Modified indium ion adsorbent, method for preparing same, and method for recovering indium from indium waste

Abstract

The present application belongs to the technical field of indium waste recovery, and particularly relates to a modified indium ion adsorbent, a preparation method thereof, and a method for recovering indium from indium waste. The preparation raw materials of the modified indium ion adsorbent include mesoporous silica, mercapto silane and diphenyl phosphine chloride; the mass molar ratio of the mesoporous silica, the mercapto silane and the diphenyl phosphine chloride is 1g:2mmol~3mmol:2.2mmol~3mmol. The modified indium ion adsorbent provided by the present application takes mesoporous silica as an adsorbent carrier; the mercapto silane is taken as a coupling agent and a reactive bridge, the lone pair electrons and nucleophilicity of the mercapto silane make it easy to react with the diphenyl phosphine group in the modifier to form a P-S bond, so as to firmly fix the target group; the diphenyl phosphine group in the modifier has strong affinity for soft acid metal ions (In 3+ ), and can selectively adsorb indium from a complex solution.

Description

Technical Field

[0001] This invention belongs to the field of indium waste recycling technology, specifically relating to a modified indium ion adsorbent and its preparation method, and a method for recovering indium from indium waste. Background Technology

[0002] Indium is an indispensable key material in high-tech fields such as aerospace and liquid crystal displays, but global resource reserves are limited, and primary indium is mainly obtained as a byproduct of zinc smelting. However, the indium content in indium waste and electronic waste is often higher than that in primary ore. Indium waste recycling can not only turn waste into treasure, but also avoid the pollution of the environment by hazardous waste.

[0003] Currently, the main process for recycling indium waste is hydrometallurgy. This involves first separating indium-containing glass through pretreatment (such as dismantling, removing polarizers, and crushing); then intensifying leaching with strong acid under the assistance of additives or external fields (such as ultrasound); followed by further separation and enrichment using extraction, adsorption, or membrane separation techniques; and finally, recovering high-purity indium through electrolysis or displacement. However, in the adsorption step, due to the often high acidity of the feed solution (strong acid leaching), many adsorbents will have their adsorption sites ionized by hydrogen ions (H+) in low pH environments. + Protonation leads to a sharp decrease in the adsorption capacity of the adsorbent for indium ions; in addition, a large number of competing ions such as iron(III), zinc(II), and copper(II) usually coexist in the feed solution. These ions have similar properties to indium ions, resulting in low selectivity of the adsorbent. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a modified indium ion adsorbent and its preparation method, as well as a method for recovering indium from indium waste. This addresses at least one aspect of solving the above-mentioned technical problems.

[0005] This invention is achieved through the following technical solution: In a first aspect, the present invention provides a modified indium ion adsorbent, the raw materials for which include mesoporous silica, mercaptosilane and diphenylphosphine chloride; The mass molar ratio of mesoporous silica, mercaptosilane, and diphenylphosphine chloride is 1 g: 2 mmol~3 mmol: 2.2 mmol~3 mmol.

[0006] In some possible implementations, the mesoporous silica includes at least one of SBA-15 and MCM-41.

[0007] In some possible implementations, the specific surface area of ​​the mesoporous silica is >500 m². 2 / g.

[0008] In some possible implementations, the average pore size of the mesoporous silica is 4 nm to 8 nm.

[0009] In some possible implementations, the mercaptosilane includes 3-mercaptopropyltrimethoxysilane.

[0010] Secondly, the present invention provides a method for preparing the above-mentioned modified indium ion adsorbent, comprising the following steps: Mesoporous silica and mercaptosilane are grafted together to obtain mercapto-modified mesoporous silica. The thiolized mesoporous silica and diphenylphosphine chloride are mixed and treated to obtain the modified indium ion adsorbent.

[0011] In some possible implementations, the grafting process includes the following steps: Under an inert atmosphere, a mixture of mesoporous silica-toluene and mercaptosilane is refluxed.

[0012] In some possible implementations, the inert atmosphere includes at least one of nitrogen, argon, and helium.

[0013] In some possible implementations, the mass-to-volume ratio of mesoporous silica to toluene in the mesoporous silica-toluene mixture is 1 g: 40 ml to 50 ml.

