Method for preparing indium oxide by utilizing indium-containing acid liquor

Abstract

The invention discloses a method for preparing indium oxide by utilizing an indium-containing acid solution, and belongs to the technical field of resource recovery. The method comprises the following steps: blending the indium-containing acid solution with sulfuric acid, converting weak acid salt into strong acid salt, adjusting pH with caustic soda flakes, precipitating metal ions to obtain relatively pure hydroxide, and dissolving the precipitate with acid to provide a good environment for extraction; the method comprises the following steps of: extracting indium in an alkaline solution to promote the extraction and separation of impurity ions, avoiding the loss of indium metal, adjusting the pH value by using caustic soda flakes, promoting the precipitation of indium in a form of completing precipitation, and finally, carrying out heat treatment twice to obtain high-quality indium oxide, and the indium oxide is low in impurity content and high in purity.

Description

Technical Field

[0001] The present invention relates to the technical field of resource recovery, and specifically relates to a method for preparing indium oxide by using indium-containing acid solution. Background Art

[0002] Indium is widely used in the fields of semiconductor materials, alloy solders, chemical catalysts, aerospace and military wear-resistant and anti-corrosion coatings, etc. It is a silver-white and rare-dispersed metal with important strategic value. At present, the indium-containing resources in primary ores are relatively scarce, and most enterprises recover indium metal from secondary indium-containing resources. Common methods include extraction method, vacuum distillation, electrochemistry metallurgy, etc.

[0003] The sources of indium-containing acid solution are extensive. For example, during the indium electrolysis process, indium-containing acid solution will be generated when washing the electrolytic cell; when washing the indium precipitation filter residue, indium-containing acid solution will also be generated, and indium-containing acid solution will also be generated during the preparation of indium sulfate; common methods for recovering indium-containing acid solution include extraction method, vacuum distillation, electrochemistry metallurgy, etc. During the recovery process, indium often coexists with a large amount of impurity metals, increasing the complexity of separating and extracting indium. Especially for the separation of indium, tin, and iron, it has not been possible to achieve high-efficiency and low-cost separation and recovery of indium metal. 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 preparing indium oxide by using indium-containing acid solution. The indium oxide prepared by the method of the present invention has low impurity content and high purity.

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

[0006] A method for preparing indium oxide by using indium-containing acid solution, comprising the following steps:

[0007] (1) Add the indium-containing acid solution to the sulfuric acid solution, stir evenly, then add flake caustic soda to adjust the pH to 7-8, stir evenly, and filter to obtain the first precipitate;

[0008] (2) Dissolve the first precipitate with hydrochloric acid solution to obtain a mixed solution, and extract the mixed solution with an extractant to obtain an extract;

[0009] (3) Add sodium sulfide to the extract, adjust the pH to 2-3 with hydrochloric acid solution, stir and react, and filter to obtain a filtrate;

[0010] (4) Adjust the pH of the filtrate to 10-12 with flake caustic soda, and filter to obtain the second precipitate;

[0011] (5) Subject the second precipitate to the first heat treatment and the second heat treatment to obtain indium oxide.

[0012] In the present invention, the indium-containing acid solution is first mixed with sulfuric acid to convert the weak acid salt into a strong acid salt, and then the pH is adjusted with flake soda to precipitate metal ions, obtaining relatively pure hydroxides. Then the precipitate is dissolved in acid to provide a good environment for extraction, promoting the extraction and separation of impurity ions and avoiding the loss of indium metal. The pH is adjusted with flake soda to promote the precipitation of indium in the form of complete precipitation. Finally, through two heat treatments, high-quality indium oxide is obtained. The indium oxide has low impurity content and high purity.

[0013] Preferably, the volume ratio of the indium-containing acid solution to the sulfuric acid solution is 1:(5 - 15).

[0014] Preferably, the concentration of the sulfuric acid solution is 10 - 30 wt%.

[0015] Preferably, the solid-liquid ratio of the first precipitate to the hydrochloric acid solution is 1 g:(6 - 8) mL.

