A method for preparing high-purity indium sulfide powder

Abstract

The invention belongs to the field of fine chemicals, and discloses a method for preparing high-purity indium sulfide powder. The technical scheme is as follows: using indium hydroxide powder as a raw material, heating it to 600-800°C and keeping it warm, calcining it into fluffy indium oxide powder, and then heating the indium oxide powder to 400-600°C and keeping it warm in a hydrogen sulfide gas atmosphere, and reacting to generate indium sulfide powder. The method does not generate wastewater and has little impact on the environment; the process is short, and the raw material indium hydroxide can obtain indium sulfide powder through two steps of decomposition and sulfidation; during the preparation process, the material does not contact the solution, anions, organic matter, etc., and the non-metallic impurity elements C, N, and O in the powder are easy to control, which cannot be achieved by wet chemical methods, and the prepared indium sulfide powder has a small particle size and high purity.

Description

Technical Field

[0001] The invention belongs to the field of fine chemicals, and in particular relates to a method for preparing high-purity indium sulfide powder. Background Art

[0002] Indium sulfide (In2S3) has a bandgap of 2.1 to 2.2 eV and is widely used in the buffer layer of copper indium gallium selenide (CIGS) thin-film solar cells to replace toxic cadmium sulfide (CdS). Using In2S3 instead of CdS in copper indium gallium selenide thin-film solar cells not only avoids the use of toxic metal elements Cd, but also has a wider bandgap bandwidth in the blue light wavelength region compared to CdS. In the process of CIGS thin-film solar cells, the n-type In2S3 buffer layer is mainly prepared by magnetron sputtering or vacuum evaporation using high-purity indium sulfide sheets or indium sulfide targets as raw materials. High-purity In2S3 powder is an essential material for preparing high-purity In2S3 pellets and In2S3 targets, especially large-sized In2S3 targets, which can only be prepared using powder metallurgy processes using powder raw materials.

[0003] At present, the process of preparing high-purity indium sulfide powder is mostly wet chemical method, that is, 3+ One or more sulfur-containing compounds are added to the solution to generate In2S3 precipitate, which is then filtered, washed, dried, calcined and crushed to obtain tetragonal In2S3 powder.

[0004] For example, in patent CN103540320A, InCl3 is used as the indium source, thiourea is added and stirred to react to obtain In2S3 precipitate, which is then centrifuged, washed, and naturally dried to obtain indium sulfide powder; in patent CN113213938A, indium sulfate is used as the indium source, hydrogen sulfide gas is introduced to react to obtain In2S3 precipitate, which is then centrifuged, washed, dried, and calcined to obtain high-purity In2S3 powder; in patent CN102335616A, indium chloride tetrahydrate is used as the indium source, thioacetamide is added to react to obtain indium sulfide precipitate, which is then filtered, washed, and dried to obtain indium sulfide powder.

[0005] The methods for preparing indium sulfide powder mentioned in the above patents all involve reacting in a solution to generate indium sulfide. The main problems with preparing indium sulfide by wet chemical methods are:

[0006] (1) Wastewater containing heavy metals is difficult to treat;

[0007] (2) The utilization rate of raw materials is low, and the indium-containing mother liquor cannot be directly reused after the reaction;

[0008] (3) The process is long and metal elements are easily dispersed;

[0009] (4) Anions in indium sulfide powder such as Cl - 、SO4 2-It is not easy to remove, especially Cl - It is difficult to reduce it to less than 50ppm by washing. Summary of the invention

[0010] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for preparing high-purity indium sulfide powder by a non-wet chemical method. The present invention provides a method for generating high-purity indium sulfide powder by reacting high-purity hydrogen sulfide gas and high-purity indium hydroxide powder as raw materials.

