arsenic smelting process.

[0016] Among them, in step one, the copper smelting waste slag is obtained by ball milling the slag after copper smelting to crush the large-particle waste slag. In terms of mass percentage, the copper smelting waste slag includes the following components: Fe2O354%, SiO229%, CaO 3%, Al2O33%, ZnO≤3%, Na4SiO4≤2%, and MgO≤1.5%.

[0017] Among them, in step 2, the specific parameters for preparing hollow spheres are: using argon and hydrogen as working gases, the argon pressure is 5-20MPa, the argon flow rate is 60-120L / min, the hydrogen pressure is 10-15MPa, and the hydrogen flow rate is 10-20L / min; the current is 280-680A; the voltage is 90-160V; the powder feeding rate is 1-10kg / min; the plasma spraying temperature is 8000-10000°C, the hollow spheres are collected with liquid nitrogen, and the hollow sphere collection distance is 100-500mm; and the exhaust gas generated during the preparation process is filtered with a bag dust collector.

[0018] Example 1 This embodiment provides a method for preparing high-quality hollow spheres using copper smelting waste slag, the steps of which are: Step 1: using copper smelting waste slag as the basic raw material, adding S accounting for 1% of the copper smelting waste slag content, mixing to form a mixture, and grinding the mixture with a ball mill to obtain a powder with a particle size of 20 μm; Step 2: prepare hollow spheres by plasma spray gun, wherein the argon pressure is 5MPa, the argon flow rate is 60L / min; the hydrogen pressure is 10MPa, the hydrogen flow rate is 10L / min; the current is 280A; the voltage is 90V; the powder feeding rate is 1kg / min; the plasma spraying temperature is 8000°C, and the hollow spheres are collected with liquid nitrogen, and the hollow sphere collection distance is 100mm; the tail gas generated during the preparation process is filtered with a bag dust collector; Step 3, screening the collected hollow spheres through an airflow screening machine; Step 4: The hollow spheres with a particle size of 20 μm and a wall thickness of 0.2-1 μm obtained by screening are calcined at a high temperature of 600°C for 2 hours under argon protection to further remove the toxic element As in the hollow spheres, thereby obtaining high-quality hollow spheres. The tail gas generated during the calcination process is filtered through a bag filter; Step 5: Return the recovered As-containing substances to the white arsenic smelting process.

[0019] The SEM image of the product prepared in this example is as follows Figure 1 As shown by Figure 1 It can be seen that hollow spherical powders were indeed generated.

[0020] Example 2 This embodiment provides a method for preparing high-quality hollow spheres using copper smelting waste slag, the steps of which are: Step 1: using copper smelting waste slag as a basic raw material, adding S accounting for 2% of the copper smelting waste slag content, mixing to form a mixture, and grinding the mixture using a ball mill to obtain a powder with a particle size of 40 μm; Step 2: prepare hollow spheres by plasma spray gun, the argon pressure is 10MPa, the argon flow rate is 80L / min; the hydrogen pressure is 12MPa, the hydrogen flow rate is 12L / min; the current is 360A; the voltage is 120V; the powder feeding rate is 4kg / min; the plasma spray melting temperature is 8500℃; the hollow spheres are collected with liquid nitrogen, and the hollow sphere collection distance is 200mm; the tail gas generated during the preparation process is filtered with a bag dust collector; Step 3, screening the collected hollow spheres through an airflow screening machine; Step 4: The hollow spheres with a particle size of 30 μm and a wall thickness of 1-2 μm obtained by screening are calcined at a high temperature of 650°C for 4 hours under argon protection to further remove the toxic element As in the hollow spheres, thereby obtaining high-quality hollow spheres. The tail gas generated during the calcination process is filtered through a bag filter; Step 5: Return the recovered As-containing substances to the white arsenic smelting process.

[0021] Example 3 This embodiment provides a method for preparing high-quality hollow spheres using copper smelting waste slag, the steps of which are: Step 1: Using copper smelting waste slag as the basic raw material, adding S accounting for 4% of the copper smelting waste slag content, mixing to form a mixture, and grinding the mixture with a ball mill to obtain a powder with a particle size of 80 μm; Step 2: prepare hollow spheres by plasma spray gun, the argon pressure is 16MPa, the argon flow rate is 100L / min; the hydrogen pressure is 13MPa, the flow rate is 16L / min; the current is 480A; the voltage is 140V; the powder feeding rate is 8kg / min; the plasma spraying temperature is 9200℃, and the hollow spheres are collected with liquid nitrogen, and the hollow sphere collection distance is 400mm; the tail gas generated during the preparation process is filtered with a bag dust collector; Step 3, screening the collected hollow spheres through an airflow screening machine; Step 4: The hollow spheres with a particle size of 50 μm and a wall thickness of 2-2.5 μm obtained by screening are calcined at a high temperature of 700°C for 8 hours under argon protection to further remove the toxic element As in the hollow spheres, that is, high-quality hollow spheres are obtained. The tail gas generated during the calcination process is filtered through a bag filter; Step 5: Return the recovered As-containing substances to the white arsenic smelting process.