[0016] Preferably, the molar concentration of the hydrochloric acid solution in step (2) is 4 - 6 mol / L.

[0017] Preferably, the molar concentration of the hydrochloric acid solution in step (3) is 4 - 6 mol / L.

[0018] Preferably, the extractant includes at least one of trialkylmethylammonium chloride, bis(2-ethylhexyl) phosphate, 2-ethylhexyl phosphate mono-2-ethylhexyl ester, and tributyl phosphate.

[0019] Preferably, the extractant includes trialkylmethylammonium chloride and bis(2-ethylhexyl) phosphate with a mass ratio of (30 - 50):(50 - 70). In particular, using these two extractants can more effectively improve the extraction effect, extract and separate impurity ions, and avoid the loss of indium metal.

[0020] Preferably, the volume ratio of the mixed solution to the extractant is 1:(2 - 4).

[0021] Preferably, the addition amount of sodium sulfide is 1.5 - 2.5 times the tin content in the extraction solution.

[0022] Preferably, the temperature of the first heat treatment is 150 - 200 °C and the time is 2 - 6 h.

[0023] Preferably, the temperature of the second heat treatment is 600 - 650 °C and the time is 6 - 10 h.

[0024] Preferably, the main element contents in the indium-containing acid solution are as follows: In 800 - 1000 ppm, Sn 20 - 30 ppm, Fe 100 - 150 ppm, Cu 5 - 10 ppm, Tl < 5 ppm, Ni < 5 ppm, Mg < 5 ppm.

[0025] The beneficial effects of the present invention are as follows: in the present invention, the indium-containing acid solution is first blended with sulfuric acid to convert the weak acid salt into a strong acid salt, and then the pH is adjusted with sodium hydroxide flakes to precipitate metal ions, obtaining relatively pure hydroxides. Then, the precipitate is dissolved in acid to provide a good environment for extraction, promoting the extraction and separation of impurity ions and avoiding the loss of indium metal. The pH is adjusted with sodium hydroxide flakes to promote the precipitation of indium in the form of complete precipitation. Finally, through two heat treatments, high-quality indium oxide is obtained. The indium oxide has low impurity content and high purity. Description of the Drawings

[0026] Figure 1 Indium oxide prepared in Example 1.

[0027] Figure 2 Indium oxide prepared in Comparative Example 7.

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below. Apparently, the described embodiments are some, but not all, of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present application.

[0029] In the present application, among the technical features described in an open-ended manner, a closed technical solution composed of the listed features is included, as well as an open technical solution including the listed features.

[0030] In the present application, regarding the numerical range, unless otherwise specified, the above numerical range is considered continuous and includes 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 an integer, each integer between the minimum and maximum values of the range is included. 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.

[0031] In the present application, there are no particular restrictions on the specific dispersion and stirring treatment methods.

[0032] Unless otherwise specified, the component raw materials or instruments used in the embodiments and comparative examples of the present invention are all commercially available raw materials or instruments, and the component raw materials used in each parallel experiment are the same.

[0033] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0034] Example 1

[0035] A method for preparing indium oxide using indium-containing acid solution, comprising the following steps:

[0036] (1) Add the indium-containing acid solution to a 20 wt% sulfuric acid solution, stir evenly, then add flake soda to adjust the pH to 8, stir evenly, filter to obtain a first precipitate (white precipitate);

[0037] The main element contents in the indium-containing acid solution are as follows: In 962 ppm, Sn 23 ppm, Fe 138 ppm, Cu 6 ppm, Tl 3 ppm, Ni 3 ppm, Mg 3 ppm.

[0038] The volume ratio of the indium-containing acid solution to the sulfuric acid solution is 1:10.

[0039] (2) Dissolve the first precipitate in a 5 mol / L hydrochloric acid solution to obtain a mixed solution, and extract the mixed solution with an extractant for 10 min to obtain an extract;

[0040] The solid-liquid ratio of the first precipitate to the hydrochloric acid solution is 1 g:6 mL.