[0011] To achieve the purpose of the invention, the present invention adopts the following technical scheme: a method for preparing high-purity indium sulfide powder, using indium hydroxide powder as a raw material, heating it to 600-800°C and keeping it warm, and calcining it into fluffy indium oxide powder. The chemical reactions occurring in this stage are mainly:

[0012] 2In(OH)3(s)=In2O3(s)+3H2O(g)

[0013] From the above reaction, it can be seen that when 1 mol of indium hydroxide is calcined into In2O3, 1.5 mol of water will be generated, and the H2O generated by the reaction accounts for 10.8% of the mass of indium hydroxide. During the calcination process, the indium hydroxide particles continuously lose water and become In2O3 particles. When the volume of the powder pile remains basically unchanged, the bulk density of the powder will decrease by 10%, and the fluffy indium oxide powder formed by calcination contains larger pores, which is conducive to the gas-solid reaction of the indium oxide particles and hydrogen sulfide in the second step.

[0014] Then, indium oxide powder is heated to 400-600°C in a hydrogen sulfide gas atmosphere and kept warm to generate indium sulfide powder. The reactions that occur at this stage are mainly:

[0015] In2O3(s)+H2S(g)=In2S3(s)+H2O(g)

[0016] Furthermore, in the above-mentioned method for preparing high-purity indium sulfide powder, after the reaction is completed, hydrogen is introduced while maintaining the temperature unchanged to deoxidize the generated indium sulfide powder, and the hydrogenation time is 8 to 10 hours.

[0017] Furthermore, in the above-mentioned method for preparing high-purity indium sulfide powder, after the hydrogenation and deoxidation is completed, heating is stopped and the temperature is lowered to room temperature, and an inert gas is introduced to replace the hydrogen.

[0018] Furthermore, in the above-mentioned method for preparing a high-purity indium sulfide powder, the indium sulfide powder is taken out and the deoxidized indium sulfide powder is dried at 20-50 kPa and 200-250° C. for 8-10 hours to remove moisture from the In2S3 powder.

[0019] Furthermore, in the above-mentioned method for preparing high-purity indium sulfide powder, the particle size of the indium hydroxide powder is <10 μm, the purity is ≥99.99%, the sum of impurity metal elements is <100 ppm, and the water content is <1wt%.

[0020] Furthermore, in the above-mentioned method for preparing high-purity indium sulfide powder, the holding time of heating to 600° C. to 800° C. and keeping warm is related to the mass of the indium hydroxide powder, which is 0.4 to 0.6 kg / h.

[0021] Furthermore, in the above-mentioned method for preparing high-purity indium sulfide powder, in order to accelerate the calcination process of indium hydroxide, an inert gas is introduced during the calcination or the gas pressure is maintained at 60-90 kPa.

[0022] Furthermore, in the above-mentioned method for preparing high-purity indium sulfide powder, the inert gas is nitrogen or argon.

[0023] Furthermore, in the above-mentioned method for preparing a high-purity indium sulfide powder, the apparent density of the fluffy indium oxide powder is less than 1.2 g / cm 3 .

[0024] Furthermore, in the above-mentioned method for preparing high-purity indium sulfide powder, the heating time of the indium oxide powder to 400-600° C. and keeping the temperature is related to the mass of the indium oxide powder and is 0.2-0.4 kg / h.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] First, the present invention uses indium hydroxide powder as a raw material, and the particle size of the prepared indium sulfide powder is smaller than that of the indium sulfide powder directly prepared using commercially available indium oxide powder. In terms of use, the indium sulfide target material made of small-particle indium sulfide powder has a smaller grain size, which is beneficial to downstream applications; the purity is higher than that of the indium sulfide powder directly prepared using commercially available indium oxide powder, and the performance is excellent;

[0027] Second, the present invention uses indium hydroxide powder and hydrogen sulfide gas as raw materials to prepare indium sulfide powder. During the process, the materials do not contact the solution, anions, organic matter, etc. The non-metallic impurity elements C, N, and O in the powder are easy to control, and the process flow is short. The process does not generate wastewater and has little impact on the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is the XRD pattern of Example 1;

[0029] Figure 2 is the XRD pattern of Comparative Example 1;

[0030] Figure 3 is the SEM image of Example 1;

[0031] Figure 4 This is the SEM image of Comparative Example 1. DETAILED DESCRIPTION

[0032] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0033] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be obtained commercially.

