Method for preparing high-purity indium from refined indium

Abstract

The invention discloses a method for preparing high-purity indium from refined indium, and belongs to the technical field of metallurgy. The refined indium is distilled for three times, low-boiling-point impurities Cd, Zn, As, Pb and Bi can be separated and purified, then glycerin, potassium iodide and iodine are used for heat treatment, the Cd impurity can be further separated from indium, then glycerin, ammonium chloride and zinc chloride are used for heat treatment, and the high-purity indium is obtained. According to the method, the Tl impurity can be separated from indium, finally, sodium hydroxide and sodium nitrate are used for heat treatment, Sn, Pb and Fe can be separated from indium, refined indium can be effectively purified through the method, the refined indium is prepared into high-purity indium, the purity of the high-purity indium is 6N, and the content of single impurity metal elements Sb, Sb, Pb and Bi can meet the 7N ultra-high-purity indium metal standard.

Description

Technical Field

[0001] The present invention relates to the technical field of metallurgy, and particularly relates to a method for preparing high-purity indium from refined indium. Background Art

[0002] Indium, with an atomic number of 49, a relative atomic mass of 114.82, has a melting point of 156.51 °C and a boiling point of 2060 °C under normal temperature and pressure, and a density of 7.3 g / cm 3 , is easy to form compounds with different metal elements, and is a silver-white, soft-textured rare metal.

[0003] Due to its unique physical and chemical properties, refined indium with a purity of more than 4N is often used in the preparation of target materials, optical materials, low-temperature solders, infrared electrode materials, etc., and has high industrial value. At present, when vacuum distillation is used to purify refined indium with a purity of more than 4N, there are problems that impurity metals such as tin, antimony, lead, and bismuth are difficult to remove, which affects the performance of the final indium-containing products.

[0004] In view of this, the present application is proposed. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method for preparing high-purity indium from refined indium. The method of the present invention can effectively purify refined indium and prepare it into high-purity indium. The purity of the high-purity indium is 6N, and the content of single impurity metal elements Sb, Sn, Pb, and Bi can meet the 7N ultra-high-purity indium metal standard.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing high-purity indium from refined indium, comprising the following steps:

[0008] (1) Subject the refined indium to first distillation, second distillation, and third distillation in sequence to obtain a first indium ingot;

[0009] (2) Add the first indium ingot, glycerol, potassium iodide, and iodine into an intermediate frequency furnace for heat treatment to obtain a second indium ingot;

[0010] (3) Add the second indium ingot, glycerol, ammonium chloride, and zinc chloride into an intermediate frequency furnace for heat treatment to obtain a third indium ingot;

[0011] (4) Add the third indium ingot, sodium hydroxide, and sodium nitrate into an intermediate frequency furnace for heat treatment to obtain high-purity indium.

[0012] The present invention creatively distills refined indium three times, which can separate and purify low-boiling-point impurities such as Cd, Zn, As, Pb, and Bi. Then, heat treatment is carried out with glycerol, potassium iodide, and iodine, which can further separate Cd impurities from indium. Then, heat treatment is carried out with glycerol, ammonium chloride, and zinc chloride, which can separate Tl impurities from indium. Finally, heat treatment is carried out with sodium hydroxide and sodium nitrate, which can separate Sn, Pb, and Fe from indium. The method of the present invention can effectively purify refined indium and prepare refined indium into high-purity indium. The purity of the high-purity indium is 6N, and the content of single impurity metal elements such as Sb, Sn, Pb, and Bi can meet the 7N ultra-high-purity indium metal standard.

[0013] As a preferred embodiment of the present invention, the purity of the refined indium is 4-4.5N.

[0014] As a preferred embodiment of the present invention, the temperature of the first distillation is 900-1000 °C, the time is 4-6 h, and the vacuum degree is 1-5×10 -3 Pa. At this temperature and vacuum degree, indium and low-boiling-point impurities have higher saturated vapor pressures, can boil and volatilize better, and realize separation from high-boiling-point impurities, so that low-boiling-point impurities such as Cd, Zn, Pb, and As are volatilized together with In metal to separate from high-boiling-point metals such as Fe, Cu, and Sn, realizing the first-step purification of refined indium.

