A method for efficiently preparing zinc-indium alloy, a negative electrode base material of zinc ion battery, by using indium-rich slag

Abstract

The application discloses a method for efficiently preparing zinc-indium alloy, a negative electrode basic material of a zinc ion battery, from indium-rich residue, and comprises reduction leaching, neutralization and precipitation, reduction roasting and vacuum distillation. The method combines a wet process and a pyrometallurgical process, and the indium-rich residue is subjected to reduction leaching by adding ZnS, so that zinc and indium are leached, and trivalent iron in the leaching solution is reduced to divalent iron, thereby avoiding the interference of the trivalent iron in the subsequent process, and the indium recovery rate is greater than 92%, and lead and iron are also enriched. The prepared zinc-indium alloy is used as a negative electrode material basic raw material of the zinc ion battery, and can effectively reduce the hydrogen evolution overpotential of the negative electrode.

Description

Technical Field

[0001] This invention relates to the field of valuable metal recycling technology, specifically to a method for recovering valuable metals zinc and indium from indium-rich slag and preparing zinc-indium alloys. The prepared zinc-indium alloys are used as the base material for the negative electrode of zinc-ion electronic batteries and can effectively reduce the hydrogen evolution overpotential of the negative electrode. Background Technology

[0002] Indium-zinc alloy is an alloy metal composed of indium and zinc. It possesses advantages such as a moderate bandgap, good lubrication properties, wear resistance, and biocompatibility, making it valuable in semiconductor materials, low-melting-point alloys, lubricants, and medical devices. It can be used to manufacture solar cells, electromagnetic shielding materials, optoelectronic devices, friction materials, and implantable medical devices.

[0003] The lead-zinc smelting system produces a large amount of zinc-indium-containing raw materials every year. The zinc oxide produced by the system undergoes three stages of countercurrent leaching: neutral leaching, low acid leaching, and high acid leaching. Indium in the raw materials is mainly enriched in the weak acid leaching supernatant. Further neutralization and precipitation yield indium-rich slag, which is rich in metals such as zinc and indium and has high recycling value.

[0004] Currently, the common method for treating indium-rich slag is to transfer it to a rotary kiln or fuming furnace for volatilization to remove zinc, indium, and other metals. However, these methods suffer from drawbacks such as low rare metal recovery rates, high energy consumption, and heavy pollution. For example, patent publication number CN109536742A, while improving the enrichment rate of zinc and indium during volatilization, cannot avoid the high indium loss rate. Another example is patent publication number CN102312083, which first uses low-iron zinc oxide for pre-neutralization, then adds zinc powder to the pre-neutralized supernatant for indium displacement precipitation, achieving initial indium enrichment. Subsequent processes such as acid leaching, extraction, and displacement are still required to extract indium. The disadvantages of these schemes are long process flow, large wastewater volume, and high cost. Summary of the Invention

[0005] This invention addresses the problems of cumbersome processes, long procedures, low recovery rate of rare metal indium, and high costs in existing technologies, and provides a process for preparing zinc-indium alloys with low impurity content using indium-rich slag as raw material.

[0006] The technical solution adopted in this invention is: a method for efficiently preparing zinc-indium alloy, the basic material for zinc-ion battery anodes, using indium-rich slag, comprising the following steps: S1, reduction leaching, indium-rich slag is leached with sulfuric acid, and sulfuric acid solution with a concentration of 90-120 g / L and ZnS are added to the indium-rich slag at a ratio of indium-rich slag (kg): sulfuric acid solution (L): zinc sulfide (kg) = 1:(4-6):(0.15-0.2). After heating and stirring at 85-95℃ for 2-4 hours, zinc, indium, and iron dissolve into the leaching solution, and at the same time, trivalent iron is reduced to divalent iron, resulting in a leaching solution containing zinc, indium, and iron and lead-rich... Leaching residue; S2, neutralization precipitation, adjusting the pH of the leachate in S1 to 5.4-5.7 to obtain a precipitate containing zinc and indium; S3, reduction roasting, drying and crushing the precipitate in S2, mixing it evenly with a carbonaceous reducing agent and sodium acetate in a certain proportion to obtain a mixed powder, and reducing it in a vacuum environment at 500-800℃ for 1-2 hours to obtain a crude zinc-indium alloy; S4, vacuum distillation, vacuum distilling the crude zinc-indium alloy in S3 at 1150-1200℃, with a vacuum degree of 1-10 Pa and a time of 1-3 hours, to volatilize the zinc and indium to obtain a zinc-indium alloy and iron-rich slag. Because the precipitate contains some zinc sulfate, indium sulfate and their basic sulfate compounds, it releases high-energy active sulfur oxides during heating. These oxides then continue to combine with carbonaceous reducing agents at high temperatures to generate highly reducing carbonyl sulfide compounds, which can enhance the reducing power of carbon. At the same time, the addition of sodium acetate further promotes the formation of carbonyl sulfide compounds, resulting in a direct recovery rate of zinc, lead and indium that is greater than 98%.