[0034] The following are used:

[0035] The particle size of the indium hydroxide powder is less than 10 μm, the purity is ≥ 99.99%, the sum of the metal element impurities is less than 100 ppm, and the water content is less than 1wt%.

[0036] Example 1

[0037] A method for preparing high-purity indium sulfide powder, taking 5kg of indium hydroxide powder and loading it into an alumina boat, the purity of the alumina boat is 99%, then putting the alumina boat loaded with indium hydroxide powder into a horizontal tube furnace, heating it to 700°C, keeping it warm for 10 hours, and all the indium hydroxide in the alumina boat is calcined into fluffy indium oxide powder. Take 100g of indium oxide powder to measure the apparent density, and the result is shown in Table 1. The remaining indium oxide powder is still maintained in the alumina boat, and the alumina boat is placed in another horizontal tube furnace, inert gas is passed to replace the air in the furnace, H2S gas is passed into the tube furnace, and the heating program is set to heat up to 600°C, keep warm for 20 hours, turn off the H2S gas, switch to hydrogen, continue to keep warm for 8 hours, turn off the heating, cool to room temperature, pass nitrogen to completely replace the hydrogen in the furnace, and then take out the alumina boat.

[0038] The In2S3 powder obtained by the above reaction was placed in a vacuum calcining furnace, evacuated to 50 kPa, heated to 210°C, and kept warm for 10 hours. Then, the vacuum furnace was opened and the indium sulfide powder was taken out.

[0039] Example 2

[0040] A method for preparing high-purity indium sulfide powder, taking 5kg of indium hydroxide powder and loading it into an alumina boat, the purity of the alumina boat is 99%, and then putting the alumina boat loaded with indium hydroxide powder into a horizontal tube furnace, heating it to 800°C, keeping it warm for 10 hours, and all the indium hydroxide in the alumina boat is calcined into fluffy indium oxide powder. Take 100g of indium oxide powder to measure the apparent density, and the result is shown in Table 1. The remaining indium oxide powder is still maintained in the alumina boat, and the alumina boat is placed in another horizontal tube furnace, inert gas is passed to replace the air in the furnace, H2S gas is passed into the tube furnace, and the heating program is set to heat up to 500°C, keep warm for 20 hours, turn off the H2S gas, switch to hydrogen, continue to keep warm for 8 hours, turn off the heating, cool to room temperature, and then pass nitrogen to completely replace the hydrogen in the furnace, and then take out the alumina boat.

[0041] The In2S3 powder obtained by the above reaction was placed in a vacuum calcining furnace, evacuated to 40 kPa, heated to 220°C, and kept warm for 10 hours. Then, the vacuum furnace was opened and the indium sulfide powder was taken out.

[0042] Example 3

[0043] A method for preparing high-purity indium sulfide powder comprises the following steps: taking 5 kg of indium hydroxide powder and loading it into an alumina boat, wherein the purity of the alumina boat is 99%, and then placing the alumina boat containing the indium hydroxide powder into a horizontal tube furnace, heating it to 600°C, maintaining the gas pressure at 60 kPa during the calcination process to accelerate the calcination process of indium hydroxide, and keeping the temperature for 10 hours, so that all the indium hydroxide in the alumina boat is calcined into fluffy indium oxide powder. 100 g of indium oxide powder is taken to measure the apparent density, and the result is shown in Table 1. The remaining indium oxide powder is still maintained in the alumina boat, and the alumina boat is placed in another horizontal tube furnace, and the air in the furnace is replaced by inert gas, and H2S gas is introduced into the tube furnace, and the heating program is set to heat up to 400°C, and the temperature is kept for 20 hours, and the H2S gas is turned off, and switched to hydrogen, and the temperature is kept for 10 hours, and the heating is turned off, and the temperature is lowered to room temperature, and then nitrogen is passed to completely replace the hydrogen in the furnace, and then the alumina boat is taken out.