[0022] Example 4 This embodiment provides a method for preparing high-quality hollow spheres using copper smelting waste slag, the steps of which are: Step 1: using copper smelting waste slag as a basic raw material, adding S accounting for 5% of the copper smelting waste slag content, mixing to form a mixture, and grinding the mixture with a ball mill to obtain a powder with a particle size of 100 μm; Step 2: prepare hollow spheres by plasma spray gun, the argon pressure is 20MPa, the argon flow rate is 120L / min; the hydrogen pressure is 15MPa, the hydrogen flow rate is 20L / min; the current is 680A; the voltage is 160V; the powder feeding rate is 10kg / min; the plasma spraying temperature is 10000℃, and the hollow spheres are collected with liquid nitrogen, and the hollow sphere collection distance is 500mm; the tail gas generated during the preparation process is filtered with a bag dust collector; Step 3, screening the collected hollow spheres through an airflow screening machine; Step 4: The hollow spheres with a particle size of 60 μm and a wall thickness of 2-3 μm obtained by screening are calcined at a high temperature of 750°C for 10 hours under argon protection to further remove the toxic element As in the hollow spheres, that is, high-quality hollow spheres are obtained. The tail gas generated during the calcination process is filtered through a bag filter; Step 5: Return the recovered As-containing substances to the white arsenic smelting process.

[0023] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that step 4 and step 5 are not included.

[0024] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that it only includes step 1.

[0025] The products obtained in Examples 1-4 and Comparative Examples 1-2 were made into test samples according to the national standard HJ / T299-2007. The test samples were acid leaching solutions prepared using the products prepared in Examples 1-4 and Comparative Examples 1-2. The As element content in the test samples was measured, and the results are shown in Table 1.

[0026] Table 1 As content in test samples As can be seen from Table 1, the As content in the test samples AD is 0.005-0.012 mg / L, which is much lower than the national standard for toxic and hazardous waste (5 mg / L). The hollow spheres prepared in Examples 1-4 can be used as industrial material products. The As content in the test sample E is 9.439 mg / L, which is greater than the national standard for toxic and hazardous waste, indicating that the content of toxic elements in the product prepared in Comparative Example 1 exceeds the national regulations; the As content in the test sample F is 15.672 mg / L, and the As content is significantly higher than the As content in the test sample E. By analyzing the 6 groups of samples, it can be seen that the preparation of hollow spheres by plasma spray gun technology can indeed reduce the content of toxic elements in the hollow spheres, and the content of toxic elements can be greatly reduced by further heat preservation and roasting of the hollow spheres.

[0027] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any equivalent changes or modifications made according to the essence of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing high-quality hollow spheres using copper smelting waste slag, characterized in that: The main steps include: Step 1: using copper smelting waste slag as the basic raw material, adding an appropriate amount of S, mixing to form a mixture, and grinding the mixture with a ball mill to obtain a powder; Step 2: Forming the powder into a hollow sphere by a plasma spray gun; Step 3: Using an airflow screening machine to screen the hollow spheres; Step 4: Under the protection of inert gas, the hollow spheres obtained by screening are calcined at high temperature to reduce the content of the toxic element As in the hollow spheres.

2. The method for preparing high-quality hollow spheres using copper smelting waste slag according to claim 1, characterized in that: In step 1, the copper smelting waste slag includes the following components in mass percentage: Fe2O3 54%, SiO2 29%, CaO3%, Al2O3 3%, ZnO≤3%, Na4SiO4≤2%, and MgO≤1.5%.

3. The method for preparing high-quality hollow spheres using copper smelting waste slag according to claim 1, characterized in that: In step 1, the amount of S added is 1-5% of the amount of copper smelting waste slag.

4. The method for preparing high-quality hollow spheres using copper smelting waste slag according to claim 1, characterized in that: In step 1, the particle size of the obtained powder is 20-100 μm.

5. The method for preparing high-quality hollow spheres using copper smelting waste slag according to claim 1, characterized in that: In step 2, the specific parameters for preparing hollow spheres are: argon and hydrogen are used as working gases, the argon pressure is 5-20MPa, the argon flow rate is 60-120L / min, the hydrogen pressure is 10-15MPa, and the hydrogen flow rate is 10-20L / min; the current is 280-680A; the voltage is 90-160V; the powder feeding rate is 1-10kg / min; and the plasma spray melting temperature is 8000-10000℃.

6. The method for preparing high-quality hollow spheres using copper smelting waste slag according to claim 1, characterized in that: In step 2, the hollow spheres are collected with liquid nitrogen at a collection distance of 100-500 mm; the tail gas generated during the preparation process is filtered through a bag filter.

7. The method for preparing high-quality hollow spheres using copper smelting waste slag according to claim 1, characterized in that: The hollow spheres obtained by screening in step three have a particle size of 20-60 μm and a wall thickness of 0.2-3 μm.

8. The method for preparing high-quality hollow spheres using copper smelting waste slag according to claim 1, characterized in that: In step 4, the hollow spheres are calcined at 600-750° C. for 2-10 hours under argon protection, and the tail gas generated during the high-temperature calcination process is filtered through a bag filter.

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