[0014] In some possible implementations, the reflux temperature is 110°C to 120°C.

[0015] In some possible implementations, the reflux time is 12h to 24h.

[0016] In some possible implementations, the mixing process includes the following steps: After the reaction solution was subjected to the first stirring reaction under an inert atmosphere and an ice-water bath, the second stirring reaction was carried out at room temperature in the dark. The reaction solution contains mercapto-modified mesoporous silica, diphenylphosphine chloride, a catalyst, and a solvent.

[0017] In some possible implementations, the catalyst comprises triethylamine.

[0018] In some possible implementations, the solvent includes dichloromethane.

[0019] In some possible implementations, the mass-to-volume ratio of the mesoporous silica, triethylamine, and dichloromethane is 1 g: 0.35 ml to 0.4 ml: 45 ml to 55 ml.

[0020] In some possible implementations, the temperature of the ice-water bath is 0°C to 5°C.

[0021] In some possible implementations, the first stirring reaction takes 1 to 2 hours.

[0022] In some possible implementations, the second stirring reaction takes 12 to 24 hours.

[0023] Thirdly, the present invention provides a method for recovering indium from indium waste, comprising the following steps: The indium waste leachate is subjected to adsorption and desorption treatment with an adsorbent to obtain a desorbed solution; wherein the adsorbent includes the modified indium ion adsorbent mentioned above. The desorption solution is subjected to electrolytic refining to obtain indium.

[0024] In some possible implementations, the adsorption-desorption process includes the following steps: After adjusting the pH of the indium waste leachate to 1.5-2.5, it is adsorbed using an adsorption column containing modified indium ion adsorbent, and then desorbed using sulfuric acid to obtain the desorbed solution.

[0025] In some possible implementations, the indium waste leachate enters the adsorption column at a flow rate of 4 mL / min to 6 mL / min.

[0026] In some possible implementations, the mass ratio of the modified indium ion adsorbent to the indium waste is 2 to 3:1.

[0027] In some possible implementations, the concentration of the sulfuric acid is 1 mol / L to 2 mol / L.

[0028] In some possible implementations, the preparation of the indium waste leachate includes the following steps: Under stirring, indium waste and nitric acid undergo a first mixing reaction, followed by a second mixing reaction with hydrogen peroxide. The filtrate is then collected to obtain indium waste leachate.

[0029] In some possible implementations, the electrolytic refining process includes the following steps: Electrolysis is performed using titanium-based IrO2 as the anode, stainless steel as the cathode, and an electrolyte containing desorption solution and additives.

[0030] The modified indium ion adsorbent provided by this invention has at least the following beneficial technical effects compared with the prior art: The modified indium ion adsorbent provided by this invention uses mesoporous silica as the adsorbent carrier; mercaptosilane acts as a coupling agent and reactive bridge, and its lone pair electrons and nucleophilicity of the mercapto group make it easy to react with the diphenylphosphine group in the modifier to form a PS bond, thereby firmly fixing the target group; the diphenylphosphine group in the modifier reacts with soft acid metal ions (In... 3+ It has a strong affinity and can selectively adsorb indium from complex solutions.

[0031] The method for preparing the modified indium ion adsorbent provided by this invention has at least the following beneficial technical effects compared with the prior art: The method for preparing the modified indium ion adsorbent provided by this invention involves first grafting mercapto groups onto the surface of mesoporous silica, and then grafting diphenylphosphine groups. This two-step grafting via covalent bonds ensures that the functional groups are firmly bonded and not easily lost.

[0032] The method for recovering indium from indium waste provided by this invention has at least the following beneficial technical effects compared with the prior art: The method for recovering indium from indium waste provided by this invention uses the modified indium ion adsorbent provided by this invention. The bifunctional groups (thiol + phosphin) work synergistically to improve the adsorption selectivity of the adsorbent for indium. After adsorption and desorption treatment, electrolytic refining is carried out. Adsorption and electrolysis are directly coupled, reducing intermediate steps and improving the recovery efficiency of indium. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described and illustrated below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. All other embodiments obtained by those skilled in the art based on the embodiments provided by this invention without inventive effort are within the scope of protection of this invention.

