Method for recovering indium and bismuth from indium electrolysis anode slime

Abstract

The invention discloses a method for recovering indium and bismuth from indium electrolysis anode slime, and belongs to the technical field of resource recycling and reutilization. The indium electrolysis anode slime is reacted and leached through a sulfuric acid solution, hydrogen peroxide and a precipitator, complex components in the anode slime can be promoted to be converted into metal ions with the highest valence state, the leaching rate is effectively increased, and the leaching time is shortened; meanwhile, indium and bismuth hydrolysis loss is avoided, and the recovery rate is increased; then the leachate is subjected to reduction leaching again, so that bismuth is separated in a precipitation form, and some heavy metals and metals such as calcium and magnesium are removed; the recovery rate of the indium ions can be improved, and the purity can be improved; bismuth-containing slag is sequentially subjected to reduction heat treatment and fused salt smelting, impurities are removed in the form of dross, and the recovery rate of bismuth is effectively increased; by adopting the method, indium and bismuth can be recovered at the same time, the recovery rate is high, and meanwhile, the impurity content in the indium chloride solution is low.

Description

Technical Field

[0001] The present invention relates to the technical field of resource recovery and reuse, and particularly relates to a method for recovering indium and bismuth from indium electrolysis anode slime. Background Art

[0002] Indium, a scarce and dispersed metal, has a low melting point, a high boiling point, good thermal conductivity, and can form a transparent conductive film with metals such as tin. Indium has many uses, but its content in the earth's crust is small and it is often associated with lead, zinc, copper, and tin concentrates. Therefore, indium metal is mainly recovered from the by-products of copper, lead, zinc, and tin smelting.

[0003] Electrolysis is a common method for metal refining and is particularly suitable for indium purification. During electrolysis, metal impurities with a lower chemical potential than indium will deposit on the anode to form anode slime, which contains not only indium but also other metal elements such as bismuth, copper, and silver. Especially, a large amount of bismuth is present. Due to the high content of bismuth, it is easy to affect the recovery rate of indium. Therefore, how to effectively recover valuable metals such as indium and bismuth from indium electrolysis anode slime has become a technical problem that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method for recovering indium and bismuth from indium electrolysis anode slime. By using the method of the present invention, indium and bismuth can be recovered simultaneously with high recovery rates, and the impurity content in the indium chloride solution is low.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] A method for recovering indium and bismuth from indium electrolysis anode slime, comprising the following steps:

[0007] (1) Mix indium electrolysis anode slime, sulfuric acid solution, hydrogen peroxide, and a precipitant evenly, react, and obtain a first leaching solution;

[0008] (2) Add iron sulfide and sulfuric acid solution to the first leaching solution, react, then add a chelating agent, stir evenly, filter, and obtain a bismuth-containing residue and a second leaching solution;

[0009] (3) Extract the second leaching solution with an extractant to obtain an extract, and back-extract the extract with a hydrochloric acid solution to obtain an indium chloride solution;

[0010] (4) Mix the bismuth-containing residue and a reducing agent evenly, perform heat treatment, and obtain a bismuth-containing alloy;

[0011] (5) Mix the bismuth-containing alloy and molten salt evenly, melt, remove the surface scum, and obtain crude bismuth.

[0012] In the present invention, indium electrolytic anode slime is first reacted and leached with sulfuric acid solution, hydrogen peroxide and a precipitant, which can promote the transformation of complex components in the anode slime into metal ions with the highest valence state, effectively improve the leaching rate, avoid hydrolysis loss of indium and bismuth, and improve the recovery rate; then the leaching solution is subjected to reduction leaching again, so that bismuth is separated in the form of precipitation, and some heavy metals and metals such as calcium and magnesium are removed; then extraction and back-extraction are carried out, which can improve the recovery rate of indium ions and improve the purity; the bismuth-containing slag is successively subjected to reduction heat treatment and molten salt smelting, and impurities are removed in the form of dross, effectively improving the recovery rate of bismuth; by using the method of the present invention, indium and bismuth can be recovered simultaneously, with high recovery rates and low impurity content in the indium chloride solution.