[0015] As a preferred embodiment of the present invention, the temperature of the second distillation is 500-600 °C, the time is 6-8 h, and the vacuum degree is 1-5×10 -3 Pa. At this temperature and vacuum degree, since the saturated vapor pressures of Cd, Zn, and As are greater than those of In and Pb and they are more likely to boil and volatilize, low-boiling-point impurities such as Cd, Zn, and As metals can be volatilized to separate from In, Pb, and Bi metals, realizing the second-step purification of indium ingots.

[0016] As a preferred embodiment of the present invention, the temperature of the third distillation is 700-800 °C, the time is 3-5 h, and the vacuum degree is 1-5×10 -3 Pa. At this temperature and vacuum degree, since the saturated vapor pressures of Pb and Bi are greater than that of In and they are more likely to boil and volatilize, low-boiling-point impurities such as Pb and Bi can be volatilized to separate from In metal, realizing the third-step purification of indium ingots.

[0017] As a preferred embodiment of the present invention, the mass ratio of the first indium ingot, glycerol, potassium iodide, and iodine is 500:(0.8-1.2):(2-6):(1-4). Cd can form CdI with I, and CdI can form K2CdI4 compound soluble in glycerol with KI to remove Cd, thereby further removing Cd.

[0018] As a preferred embodiment of the present invention, the heat treatment temperature in step (2) is 200 - 300 °C, and the heat treatment time is 1 - 3 h.

[0019] As a preferred embodiment of the present invention, the mass ratio of the second indium ingot, glycerol, ammonium chloride, and zinc chloride is 500:(0.8 - 1.2):(8 - 15):(1 - 4). Tl and Cl can form a compound soluble in glycerol to remove Tl.

[0020] As a preferred embodiment of the present invention, the heat treatment temperature in step (3) is 200 - 300 °C, and the heat treatment time is 0.5 - 2 h.

[0021] As a preferred embodiment of the present invention, the mass ratio of the third indium ingot, sodium hydroxide, and sodium nitrate is 10:(0.8 - 1.2):(1.5 - 2.2). Sn, Pb, etc. can form a compound with a density lower than that of indium metal under the condition of alkaline compounds and float on the surface of the indium liquid, thus being removed.

[0022] As a preferred embodiment of the present invention, the heat treatment temperature in step (4) is 280 - 320 °C, and the heat treatment time is 1 - 3 h.

[0023] The beneficial effects of the present invention are as follows: The refined indium in the present invention is distilled three times, and low-boiling impurities such as Cd, Zn, As, Pb, and Bi can be separated and purified. Then, heat treatment with glycerol, potassium iodide, and iodine can further separate the Cd impurity from indium. Heat treatment with glycerol, ammonium chloride, and zinc chloride can separate the Tl impurity from indium. Finally, heat treatment with sodium hydroxide and sodium nitrate can separate Sn, Pb, and Fe from indium. The method of the present invention can effectively purify refined indium and prepare it into high-purity indium. The purity of the high-purity indium is 6N, and the content of single impurity metal elements Sb, Sb, Pb, and Bi can meet the 7N ultra-high-purity indium metal standard. Description of the Drawings

[0024] Figure 1 It is a flow chart of the method for preparing high-purity indium using refined indium in the present invention. Detailed Embodiments

[0025] 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. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments in the present application belong to the scope of protection of the present application.

[0026] 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 containing the listed features.

[0027] In this application, when it comes to 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.

[0028] In this application, there is no particular limitation on the specific dispersion and stirring treatment methods.

[0029] 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 type.

[0030] In addition, the terms "first" and "second" are used only for descriptive purposes and cannot 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 of such features. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0031] The following examples are provided to facilitate the understanding of the present invention. These examples are not provided to limit the scope of the claims.