[0041] The volume ratio of the mixed solution to the extractant is 1:4;

[0042] The extractant comprises trialkylmethylammonium chloride and bis(2-ethylhexyl) phosphate with a mass ratio of 30:70.

[0043] (3) Add sodium sulfide to the extract, adjust the pH to 2 with a 5 mol / L hydrochloric acid solution, stir and react until no white precipitate is produced, filter to obtain a filtrate;

[0044] The addition amount of sodium sulfide is 2 times the tin content in the extract.

[0045] (4) Adjust the pH of the filtrate to 12 with flake soda, filter to obtain a second precipitate;

[0046] (5) Add the second precipitate to a muffle furnace, heat-treat at 200 °C for 4 h, and then heat-treat at 600 °C for 5 h to obtain indium oxide as Figure 1 shown.

[0047] Example 2

[0048] A method for preparing indium oxide from indium-containing acid solution, comprising the following steps:

[0049] (1) Add the indium-containing acid solution to a 20 wt% sulfuric acid solution, stir evenly, then add flake caustic to adjust the pH to 8, stir evenly, and filter to obtain a first precipitate (white precipitate);

[0050] The main element contents in the indium-containing acid solution are as follows: In 962 ppm, Sn 23 ppm, Fe 138 ppm, Cu 6 ppm, Tl 3 ppm, Ni 3 ppm, Mg 3 ppm.

[0051] The volume ratio of the indium-containing acid solution to the sulfuric acid solution is 1:10.

[0052] (2) Dissolve the first precipitate in a 5 mol / L hydrochloric acid solution to obtain a mixed solution, and extract the mixed solution with an extractant for 10 min to obtain an extract;

[0053] The solid-liquid ratio of the first precipitate to the hydrochloric acid solution is 1 g:6 mL.

[0054] The volume ratio of the mixed solution to the extractant is 1:4;

[0055] The extractant comprises trialkylmethylammonium chloride and bis(2-ethylhexyl) phosphoric acid ester with a mass ratio of 50:50.

[0056] (3) Add sodium sulfide to the extract, adjust the pH to 2 with a 5 mol / L hydrochloric acid solution, stir and react until no white precipitate is produced, and filter to obtain a filtrate;

[0057] The addition amount of sodium sulfide is 2 times the tin content in the extract.

[0058] (4) Adjust the pH of the filtrate to 12 with flake caustic and filter to obtain a second precipitate;

[0059] (5) Add the second precipitate to a muffle furnace, heat-treat it at 200 °C for 4 h, and then heat-treat it at 600 °C for 5 h to obtain indium oxide.

[0060] Example 3

[0061] A method for preparing indium oxide from indium-containing acid solution, comprising the following steps:

[0062] (1) Add the indium-containing acid solution to a 20 wt% sulfuric acid solution, stir evenly, then add flake caustic to adjust the pH to 8, stir evenly, and filter to obtain a first precipitate (white precipitate);

[0063] The main element contents in the indium-containing acid solution are as follows: In 962 ppm, Sn 23 ppm, Fe 138 ppm, Cu 6 ppm, Tl 3 ppm, Ni 3 ppm, Mg 3 ppm.

[0064] The volume ratio of the indium-containing acid solution to the sulfuric acid solution is 1:10.

[0065] (2) Dissolve the first precipitate in a 5 mol / L hydrochloric acid solution to obtain a mixed solution, and extract the mixed solution with an extractant for 10 min to obtain an extract;

[0066] The solid-liquid ratio of the first precipitate to the hydrochloric acid solution is 1 g:6 mL.

[0067] The volume ratio of the mixed solution to the extractant is 1:4;

[0068] The extractant includes trialkylmethylammonium chloride and bis(2-ethylhexyl) phosphate with a mass ratio of 30:70.

[0069] (3) Add sodium sulfide to the extract, adjust the pH to 3 with a 5 mol / L hydrochloric acid solution, stir and react until no white precipitate is produced, and filter to obtain a filtrate;

[0070] The addition amount of sodium sulfide is twice the tin content in the extract.