[0034] Obviously, the following description is merely some examples or embodiments of the present invention. Those skilled in the art can apply the present invention to other similar scenarios without any inventive effort. Furthermore, it is understood that although the effort involved in such development may be complex and lengthy, for those skilled in the art related to the content disclosed in this invention, modifications to design, manufacturing, or production based on the technical content disclosed in this invention are merely conventional technical means and should not be construed as insufficient disclosure of the present invention.

[0035] However, there may be instances where unnecessary detailed descriptions are omitted. For example, detailed descriptions of well-known matters or repetitive descriptions of essentially the same structures may be omitted. This is to avoid making the following description unnecessarily lengthy and to facilitate understanding by those skilled in the art. Furthermore, the following description is provided to enable those skilled in the art to fully understand the invention and is not intended to limit the subject matter of the claims.

[0036] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions, and all technical features and optional technical features of the present invention can be combined with each other to form new technical solutions.

[0037] Modified indium ion adsorbent The first aspect of this invention provides a modified indium ion adsorbent, the raw materials for which include mesoporous silica, mercaptosilane, and diphenylphosphine chloride; The mass molar ratio of mesoporous silica, mercaptosilane, and diphenylphosphine chloride is 1 g : (2 mmol~3 mmol) : (2.2 mmol~3 mmol).

[0038] The modified indium ion adsorbent provided in this invention uses mesoporous silica as the adsorbent carrier; mercaptosilane acts as a coupling agent and reactive bridge, and its lone pair electrons and nucleophilicity of the mercapto group make it easy to react with the diphenylphosphine group in the modifier to form a PS bond, thereby firmly fixing the target group; the diphenylphosphine group in the modifier reacts with soft acid metal ions (In... 3+ It has a strong affinity and can selectively adsorb indium from complex solutions.

[0039] In some embodiments, mesoporous silica includes at least one of SBA-15 and MCM-41.

[0040] In some embodiments, the specific surface area of ​​mesoporous silica is >500 m². 2 / g.

[0041] In some embodiments, the average pore size of mesoporous silica is 4 nm to 8 nm.

[0042] In some embodiments, mercaptosilanes include 3-mercaptopropyltrimethoxysilane (MPTMS).

[0043] Preparation method of modified indium ion adsorbent A second aspect of this invention provides a method for preparing a modified indium ion adsorbent, comprising the following steps: S10. Mesoporous silica and mercaptosilane are grafted to obtain mercapto-modified mesoporous silica.

[0044] S20. Thiolized mesoporous silica and diphenylphosphine chloride are mixed and treated to obtain a modified indium ion adsorbent.

[0045] The method for preparing the modified indium ion adsorbent provided in this invention involves first grafting thiol groups onto the surface of mesoporous silica, and then grafting diphenylphosphine groups. This two-step grafting via covalent bonds ensures that the functional groups are firmly bonded and not easily lost.

[0046] In some embodiments, the grafting process in step S10 above includes the following steps: S101. Under an inert atmosphere, a mixture of mesoporous silica-toluene and mercaptosilane is refluxed.

[0047] In some embodiments, in step S101 above, the inert atmosphere includes at least one of nitrogen atmosphere, argon atmosphere, and helium atmosphere.

[0048] In some embodiments, in step S101 above, the mass-volume ratio of mesoporous silica to toluene in the mesoporous silica-toluene mixture is 1 g: (40 ml~50 ml).

[0049] In some embodiments, in step S101 above, the reflux temperature is 110°C to 120°C.

[0050] In some embodiments, the reflux time in step S101 is 12h to 24h.

[0051] In some embodiments, step S10 above further includes the following step: S102. The product obtained from the grafting treatment is washed and then vacuum dried.

[0052] In this case, washing can remove physically adsorbed silanes, and drying removes washing residue and toluene solvent.

[0053] In some embodiments, in step S102 above, washing includes the following steps: The grafted product was washed sequentially with anhydrous toluene and ethanol.

[0054] It should be noted that the number of times and the amount of anhydrous toluene and ethanol used in the above washing process are conventional practices in the field, and therefore, they are not specifically limited in the embodiments of the present invention.

[0055] In some embodiments, in step S102 above, the temperature of vacuum drying is 60°C to 70°C.