[0032] Example 1

[0033] As Figure 1 shown, this example provides a method for preparing high-purity indium using refined indium, including the following steps:

[0034] (1) In a ten-thousand-class clean room, load the refined indium into a graphite crucible, then place it into a vacuum device, adjust the vacuum degree to 1×10 -3 Pa, distill at 1000 °C for 5 h, after the distillation ends, fill with 5N nitrogen at a rate of 10 L / min to cool down, cool down to below 200 °C, and take out;

[0035] Load the refined indium into a graphite crucible again, then place it into a vacuum device, adjust the vacuum degree to 1×10 -3 Pa, distill at 600 °C for 7 h, after the distillation ends, fill with 5N nitrogen at a rate of 10 L / min to cool down, cool down to below 200 °C, and take out;

[0036] Then, load the refined indium into a graphite crucible, and then place it in a vacuum device. Adjust the vacuum degree to 1×10 -3 Pa, distill at 800 °C for 4 h. After the distillation is completed, fill with 5N nitrogen gas at a rate of 10 L / min to cool down. When the temperature drops below 200 °C, take it out to obtain the first indium ingot;

[0037] (2) Add the first indium ingot, glycerol, potassium iodide, and iodine to an intermediate frequency furnace according to a mass ratio of 500:1:5:2, and perform heat treatment at 300 °C for 2 h, then cool to obtain the second indium ingot;

[0038] (3) Add the second indium ingot, glycerol, ammonium chloride, and zinc chloride to an intermediate frequency furnace according to a mass ratio of 500:1:10:5, and perform heat treatment at 300 °C for 1 h, then cool to obtain the third indium ingot;

[0039] (4) Add the third indium ingot, sodium hydroxide, and sodium nitrate to an intermediate frequency furnace according to a mass ratio of 10:1:2, and perform heat treatment at 300 °C for 2 h, then cool to obtain high-purity indium.

[0040] Example 2

[0041] As Figure 1 shown, this example provides a method for preparing high-purity indium from refined indium, including the following steps:

[0042] (1) Under a ten-thousand-class clean room, load the refined indium into a graphite crucible, and then place it in a vacuum device. Adjust the vacuum degree to 1×10 -3 Pa, distill at 900 °C for 5 h. After the distillation is completed, fill with 5N nitrogen gas at a rate of 10 L / min to cool down. When the temperature drops below 200 °C, take it out;

[0043] Then, load the refined indium into a graphite crucible, and then place it in a vacuum device. Adjust the vacuum degree to 1×10 -3 Pa, distill at 600 °C for 7 h. After the distillation is completed, fill with 5N nitrogen gas at a rate of 10 L / min to cool down. When the temperature drops below 200 °C, take it out;

[0044] Then, load the refined indium into a graphite crucible, and then place it in a vacuum device. Adjust the vacuum degree to 1×10 -3 Pa, distill at 800 °C for 4 h. After the distillation is completed, fill with 5N nitrogen gas at a rate of 10 L / min to cool down. When the temperature drops below 200 °C, take it out to obtain the first indium ingot;

[0045] (2) Add the first indium ingot, glycerol, potassium iodide, and iodine to an intermediate frequency furnace according to a mass ratio of 500:1:5:2, and perform heat treatment at 300 °C for 2 h, then cool to obtain the second indium ingot;

[0046] (3) Add the second indium ingot, glycerol, ammonium chloride, and zinc chloride into an intermediate frequency furnace according to a mass ratio of 500:1:10:5, heat-treat at 300 °C for 1 h, and then cool to obtain the third indium ingot;

[0047] (4) Add the third indium ingot, sodium hydroxide, and sodium nitrate into an intermediate frequency furnace according to a mass ratio of 10:1:2, heat-treat at 300 °C for 2 h, and then cool to obtain high-purity indium.