[0071] (4) Adjust the pH of the filtrate to 12 with flake caustic and filter to obtain a second precipitate;

[0072] (5) Add the second precipitate to a muffle furnace, heat-treat it at 200 °C for 4 h, and then heat-treat it at 600 °C for 5 h to obtain indium oxide.

[0073] Example 4

[0074] A method for preparing indium oxide from an indium-containing acid solution, comprising the following steps:

[0075] (1) Add the indium-containing acid solution to a 20 wt% sulfuric acid solution, stir evenly, then add flake caustic to adjust the pH to 8, stir evenly, and filter to obtain a first precipitate (white precipitate);

[0076] The main element contents in the indium-containing acid solution are as follows: In 962 ppm, Sn 23 ppm, Fe 138 ppm, Cu 6 ppm, Tl 3 ppm, Ni 3 ppm, Mg 3 ppm.

[0077] The volume ratio of the indium-containing acid solution to the sulfuric acid solution is 1:10.

[0078] (2) Dissolve the first precipitate in a 5 mol / L hydrochloric acid solution to obtain a mixed solution, and extract the mixed solution with an extractant for 10 min to obtain an extract;

[0079] The solid-liquid ratio of the first precipitate to the hydrochloric acid solution is 1 g: 6 mL.

[0080] The volume ratio of the mixed solution to the extractant is 1:4;

[0081] The extractant includes trialkylmethylammonium chloride and bis(2-ethylhexyl) phosphate with a mass ratio of 30:70.

[0082] (3) Add sodium sulfide to the extract, adjust the pH to 2 with a 5 mol / L hydrochloric acid solution, stir and react until no white precipitate is produced, and filter to obtain a filtrate;

[0083] The addition amount of the sodium sulfide is 2 times the tin content in the extract.

[0084] (4) Adjust the pH of the filtrate to 10 with caustic soda and filter to obtain a second precipitate;

[0085] (5) Add the second precipitate to a muffle furnace, perform heat treatment at 200 °C for 4 h, and then perform heat treatment at 600 °C for 5 h to obtain indium oxide.

[0086] Example 5

[0087] A method for preparing indium oxide from indium-containing acid solution, comprising the following steps:

[0088] (1) Add the indium-containing acid solution to a 20 wt% sulfuric acid solution, stir evenly, then add caustic soda to adjust the pH to 8, stir evenly, and filter to obtain a first precipitate (white precipitate);

[0089] The main element contents in the indium-containing acid solution are as follows: In 962 ppm, Sn 23 ppm, Fe 138 ppm, Cu 6 ppm, Tl 3 ppm, Ni 3 ppm, Mg 3 ppm.

[0090] The volume ratio of the indium-containing acid solution to the sulfuric acid solution is 1:10.

[0091] (2) Dissolve the first precipitate in a 5 mol / L hydrochloric acid solution to obtain a mixed solution, and extract the mixed solution with an extractant for 10 min to obtain an extract;

[0092] The solid-liquid ratio of the first precipitate to the hydrochloric acid solution is 1 g: 6 mL.

[0093] The volume ratio of the mixed solution to the extractant is 1:4;

[0094] The extractant includes trialkylmethylammonium chloride and bis(2-ethylhexyl) phosphate with a mass ratio of 30:70.

[0095] (3) Add sodium sulfide to the extract, adjust the pH to 2 with 5 mol / L hydrochloric acid solution, stir and react until no white precipitate is produced, then filter to obtain a filtrate.

[0096] The addition amount of the sodium sulfide is twice the tin content in the extract.

[0097] (4) Adjust the pH of the filtrate to 12 with sodium hydroxide flakes, then filter to obtain a second precipitate.

[0098] (5) Add the second precipitate to a muffle furnace, perform heat treatment at 200 °C for 4 h, and then perform heat treatment at 650 °C for 5 h to obtain indium oxide.