[0013] Preferably, the mass ratio of the indium electrolytic anode slime, sulfuric acid solution, hydrogen peroxide and precipitant is 1:(4 - 6):(0.05 - 0.1):(0.005 - 0.02).

[0014] Preferably, the addition amount of iron sulfide is 1.5 - 2 times the total content of iron and bismuth in the first leaching solution.

[0015] Preferably, the mass ratio of the sulfuric acid solution, the first leaching solution and the chelating agent is (10 - 20):1:(0.01 - 0.02).

[0016] Preferably, the precipitant is 1,3,5-benzenetricarbonyl chloride;

[0017] The chelating agent is SDD heavy metal chelating agent.

[0018] Preferably, the extractant includes bis(2-ethylhexyl) phosphate, trialkyl phosphine oxide and sulfonated kerosene with a mass ratio of (10 - 20):(2 - 10):(70 - 88).

[0019] Preferably, the volume ratio of the second leaching solution to the extractant is 1:(2 - 4).

[0020] Preferably, the molar concentration of the hydrochloric acid solution is 4 - 6 mol / L; the volume ratio of the extraction solution to the hydrochloric acid solution is 1:(4 - 8).

[0021] Preferably, the reducing agent includes at least one of anthracite, coke, flour and carbonized coconut shell powder;

[0022] The mass ratio of the bismuth-containing slag to the reducing agent is (3 - 5):1;

[0023] The heat treatment temperature is 600 - 700 °C and the time is 4 - 6 h.

[0024] Preferably, the molten salt includes at least one of sodium sulfide, sodium borate, quartz sand and calcium oxide;

[0025] The mass ratio of the bismuth-containing alloy to the molten salt is (10-15):1;

[0026] The temperature of the smelting is 500-600 °C, and the time is 2-3 h.

[0027] Preferably, the reaction temperature in step (1) is 80-90 °C, and the time is 3-4 h.

[0028] Preferably, the concentration of the sulfuric acid solution in step (1) is 10-20 wt%.

[0029] Preferably, the reaction temperature in step (2) is 45-55 °C, and the time is 0.5-2 h.

[0030] Preferably, the concentration of the sulfuric acid solution in step (2) is 5-10 wt%.

[0031] Preferably, the extraction time is 5-10 min.

[0032] Preferably, the stripping time is 3-6 min.

[0033] Preferably, the concentration of the hydrogen peroxide is 20-40 wt%.

[0034] Preferably, the mass percentage of indium in the indium electrolytic anode slime is 30-35%.

[0035] Preferably, the mass percentage of bismuth in the indium electrolytic anode slime is 50-60%.

[0036] Preferably, the mass percentage of the main elements in the indium electrolytic anode slime is: In 30-35%, Bi 50-60%, Pb 0.04-2%, Cu 0.06-0.15%, Ag 0.03-0.12%, Fe 0.082-0.35%.

[0037] The beneficial effects of the present invention are as follows: The present invention first reacts and leaches the indium electrolytic anode slime with a sulfuric acid solution, hydrogen peroxide, and a precipitant, which can promote the transformation of the complex components in the anode slime into metal ions with the highest valence state, effectively improve the leaching rate, avoid the hydrolysis loss of indium and bismuth, and improve the recovery rate; then the leaching solution is subjected to reduction leaching again, so that bismuth is separated in the form of a precipitate, and some heavy metals and metals such as calcium and magnesium are removed; then extraction and stripping are carried out, which can improve the recovery rate of indium ions and improve the purity; the bismuth-containing slag is successively subjected to reduction heat treatment and molten salt smelting, and the impurities are removed in the form of dross, effectively improving the recovery rate of bismuth; by using the method of the present invention, indium and bismuth can be recovered simultaneously, with a high recovery rate and low impurity content in the indium chloride solution. Detailed Embodiments

[0038] To make the objectives, technical solutions and advantages of the embodiments of this application clearer, the following will clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, rather than all of them. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of this application.