[0007] As a further improvement of the present invention, the indium-rich slag contains 1.3-3.2% indium, 26.1-32.6% zinc, 9.3-11.8% lead, 8.6-9.8% iron, 2.0-2.7% arsenic, and 0.4-0.6% copper. The indium-rich slag is a waste residue from a wet process.

[0008] As a further improvement of the present invention, in step S2, a sodium hydroxide solution with a concentration of 100-200 g / L is used to adjust the pH value.

[0009] As a further improvement of the present invention, in step S3, the precipitate is crushed and ground to a particle size of less than 120 μm.

[0010] As a further improvement of the present invention, in S3, the mass ratio of carbonaceous reducing agent: sodium acetate: calcination product is 20-25:1-3:100.

[0011] As a further improvement of the present invention, the carbonaceous reducing agent is graphite powder, activated carbon, or coke.

[0012] The beneficial effects of this invention are as follows: 1. By adding ZnS for reduction leaching of indium-rich slag, the ferric iron in the leachate is reduced to ferrous iron (Fe2+) simultaneously with the leaching of zinc and indium, thus avoiding interference from ferric iron in subsequent processes. The leaching rates of both zinc and indium are above 96%, and ferrous iron accounts for more than 95% of the total iron content in the leachate.

[0013] 2. This invention features a short process flow, combining wet and pyrometallurgical processes to recover zinc and indium from indium-rich slag and prepare a zinc-indium alloy. The indium recovery rate is >92%, and lead and iron are also enriched during the process. The resulting zinc-indium alloy contains 5-7% indium and can be used as a basic raw material for the negative electrode material of zinc-ion batteries, effectively reducing the hydrogen evolution overpotential of the negative electrode. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the present invention. Detailed Implementation

[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0016] As shown in the figure, Example 1 illustrates a method for preparing zinc-indium alloy from indium-rich slag. In this example, the indium-rich slag contains 1.36% indium, 27.2% zinc, 9.3% lead, 9.1% iron, 2.2% arsenic, and 0.4% copper. The method is carried out according to the following steps:

[0017] (1) Reduction leaching: The indium-rich slag is leached with sulfuric acid. According to the ratio of indium-rich slag (kg): sulfuric acid solution (L): zinc sulfide (kg) = 1:5:0.16, sulfuric acid solution with a concentration of 100g / L and ZnS are added to the indium-rich slag. After heating and stirring at 90℃ for 3h, zinc, indium and iron dissolve into the leaching solution. At the same time, trivalent iron is reduced to divalent iron, and leaching solution containing zinc, indium and iron and lead-rich leaching slag are obtained.

[0018] (2) Neutralization and precipitation: Adjust the pH of the leachate to 5.6 to obtain a precipitate containing zinc and indium.

[0019] (3) Reduction calcination: After drying and crushing the precipitate, the mass ratio of carbonaceous reducing agent: sodium acetate: calcination product is 20:1:100 to obtain mixed powder, which is then reduced at 600℃ for 2 hours in a vacuum environment to obtain zinc-indium crude alloy.

[0020] (4) Vacuum distillation: The crude alloy is vacuum distilled at 1150℃ with a vacuum degree of 1-10 Pa for 2 hours to volatilize the zinc and indium to obtain zinc-indium alloy and iron-rich slag.

[0021] The zinc-indium alloy contains 94.83% zinc, 5.15% indium, 0.007% iron, 0.001% copper, and 0.0005% lead. The negative electrode material prepared using the above zinc-indium alloy can effectively reduce the hydrogen evolution overpotential of the negative electrode.

[0022] Example 2: A method for efficiently preparing zinc-indium alloy, the basic material for zinc-ion battery anodes, using indium-rich slag. In this example, the indium-rich slag contains 1.36% indium, 27.2% zinc, 9.3% lead, 9.1% iron, 2.2% arsenic, and 0.4% copper. The method is carried out according to the following steps:

[0023] (1) Reduction leaching: The indium-rich slag is leached with sulfuric acid. According to the ratio of indium-rich slag (kg): sulfuric acid solution (L): zinc sulfide (kg) = 1:5:0.18, sulfuric acid solution with a concentration of 120g / L and ZnS are added to the indium-rich slag. After heating and stirring at 90℃ for 3h, zinc, indium and iron dissolve into the leaching solution. At the same time, trivalent iron is reduced to divalent iron, and leaching solution containing zinc, indium and iron and lead-rich leaching slag are obtained.

