Method for preparing indium methanesulfonate solution by electrolysis

Abstract

The invention discloses a method for preparing an indium methanesulfonate solution by utilizing an electrolytic method. The method comprises the following steps: electrochemically dissolving a high-purity indium plate into an indium methanesulfonate solution at room temperature in an ion exchange membrane electrolytic cell; then removing impurities, filtering, low-temperature vacuum concentration and crystallization, and solid-liquid separation to obtain indium methanesulfonate crystals; and then preparing the indium methanesulfonate solution with an indium ion content of 120-200 g / L and a free acid content of 30-50 g / L. The method can fill the technical gap in the domestic preparation of indium methanesulfonate solutions. The prepared indium methanesulfonate solution has high purity, good quality, and a high indium recovery rate, can be widely used in the fields of thin-film solar cells, metal substrates of semiconductor wafers, special welding layers of electronic circuit boards, etc., has low production costs, and has great market prospects.

Description

Technical Field

[0001] The invention relates to a method for preparing an indium methanesulfonate solution by utilizing an electrolysis method. Background Art

[0002] Indium is a silvery-gray, extremely soft, fusible metal. Its content in the Earth's crust is extremely low and widely dispersed, making it a rare metal. Due to its low melting point, corrosion resistance, good reflectivity, and strong plasticity and ductility, indium is known as the "vitamin of alloys" and is widely used in industries such as liquid crystal displays, flat-panel displays, electronic semiconductors, and solar photovoltaic cells. Taiwan Patent TW201804023A provides an indium electroplating composition and a method for its preparation. The indium electroplating composition can be applied to the metal layer of semiconductor wafers and substrates to improve the performance and reliability of semiconductor devices, which is of great significance to the semiconductor industry. However, the preparation of the indium methanesulfonate used in this patent is rarely reported. A paper by Belgian scholar KU Leuven, published in the Journal of Physical Chemistry and Physics, Issue 42, 2020, mentions the synthesis of indium methanesulfonate from indium oxide and methanesulfonic acid. Currently, there are no domestic manufacturers of indium methanesulfonate. Currently, all indium methanesulfonate used in the electroplating industry must be imported from abroad, which is expensive and has long lead times. Summary of the Invention

[0003] In order to solve the above problems, the present invention provides a method for preparing an indium methanesulfonate solution by electrolysis, comprising the following steps:

[0004] Ion membrane pretreatment: The anion exchange membrane is first immersed in pure water and then immersed in 20-35 wt% methanesulfonic acid for 12-24 hours. After the immersion treatment, the anion exchange membrane is placed in an electrolytic cell, and the electrolytic cell is divided into a cathode area and an anode area. A 20-35 wt% methanesulfonic acid solution is injected into the cathode area and the anode area respectively for standby use; the method for preparing the methanesulfonic acid solution is common knowledge. A methanesulfonic acid solution can be obtained by adding a certain mass of pure methanesulfonic acid to a certain volume of water and stirring. No further details are given;

[0005] Synthesis of indium methanesulfonate: Place an indium plate with a thickness of 5~10mm in the anode area of ​​the electrolytic cell and a 2~5mm thick indium plate in the cathode area of ​​the electrolytic cell. Pass direct current at 15~35℃ and a current density of 1.5~2.5A / dm 2 When the indium ion mass concentration in the anode region is 120-240 g / L, the electrolyte in the anode region is taken out and the filtrate is filtered for later use;

[0006] Preparation of low-free-acid indium methanesulfonate crystals: concentrating the filtrate, cooling the crystals, and centrifuging to obtain low-free-acid indium methanesulfonate crystals;

[0007] Prepare indium methanesulfonate solution: Slowly add low-free acid indium methanesulfonate crystals to pre-prepared deionized water while stirring to prepare an indium methanesulfonate solution for electroplating with an indium ion content of 120-200 g / L and free methanesulfonic acid of 30-50 g / L.

[0008] Preferably, during the synthesis of indium methanesulfonate, the electrolyte in the anode region is removed and then re-injected with 20-35 wt% methanesulfonic acid solution, and then electrolysis is continued until the indium plate in the anode region is replaced when the thickness of the indium plate is 2-5 mm.

[0009] Preferably, the 2-5 mm indium plate replaced in the anode region is reinstalled in the cathode region of the electrolytic cell.