[0039] In this application, among the technical features described in an open-ended manner, it includes a closed technical solution composed of the listed features, as well as an open technical solution including the listed features.

[0040] In this application, regarding numerical ranges, unless otherwise specified, the above numerical ranges are considered continuous and include the minimum and maximum values of the range, as well as each value between such minimum and maximum values. Further, when the range refers to integers, it includes each integer between the minimum and maximum values of the range. In addition, when multiple ranges are provided to describe features or characteristics, these ranges can be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all sub-ranges subsumed therein.

[0041] In this application, there are no particular restrictions on the specific dispersion and stirring treatment methods.

[0042] Unless otherwise specified, the component raw materials or instruments used in each embodiment and comparative example of the present invention are all commercially available raw materials or instruments, and the component raw materials used in each parallel experiment are of the same kind.

[0043] Example 1

[0044] A method for recovering indium and bismuth from indium electrolysis anode slime, comprising the following steps:

[0045] (1) Add indium electrolysis anode slime to a reaction kettle, add sulfuric acid solution with a concentration of 15 wt%, hydrogen peroxide with a concentration of 30 wt%, and a TMC precipitant (1,3,5-benzenetricarbonyl chloride), react at 85 °C for 4 h, and filter to obtain a first leaching solution;

[0046] The main element contents of the indium electrolysis anode slime are: In 34.85%, Bi 52.17%, Pb 1.74%, Cu 0.12%, Ag 0.08%, Fe 0.27%.

[0047] The mass ratio of the indium electrolysis anode slime, sulfuric acid solution, hydrogen peroxide, and precipitant is 1:6:0.05:0.02.

[0048] (2) Add iron sulfide and sulfuric acid solution with a concentration of 8 wt% to the first leaching solution, react at 50 °C for 1 h, then add SDD heavy metal chelating agent, stir evenly, filter to obtain bismuth-containing slag and the second leaching solution;

[0049] The addition amount of the iron sulfide is 2 times the total content of iron and bismuth in the first leaching solution.

[0050] The mass ratio of the sulfuric acid solution, the first leaching solution, and the chelating agent is 15:1:0.02.

[0051] (3) Extract the second leaching solution with an extractant for 8 min to obtain an extract, and back-extract the extract with 5 mol / L hydrochloric acid solution for 5 min to obtain indium chloride solution;

[0052] The extractant includes bis(2-ethylhexyl) phosphate, trialkyl phosphine oxide, and sulfonated kerosene with a mass ratio of 20:10:70. The volume ratio of the second leaching solution to the extractant is 1:4.

[0053] The volume ratio of the extract to the hydrochloric acid solution is 1:6.

[0054] (4) Mix the bismuth-containing slag and coke evenly according to a mass ratio of 5:1, and heat-treat at 600 °C for 4 h to obtain a bismuth-containing alloy;

[0055] (5) Mix the bismuth-containing alloy and sodium borate evenly according to a mass ratio of 10:1, melt at 500 °C for 3 h, remove the surface scum to obtain crude bismuth.

[0056] Example 2

[0057] A method for recovering indium and bismuth from indium electrolysis anode slime, comprising the following steps:

[0058] (1) Add indium electrolysis anode slime to a reaction kettle, add sulfuric acid solution with a concentration of 15 wt%, 30 wt% hydrogen peroxide, and TMC precipitating agent (1,3,5-benzenetricarbonyl chloride), react at 85 °C for 4 h, filter to obtain the first leaching solution;

[0059] The main element contents of the indium electrolysis anode slime are: In 34.85%, Bi 52.17%, Pb 1.74%, Cu 0.12%, Ag 0.08%, Fe 0.27%.

[0060] The mass ratio of the indium electrolysis anode slime, sulfuric acid solution, hydrogen peroxide, and precipitating agent is 1:4:0.1:0.005.