[0056] In some embodiments, in step S102 above, the vacuum drying time is 6h to 8h.

[0057] In some embodiments, the mixing process in step S20 above includes the following steps: S201. After the reaction solution is subjected to the first stirring reaction under an inert atmosphere and an ice-water bath, the second stirring reaction is carried out at room temperature in the dark. The reaction solution contains mercapto-modified mesoporous silica, diphenylphosphine chloride, a catalyst, and a solvent.

[0058] In this case, in the reaction solution, the P-Cl bond and the mercapto (-SH) group in diphenylphosphine chloride undergo a nucleophilic substitution reaction to graft PS bonds.

[0059] In some embodiments, in step S201 above, the catalyst comprises triethylamine.

[0060] In some embodiments, in step S201 above, the solvent includes dichloromethane.

[0061] In some embodiments, the mass-to-volume ratio of mesoporous silica, triethylamine, and dichloromethane is 1 g : (0.35 ml to 0.4 ml) : (45 ml to 55 ml).

[0062] In some embodiments, in step S201 above, the temperature of the ice water bath is 0°C to 5°C.

[0063] In some embodiments, in step S201 above, the time for the first stirring reaction is 1h to 2h.

[0064] In some embodiments, in step S201 above, the second stirring reaction time is 12h to 24h.

[0065] In some embodiments, step S20 above further includes the following steps: S202. The product obtained from the mixing process is washed and then vacuum dried.

[0066] In this case, the catalyst and unreacted residual feed are removed by washing, and the solvent is removed by vacuum drying.

[0067] In some embodiments, in step S202 above, washing includes the following steps: The product was obtained by washing and mixing with dichloromethane, ethanol, and deionized water in sequence.

[0068] It should be noted that the number of times and the amount of dichloromethane, ethanol and deionized water used in the above washing process are conventional practices in the field, and therefore, they are not particularly limited in the embodiments of the present invention.

[0069] In some embodiments, in step S202 above, the temperature of vacuum drying is 50°C to 60°C.

[0070] In some embodiments, in step S102 above, the vacuum drying time is 12h to 18h.

[0071] Methods for recovering indium from indium waste A third aspect of this invention provides a method for recovering indium from indium waste, comprising the following steps: X10. The indium waste leachate is subjected to adsorption and desorption treatment with an adsorbent to obtain the desorbed solution; The adsorbent includes the modified indium ion adsorbent provided in the embodiments of the present invention.

[0072] X20. The desorption solution is subjected to electrolytic refining to obtain indium.

[0073] The method for recovering indium from indium waste provided in this embodiment of the invention uses a modified indium ion adsorbent provided in this embodiment of the invention. The bifunctional groups (thiol + phosphin) work synergistically to improve the adsorption selectivity of the adsorbent for indium. After adsorption and desorption treatment, electrolytic refining is carried out. Adsorption and electrolysis are directly coupled, reducing intermediate steps and improving the recovery efficiency of indium.

[0074] In some embodiments, in step X10 above, the source of indium waste includes at least one of ITO sputtering target waste, indium-containing liquid crystal panels, and indium-containing alloy waste.

[0075] In some embodiments, in step X10 above, the particle size of the indium waste is <2 mm.

[0076] In some embodiments, the preparation of the indium waste leaching solution in step X10 above includes the following steps: X101. Under stirring, indium waste and nitric acid undergo a first mixing reaction, followed by a second mixing reaction with hydrogen peroxide. The filtrate is then collected to obtain indium waste leachate.

[0077] In the preparation of the above-mentioned indium waste leachate, nitric acid can selectively dissolve indium and its oxides in the indium waste; hydrogen peroxide can oxidize the low-valence indium in the system to trivalent indium ions, thereby improving the dissolution efficiency of the indium waste.

[0078] In some embodiments, in step X101 above, the mass-to-volume ratio of indium waste to nitric acid is 1 g: (3 ml~5 ml).

[0079] In some embodiments, in step X101 above, the concentration of nitric acid is 6 mol / L to 8 mol / L.

[0080] In some embodiments, in step X101 above, the temperature of the first mixing reaction is 80°C to 90°C.

[0081] In some embodiments, in step X101 above, the time for the first mixing reaction is 4h to 6h.