[0010] Preferably, during the ion membrane pretreatment process, each 1 kg of anion exchange membrane needs to be repeatedly soaked in 20 L of pure water for 24 to 48 hours.

[0011] Preferably, during the synthesis of indium methanesulfonate, the indium content in the indium plates respectively loaded into the anode region and the cathode region is not less than 99.99%.

[0012] Preferably, during the ion membrane pretreatment process, before injecting the 20-35 weight% methanesulfonic acid solution into the cathode region and the anode region respectively, activated carbon powder and 27.5 mass% hydrogen peroxide are added to the 20-35 weight% methanesulfonic acid solution in advance, reacted for 4-8 hours and then filtered, wherein the ratio of 20-35 weight% methanesulfonic acid solution: activated carbon powder: 27.5 mass% hydrogen peroxide is 1000 L: 0.5-1 kg: 200-1000 L.

[0013] Preferably, in the process of preparing low-free acid indium methanesulfonate crystals, vacuum decompression is used to concentrate until the soluble solid content is 55-65%, and then cooling and crystallizing, wherein the vacuum degree is 30-60 mbar.

[0014] Preferably, during the preparation of low-free acid indium methanesulfonate crystals, a centrifuge is used for separation, and the centrifuge speed is 2000-4000 rpm.

[0015] Preferably, the separation time of the centrifuge is 10 to 15 minutes.

[0016] Preferably, during the preparation of the indium methanesulfonate solution, the stirring speed is 200-400 r / min.

[0017] The beneficial effect is that the present application utilizes an ion exchange membrane electrolyzer to electrochemically dissolve a high-purity indium plate into an indium methanesulfonate solution at room temperature, and then obtains indium methanesulfonate crystals through impurity removal, filtration, low-temperature vacuum concentration crystallization, and solid-liquid separation. The indium methanesulfonate solution is then prepared into an indium methanesulfonate solution with an indium ion content of 120-200 g / L and a free acid content of 30-50 g / L. This method can fill the technical gap in the domestic preparation of indium methanesulfonate solutions. The prepared indium methanesulfonate solution has high purity, good quality, and a high indium recovery rate. It can be widely used in thin-film solar cells, semiconductor wafer metal substrates, special welding layers of electronic circuit boards, and other fields. The production cost is low and the market prospect is broad. DETAILED DESCRIPTION

[0018] The present invention will be further described in detail below with reference to specific embodiments so that those skilled in the art can understand the present invention more clearly.

[0019] The following embodiments are only used to illustrate the present invention, but are not intended to limit the scope of the present invention. Based on the specific embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention.

[0020] In the examples of the present invention, unless otherwise specified, all raw material components are commercially available products well known to those skilled in the art; in the examples of the present invention, unless otherwise specified, the technical means used are conventional means well known to those skilled in the art.

[0021] Source of raw materials:

[0022] Metal indium bars with an indium content greater than 99.99% were purchased from Changsha Youcheng Metal Materials Co., Ltd.

[0023] Methanesulfonic acid was purchased from Guangdong Wengjiang Chemical Reagent Co., Ltd.

[0024] The remaining reagents are commercially available.

[0025] Example 1

[0026] This embodiment provides a method for preparing an indium methanesulfonate solution by electrolysis, comprising the following steps:

[0027] Ion membrane pretreatment: 0.5 kg of anion exchange membrane was first soaked in 10 L of pure water for 36 h and then soaked in a 27 wt% methanesulfonic acid solution for 18 h. After soaking, the anion exchange membrane was placed in an electrolytic cell, which was divided into a cathode area and an anode area. 27 wt% methanesulfonic acid solution was injected into the cathode area and the anode area respectively for standby use;

[0028] Synthesis of indium methanesulfonate: Place an indium plate with a thickness of 7 mm and an indium content of not less than 99.99% in the anode area of ​​the electrolytic cell, and place an indium plate with a thickness of 3 mm and an indium content of not less than 99.99% in the cathode area of ​​the electrolytic cell. Pass direct current at 25°C and a current density of 2.0 A / dm 2 When the indium ion mass concentration in the anode region is 180 g / L, the electrolyte in the anode region is removed, and the filtrate is filtered and used for standby. After the electrolyte in the anode region is removed, a 28 wt % methanesulfonic acid solution is re-injected, and then the electrolysis is continued until the indium plate in the anode region has a thickness of 2-5 mm, and the indium plate in the anode region is replaced, and the 2-5 mm indium plate replaced in the anode region is re-installed in the cathode region of the electrolytic cell;