[0061] (2) Add iron sulfide and a sulfuric acid solution with a concentration of 8 wt% to the first leaching solution, react at 50 °C for 1 h, then add an SDD heavy metal chelating agent, stir evenly, filter to obtain a bismuth-containing residue and a second leaching solution;

[0062] The addition amount of the iron sulfide is 2 times the total content of iron and bismuth in the first leaching solution.

[0063] The mass ratio of the sulfuric acid solution, the first leaching solution, and the chelating agent is 15:1:0.02.

[0064] (3) Extract the second leaching solution with an extractant for 8 min to obtain an extract, and back-extract the extract with a 5 mol / L hydrochloric acid solution for 5 min to obtain an indium chloride solution;

[0065] The extractant includes bis(2-ethylhexyl) phosphate, trialkylphosphine oxide, and sulfonated kerosene with a mass ratio of 20:10:70. The volume ratio of the second leaching solution to the extractant is 1:4.

[0066] The volume ratio of the extract to the hydrochloric acid solution is 1:6.

[0067] (4) Mix the bismuth-containing residue and coke evenly according to a mass ratio of 5:1, and heat-treat at 600 °C for 4 h to obtain a bismuth-containing alloy;

[0068] (5) Mix the bismuth-containing alloy and sodium borate evenly according to a mass ratio of 10:1, melt at 500 °C for 3 h, remove the surface scum to obtain crude bismuth.

[0069] Example 3

[0070] A method for recovering indium and bismuth from indium electrolysis anode slime, comprising the following steps:

[0071] (1) Add indium electrolysis anode slime to a reaction kettle, add a sulfuric acid solution with a concentration of 15 wt%, 30 wt% hydrogen peroxide, and a TMC precipitating agent (1,3,5-benzenetricarbonyl chloride), react at 85 °C for 4 h, filter to obtain a first leaching solution;

[0072] The main element contents of the indium electrolysis anode slime are: In 34.85%, Bi 52.17%, Pb 1.7%, Cu 0.12%, Ag 0.08%, Fe 0.27%.

[0073] The mass ratio of the indium electrolysis anode slime, the sulfuric acid solution, hydrogen peroxide, and the precipitating agent is 1:6:0.05:0.02.

[0074] (2) Add iron sulfide and sulfuric acid solution with a concentration of 8 wt% to the first leaching solution, react at 50 °C for 1 h, then add SDD heavy metal chelating agent, stir evenly, filter to obtain bismuth-containing slag and the second leaching solution;

[0075] The addition amount of the iron sulfide is 2 times the total content of iron and bismuth in the first leaching solution.

[0076] The mass ratio of the sulfuric acid solution, the first leaching solution, and the chelating agent is 15:1:0.02.

[0077] (3) Extract the second leaching solution with an extractant for 8 min to obtain an extract, and back-extract the extract with 5 mol / L hydrochloric acid solution for 5 min to obtain indium chloride solution;

[0078] The extractant includes bis(2-ethylhexyl) phosphate, trialkyl phosphine oxide, and sulfonated kerosene with a mass ratio of 20:2:78. The volume ratio of the second leaching solution to the extractant is 1:2.

[0079] The volume ratio of the extract to the hydrochloric acid solution is 1:6.

[0080] (4) Mix the bismuth-containing slag and coke evenly according to a mass ratio of 5:1, and heat-treat at 600 °C for 4 h to obtain a bismuth-containing alloy;

[0081] (5) Mix the bismuth-containing alloy and sodium borate evenly according to a mass ratio of 10:1, melt at 500 °C for 3 h, remove the surface scum to obtain crude bismuth.

[0082] Example 4

[0083] A method for recovering indium and bismuth from indium electrolysis anode slime, comprising the following steps:

[0084] (1) Add indium electrolysis anode slime to a reaction kettle, add sulfuric acid solution with a concentration of 15 wt%, 30 wt% hydrogen peroxide, and TMC precipitating agent (1,3,5-benzenetricarbonyl chloride), react at 85 °C for 4 h, filter to obtain the first leaching solution;

[0085] The main element contents of the indium electrolysis anode slime are: In 34.85%, Bi 52.17%, Pb 1.74%, Cu 0.12%, Ag 0.08%, Fe 0.27%.