[0082] In some embodiments, in step X101 above, the mass concentration of hydrogen peroxide is 30% to 40%.

[0083] In some embodiments, in step X101 above, the volume of hydrogen peroxide used is 5% to 7% of the volume of nitric acid.

[0084] In some embodiments, in step X101 above, the temperature of the second mixing reaction is 80°C to 90°C.

[0085] In some embodiments, in step X101 above, the time for the second mixing reaction is 1 h to 2 h.

[0086] In some embodiments, in step X10 above, the adsorption-desorption process includes the following steps: X102. After adjusting the pH of the indium waste leachate to 1.5~2.5, adsorption was performed using an adsorption column containing modified indium ion adsorbent, followed by desorption with sulfuric acid to obtain the desorbed solution.

[0087] In the above adsorption and desorption treatment, the selectivity coefficient of the modified indium ion adsorbent to indium was greatly improved when the pH value was between 1.5 and 2.5.

[0088] In some embodiments, in step X102 above, the flow rate of the indium waste leachate into the adsorption column is 4 mL / min to 6 mL / min.

[0089] In some embodiments, in step X102 above, the mass ratio of the adsorbent loading to the indium waste is (2~3):1.

[0090] In some embodiments, in step X102 above, the concentration of sulfuric acid is 1 mol / L to 2 mol / L.

[0091] In some embodiments, in step X20 above, the electrolytic refining process includes the following steps: X201. Electrolysis is performed using titanium-based IrO2 as the anode, stainless steel as the cathode, and an electrolyte containing desorption solution and additives.

[0092] In the above electrolytic refining process, additives can improve the crystal morphology and prevent or reduce dendrite formation.

[0093] In some embodiments, in step X201 above, sulfuric acid is used to adjust the pH of the desorption solution to 0.5~1.5.

[0094] In some embodiments, in step X201 above, the concentration of the additive in the electrolyte is 0.05 g / L to 0.15 g / L.

[0095] In some embodiments, in step X201 above, the additives include gelatin and β-naphthol. In this case, gelatin, as a surfactant, is adsorbed on the cathode surface, increasing cathode polarization, thereby improving the quality of the deposited layer and refining the grains; β-naphthol and gelatin synergistically enhance cathode polarization, thereby making the crystals denser.

[0096] In some embodiments, the mass ratio of gelatin to β-naphthol in the electrolyte is 1:(0.4~0.6).

[0097] In some embodiments, during step X201 above, the current density during electrolysis is 140 A / m. 2 ~160A / m2 .

[0098] In some embodiments, during step X201 above, the voltage during electrolysis is 2.5V to 3V.

[0099] In some embodiments, during step X201 above, the electrolysis temperature is 35°C to 40°C.

[0100] In some embodiments, during step X201 above, the electrode spacing is 5cm to 7cm during electrolysis.

[0101] In some embodiments, in step X201 above, the electrolysis endpoint is defined as the concentration of indium ions in the electrolyte being <1 g / L.

[0102] The following description, in conjunction with specific embodiments, provides further details. For ease of explanation, the following embodiments and comparative examples involve: The mesoporous silica underwent the following pretreatment: It was placed in a muffle furnace and calcined at 350°C for 5 hours to completely remove surface-adsorbed water and organic matter, generating a large number of active silanol groups. The calcined silica was then rapidly transferred to a desiccator for cooling and later use.

[0103] Example 1 Example 1 provides a modified indium ion adsorbent, prepared from mesoporous silica SBA-15, 3-mercaptopropyltrimethoxysilane and diphenylphosphine chloride in a mass molar ratio of 1g:2.5mmol:2.75mmol.

[0104] Among them, the specific surface area of ​​mesoporous silica SBA-15 is 800 m². 2 / g, average pore size is 6nm.

[0105] This embodiment also provides a method for preparing the modified indium ion adsorbent of this embodiment, the steps of which are as follows: E10. Preparation of thiolized mesoporous silica E101. Grafting treatment: Under a nitrogen atmosphere, a mixture of mesoporous silica-toluene and 3-mercaptopropyltrimethoxysilane is refluxed. In the mesoporous silica-toluene mixture, the mass-volume ratio of mesoporous silica to toluene is 1g:50ml; The reflux temperature was 110℃ and the time was 12h.