[0029] Preparation of low-free-acid indium methanesulfonate crystals: The filtrate was concentrated under vacuum to a soluble solid content of 55-65%, and then cooled for crystallization, wherein the vacuum degree was 50 mbar, and centrifuged in a centrifuge at a speed of 3000 rpm for 12 minutes to obtain low-free-acid indium methanesulfonate crystals;

[0030] Preparation of indium methanesulfonate solution: Slowly add low-free acid indium methanesulfonate crystals to pre-prepared deionized water while stirring at a stirring speed of 300 r / min to prepare an indium methanesulfonate solution for electroplating with an indium ion content of 163 g / L and free methanesulfonic acid of 38 g / L.

[0031] Example 2

[0032] This embodiment provides a method for preparing an indium methanesulfonate solution by electrolysis, comprising the following steps:

[0033] Ion membrane pretreatment: 1 kg of anion exchange membrane was first placed in 20 L of pure water and soaked for 48 hours, and then placed in a 35% by weight methanesulfonic acid solution for soaking for 24 hours. After the soaking treatment, the anion exchange membrane was placed in an electrolytic cell, and the electrolytic cell was divided into a cathode area and an anode area. 35% by weight methanesulfonic acid solution was injected into the cathode area and the anode area respectively for standby use. Before the 35% by weight methanesulfonic acid solution was injected into the cathode area and the anode area respectively, activated carbon powder and 27.5% by weight hydrogen peroxide were added to the 35% by weight methanesulfonic acid solution in advance, reacted for 8 hours, and then filtered. The ratio of 35% by weight methanesulfonic acid solution: activated carbon powder: 27.5% by weight hydrogen peroxide was 1000 L: 0.75 kg: 600 L;

[0034] Synthesis of indium methanesulfonate: Place an indium plate with a thickness of 10 mm and an indium content of not less than 99.99% in the anode area of ​​the electrolytic cell, and place an indium plate with a thickness of 5 mm and an indium content of not less than 99.99% in the cathode area of ​​the electrolytic cell. Pass direct current at 35°C and a current density of 2.5 A / dm 2When the indium ion mass concentration in the anode region is 240 g / L, the electrolyte in the anode region is removed, and the filtrate is filtered and used for standby. After the electrolyte in the anode region is removed, a 35 wt % methanesulfonic acid solution is re-injected, and then the electrolysis is continued until the indium plate in the anode region has a thickness of 2-5 mm, and the indium plate in the anode region is replaced, and the 2-5 mm indium plate replaced in the anode region is re-installed in the cathode region of the electrolytic cell;

[0035] Preparation of low-free-acid indium methanesulfonate crystals: The filtrate was concentrated under vacuum to a soluble solid content of 55-65%, and then cooled for crystallization, wherein the vacuum degree was 60 mbar, and centrifuged in a centrifuge at a speed of 4000 rpm for 10 minutes to obtain low-free-acid indium methanesulfonate crystals;

[0036] Preparation of indium methanesulfonate solution: Slowly add low-free acid indium methanesulfonate crystals to pre-prepared deionized water while stirring at a stirring speed of 200 r / min to prepare an indium methanesulfonate solution with an indium ion content of 200 g / L and free methanesulfonic acid of 50 g / L.

[0037] Example 3

[0038] This embodiment provides a method for preparing an indium methanesulfonate solution by electrolysis, comprising the following steps:

[0039] Ion membrane pretreatment: 0.1 kg of anion exchange membrane was first placed in 2 L of pure water and soaked for 24 hours, and then placed in a 20% by weight methanesulfonic acid solution for soaking for 12 hours. After the soaking treatment, the anion exchange membrane was placed in an electrolytic cell, and the electrolytic cell was divided into a cathode area and an anode area. 20% by weight methanesulfonic acid solution was injected into the cathode area and the anode area respectively for standby use. Before the 20% by weight methanesulfonic acid solution was injected into the cathode area and the anode area respectively, activated carbon powder and 27.5% by weight hydrogen peroxide were added to the 20% by weight methanesulfonic acid solution in advance, reacted for 4 hours, and then filtered. The ratio of 20% by weight methanesulfonic acid solution: activated carbon powder: 27.5% by weight hydrogen peroxide was 1000 L: 1 kg: 1000 L;

