Method for preparing indium methanesulfonate solution by using electrolytic method

Abstract

The invention discloses a method for preparing an indium methanesulfonate solution by using an electrolytic method, which comprises the following steps of: electrochemically dissolving a high-purity indium plate into the indium methanesulfonate solution at normal temperature by using an ion exchange membrane electrolytic cell, removing impurities, filtering, carrying out low-temperature vacuum concentration crystallization and solid-liquid separation to obtain indium methanesulfonate crystals, and blending the indium methanesulfonate crystals into the indium methanesulfonate solution with the indium ion concentration of 120-200g / L and the indium ion concentration of 200-300g / L, the free acid is 30-50g / L, the technical blank of preparing the indium methanesulfonate solution in China can be filled, and the prepared indium methanesulfonate solution is high in purity, good in quality, high in indium recovery rate, capable of being widely applied to the fields of thin-film solar cells, semiconductor wafer metal substrates, electronic circuit board special welding layers and the like, low in production cost and suitable for industrial production. The market prospect is wide.

Description

Technical Field

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

[0002] Indium is a silver-grey, extremely soft, fusible metal with extremely low content and high dispersion in the earth's crust. It is a rare metal. Indium has the characteristics of low melting point, corrosion resistance, good reflectivity, strong plasticity and ductility. It is called the "vitamin of alloys" and is widely used in industries such as liquid crystal displays, flat panels, electronic semiconductors, and solar photovoltaic cells. Taiwan Patent TW201804023A provides an indium electroplating composition and a preparation method thereof. The indium electroplating composition provided can be used on semiconductor wafers and their substrate metal layers to improve the performance and reliability of semiconductor devices, which is of great significance to the semiconductor industry. However, there are few literature reports on how the indium methanesulfonate used in this patent is prepared. Only one paper published by Belgian scholar KU Leuven in the 42nd issue of "Physical Chemistry and Physics" in 2020 mentioned that indium methanesulfonate can be synthesized from indium oxide and methanesulfonic acid. At present, there are no manufacturers of indium methanesulfonate in China. At present, the indium methanesulfonate used in the electroplating industry must be imported from abroad, which has problems such as high prices and long order cycles. 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: Ion membrane pretreatment: the anion exchange membrane is first soaked in pure water and then soaked in 20-35 wt% methanesulfonic acid for 12-24 hours. After the soaking 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 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. It will not be repeated here. 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 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 and used for later use; Preparation of low-free-acid indium methanesulfonate crystals: concentrating the filtrate, cooling and crystallizing, and centrifuging to obtain low-free-acid indium methanesulfonate crystals; Preparation of indium methanesulfonate solution: Slowly add low-free acid indium methanesulfonate crystals into 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.

[0004] Preferably, during the synthesis of indium methanesulfonate, after the electrolyte in the anode region is taken out, 20-35 wt% methanesulfonic acid solution is re-injected, and then electrolysis is continued until the indium plate in the anode region is replaced when the thickness of the indium plate in the anode region is 2-5 mm.

[0005] Preferably, the 2-5 mm indium plate replaced from the anode region is reinstalled into the cathode region of the electrolytic cell.

[0006] 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.

[0007] Preferably, in the process of synthesizing 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%.

[0008] Preferably, during the ion membrane pretreatment process, before injecting 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 1000L: 0.5~1kg: 200~1000L.

[0009] 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 cool and crystallize, wherein the vacuum degree is 30-60 mbar.

[0010] Preferably, in the process of preparing low-free acid indium methanesulfonate crystals, a centrifuge is used for separation, and the centrifuge speed is 2000-4000 rpm.

[0011] Preferably, the separation time of the centrifuge is 10 to 15 minutes.

[0012] Preferably, during the preparation of the indium methanesulfonate solution, the stirring speed is 200-400 r / min.

[0013] The beneficial effect is that the present invention 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, and then prepares an indium methanesulfonate solution with an indium ion content of 120-200 g / L and a free acid content of 30-50 g / L, which can fill the technical gap in the domestic preparation of indium methanesulfonate solutions. The prepared indium methanesulfonate solution has high purity, good quality, and high indium recovery rate, and can be widely used in thin-film solar cells, semiconductor wafer metal substrates, special welding layers of electronic circuit boards, and other fields, with low production costs and great market prospects. DETAILED DESCRIPTION

[0014] The present invention is further described in detail below in conjunction with specific embodiments so that those skilled in the art can understand the present invention more clearly.

[0015] The following embodiments are only used to illustrate the present invention, but are not limited to the scope of the present invention. Based on the specific embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work belong to the protection scope of the present invention.