[0048] Example 3

[0049] As Figure 1 shown, this example provides a method for preparing high-purity indium from refined indium, including the following steps:

[0050] (1) Under a ten-thousand-class clean room, load the refined indium into a graphite crucible, then place it into a vacuum device, adjust the vacuum degree to 1×10 -3 Pa, distill at 1000 °C for 5 h. After the distillation ends, fill with 5N nitrogen at a rate of 10 L / min to cool down. When the temperature drops below 200 °C, take it out;

[0051] Load the refined indium into a graphite crucible again, then place it into a vacuum device, adjust the vacuum degree to 1×10 -3 Pa, distill at 500 °C for 7 h. After the distillation ends, fill with 5N nitrogen at a rate of 10 L / min to cool down. When the temperature drops below 200 °C, take it out;

[0052] Load the refined indium into a graphite crucible again, then place it into a vacuum device, adjust the vacuum degree to 1×10 -3 Pa, distill at 800 °C for 4 h. After the distillation ends, fill with 5N nitrogen at a rate of 10 L / min to cool down. When the temperature drops below 200 °C, take it out to obtain the first indium ingot;

[0053] (2) Add the first indium ingot, glycerol, potassium iodide, and iodine into an intermediate frequency furnace according to a mass ratio of 500:1:5:2, heat-treat at 300 °C for 2 h, and then cool to obtain the second indium ingot;

[0054] (3) Add the second indium ingot, glycerol, ammonium chloride, and zinc chloride into an intermediate frequency furnace according to a mass ratio of 500:1:10:5, heat-treat at 300 °C for 1 h, and then cool to obtain the third indium ingot;

[0055] (4) Add the third indium ingot, sodium hydroxide, and sodium nitrate into an intermediate frequency furnace according to a mass ratio of 10:1:2, heat-treat at 300 °C for 2 h, and then cool to obtain high-purity indium.

[0056] Example 4

[0057] As Figure 1 shown, this example provides a method for preparing high-purity indium from refined indium, including the following steps:

[0058] (1) Under a ten-thousand-class clean room, load refined indium into a graphite crucible, then place it into a vacuum device, adjust the vacuum degree to 1×10 -3 Pa, distill at 1000 °C for 5 h, after the distillation ends, fill in 5N nitrogen gas at a rate of 10 L / min to cool down, cool down to below 200 °C, and take out;

[0059] Then load refined indium into a graphite crucible again, place it into a vacuum device again, adjust the vacuum degree to 1×10 -3 Pa, distill at 600 °C for 7 h, after the distillation ends, fill in 5N nitrogen gas at a rate of 10 L / min to cool down, cool down to below 200 °C, and take out;

[0060] Then load refined indium into a graphite crucible again, place it into a vacuum device again, adjust the vacuum degree to 1×10 -3 Pa, distill at 700 °C for 4 h, after the distillation ends, fill in 5N nitrogen gas at a rate of 10 L / min to cool down, cool down to below 200 °C, and take out to obtain the first indium ingot;

[0061] (2) Add the first indium ingot, glycerol, potassium iodide, and iodine into an intermediate frequency furnace according to a mass ratio of 500:1:5:2, perform heat treatment at 300 °C for 2 h, and cool to obtain the second indium ingot;

[0062] (3) Add the second indium ingot, glycerol, ammonium chloride, and zinc chloride into an intermediate frequency furnace according to a mass ratio of 500:1:10:5, perform heat treatment at 300 °C for 1 h, and cool to obtain the third indium ingot;

[0063] (4) Add the third indium ingot, sodium hydroxide, and sodium nitrate into an intermediate frequency furnace according to a mass ratio of 10:1:2, perform heat treatment at 300 °C for 2 h, and cool to obtain high-purity indium.

[0064] Example 5

[0065] As Figure 1 shown, this example provides a method for preparing high-purity indium from refined indium, including the following steps:

[0066] (1) Under a ten-thousand-class clean room, load refined indium into a graphite crucible, then place it into a vacuum device, adjust the vacuum degree to 1×10 -3 Pa, distill at 1000 °C for 5 h, after the distillation ends, fill in 5N nitrogen gas at a rate of 10 L / min to cool down, cool down to below 200 °C, and take out;

[0067] Then load refined indium into a graphite crucible again, place it into a vacuum device again, adjust the vacuum degree to 1×10 -3Pa, distill at 600 °C for 7 h. After the distillation, fill with 5N nitrogen at a rate of 10 L / min to cool down. When the temperature drops below 200 °C, take it out;