[0044] The In2S3 powder obtained by the above reaction was placed in a vacuum calcining furnace, evacuated to 70 kPa, heated to 200°C, and kept warm for 8 hours. Then, the vacuum furnace was opened and the indium sulfide powder was taken out.

[0045] Example 4

[0046] A method for preparing high-purity indium sulfide powder comprises the following steps: taking 5 kg of indium hydroxide powder and loading it into an alumina boat, wherein the purity of the alumina boat is 99%, and then placing the alumina boat containing the indium hydroxide powder into a horizontal tube furnace, heating it to 800°C, introducing inert gas argon during the calcination process to accelerate the calcination process of indium hydroxide, and keeping the temperature for 10 hours, so that all the indium hydroxide in the alumina boat is calcined into fluffy indium oxide powder. 100 g of indium oxide powder is taken to measure the apparent density, and the result is shown in Table 1. The remaining indium oxide powder is still maintained in the alumina boat, and the alumina boat is placed in another horizontal tube furnace, and the air in the furnace is replaced by inert gas, and H2S gas is introduced into the tube furnace, and the heating program is set to heat up to 400°C, and keep the temperature for 20 hours, and the H2S gas is turned off, and switched to hydrogen, and the temperature is kept for 9 hours, and the heating is turned off, and the temperature is lowered to room temperature, and then nitrogen is introduced to completely replace the hydrogen in the furnace, and then the alumina boat is taken out.

[0047] The In2S3 powder obtained by the above reaction was placed in a vacuum calcining furnace, evacuated to 60 kPa, heated to 250°C, and kept warm for 9 hours. Then, the vacuum furnace was opened and the indium sulfide powder was taken out.

[0048] Comparative Example 1

[0049] Indium oxide powder with a purity greater than 99.99% was purchased directly. Before the experiment, 100g of the sample was taken to test the apparent density of the powder, and the results are shown in Table 1. 4.3kg of the purchased alumina powder was put into an alumina boat, loaded into a tubular furnace, and the air in the furnace was replaced by inert gas. H2S gas was introduced into the tubular furnace, and the heating program was set to heat up to 600°C, kept warm for 20h, the H2S gas was turned off, switched to hydrogen, and kept warm for 8h, the heating was turned off, cooled to room temperature, and nitrogen was introduced to completely replace the hydrogen in the furnace, and the alumina boat was taken out.

[0050] The In2S3 powder obtained by the above reaction was placed in a vacuum calcining furnace, evacuated to 50 kPa, heated to 210°C, and kept warm for 10 hours. Then, the vacuum furnace was opened and the indium sulfide powder was taken out.

[0051] Sample testing experiment

[0052] The purity, particle size, indium content, C, N, O, XRD, SEM, etc. of the indium sulfide powder of Examples 1 to 4 and Comparative Example 1 were tested by sampling.

[0053] Table 1 gives the apparent density and other parameters of the indium oxide powder and the indium sulfide powder in Examples 1 to 4 and Comparative Example 1, and Table 2 gives the results of the metal and impurity elements such as C, N, and O of the indium sulfide powder.

[0054] Figure 1 and Figure 2 They are the XRD patterns of Example 1 and Comparative Example 1 respectively; Figure 3 and Figure 4They are SEM images of Example 1 and Comparative Example 1 respectively.