[0099] Comparative Example 1

[0100] A method for preparing indium oxide from indium-containing acid solution includes the following steps:

[0101] (1) Add the indium-containing acid solution to a 20 wt% sulfuric acid solution, stir evenly, then add sodium hydroxide flakes to adjust the pH to 8, stir evenly, and filter to obtain a first precipitate (white precipitate).

[0102] The main element contents in the indium-containing acid solution are as follows: In 962 ppm, Sn 23 ppm, Fe 138 ppm, Cu 6 ppm, Tl 3 ppm, Ni 3 ppm, Mg 3 ppm.

[0103] The volume ratio of the indium-containing acid solution to the sulfuric acid solution is 1:10.

[0104] (2) Dissolve the first precipitate with 5 mol / L hydrochloric acid solution to obtain a mixed solution, extract the mixed solution with an extractant for 10 min to obtain an extract.

[0105] The solid-liquid ratio of the first precipitate to the hydrochloric acid solution is 1 g:6 mL.

[0106] The volume ratio of the mixed solution to the extractant is 1:4;

[0107] The extractant includes trialkylmethylammonium chloride and bis(2-ethylhexyl) phosphate with a mass ratio of 30:70.

[0108] (3) Add sodium sulfide to the extract, adjust the pH to 1 with 5 mol / L hydrochloric acid solution, stir and react until no white precipitate is produced, then filter to obtain a filtrate.

[0109] The addition amount of the sodium sulfide is twice the tin content in the extract.

[0110] (4) Adjust the pH of the filtrate to 12 with sodium hydroxide flakes, filter to obtain the second precipitate;

[0111] (5) Add the second precipitate to a muffle furnace, heat-treat it at 200 °C for 4 h, and then heat-treat it at 600 °C for 5 h to obtain indium oxide.

[0112] Comparative Example 2

[0113] A method for preparing indium oxide from indium-containing acid solution, comprising the following steps:

[0114] (1) Add the indium-containing acid solution to a 20 wt% sulfuric acid solution, stir evenly, then add sodium hydroxide flakes to adjust the pH to 8, stir evenly, filter to obtain the first precipitate (white precipitate);

[0115] The main element contents in the indium-containing acid solution are as follows: In 962 ppm, Sn 23 ppm, Fe 138 ppm, Cu 6 ppm, Tl 3 ppm, Ni 3 ppm, Mg 3 ppm.

[0116] The volume ratio of the indium-containing acid solution to the sulfuric acid solution is 1:10.

[0117] (2) Dissolve the first precipitate in a 5 mol / L hydrochloric acid solution to obtain a mixed solution, extract the mixed solution with an extractant for 10 min to obtain an extract;

[0118] The solid-liquid ratio of the first precipitate to the hydrochloric acid solution is 1 g:6 mL.

[0119] The volume ratio of the mixed solution to the extractant is 1:4;

[0120] The extractant comprises trialkylmethylammonium chloride and bis(2-ethylhexyl) phosphate with a mass ratio of 30:70.

[0121] (3) Add sodium sulfide to the extract, adjust the pH to 4 with a 5 mol / L hydrochloric acid solution, stir and react until no white precipitate is produced, filter to obtain a filtrate;

[0122] The addition amount of sodium sulfide is 2 times the tin content in the extract.

[0123] (4) Adjust the pH of the filtrate to 12 with sodium hydroxide flakes, filter to obtain the second precipitate;

[0124] (5) Add the second precipitate to a muffle furnace, heat-treat it at 200 °C for 4 h, and then heat-treat it at 600 °C for 5 h to obtain indium oxide.

[0125] Comparative Example 3

[0126] A method for preparing indium oxide from indium-containing acid solution, comprising the following steps:

[0127] (1) Add the indium-containing acid solution to a 20 wt% sulfuric acid solution, stir evenly, then add sodium hydroxide flakes to adjust the pH to 8, stir evenly, and filter to obtain the first precipitate (white precipitate).

[0128] The main element contents in the indium-containing acid solution are as follows: In 962 ppm, Sn 23 ppm, Fe 138 ppm, Cu 6 ppm, Tl 3 ppm, Ni 3 ppm, Mg 3 ppm.