[0040] Synthesis of indium methanesulfonate: Place an indium plate with a thickness of 5 mm and an indium content of not less than 99.99% in the anode area of ​​the electrolytic cell, and place an indium plate with a thickness of 2 mm and an indium content of not less than 99.99% in the cathode area of ​​the electrolytic cell. Pass direct current at 15°C and a current density of 1.5 A / dm 2When the indium ion mass concentration in the anode region is 120 g / L, the electrolyte in the anode region is removed, and the filtrate is filtered and used for standby. After the electrolyte in the anode region is removed, a 20 wt % methanesulfonic acid solution is re-injected, and then the electrolysis is continued until the indium plate in the anode region has a thickness of 2-5 mm, and the indium plate in the anode region is replaced, and the 2-5 mm indium plate replaced in the anode region is re-installed in the cathode region of the electrolytic cell;

[0041] Preparation of low-free-acid indium methanesulfonate crystals: The filtrate is concentrated under vacuum to a soluble solid content of 55-65%, and then cooled for crystallization, wherein the vacuum degree is 30 mbar, and centrifuged in a centrifuge at a speed of 2000 rpm for 15 minutes to obtain low-free-acid indium methanesulfonate crystals;

[0042] Preparation of indium methanesulfonate solution: Slowly add low-free acid indium methanesulfonate crystals to pre-prepared deionized water while stirring at a stirring speed of 400 r / min to prepare an indium methanesulfonate solution with an indium ion content of 120 g / L and free methanesulfonic acid of 30 g / L.

[0043] Example 4

[0044] This embodiment provides a method for preparing an indium methanesulfonate solution by electrolysis, comprising the following steps:

[0045] Ion membrane pretreatment: 0.2 kg of anion exchange membrane was first placed in 4 L of pure water and soaked for 30 hours, and then placed in a 30% by weight methanesulfonic acid solution for soaking for 14 hours. After the soaking treatment, the anion exchange membrane was placed in an electrolytic cell, and the electrolytic cell was divided into a cathode area and an anode area. 30% by weight methanesulfonic acid solution was injected into the cathode area and the anode area respectively for standby use. Before the 30% by weight methanesulfonic acid solution was injected into the cathode area and the anode area respectively, activated carbon powder and 27.5% by weight hydrogen peroxide were added to the 30% by weight methanesulfonic acid solution in advance, reacted for 6 hours, and then filtered. The ratio of 30% by weight methanesulfonic acid solution: activated carbon powder: 27.5% by weight hydrogen peroxide was 1000 L: 0.5 kg: 200 L;

[0046] Synthesis of indium methanesulfonate: Place an 8mm thick indium plate with an indium content of not less than 99.99% in the anode area of ​​the electrolytic cell, and place a 4mm thick indium plate with an indium content of not less than 99.99% in the cathode area of ​​the electrolytic cell. Pass direct current at 27°C and a current density of 2.2A / dm 2When the indium ion mass concentration in the anode region is 200 g / L, the electrolyte in the anode region is removed, and the filtrate is filtered and used for standby. After the electrolyte in the anode region is removed, 30 wt % methanesulfonic acid solution is re-injected, and then the electrolysis is continued until the indium plate in the anode region has a thickness of 2-5 mm, and the indium plate in the anode region is replaced, and the 2-5 mm indium plate replaced in the anode region is re-installed in the cathode region of the electrolytic cell;

[0047] Preparation of low-free-acid indium methanesulfonate crystals: The filtrate is concentrated under vacuum to a soluble solid content of 55-65%, and then cooled for crystallization, wherein the vacuum degree is 30 mbar, and centrifuged in a centrifuge at a speed of 2500 rpm for 14 minutes to obtain low-free-acid indium methanesulfonate crystals;

[0048] Preparation of indium methanesulfonate solution: Slowly add low-free acid indium methanesulfonate crystals to pre-prepared deionized water while stirring at a stirring speed of 350 r / min to prepare an indium methanesulfonate solution with an indium ion content of 142 g / L and free methanesulfonic acid of 42 g / L.

[0049] The indium methanesulfonate solutions prepared in Examples 1 to 4 were tested.

[0050] Test Method

[0051] Indium (In) concentration is tested in accordance with YS / T 276.9-2011 "Chemical analysis of indium - Part 9: Determination of indium content - Na2EDTA titration method";

[0052] The free acid concentration (measured as CH3SO3H) was determined using the method in the Manual of Analytical Methods for General Chemical Products; the test results are shown in Table 1.