[0086] The mass ratio of the indium electrolysis anode slime, the sulfuric acid solution, the hydrogen peroxide, and the precipitating agent is 1:6:0.05:0.02.

[0087] (2) Add iron sulfide and a sulfuric acid solution with a concentration of 8 wt% to the first leaching solution, react at 50 °C for 1 h, then add an SDD heavy metal chelating agent, stir evenly, filter to obtain a bismuth-containing residue and a second leaching solution;

[0088] The addition amount of the iron sulfide is 2 times the total content of iron and bismuth in the first leaching solution.

[0089] The mass ratio of the sulfuric acid solution, the first leaching solution, and the chelating agent is 15:1:0.02.

[0090] (3) Extract the second leaching solution with an extractant for 8 min to obtain an extract, and back-extract the extract with a 5 mol / L hydrochloric acid solution for 5 min to obtain an indium chloride solution;

[0091] The extractant includes bis(2-ethylhexyl) phosphate, trialkyl phosphine oxide, and sulfonated kerosene with a mass ratio of 20:10:70. The volume ratio of the second leaching solution to the extractant is 1:4.

[0092] The volume ratio of the extract to the hydrochloric acid solution is 1:6.

[0093] (4) Mix the bismuth-containing residue and coke evenly according to a mass ratio of 3:1, and heat-treat at 700 °C for 4 h to obtain a bismuth-containing alloy;

[0094] (5) Mix the bismuth-containing alloy and sodium borate evenly according to a mass ratio of 10:1, melt at 500 °C for 3 h, remove the surface scum to obtain crude bismuth.

[0095] Example 5

[0096] A method for recovering indium and bismuth from indium electrolysis anode slime, comprising the following steps:

[0097] (1) Add indium electrolysis anode slime to a reaction kettle, add a sulfuric acid solution with a concentration of 15 wt%, 30 wt% hydrogen peroxide, and a TMC precipitating agent (1,3,5-benzenetricarbonyl chloride), react at 85 °C for 4 h, filter to obtain a first leaching solution;

[0098] The main element contents of the indium electrolysis anode slime are: In 34.85%, Bi 52.17%, Pb 1.74%, Cu 0.12%, Ag 0.08%, Fe 0.27%.

[0099] The mass ratio of the indium electrolysis anode slime, the sulfuric acid solution, hydrogen peroxide, and the precipitating agent is 1:6:0.05:0.02.

[0100] (2) Add iron sulfide and a sulfuric acid solution with a concentration of 8 wt% to the first leaching solution, react at 50 °C for 1 h, then add the SDD heavy metal chelating agent, stir evenly, filter to obtain a bismuth-containing residue and a second leaching solution;

[0101] The addition amount of the iron sulfide is 2 times the total content of iron and bismuth in the first leaching solution.

[0102] The mass ratio of the sulfuric acid solution, the first leaching solution, and the chelating agent is 15:1:0.02.

[0103] (3) Extract the second leaching solution with an extractant for 8 min to obtain an extract, and back-extract the extract with a 5 mol / L hydrochloric acid solution for 5 min to obtain an indium chloride solution;

[0104] The extractant includes bis(2-ethylhexyl) phosphate, trialkyl phosphine oxide, and sulfonated kerosene with a mass ratio of 20:10:70. The volume ratio of the second leaching solution to the extractant is 1:4.

[0105] The volume ratio of the extract to the hydrochloric acid solution is 1:6.

[0106] (4) Mix the bismuth-containing residue and coke evenly according to a mass ratio of 5:1, and heat-treat at 600 °C for 4 h to obtain a bismuth-containing alloy;

[0107] (5) Mix the bismuth-containing alloy and sodium borate evenly according to a mass ratio of 15:1, melt at 600 °C for 2 h, remove the surface scum to obtain crude bismuth.