[0016] 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.

[0017] Source of raw materials: Metal indium bars with an indium content greater than 99.99% were purchased from Changsha Youcheng Metal Materials Co., Ltd. Methanesulfonic acid was purchased from Guangdong Wengjiang Chemical Reagent Co., Ltd.; The remaining reagents are commercially available.

[0018] Example 1 This embodiment provides a method for preparing an indium methanesulfonate solution by electrolysis, comprising the following steps: Ion membrane pretreatment: 0.5 kg of anion exchange membrane was first soaked in 10 L of pure water for 36 hours and then soaked in a 27 wt % methanesulfonic acid solution for 18 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. A 27 wt % methanesulfonic acid solution was 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 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 at a current density of 2.0 A / dm 2When the mass concentration of indium ions in the anode region is 180 g / L, the electrolyte in the anode region is taken out, and the filtrate is filtered and used for standby, and after the electrolyte in the anode region is taken out, 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; Preparation of low-free acid indium methanesulfonate crystals: vacuum decompression and concentration of the filtrate to a soluble solid content of 55-65% and then cooling and crystallization, wherein the vacuum degree is 50 mbar, and centrifugal separation is performed by centrifuge to obtain low-free acid indium methanesulfonate crystals, the centrifuge speed is 3000 rpm, and the separation time is 12 minutes; Preparation of indium methanesulfonate solution: Low free acid indium methanesulfonate crystals were slowly added 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.

[0019] Example 2 This embodiment provides a method for preparing an indium methanesulfonate solution by electrolysis, comprising the following steps: Ion membrane pretreatment: 1 kg of anion exchange membrane is first placed in 20 L of pure water and soaked for 48 hours and then placed in a 35% by weight methane sulfonic acid solution for soaking for 24 hours. After the anion exchange membrane is soaked, it is placed in an electrolytic cell to divide the electrolytic cell into a cathode area and an anode area, and a 35% by weight methane sulfonic acid solution is injected into the cathode area and the anode area respectively for standby use. Before the 35% by weight methane sulfonic acid solution is injected into the cathode area and the anode area respectively, activated carbon powder and 27.5% by weight hydrogen peroxide are added to the 35% by weight methane sulfonic acid solution in advance to react for 8 hours and then filtered, wherein the 35% by weight methane sulfonic acid solution: activated carbon powder: 27.5% by weight hydrogen peroxide is 1000 L: 0.75 kg: 600 L; 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 at a current density of 2.5 A / dm 2 When the mass concentration of indium ions in the anode region is 240 g / L, the electrolyte in the anode region is taken out, and the filtrate is filtered and used for standby, and after the electrolyte in the anode region is taken out, 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; Preparation of low-free acid indium methanesulfonate crystals: vacuum decompression and concentration of the filtrate to a soluble solid content of 55-65% and then cooling and crystallization, wherein the vacuum degree is 60 mbar, and centrifugal separation is performed by centrifuge to obtain low-free acid indium methanesulfonate crystals, the centrifuge speed is 4000 rpm, and the separation time is 10 minutes; Preparation of indium methanesulfonate solution: Low free acid indium methanesulfonate crystals were slowly added 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.

[0020] Example 3 This embodiment provides a method for preparing an indium methanesulfonate solution by electrolysis, comprising the following steps: Ion membrane pretreatment: 0.1 kg of anion exchange membrane is first placed in 2L of pure water and soaked for 24 hours and then placed in a 20% by weight methane sulfonic acid solution for soaking for 12 hours. After the anion exchange membrane is soaked, it is placed in an electrolytic cell to divide the electrolytic cell into a cathode area and an anode area, and a 20% by weight methane sulfonic acid solution is injected into the cathode area and the anode area respectively for standby use. Before the 20% by weight methane sulfonic acid solution is injected into the cathode area and the anode area respectively, activated carbon powder and 27.5% by weight hydrogen peroxide are added to the 20% by weight methane sulfonic acid solution in advance to react for 4 hours and then filtered, wherein the 20% by weight methane sulfonic acid solution: activated carbon powder: 27.5% by weight hydrogen peroxide is 1000L: 1kg: 1000L; 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 at a current density of 1.5 A / dm 2 When the mass concentration of indium ions in the anode region is 120 g / L, the electrolyte in the anode region is taken out, and the filtrate is filtered and used for later use. After the electrolyte in the anode region is taken out, 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; Preparation of low-free acid indium methanesulfonate crystals: vacuum decompression and concentration of the filtrate to a soluble solid content of 55-65%, and then cooling and crystallization, wherein the vacuum degree is 30 mbar, and centrifugal separation is performed to obtain low-free acid indium methanesulfonate crystals, the centrifuge speed is 2000 rpm, the separation time is 15 minutes, and centrifugal separation is performed to obtain low-free acid indium methanesulfonate crystals; Preparation of indium methanesulfonate solution: Low free acid indium methanesulfonate crystals were slowly added 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.

