Method for efficiently preparing zinc-indium alloy serving as cathode base material of zinc ion battery by utilizing indium-rich slag

Abstract

The invention discloses a method for efficiently preparing a zinc-indium alloy serving as a negative electrode base material of a zinc ion battery by utilizing indium-rich slag. The method comprises the steps of reduction leaching, neutralization precipitation, reduction roasting and vacuum distillation. According to the method, a wet process and a pyrogenic process are combined, reduction leaching is carried out on the indium-rich residues by adding ZnS, ferric iron in a leaching solution is reduced into ferrous iron while zinc and indium are leached, interference of the ferric iron in the follow-up process is avoided, the indium recovery rate is larger than 92%, and meanwhile lead and iron are enriched. The prepared zinc-indium alloy is used as a basic raw material of a negative electrode material of a zinc ion battery, and the negative electrode hydrogen evolution overpotential can be effectively reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of valuable metal recovery, and in particular to a method for recovering valuable metals zinc and indium from indium-rich slag and preparing a zinc-indium alloy. The prepared zinc-indium alloy is used as a negative electrode basic material for a zinc ion electronic battery and can effectively reduce the negative electrode hydrogen evolution overpotential. Background Art

[0002] Indium zinc alloy is an alloy metal composed of indium and zinc. It has the advantages of moderate energy gap width, good lubrication performance, wear resistance and biocompatibility. It has important application value in the fields of semiconductor materials, low melting point alloys, lubricating materials, medical devices, etc. It can be used to manufacture solar cells, electromagnetic shielding materials, optoelectronic devices, friction materials and implantable medical devices.

[0003] A large amount of zinc-indium-containing raw materials are produced every year in the lead-zinc smelting system. The zinc oxide produced by the system is subjected to three-stage countercurrent leaching of neutral leaching, low-acid leaching and high-acid leaching. The indium in the raw material is mainly enriched in the weak acid leaching supernatant, and further indium-rich slag is obtained through neutralization and precipitation. The indium-rich slag is rich in metals such as zinc and indium and has a high recovery value.

[0004] At present, the treatment method for this type of indium-rich slag is generally to transfer it to a rotary kiln or a fuming furnace to volatilize the zinc, indium and other metals therein, but the above treatment method has the disadvantages of low rare metal recovery rate, high energy consumption, and heavy pollution. For example, the patent with the publication number CN109536742A, although it improves the enrichment rate of zinc and indium during the volatilization process, it cannot avoid the disadvantage of a high indium loss rate. For example, the patent with the publication number CN102312083 first uses low-iron zinc oxide for pre-neutralization, and then uses the pre-neutralized supernatant to add zinc powder to replace and precipitate indium to achieve the initial enrichment of indium, and then it is necessary to extract indium through acid leaching, extraction, replacement and other processes; the above scheme has the disadvantages of long process flow, large amount of wastewater and high cost. Summary of the invention

[0005] The invention solves the problems of complicated process, long process, low recovery rate of rare metal indium and high cost in the prior art, and provides a process method for preparing zinc-indium alloy with low impurity content by using indium-rich slag as raw material.

[0006] The technical scheme adopted by the present invention is: a method for efficiently preparing zinc-indium alloy, a negative electrode basic material of zinc ion battery, by using indium-rich slag, comprising the following steps: S1, reduction leaching, the indium-rich slag is leached with sulfuric acid, and a sulfuric acid solution and ZnS with a concentration of 90-120 g / L are added to the indium-rich slag in a ratio of indium-rich slag (kg): sulfuric acid solution (L): zinc sulfide (kg) = 1: (4-6): (0.15-0.2), and after heating and stirring at 85-95°C for 2-4 hours, zinc, indium and iron are dissolved into the leachate, and at the same time, trivalent iron is reduced to divalent iron to obtain a leachate containing zinc, indium and iron and a lead-rich slag. Leaching residue; S2, neutralization precipitation, adjusting the pH value 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, and then mixing it with a carbonaceous reducing agent and sodium acetate in a certain proportion to obtain a mixed powder, and reducing it at 500-800°C in a vacuum environment for 1-2h to obtain a zinc-indium crude alloy; S4, vacuum distillation, vacuum distilling the zinc-indium crude alloy in S3 at 1150-1200°C, with a vacuum degree of 1-10Pa, for 1-3h, so that the zinc and indium therein are volatilized to obtain a zinc-indium alloy and iron-rich slag. Since the precipitate contains some zinc sulfate, indium sulfate and their basic sulfate compounds, high-energy active sulfur oxides will be released in the heated material, and then continue to combine with the carbonaceous reducing agent at high temperature to generate strongly reducing carbonyl sulfide compounds, which can enhance the reducing ability of carbon; at the same time, the addition of sodium acetate further promotes the formation of carbonyl sulfide compounds, so that the direct recovery rates of zinc, lead and indium are all greater than 98%.

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

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

[0009] As a further improvement of the present invention, in 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: roasting 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 invention has the following beneficial effects: 1. The indium-rich slag is reduced and leached by adding ZnS, which reduces the trivalent iron in the leachate to divalent iron while leaching zinc and indium, thus avoiding the interference of trivalent iron in the subsequent process. The leaching rates of zinc and indium are both above 96%, and the divalent iron in the leachate accounts for more than 95% of the total iron content.