[0108] Comparative Example 1

[0109] A method for recovering indium and bismuth from indium electrolysis anode slime, comprising the following steps:

[0110] (1) Add indium electrolysis anode slime to a reaction kettle, add a sulfuric acid solution with a concentration of 15 wt%, react at 85 °C for 4 h, filter to obtain a first leaching solution;

[0111] The main element contents of the indium electrolysis anode slime are: In 34.85%, Bi 52.17%, Pb 1.74%, Cu 0.12%, Ag 0.08%, Fe 0.27%.

[0112] The mass ratio of the indium electrolysis anode slime to the sulfuric acid solution is 1:6.

[0113] (2) Add iron sulfide and a sulfuric acid solution with a concentration of 8 wt% to the first leaching solution, react at 50 °C for 1 h, then add the SDD heavy metal chelating agent, stir evenly, filter to obtain a bismuth-containing residue and a second leaching solution;

[0114] The addition amount of the iron sulfide is 2 times the total content of iron and bismuth in the first leaching solution.

[0115] The mass ratio of the sulfuric acid solution, the first leaching solution, and the chelating agent is 15:1:0.02.

[0116] (3) The second leaching solution is extracted with an extractant for 8 min to obtain an extraction solution, and the extraction solution is back-extracted with a 5 mol / L hydrochloric acid solution for 5 min to obtain an indium chloride solution;

[0117] The extractant described includes bis(2-ethylhexyl) phosphate, trialkyl phosphine oxide, and sulfonated kerosene with a mass ratio of 20:10:70. The volume ratio of the second leaching solution to the extractant is 1:4.

[0118] The volume ratio of the extraction solution to the hydrochloric acid solution is 1:6.

[0119] (4) The bismuth-containing slag and coke are mixed evenly according to a mass ratio of 5:1 and heat-treated at 600 °C for 4 h to obtain a bismuth-containing alloy;

[0120] (5) The bismuth-containing alloy and sodium borate are mixed evenly according to a mass ratio of 10:1 and melted at 500 °C for 3 h to remove the surface scum to obtain crude bismuth.

[0121] Comparative Example 2

[0122] The difference between Comparative Example 2 and Example 1 is that the mass ratio of indium electrolytic anode slime, sulfuric acid solution, hydrogen peroxide, and precipitant in Comparative Example 2 is not within the scope of the present invention.

[0123] The mass ratio of indium electrolytic anode slime, sulfuric acid solution, hydrogen peroxide, and precipitant in this comparative example is 1:2:0.2:0.001.

[0124] Comparative Example 3

[0125] The difference between Comparative Example 3 and Example 1 is that the mass ratio of indium electrolytic anode slime, sulfuric acid solution, hydrogen peroxide, and precipitant in Comparative Example 3 is not within the scope of the present invention.

[0126] The mass ratio of indium electrolytic anode slime, sulfuric acid solution, hydrogen peroxide, and precipitant in this comparative example is 1:8:0.02:0.04.

[0127] Comparative Example 4

[0128] The difference between Comparative Example 4 and Example 1 is that the addition amount of iron sulfide in Comparative Example 4 is 1 times the total content of iron and bismuth in the first leaching solution.

[0129] Comparative Example 5

[0130] The difference between Comparative Example 5 and Example 1 is that the addition amount of iron sulfide in Comparative Example 5 is 3 times the total content of iron and bismuth in the first leaching solution.

[0131] Test Example

[0132] Among them, the main impurity contents in the indium chloride solution are shown in Table 1, and the indium recovery rates are shown in Table 1.

[0133] The purity and recovery rate of crude bismuth are shown in Table 1.