[0106] E102. Post-treatment: The grafted product was washed sequentially with anhydrous toluene and ethanol, and then vacuum dried to obtain mercaptoized mesoporous silica. The vacuum drying process involves a temperature of 60℃ and a time of 6 hours.

[0107] E20. Preparation of Modified Indium Ion Adsorbent E201. Preparation of reaction solution: Thiolized mesoporous silica, diphenylphosphine chloride, triethylamine and dichloromethane are mixed to obtain the reaction solution; The mass-to-volume ratio of mesoporous silica, triethylamine, and dichloromethane is 1 g: 0.38 ml: 50 ml.

[0108] E202. Mixing treatment: After the reaction solution is subjected to the first stirring reaction in a nitrogen atmosphere and an ice-water bath (0℃~5℃), the second stirring reaction is carried out at room temperature in the dark. The first stirring reaction lasted for 1 hour, and the second stirring reaction lasted for 18 hours.

[0109] E203. Post-treatment: The product obtained by washing and mixing with dichloromethane, ethanol and deionized water in sequence is then dried under vacuum to obtain the modified indium ion adsorbent. The vacuum drying process involves a temperature of 50℃ and a time of 12 hours.

[0110] Example 2 Example 2 provides a modified indium ion adsorbent, prepared from mesoporous silica SBA-15, 3-mercaptopropyltrimethoxysilane and diphenylphosphine chloride in a mass molar ratio of 1g:2mmol:2.2mmol.

[0111] Among them, the specific surface area of ​​mesoporous silica SBA-15 is 600 m². 2 / g, average pore size is 8nm.

[0112] This embodiment also provides a method for preparing the modified indium ion adsorbent of this embodiment, the steps of which are the same as those in Embodiment 1.

[0113] Example 3 Example 3 provides a modified indium ion adsorbent, prepared from mesoporous silica SBA-15, 3-mercaptopropyltrimethoxysilane, and diphenylphosphine chloride in a mass molar ratio of 1g:3mmol:3mmol.

[0114] Among them, the specific surface area of ​​mesoporous silica SBA-15 is 900 m². 2 / g, average pore size is 4nm.

[0115] This embodiment also provides a method for preparing the modified indium ion adsorbent of this embodiment, the steps of which are the same as those in Embodiment 1.

[0116] Example 4 Example 4 provides a method for recovering indium from indium waste, the steps of which are as follows: Preparation of M10. Indium waste leachate Under stirring, indium waste and nitric acid undergo a first mixing reaction, followed by a second mixing reaction with hydrogen peroxide. The filtrate is then collected to obtain indium waste leachate. The mass-to-volume ratio of indium waste to nitric acid is 1g:3ml; The concentration of nitric acid is 6 mol / L; The temperature for the first mixing reaction was 80℃ and the time was 4 hours. The hydrogen peroxide has a mass concentration of 30% and a volume usage of 5% of the nitric acid volume. The second mixing reaction was carried out at a temperature of 80°C for 1 hour.

[0117] M20. Adsorption-desorption treatment After adjusting the pH of the indium waste leachate to 2, it was adsorbed using an adsorption column loaded with the modified indium ion adsorbent provided in Example 1, and then desorbed using sulfuric acid to obtain the desorbed solution. The flow rate of the indium waste leachate entering the adsorption column was 5 mL / min. The ratio of adsorbent loading to indium waste mass is 2:1; The concentration of sulfuric acid is 1.5 mol / L.

[0118] M30. Electrolytic refining process Indium was obtained by electrolysis using titanium-based IrO2 as the anode, stainless steel as the cathode, and an electrolyte containing a desorption solution (adjusted to pH 1), gelatin, and β-naphthol. In the electrolyte, the total concentration of gelatin and β-naphthol was 0.15 g / L, and the mass ratio was 1:0.5. During electrolysis, the current density is 150 A / m 2 The voltage is 2.8±0.2V, the electrolysis temperature is 35℃, the electrode spacing is 5cm, and the electrolysis endpoint is when the concentration of indium ions in the electrolyte is <1g / L.