[0021] Example 4 This embodiment provides a method for preparing an indium methanesulfonate solution by electrolysis, comprising the following steps: Ion membrane pretreatment: 0.2 kg of anion exchange membrane is first placed in 4 L of pure water and soaked for 30 hours, and then placed in a 30% by weight methane sulfonic acid solution for soaking for 14 hours. After the anion exchange membrane is soaked, it is placed in an electrolytic cell, and the electrolytic cell is divided into a cathode area and an anode area. A 30% by weight methane sulfonic acid solution is injected into the cathode area and the anode area respectively for standby use. Before the 30% by weight methane sulfonic acid solution is injected into the cathode area and the anode area respectively, activated carbon powder and 27.5% by weight hydrogen peroxide are added to the 30% by weight methane sulfonic acid solution in advance to react for 6 hours and then filtered, wherein the 30% by weight methane sulfonic acid solution: activated carbon powder: 27.5% by weight hydrogen peroxide is 1000 L: 0.5 kg: 200 L; Synthesis of indium methanesulfonate: Place an indium plate with a thickness of 8 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 4 mm and an indium content of not less than 99.99% in the cathode area of ​​the electrolytic cell. Pass direct current at 27°C and at a current density of 2.2 A / dm 2 When the mass concentration of indium ions in the anode region is 200 g / L, the electrolyte in the anode region is taken out, and the filtrate is filtered and used for standby, and after the electrolyte in the anode region is taken out, 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; Preparation of low-free acid indium methanesulfonate crystals: vacuum decompression and concentration of the filtrate to a soluble solid content of 55-65%, and then cooling and crystallization, wherein the vacuum degree is 30 mbar, and centrifugal separation is performed to obtain low-free acid indium methanesulfonate crystals, the centrifuge speed is 2500 rpm, the separation time is 14 minutes, and centrifugal separation is performed to obtain low-free acid indium methanesulfonate crystals; Preparation of indium methanesulfonate solution: Low free acid indium methanesulfonate crystals were slowly added 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.

[0022] The indium methanesulfonate solutions prepared in Examples 1 to 4 were tested.

[0023] Test Method Indium (In) concentration detection is in accordance with YS / T 276.9-2011 "Indium Chemical Analysis Method Part 9: Determination of Indium Content Na2EDTA Titration Method"; The free acid concentration (measured in CH3SO3H) was determined using the method in the Manual of Analytical Methods for General Chemical Products; the test results are shown in Table 1.

[0024] Table 1 Test results of indium methanesulfonate solution

[0025] The above is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A method for preparing indium methanesulfonate solution by electrolysis, It is 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 to divide the electrolytic cell into a cathode area and an anode area, and 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: an indium plate with a thickness of 5 to 10 mm is placed in the anode region of the electrolytic cell, and an indium plate with a thickness of 2 to 5 mm is placed in the cathode region of the electrolytic cell, direct current is passed at 15 to 35°C, and a current density of 1.5 to 2.5 A / dm 2 When the mass concentration of indium ions in the anode region is 120-240 g / L, the electrolyte in the anode region is taken out, and the filtrate is filtered and used for later use; Preparation of low-free-acid indium methanesulfonate crystals: concentrating the filtrate, cooling and crystallizing, and centrifuging to obtain low-free-acid indium methanesulfonate crystals; Preparation of indium methanesulfonate solution: slowly adding the low free acid indium methanesulfonate crystals into 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 indium methanesulfonate solution by electrolysis according to claim 1, It is characterized in that During the synthesis of the indium methanesulfonate, the electrolyte in the anode region is taken out, 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 is replaced when the thickness of the indium plate in the anode region is 2-5 mm.

3. The method for preparing indium methanesulfonate solution by electrolysis according to claim 2, It is characterized in that The 2-5 mm indium plate replaced from the anode region is reinstalled into the cathode region of the electrolytic cell.

4. The method for preparing indium methanesulfonate solution by electrolysis according to claim 1, It is characterized in that 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 indium methanesulfonate solution by electrolysis according to claim 1, It is characterized in that In the process of synthesizing the 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%.

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

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

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

9. The method for preparing indium methanesulfonate solution by electrolysis according to claim 8, It is characterized in that The separation time of the centrifuge is 10 to 15 minutes.

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

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