[0129] The volume ratio of the indium-containing acid solution to the sulfuric acid solution is 1:10.

[0130] (2) Dissolve the first precipitate in a 5 mol / L hydrochloric acid solution to obtain a mixed solution, and extract the mixed solution with an extractant for 10 min to obtain an extract.

[0131] The solid-liquid ratio of the first precipitate to the hydrochloric acid solution is 1 g:6 mL.

[0132] The volume ratio of the mixed solution to the extractant is 1:4.

[0133] The extractant includes trialkylmethylammonium chloride and bis(2-ethylhexyl) phosphoric acid ester with a mass ratio of 30:70.

[0134] (3) Add sodium sulfide to the extract, adjust the pH to 2 with a 5 mol / L hydrochloric acid solution, stir and react until no more white precipitate is produced, and filter to obtain a filtrate.

[0135] The addition amount of sodium sulfide is twice the tin content in the extract.

[0136] (4) Adjust the pH of the filtrate to 9 with sodium hydroxide flakes and filter to obtain the second precipitate.

[0137] (5) Add the second precipitate to a muffle furnace, heat-treat it at 200 °C for 4 h, and then heat-treat it at 600 °C for 5 h to obtain indium oxide.

[0138] Comparative Example 4

[0139] A method for preparing indium oxide from an indium-containing acid solution, comprising the following steps:

[0140] (1) Add the indium-containing acid solution to a 20 wt% sulfuric acid solution, stir evenly, then add sodium hydroxide flakes to adjust the pH to 8, stir evenly, and filter to obtain the first precipitate (white precipitate).

[0141] The main element contents in the indium-containing acid solution are as follows: In 962 ppm, Sn 23 ppm, Fe 138 ppm, Cu 6 ppm, Tl 3 ppm, Ni 3 ppm, Mg 3 ppm.

[0142] The volume ratio of the indium-containing acid solution to the sulfuric acid solution is 1:10.

[0143] (2) Dissolve the first precipitate in a 5 mol / L hydrochloric acid solution to obtain a mixed solution, and extract the mixed solution with an extractant for 10 min to obtain an extract.

[0144] The solid-liquid ratio of the first precipitate to the hydrochloric acid solution is 1 g:6 mL.

[0145] The volume ratio of the mixed solution to the extractant is 1:4;

[0146] The extractant includes trialkylmethylammonium chloride and bis(2-ethylhexyl) phosphate with a mass ratio of 30:70.

[0147] (3) Add sodium sulfide to the extract, adjust the pH to 2 with a 5 mol / L hydrochloric acid solution, stir and react until no white precipitate is produced, and filter to obtain a filtrate.

[0148] The addition amount of sodium sulfide is 2 times the tin content in the extract.

[0149] (4) Adjust the pH of the filtrate to 13 with flake caustic and filter to obtain a second precipitate.

[0150] (5) Add the second precipitate to a muffle furnace, heat-treat it at 200 °C for 4 h, and then heat-treat it at 600 °C for 5 h to obtain indium oxide.

[0151] Comparative Example 5

[0152] A method for preparing indium oxide from an indium-containing acid solution, comprising the following steps:

[0153] (1) Add the indium-containing acid solution to a 20 wt% sulfuric acid solution, stir evenly, then add flake caustic to adjust the pH to 8, stir evenly, and filter to obtain a first precipitate (white precipitate).

[0154] The main element contents in the indium-containing acid solution are as follows: In 962 ppm, Sn 23 ppm, Fe 138 ppm, Cu 6 ppm, Tl 3 ppm, Ni 3 ppm, Mg 3 ppm.

[0155] The volume ratio of the indium-containing acid solution to the sulfuric acid solution is 1:10.

[0156] (2) Dissolve the first precipitate in a 5 mol / L hydrochloric acid solution to obtain a mixed solution, and extract the mixed solution with an extractant for 10 min to obtain an extract.