[0068] Then put the refined indium into a graphite crucible and place it in a vacuum equipment. Adjust the vacuum degree to 1×10 -3 Pa, distill at 800 °C for 4 h. After the distillation, fill with 5N nitrogen at a rate of 10 L / min to cool down. When the temperature drops below 200 °C, take it out to obtain the first indium ingot;

[0069] (2) Add the first indium ingot, glycerol, potassium iodide, and iodine into an intermediate frequency furnace according to the mass ratio of 500:0.8:6:1, and perform heat treatment at 300 °C for 2 h, then cool to obtain the second indium ingot;

[0070] (3) Add the second indium ingot, glycerol, ammonium chloride, and zinc chloride into an intermediate frequency furnace according to the mass ratio of 500:0.8:15:1, and perform heat treatment at 300 °C for 1 h, then cool to obtain the third indium ingot;

[0071] (4) Add the third indium ingot, sodium hydroxide, and sodium nitrate into an intermediate frequency furnace according to the mass ratio of 10:0.8:2.2, and perform heat treatment at 300 °C for 2 h, then cool to obtain high-purity indium.

[0072] Example 6

[0073] As Figure 1 shown, this example provides a method for preparing high-purity indium from refined indium, including the following steps:

[0074] (1) Under a ten-thousand-class clean room, put the refined indium into a graphite crucible and place it in a vacuum equipment. Adjust the vacuum degree to 1×10 -3 Pa, distill at 1000 °C for 5 h. After the distillation, fill with 5N nitrogen at a rate of 10 L / min to cool down. When the temperature drops below 200 °C, take it out;

[0075] Then put the refined indium into a graphite crucible and place it in a vacuum equipment. Adjust the vacuum degree to 1×10 -3 Pa, distill at 600 °C for 7 h. After the distillation, fill with 5N nitrogen at a rate of 10 L / min to cool down. When the temperature drops below 200 °C, take it out;

[0076] Then put the refined indium into a graphite crucible and place it in a vacuum equipment. Adjust the vacuum degree to 1×10 -3 Pa, distill at 800 °C for 4 h. After the distillation, fill with 5N nitrogen at a rate of 10 L / min to cool down. When the temperature drops below 200 °C, take it out to obtain the first indium ingot;

[0077] (2) Add the first indium ingot, glycerol, potassium iodide, and iodine into an intermediate frequency furnace according to a mass ratio of 500:1.2:6:4, perform heat treatment at 300 °C for 2 h, and then cool to obtain the second indium ingot;

[0078] (3) Add the second indium ingot, glycerol, ammonium chloride, and zinc chloride into an intermediate frequency furnace according to a mass ratio of 500:1.2:8:4, perform heat treatment at 300 °C for 1 h, and then cool to obtain the third indium ingot;

[0079] (4) Add the third indium ingot, sodium hydroxide, and sodium nitrate into an intermediate frequency furnace according to a mass ratio of 10:1.2:1.5, perform heat treatment at 300 °C for 2 h, and then cool to obtain high-purity indium.

[0080] Comparative Example 1

[0081] A method for preparing high-purity indium from refined indium includes the following steps:

[0082] (1) Under a ten-thousand-class clean room, load the refined indium into a graphite crucible, then place it into a vacuum device, adjust the vacuum degree to 1×10 -3 Pa, perform distillation at 1000 °C for 5 h, after the distillation ends, fill in 5N nitrogen gas at a rate of 10 L / min to cool down, cool down to below 200 °C, and take it out;

[0083] Load the refined indium into a graphite crucible again, then place it into a vacuum device, adjust the vacuum degree to 1×10 -3 Pa, perform distillation at 600 °C for 7 h, after the distillation ends, fill in 5N nitrogen gas at a rate of 10 L / min to cool down, cool down to below 200 °C, and take it out;

[0084] Load the refined indium into a graphite crucible again, then place it into a vacuum device, adjust the vacuum degree to 1×10 -3 Pa, perform distillation at 800 °C for 4 h, after the distillation ends, fill in 5N nitrogen gas at a rate of 10 L / min to cool down, cool down to below 200 °C, and take it out to obtain an indium ingot.