[0055] Table 1 Properties of indium oxide and indium sulfide powders

[0056]

[0057] The theoretical amount of indium in In2S3 is 70.52%, and the theoretical amount of indium in In2O3 is 82.97%. Since it is difficult to completely sulfidize indium oxide powder, a small amount of In2O3 will be mixed in the indium sulfide powder of both the embodiment and the comparative example, so the indium content in the indium sulfide powder will be greater than the theoretical amount. The closer the indium content in the indium sulfide powder is to the theoretical amount, the higher its purity.

[0058] It can be seen from Table 1 that the indium content of the indium sulfide powders of Examples 1-4 is lower than that of the indium sulfide powder of Comparative Example 1, indicating that the indium sulfide powders of Examples 1-4 are higher in purity than that of the indium sulfide powder of Comparative Example 1.

[0059] And it can be seen from Table 1 that the particle size of the indium sulfide powder of Examples 1-4 is much smaller than that of the indium sulfide powder of Comparative Example 1. In terms of usage, the indium sulfide target material made of small-particle indium sulfide powder has a smaller grain size, which is beneficial to downstream applications.

[0060] Table 2 In2S3 powder purity ppm

[0061] element C N O Ag Al As Bi Cd Co Fe Mg Mn Pb Si Zr Example 1 27 <10 65 6 2 <1 <1 5 <1 <1 <1 <1 5 3 <1 Example 2 20 <10 350 5 4 4 <1 7 <1 <1 <1 <1 8 2 <1 Example 3 31 <10 65 3 2 <1 <1 6 <1 <1 <1 <1 7 3 <1 Example 4 25 <10 1210 4 5 4 <1 7 <1 <1 <1 <1 6 2 <1 Comparative Example 1 18 <10 5500 5 6 7 10 8 9 8 <1 <1 4 4 12

[0062] From the In2S3 powder purity ppm data in Table 2, it can be seen that compared with Comparative Example 1, the final product In2S3 powder of Examples 1-4 contains fewer impurity elements, which means higher purity. Among them, Example 1 and Comparative Example 1 are the same except for the source of indium oxide powder in the stage of preparing indium sulfide from indium oxide powder. However, it can be seen that the impurity elements in Example 1 are basically much less than those in Comparative Example 1, proving that directly purchasing indium oxide powder with a purity greater than 99.99% as a raw material cannot achieve the effect of the technical solution of the present invention using indium hydroxide powder as a raw material. The indium sulfide powder prepared by the technical solution of the present invention is more excellent.

[0063] The applicant declares that the present invention illustrates the process method of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned process steps, that is, it does not mean that the present invention must rely on the above-mentioned process steps to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the raw materials selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing high-purity indium sulfide powder, characterized in that: Indium hydroxide powder is used as raw material, and the gas pressure is maintained at 60kPa, heated to 600°C and kept warm to calcine into fluffy indium oxide powder. The holding time is related to the mass of the indium hydroxide powder and is 0.4~0.6kg / h. Then, indium oxide powder is heated to 400°C in a hydrogen sulfide gas atmosphere and kept warm to react to generate indium sulfide powder. The holding time is related to the mass of the indium oxide powder and is 0.2~0.4kg / h. After the reaction is completed, hydrogen is introduced while maintaining the temperature constant to deoxidize the generated indium sulfide powder, and the hydrogenation time is 8 to 10 hours.

2. The method for preparing high-purity indium sulfide powder according to claim 1, characterized in that: After the hydrodeoxygenation is completed, heating is stopped and the temperature is lowered to room temperature, and an inert gas is introduced to replace the hydrogen.

3. The method for preparing high-purity indium sulfide powder according to claim 2, characterized in that: The indium sulfide powder is taken out and the deoxidized indium sulfide powder is dried at 20-50 kPa and 200-250° C. for 8-10 hours.

4. The method for preparing high-purity indium sulfide powder according to claim 1, characterized in that: The indium hydroxide powder has a particle size of less than 10 μm, a purity of ≥99.99%, a sum of impure metal elements of less than 100 ppm, and a water content of less than 1 wt%.

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