[0157] The solid-liquid ratio of the first precipitate to the hydrochloric acid solution is 1 g:6 mL.

[0158] The volume ratio of the mixed solution to the extractant is 1:4;

[0159] The extractant comprises trialkylmethylammonium chloride and bis(2-ethylhexyl) phosphate with a mass ratio of 30:70.

[0160] (3) Add sodium sulfide to the extract, adjust the pH to 2 with 5 mol / L hydrochloric acid solution, stir and react until no white precipitate is produced, then filter to obtain a filtrate;

[0161] The addition amount of the sodium sulfide is twice the tin content in the extract.

[0162] (4) Adjust the pH of the filtrate to 12 with sodium hydroxide flakes, then filter to obtain a second precipitate;

[0163] (5) Add the second precipitate to a muffle furnace, perform heat treatment at 200 °C for 4 h, and then perform heat treatment at 500 °C for 5 h to obtain indium oxide.

[0164] Comparative Example 6

[0165] A method for preparing indium oxide from indium-containing acid solution, comprising the following steps:

[0166] (1) Add the indium-containing acid solution to a 20 wt% sulfuric acid solution, stir evenly, then add sodium hydroxide flakes to adjust the pH to 8, stir evenly, and filter to obtain a first precipitate (white precipitate);

[0167] The main element contents in the indium-containing acid solution are as follows: In 962 ppm, Sn 23 ppm, Fe 138 ppm, Cu 6 ppm, Tl 3 ppm, Ni 3 ppm, Mg 3 ppm.

[0168] The volume ratio of the indium-containing acid solution to the sulfuric acid solution is 1:10.

[0169] (2) Dissolve the first precipitate with 5 mol / L hydrochloric acid solution to obtain a mixed solution, and extract the mixed solution with an extractant for 10 min to obtain an extract;

[0170] The solid-liquid ratio of the first precipitate to the hydrochloric acid solution is 1 g:6 mL.

[0171] The volume ratio of the mixed solution to the extractant is 1:4;

[0172] The extractant comprises trialkylmethylammonium chloride and bis(2-ethylhexyl) phosphate with a mass ratio of 30:70.

[0173] (3) Add sodium sulfide to the extract, adjust the pH to 2 with 5 mol / L hydrochloric acid solution, stir and react until no white precipitate is produced, then filter to obtain a filtrate;

[0174] The addition amount of sodium sulfide is twice the tin content in the extraction solution.

[0175] (4) Adjust the pH of the filtrate to 12 with sodium hydroxide flakes, filter, and obtain the second precipitate.

[0176] (5) Add the second precipitate into a muffle furnace, heat-treat it at 200 °C for 4 h, and then heat-treat it at 750 °C for 5 h to obtain indium oxide.

[0177] Comparative Example 7

[0178] A method for preparing indium oxide from indium-containing acid solution, comprising the following steps:

[0179] (1) Add the indium-containing acid solution into a 20 wt% sulfuric acid solution, stir evenly, then add sodium hydroxide flakes to adjust the pH to 8, stir evenly, filter, and obtain the first precipitate (white precipitate).

[0180] The main element contents in the indium-containing acid solution are as follows: In 962 ppm, Sn 23 ppm, Fe 138 ppm, Cu 6 ppm, Tl 3 ppm, Ni 3 ppm, Mg 3 ppm.

[0181] The volume ratio of the indium-containing acid solution to the sulfuric acid solution is 1:10.

[0182] (2) Dissolve the first precipitate with a 5 mol / L hydrochloric acid solution to obtain a mixed solution, extract the mixed solution with an extractant for 10 min, and obtain an extraction solution.

[0183] The solid-liquid ratio of the first precipitate to the hydrochloric acid solution is 1 g:6 mL.

[0184] The volume ratio of the mixed solution to the extractant is 1:4;

[0185] The extractant is tributyl phosphate.

[0186] (3) Add sodium sulfide into the extraction solution, adjust the pH to 2 with a 5 mol / L hydrochloric acid solution, stir and react until no white precipitate is produced, filter, and obtain a filtrate.