[0085] Comparative Example 2

[0086] A method for preparing high-purity indium from refined indium includes the following steps:

[0087] (1) Under a ten-thousand-class clean room, load the refined indium into a graphite crucible, then place it into a vacuum device, adjust the vacuum degree to 1×10 -3 Pa, perform distillation at 1000 °C for 5 h, after the distillation ends, fill in 5N nitrogen gas at a rate of 10 L / min to cool down, cool down to below 200 °C, and take it out;

[0088] Load the refined indium into a graphite crucible again, then place it into a vacuum device, adjust the vacuum degree to 1×10 -3Pa, distill at 600 °C for 7 h. After the distillation, fill with 5N nitrogen at a rate of 10 L / min to cool down. When the temperature drops below 200 °C, take it out;

[0089] Then put the refined indium into a graphite crucible and place it in a vacuum equipment. Adjust the vacuum degree to 1×10 -3 Pa, distill at 800 °C for 4 h. After the distillation, fill with 5N nitrogen at a rate of 10 L / min to cool down. When the temperature drops below 200 °C, take it out to obtain the first indium ingot;

[0090] (2) Add the first indium ingot, glycerol, potassium iodide, and iodine into an intermediate frequency furnace according to the mass ratio of 500:1:5:2, and perform heat treatment at 300 °C for 2 h, then cool to obtain the second indium ingot;

[0091] (3) Add the second indium ingot, glycerol, ammonium chloride, and zinc chloride into an intermediate frequency furnace according to the mass ratio of 500:1:10:5, and perform heat treatment at 300 °C for 1 h, then cool to obtain the indium ingot.

[0092] Comparative Example 3

[0093] A method for preparing high-purity indium from refined indium, comprising the following steps:

[0094] (1) Under a ten-thousand-class clean room, put the refined indium into a graphite crucible and place it in a vacuum equipment. Adjust the vacuum degree to 1×10 -3 Pa, distill at 1000 °C for 5 h. After the distillation, fill with 5N nitrogen at a rate of 10 L / min to cool down. When the temperature drops below 200 °C, take it out;

[0095] Then put the refined indium into a graphite crucible and place it in a vacuum equipment. Adjust the vacuum degree to 1×10 -3 Pa, distill at 600 °C for 7 h. After the distillation, fill with 5N nitrogen at a rate of 10 L / min to cool down. When the temperature drops below 200 °C, take it out;

[0096] Then put the refined indium into a graphite crucible and place it in a vacuum equipment. Adjust the vacuum degree to 1×10 -3 Pa, distill at 800 °C for 4 h. After the distillation, fill with 5N nitrogen at a rate of 10 L / min to cool down. When the temperature drops below 200 °C, take it out to obtain the first indium ingot;

[0097] (2) Add the first indium ingot, glycerol, potassium iodide, and iodine into an intermediate frequency furnace according to the mass ratio of 500:1:5:2, and perform heat treatment at 300 °C for 2 h, then cool to obtain the second indium ingot;

[0098] (3) Add the second indium ingot, sodium hydroxide, and sodium nitrate into an intermediate frequency furnace according to the mass ratio of 10:1:2, and perform heat treatment at 300 °C for 2 h, then cool to obtain the indium ingot.

[0099] Comparative Example 4

[0100] A method for preparing high-purity indium from refined indium, comprising the following steps:

[0101] (1) Under a ten-thousand-class clean room, load the refined indium into a graphite crucible, then place it into a vacuum device, adjust the vacuum degree to 1×10 -3 Pa, distill at 1000 °C for 5 h, after the distillation ends, fill with 5N nitrogen gas at a rate of 10 L / min to cool down, cool down to below 200 °C, and take out;

[0102] Load the refined indium into a graphite crucible again, then place it into a vacuum device, adjust the vacuum degree to 1×10 -3 Pa, distill at 600 °C for 7 h, after the distillation ends, fill with 5N nitrogen gas at a rate of 10 L / min to cool down, cool down to below 200 °C, and take out;

[0103] Load the refined indium into a graphite crucible again, then place it into a vacuum device, adjust the vacuum degree to 1×10 -3 Pa, distill at 800 °C for 4 h, after the distillation ends, fill with 5N nitrogen gas at a rate of 10 L / min to cool down, cool down to below 200 °C, and take out to obtain the first indium ingot;