[0134] Table 1

[0135]

[0136] As can be seen from Table 1, in the present invention, the indium electrolytic anode slime is first reacted and leached with a sulfuric acid solution, hydrogen peroxide, and a precipitant, which can promote the conversion of the complex components in the anode slime into metal ions with the highest valence state, effectively improve the leaching rate, avoid the hydrolysis loss of indium and bismuth, and improve the recovery rate; then the leaching solution is subjected to reduction leaching again, so that bismuth is separated in the form of a precipitate, and some heavy metals and metals such as calcium and magnesium are removed; then extraction and back-extraction are carried out, which can improve the recovery rate of indium ions and improve the purity; the bismuth-containing slag is successively subjected to reduction heat treatment and molten salt smelting, and the impurities are removed in the form of dross, effectively improving the recovery rate of bismuth; by adopting the method of the present invention, indium and bismuth can be recovered simultaneously, with a high recovery rate and low impurity content in the indium chloride solution.

[0137] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and do not limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for recovering indium and bismuth from indium electrolysis anode slime, characterized in that, It includes the following steps: (1) Mix indium electrolytic anode slime, sulfuric acid solution, hydrogen peroxide and a precipitant evenly, react to obtain a first leaching solution; (2) Add iron sulfide and sulfuric acid solution to the first leaching solution, react, then add a chelating agent, stir evenly, filter to obtain a bismuth-containing residue and a second leaching solution; (3) Extract the second leaching solution with an extractant to obtain an extraction solution, and back-extract the extraction solution with a hydrochloric acid solution to obtain an indium chloride solution; (4) Mix the bismuth-containing residue and a reducing agent evenly, perform heat treatment to obtain a bismuth-containing alloy; (5) Mix the bismuth-containing alloy and molten salt evenly, smelt, remove the surface scum to obtain crude bismuth.

2. The method for recovering indium and bismuth from indium electrolysis anode slime according to claim 1, characterized in that, The mass ratio of the indium electrolytic anode slime, sulfuric acid solution, hydrogen peroxide and the precipitant is 1:(4 - 6):(0.05 - 0.1):(0.005 - 0.02).

3. The method for recovering indium and bismuth from indium electrolysis anode slime according to claim 1, characterized in that, The addition amount of the iron sulfide is 1.5 - 2 times the total content of iron and bismuth in the first leaching solution.

4. The method for recovering indium and bismuth from indium electrolysis anode slime according to claim 1, characterized in that, The mass ratio of the sulfuric acid solution, the first leaching solution and the chelating agent is (10 - 20):1:(0.01 - 0.02).

5. The method for recovering indium and bismuth from indium electrolysis anode slime according to claim 1, characterized in that, The precipitant is 1,3,5-benzenetricarbonyl chloride; The chelating agent is SDD heavy metal chelating agent.

6. The method for recovering indium and bismuth from indium electrolysis anode slime according to claim 1, characterized in that, The extractant includes bis(2-ethylhexyl) phosphate, trialkyl phosphine oxide and sulfonated kerosene with a mass ratio of (10 - 20):(2 - 10):(70 - 88).

7. The method for recovering indium and bismuth from indium electrolysis anode slime according to claim 1, characterized in that, The volume ratio of the second leaching solution to the extractant is 1:(2 - 4).

8. The method for recovering indium and bismuth from indium electrolysis anode slime according to claim 1, characterized in that, The molar concentration of the hydrochloric acid solution is 4 - 6 mol / L; the volume ratio of the extraction solution to the hydrochloric acid solution is 1:(4 - 8).

9. The method for recovering indium and bismuth from indium electrolysis anode slime according to claim 1, characterized in that, The reducing agent includes at least one of anthracite, coke, flour and carbonized coconut shell powder; The mass ratio of the bismuth-containing residue to the reducing agent is (3 - 5):1; The heat treatment temperature is 600 - 700 °C and the time is 4 - 6 h.

10. The method for recovering indium and bismuth from indium electrolysis anode slime according to claim 1, characterized in that, The molten salt includes at least one of sodium sulfide, sodium borate, quartz sand and calcium oxide; The mass ratio of the bismuth-containing alloy to the molten salt is (10 - 15):1; The smelting temperature is 500 - 600 °C and the time is 2 - 3 h.

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