[0053] Table 1 Test results of indium methanesulfonate solution

[0054]

[0055] The above is merely an embodiment of the present invention and is not intended to limit the present invention. It will be apparent to those skilled in the art that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of the claims of the present invention.

Claims

1. A method for preparing an indium methanesulfonate solution by electrolysis, characterized in that: The following steps are involved: Ion membrane pretreatment: The anion exchange membrane is first immersed in pure water and then immersed in 20-35 wt% methanesulfonic acid. After the immersion treatment, the anion exchange membrane is placed in an electrolytic cell, and the electrolytic cell is divided into a cathode area and an anode area. A 20-35 wt% methanesulfonic acid solution is injected into the cathode area and the anode area respectively for standby use; Synthesis of indium methanesulfonate: Place an indium plate with a thickness of 5-10 mm in the anode area of ​​the electrolytic cell and a 2-5 mm indium plate in the cathode area of ​​the electrolytic cell, pass direct current at 15-35°C, and at a current density of 1.5-2.5 A / dm 2 When the indium ion mass concentration in the anode region is 120-240 g / L, the electrolyte in the anode region is taken out and the filtrate is filtered for later use; Preparation of low-free-acid indium methanesulfonate crystals: concentrating the filtrate, cooling for crystallization, and centrifuging to obtain low-free-acid indium methanesulfonate crystals; Preparation of indium methanesulfonate solution: slowly adding the low-free acid indium methanesulfonate crystals to pre-prepared deionized water while stirring to prepare an indium methanesulfonate solution for electroplating with an indium ion content of 120-200 g / L and free methanesulfonic acid of 30-50 g / L.

2. The method for preparing an indium methanesulfonate solution by electrolysis according to claim 1, wherein: During the synthesis of the indium methanesulfonate, the electrolyte in the anode region is removed, and then 20-35 wt% of the methanesulfonic acid solution is re-injected, and then electrolysis is continued until the indium plate in the anode region has a thickness of 2-5 mm, and the indium plate in the anode region is replaced.

3. The method for preparing an indium methanesulfonate solution by electrolysis according to claim 2, wherein: The 2-5 mm indium plate replaced in the anode area is reinstalled in the cathode area of ​​the electrolytic cell.

4. The method for preparing an indium methanesulfonate solution by electrolysis according to claim 1, wherein: During the ion membrane pretreatment process, each 1 kg of anion exchange membrane needs to be repeatedly soaked in 20 L of pure water for 24 to 48 hours.

5. The method for preparing an indium methanesulfonate solution by electrolysis according to claim 1, wherein: During the synthesis of the indium methanesulfonate, the indium contents in the indium plates respectively loaded into the anode region and the cathode region are not less than 99.99%.

6. The method for preparing an indium methanesulfonate solution by electrolysis according to claim 1, wherein: During the ion membrane pretreatment process, before the 20-35 weight percent methanesulfonic acid solution is injected into the cathode region and the anode region respectively, activated carbon powder and 27.5 mass percent hydrogen peroxide are added to the 20-35 weight percent methanesulfonic acid solution in advance, reacted for 4-8 hours, and then filtered, wherein the ratio of the 20-35 weight percent methanesulfonic acid solution: activated carbon powder: 27.5 mass percent hydrogen peroxide is 1000 L: 0.5-1 kg: 200-1000 L.

7. The method for preparing an indium methanesulfonate solution by electrolysis according to claim 1, wherein: In the process of preparing the low-free acid indium methanesulfonate crystal, vacuum decompression is adopted to concentrate until the soluble solid content is 55-65%, and then cooling and crystallizing is carried out, wherein the vacuum degree is 30-60 mbar.

8. The method for preparing an indium methanesulfonate solution by electrolysis according to claim 1, wherein: In the process of preparing the low-free acid indium methanesulfonate crystals, a centrifuge is used for separation, and the centrifuge speed is 2000-4000 rpm.

9. The method for preparing an indium methanesulfonate solution by electrolysis according to claim 8, wherein: The separation time of the centrifuge is 10 to 15 minutes.

10. The method for preparing an indium methanesulfonate solution by electrolysis according to claim 1, wherein: During the preparation of the indium methanesulfonate solution, the stirring speed is 200-400 r / min.

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