[0024] (2) Neutralization and precipitation: Adjust the pH of the leachate to 5.6 to obtain a precipitate containing zinc and indium.

[0025] (3) Reduction calcination: After drying and crushing the precipitate, the mass ratio of carbonaceous reducing agent: sodium acetate: calcination product is 25:3:100 to obtain a mixed powder, which is then reduced at 500°C for 2 hours in a vacuum environment to obtain a zinc-indium crude alloy.

[0026] (4) Vacuum distillation: The crude alloy is vacuum distilled at 1200℃ with a vacuum degree of 1-10 Pa for 2 hours to volatilize the zinc and indium to obtain zinc-indium alloy and iron-rich slag.

[0027] The zinc-indium alloy contains 94.02% zinc, 5.97% indium, 0.003% iron, 0.0004% copper, and 0.0001% lead. The negative electrode material prepared using the above zinc-indium alloy can effectively reduce the hydrogen evolution overpotential of the negative electrode.

[0028] Those skilled in the art should understand that the protection scheme of the present invention is not limited to the above embodiments, and various arrangements, combinations and transformations can be made on the basis of the above embodiments. Without departing from the spirit of the present invention, all transformations made to the present invention fall within the protection scope of the present invention.

Claims

1. A method for efficiently preparing zinc-indium alloy, the basic material for zinc-ion battery anodes, using indium-rich slag, characterized in that: Includes the following steps: S1, Reduction Leaching: Indium-rich slag is leached with sulfuric acid. A sulfuric acid solution with a concentration of 90-120 g / L and ZnS are added to the indium-rich slag at a ratio of indium-rich slag: sulfuric acid solution: zinc sulfide = 1:(4~6):(0.15~0.2). After heating and stirring at 85-95℃ for 2-4 hours, zinc, indium, and iron dissolve into the leaching solution. Simultaneously, ferric iron is reduced to ferrous iron, yielding a leaching solution containing zinc, indium, and iron, and lead-rich leaching slag. The units for indium-rich slag and zinc sulfide are kg, and the unit for sulfuric acid solution is L. S2, neutralize the precipitate, adjust the pH of the leachate in S1 to 5.4~5.7, and obtain a precipitate containing zinc and indium; S3, reduction roasting: The precipitate in S2 is dried, crushed and ground, and then mixed with carbonaceous reducing agent and sodium acetate in a certain proportion to obtain a mixed powder. The powder is then reduced in a vacuum environment at 500~800℃ for 1~2h to obtain zinc-indium crude alloy. S4, vacuum distillation: The zinc-indium crude alloy in S3 is vacuum distilled at 1150~1200℃, with a vacuum degree of 1~10Pa and a time of 1~3h, so that the zinc and indium are volatilized to obtain zinc-indium alloy and iron-rich slag.

2. The method for efficiently preparing zinc-indium alloy, the basic material for zinc-ion battery anodes, using indium-rich slag according to claim 1, is characterized in that... The indium-rich slag contains 1.3-3.2% indium, 26.1-32.6% zinc, 9.3-11.8% lead, 8.6-9.8% iron, 2.0-2.7% arsenic, and 0.4-0.6% copper; the indium-rich slag is waste residue from a wet process.

3. The method for efficiently preparing zinc-indium alloy, the basic material for zinc-ion battery anodes, using indium-rich slag according to claim 1, is characterized in that... In step S2, a sodium hydroxide solution with a concentration of 100~200g / L is used to adjust the pH value.

4. The method for efficiently preparing zinc-indium alloy, the basic material for zinc-ion battery anodes, using indium-rich slag according to claim 1, is characterized in that... In step S3, the precipitate is crushed and ground to a particle size of less than 120 μm.

5. The method for efficiently preparing zinc-indium alloy, the basic material for zinc-ion battery anodes, using indium-rich slag according to claim 1, is characterized in that... In S3, the mass ratio of carbonaceous reducing agent: sodium acetate: calcination product is 20~25:1~3:

100.

6. A method for efficiently preparing zinc-indium alloy, the basic material for zinc-ion battery anodes, using indium-rich slag according to any one of claims 1 to 5, characterized in that: The carbonaceous reducing agent is graphite powder, activated carbon, or coke.

Images