[0013] 2. The process of the present invention is relatively short, and it combines the hydrometallurgical process and the pyrometallurgical process, so as to realize the recovery of zinc and indium from indium-rich slag and prepare zinc-indium alloy, and the indium recovery rate is greater than 92%. In the process, lead and iron are also enriched. The indium content in the obtained zinc-indium alloy is 5-7%, which is used to make the basic raw material of the negative electrode material of zinc ion battery, and can effectively reduce the negative electrode hydrogen evolution overpotential. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the present invention. DETAILED DESCRIPTION

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

[0016] As shown in the figure, Example 1 is a method for preparing a zinc-indium alloy from indium-rich slag. In this embodiment, the indium content in the indium-rich slag is 1.36%, the zinc content is 27.2%, the lead content is 9.3%, the iron content is 9.1%, the arsenic content is 2.2%, and the copper content is 0.4%; the following steps are followed:

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

[0018] (2) Neutralization precipitation: The pH value of the leaching solution is adjusted to 5.6 to obtain a precipitate containing zinc and indium.

[0019] (3) Reduction roasting: After the precipitate is dried and crushed, the mass ratio of carbonaceous reducing agent: sodium acetate: roasting product is 20:1:100 to obtain a mixed powder, which is reduced at 600°C for 2h in a vacuum environment to obtain a zinc-indium crude alloy.

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

[0021] Among them, the zinc-indium alloy composition is: 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 negative electrode hydrogen evolution overpotential.

[0022] Example 2, a method for efficiently preparing zinc-indium alloy as a negative electrode basic material of zinc ion battery using indium-rich slag. In this embodiment, the indium content of the indium-rich slag is 1.36%, the zinc content is 27.2%, the lead content is 9.3%, the iron content is 9.1%, the arsenic content is 2.2%, and the copper content is 0.4%; proceed according to the following steps:

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

[0024] (2) Neutralization precipitation: The pH value of the leaching solution is adjusted to 5.6 to obtain a precipitate containing zinc and indium.

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

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

[0027] Among them, the zinc-indium alloy composition is: 94.02% zinc, 5.97% indium, 0.003% iron, 0.0004% copper, and 0.0001% lead. The negative electrode material prepared by the above zinc-indium alloy can effectively reduce the negative electrode hydrogen evolution overpotential.

[0028] Those skilled in the art should be aware that the protection scheme of the present invention is not limited to the above-mentioned embodiments, and various arrangements, combinations and transformations can be performed on the basis of the above-mentioned embodiments. Without violating the spirit of the present invention, various transformations of the present invention fall within the protection scope of the present invention.

Claims

1. A method for efficiently preparing zinc-indium alloy as a negative electrode basic material for zinc ion batteries using indium-rich slag, Its characteristics are The steps include: S1, reduction leaching, the indium-rich slag is leached with sulfuric acid, and a sulfuric acid solution and ZnS with a concentration of 90-120 g / L are added to the indium-rich slag in a ratio of indium-rich slag (kg): sulfuric acid solution (L): zinc sulfide (kg) = 1: (4-6): (0.15-0.2), and after heating and stirring at 85-95°C for 2-4 hours, zinc, indium and iron are dissolved into the leachate, and at the same time, the trivalent iron is reduced to divalent iron, and a leachate containing zinc, indium and iron and lead-rich leaching slag are obtained; S2, neutralization precipitation, adjusting the pH value of the leaching solution in S1 to 5.4-5.7, and obtaining a precipitate containing zinc and indium; S3, reduction roasting, drying and crushing the precipitate in S2, and then mixing it with a carbonaceous reducing agent and sodium acetate in a certain proportion to obtain a mixed powder, and reducing it at 500-800° C. for 1-2 hours in a vacuum environment to obtain a zinc-indium crude alloy; S4, vacuum distillation, vacuum distilling the zinc-indium crude alloy in S3 at 1150-1200° C., with a vacuum degree of 1-10 Pa, for 1-3 hours, so that the zinc and indium therein are volatilized to obtain zinc-indium alloy and iron-rich slag.

2. A method for efficiently preparing zinc-indium alloy as a negative electrode basic material for zinc ion batteries using indium-rich slag according to claim 1, Its characteristics are The indium content in the indium-rich slag is 1.3-3.2%, the zinc content is 26.1-32.6%, the lead content is 9.3-11.8%, the iron content is 8.6-9.8%, the arsenic content is 2.0-2.7%, and the copper content is 0.4-0.6%; the indium-rich slag is the waste slag of the wet process.

3. The method for efficiently preparing zinc-indium alloy as a negative electrode basic material of zinc ion batteries by using indium-rich slag according to claim 1, Its characteristics are In S2, a sodium hydroxide solution with a concentration of 100 to 200 g / L is used to adjust the pH value.

4. A method for efficiently preparing zinc-indium alloy as a negative electrode basic material for zinc ion batteries using indium-rich slag according to claim 1, Its characteristics are In 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 as a negative electrode basic material of zinc ion batteries by using indium-rich slag according to claim 1, Its characteristics are In S3, the mass ratio of carbonaceous reducing agent: sodium acetate: calcined product is 20-25:1-3:

100.

6. A method for efficiently preparing zinc-indium alloy, a negative electrode basic material for zinc ion batteries, by using indium-rich slag according to any one of claims 1 to 5, Its characteristics are The carbonaceous reducing agent is graphite powder, activated carbon or coke.

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