[0104] (2) Add the first indium ingot, glycerol, ammonium chloride, and zinc chloride to an intermediate frequency furnace according to a mass ratio of 500:1:10:5, perform heat treatment at 300 °C for 1 h, and cool to obtain the second indium ingot;

[0105] (3) Add the second indium ingot, sodium hydroxide, and sodium nitrate to an intermediate frequency furnace according to a mass ratio of 10:1:2, perform heat treatment at 300 °C for 2 h, and cool to obtain high-purity indium.

[0106] Comparative Example 5

[0107] A method for preparing high-purity indium from refined indium, comprising the following steps:

[0108] (1) Under a ten-thousand-class clean room, load the refined indium into a graphite crucible, then place it into a vacuum device, adjust the vacuum degree to 1×10 -3 Pa, distill at 1000 °C for 5 h, after the distillation ends, fill with 5N nitrogen gas at a rate of 10 L / min to cool down, cool down to below 200 °C, and take out;

[0109] Load the refined indium into a graphite crucible again, then place it into a vacuum device, adjust the vacuum degree to 1×10 -3 Pa, distill at 800 °C for 4 h, after the distillation ends, fill with 5N nitrogen gas at a rate of 10 L / min to cool down, cool down to below 200 °C, and take out to obtain the first indium ingot;

[0110] (2) Add the first indium ingot, glycerol, potassium iodide, and iodine into an intermediate frequency furnace according to a mass ratio of 500:1:5:2, perform heat treatment at 300 °C for 2 h, and then cool to obtain the second indium ingot;

[0111] (3) Add the second indium ingot, glycerol, ammonium chloride, and zinc chloride into an intermediate frequency furnace according to a mass ratio of 500:1:10:5, perform heat treatment at 300 °C for 1 h, and then cool to obtain the third indium ingot;

[0112] (4) Add the third indium ingot, sodium hydroxide, and sodium nitrate into an intermediate frequency furnace according to a mass ratio of 10:1:2, perform heat treatment at 300 °C for 2 h, and then cool to obtain high-purity indium.

[0113] Comparative Example 6

[0114] A method for preparing high-purity indium from refined indium includes the following steps:

[0115] (1) Under a ten-thousand-class clean room, load the refined indium into a graphite crucible, then place it into a vacuum device, adjust the vacuum degree to 1×10 -3 Pa, perform distillation at 1000 °C for 5 h, after the distillation ends, fill in 5N nitrogen gas at a rate of 10 L / min for cooling, cool down to below 200 °C, and then take it out;

[0116] Load the refined indium into a graphite crucible again, then place it into a vacuum device, adjust the vacuum degree to 1×10 -3 Pa, perform distillation at 600 °C for 7 h, after the distillation ends, fill in 5N nitrogen gas at a rate of 10 L / min for cooling, cool down to below 200 °C, and then take it out;

[0117] (2) Add the first indium ingot, glycerol, potassium iodide, and iodine into an intermediate frequency furnace according to a mass ratio of 500:1:5:2, perform heat treatment at 300 °C for 2 h, and then cool to obtain the second indium ingot;

[0118] (3) Add the second indium ingot, glycerol, ammonium chloride, and zinc chloride into an intermediate frequency furnace according to a mass ratio of 500:1:10:5, perform heat treatment at 300 °C for 1 h, and then cool to obtain the third indium ingot;

[0119] (4) Add the third indium ingot, sodium hydroxide, and sodium nitrate into an intermediate frequency furnace according to a mass ratio of 10:1:2, perform heat treatment at 300 °C for 2 h, and then cool to obtain high-purity indium.