[0187] The addition amount of sodium sulfide is twice the tin content in the extraction solution.

[0188] (4) Adjust the pH of the filtrate to 12 with sodium hydroxide flakes, filter, and obtain the second precipitate.

[0189] (5) Add the second precipitate into a muffle furnace, heat-treat it at 200 °C for 4 h, and then heat-treat it at 600 °C for 5 h to obtain the indium oxide as Figure 2 shown.

[0190] Test Example

[0191] Among them, the indium recovery rate and the total impurity content of indium oxide in the examples and comparative examples are shown in Table 1.

[0192] Indium metal recovery rate = metal content in indium oxide / indium metal mass in indium-containing acid solution * 100%.

[0193] Table 1

[0194]

[0195]

[0196] As can be seen from Table 1, in the present invention, the indium-containing acid solution is first mixed with sulfuric acid to convert the weak acid salt into a strong acid salt, the pH is adjusted with flake soda to precipitate metal ions, and relatively pure hydroxides are obtained. Then the precipitate is acid-dissolved to provide a good environment for extraction, promote the extraction and separation of impurity ions, and avoid the loss of indium metal. The pH is adjusted with flake soda to promote the precipitation of indium in the form of complete precipitation. Finally, through two heat treatments, high-quality indium oxide is obtained. The indium oxide has a low impurity content and high purity.

[0197] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to 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 preparing indium oxide using indium-containing acid solution, characterized in that, It includes the following steps: (1) Add indium-containing acid solution into sulfuric acid solution, stir evenly, then add sodium hydroxide flakes to adjust the pH to 7 - 8, stir evenly, filter to obtain the first precipitate; (2) Dissolve the first precipitate with hydrochloric acid solution to obtain a mixed solution, and extract the mixed solution with an extractant to obtain an extract; (3) Add sodium sulfide into the extract, adjust the pH to 2 - 3 with hydrochloric acid solution, stir and react, filter to obtain a filtrate; (4) Adjust the pH of the filtrate to 10 - 12 with sodium hydroxide flakes, filter to obtain the second precipitate; (5) Subject the second precipitate to the first heat treatment and the second heat treatment to obtain indium oxide.

2. The method for preparing indium oxide by using indium-containing acid solution according to claim 1, wherein The volume ratio of the indium-containing acid solution to the sulfuric acid solution is 1:(5 - 15); The concentration of the sulfuric acid solution is 10 - 30 wt%.

3. The method for preparing indium oxide by using indium-containing acid solution according to claim 1, wherein The solid-liquid ratio of the first precipitate to the hydrochloric acid solution is 1 g:(6 - 8) mL.

4. The method for preparing indium oxide by using indium-containing acid solution according to claim 1, characterized in that, The molar concentration of the hydrochloric acid solution in step (2) is 4 - 6 mol / L.

5. The method for preparing indium oxide by using indium-containing acid solution according to claim 1, characterized in that, The molar concentration of the hydrochloric acid solution in step (3) is 4 - 6 mol / L.

6. The method for preparing indium oxide by using indium-containing acid solution according to claim 1, characterized in that, The extractant includes at least one of trialkylmethylammonium chloride, bis(2-ethylhexyl) phosphate, 2-ethylhexyl phosphate mono-2-ethylhexyl ester, and tributyl phosphate.

7. The method for preparing indium oxide by using indium-containing acid solution according to claim 1, characterized in that, The volume ratio of the mixed solution to the extractant is 1:(2 - 4).

8. The method for preparing indium oxide by using indium-containing acid solution according to claim 1, wherein The addition amount of sodium sulfide is 1.5 - 2.5 times the tin content in the extract.

9. The method for preparing indium oxide by using indium-containing acid solution according to claim 1, wherein The temperature of the first heat treatment is 150 - 200 °C, and the time is 2 - 6 h.

10. The method for preparing indium oxide using indium-containing acid solution according to claim 1, wherein The temperature of the second heat treatment is 600 - 650 °C, and the time is 6 - 10 h.

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