[0120] Comparative Example 7

[0121] A method for preparing high-purity indium from refined indium includes the following steps:

[0122] (1) Under a ten-thousand-class clean room, load the refined indium into a graphite crucible, then place it into a vacuum device, adjust the vacuum degree to 1×10 -3Pa, distilled at 600 °C for 7 h. After the distillation, it was filled with 5N nitrogen at a rate of 10 L / min to cool down, and when the temperature dropped below 200 °C, it was taken out;

[0123] Then put the refined indium into a graphite crucible and place it in a vacuum device. Adjust the vacuum degree to 1×10 -3 Pa, distilled at 800 °C for 4 h. After the distillation, it was filled with 5N nitrogen at a rate of 10 L / min to cool down, and when the temperature dropped below 200 °C, it was taken out to obtain the first indium ingot;

[0124] (2) Add the first indium ingot, glycerol, potassium iodide, and iodine to the intermediate frequency furnace according to the mass ratio of 500:1:5:2, and heat-treat at 300 °C for 2 h, then cool to obtain the second indium ingot;

[0125] (3) Add the second indium ingot, glycerol, ammonium chloride, and zinc chloride to the intermediate frequency furnace according to the mass ratio of 500:1:10:5, and heat-treat at 300 °C for 1 h, then cool to obtain the third indium ingot;

[0126] (4) Add the third indium ingot, sodium hydroxide, and sodium nitrate to the intermediate frequency furnace according to the mass ratio of 10:1:2, and heat-treat at 300 °C for 2 h, then cool to obtain high-purity indium.

[0127] Test Example

[0128] The purity of the indium ingots in the examples and comparative examples was detected by GDMS.

[0129] Table 1

[0130]

[0131]

[0132] It can be seen from Table 1 that the method of the present invention can effectively purify refined indium and prepare high-purity indium. The purity of the high-purity indium is 6N, and the contents of single impurity metal elements Sn, Sb, Pb, and Bi can meet the 7N ultra-high purity indium metal standard.

[0133] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than 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 high-purity indium using refined indium, characterized in that: The following steps are involved: (1) subjecting refined indium to a first distillation, a second distillation, and a third distillation in succession to obtain a first indium ingot; (2) adding the first indium ingot, glycerol, potassium iodide, and iodine into a medium frequency furnace for heat treatment to obtain a second indium ingot; (3) adding the second indium ingot, glycerol, ammonium chloride, and zinc chloride into a medium frequency furnace for heat treatment to obtain a third indium ingot; (4) Adding the third indium ingot, sodium hydroxide and sodium nitrate into a medium frequency furnace for heat treatment to obtain high-purity indium.

2. The method for preparing high-purity indium using refined indium according to claim 1, characterized in that: The temperature of the first distillation is 900-1000°C, the time is 4-6 hours, and the vacuum degree is 1-5×10 -3 Pa.

3. The method for preparing high-purity indium using refined indium according to claim 1, characterized in that: The temperature of the second distillation is 500-600°C, the time is 6-8h, and the vacuum degree is 1-5×10 -3 Pa.

4. The method for preparing high-purity indium using refined indium according to claim 1, characterized in that: The temperature of the third distillation is 700-800°C, the time is 3-5h, and the vacuum degree is 1-5×10 -3 Pa.

5. The method for preparing high-purity indium using refined indium according to claim 1, characterized in that: The mass ratio of the first indium ingot, glycerol, potassium iodide and iodine is 500:(0.8-1.2):(2-6):(1-4).

6. The method for preparing high-purity indium using refined indium according to claim 1, characterized in that: The heat treatment temperature in step (2) is 200-300° C., and the heat treatment time is 1-3 hours.

7. The method for preparing high-purity indium using refined indium according to claim 1, characterized in that: The mass ratio of the second indium ingot, glycerol, ammonium chloride and zinc chloride is 500:(0.8-1.2):(8-15):(1-4).

8. The method for preparing high-purity indium using refined indium according to claim 1, characterized in that: The heat treatment temperature in step (3) is 200-300° C., and the heat treatment time is 0.5-2 h.

9. The method for preparing high-purity indium using refined indium according to claim 1, characterized in that: The mass ratio of the third indium ingot, sodium hydroxide and sodium nitrate is 10:(0.8-1.2):(1.5-2.2).

10. The method for preparing high-purity indium using refined indium according to claim 1, characterized in that: The heat treatment temperature in step (4) is 280-320° C., and the heat treatment time is 1-3 hours.

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