[0119] Example 5 Example 5 provides a method for recovering indium from indium waste. The steps are basically the same as those in Example 4, except that: In step M20, the adsorbent is the modified indium ion adsorbent provided in Example 2.

[0120] Example 6 Example 6 provides a method for recovering indium from indium waste. The steps are basically the same as those in Example 4, except that: In step M20, the adsorbent is the modified indium ion adsorbent provided in Example 3.

[0121] Comparative Example 1 Comparative Example 1 provides a method for recovering indium from indium waste, the steps of which are basically the same as those in Example 4, except that: In step M20, the adsorbent is macroporous styrene-divinylbenzene resin (Lewatit TP 208).

[0122] Comparative Example 2 Comparative Example 2 provides a method for recovering indium from indium waste, the steps of which are as follows: D10. Preparation of indium waste leachate Under stirring, indium waste and nitric acid undergo a first mixing reaction, followed by a second mixing reaction with hydrogen peroxide. The filtrate is then collected to obtain indium waste leachate. The mass-to-volume ratio of indium waste to nitric acid is 1g:3ml; The concentration of nitric acid is 6 mol / L; The temperature for the first mixing reaction was 80℃ and the time was 4 hours. The hydrogen peroxide has a mass concentration of 30% and a volume usage of 5% of the nitric acid volume. The second mixing reaction was carried out at a temperature of 80°C for 1 hour.

[0123] D20. Electrolytic refining process Indium was obtained by electrolysis using titanium-based IrO2 as the anode, stainless steel as the cathode, and an electrolyte containing indium waste leachate (with pH adjusted to 1), gelatin, and β-naphthol. In the electrolyte, the total concentration of gelatin and β-naphthol was 0.15 g / L, and the mass ratio was 1:0.5. During electrolysis, the current density is 150 A / m 2 The voltage is 2.8±0.2V, the electrolysis temperature is 35℃, the electrode spacing is 5cm, and the electrolysis endpoint is when the concentration of indium ions in the electrolyte is <1g / L.

[0124] To verify the advancements of the modified indium ion adsorbent and its preparation method, as well as the method for recovering indium from indium waste provided in the embodiments of the present invention, the recovery rate and purity of indium in the methods for recovering indium from indium waste provided in the embodiments and comparative examples of the present invention were tested and calculated, and the results are shown in Table 1 below.

[0125] Table 1

[0126] From the table above, at least the following conclusions can be drawn: (1) In the table above, the recovery rate and purity of indium obtained by using the modified indium ion adsorbent provided in the embodiments of the present invention to adsorb indium in the leachate are higher than those of Comparative Example 1. It can be seen that the present invention provides a method using mesoporous silica as the adsorbent carrier; mercaptosilane as a coupling agent and reactive bridge, whose lone pair electrons and nucleophilicity of the mercapto group make it easy to react with the diphenylphosphine group in the modifier to form a PS bond, thereby firmly fixing the target group; the diphenylphosphine group in the modifier reacts with soft acid metal ions (In... 3+ It has a strong affinity and can selectively adsorb indium from complex solutions.

[0127] (2) In the table above, Comparative Example 2 used acid leaching followed by direct electrolysis to obtain indium, which significantly reduced the recovery rate and purity of indium. Therefore, the method for recovering indium from indium waste provided in this embodiment of the invention utilizes the modified indium ion adsorbent provided in this embodiment of the invention. The synergistic effect of the bifunctional groups (thiol + phosphinol) improves the adsorption selectivity of the adsorbent for indium. After adsorption and desorption treatment, electrolytic refining is performed, directly coupling adsorption and electrolysis, reducing intermediate steps and improving the recovery efficiency of indium.

[0128] It should be noted that the present invention is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments that have the same structure and perform the same effects as the technical concept within the scope of the present invention are included within the scope of the present invention. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of the present invention, are also included within the scope of the present invention.

Claims

1. A modified indium ion adsorbent, characterized in that, The raw materials for preparation include mesoporous silica, mercaptosilane, and diphenylphosphine chloride; The mass molar ratio of mesoporous silica, mercaptosilane, and diphenylphosphine chloride is 1 g: 2 mmol~3 mmol: 2.2 mmol~3 mmol.

2. The modified indium ion adsorbent according to claim 1, characterized in that, It satisfies at least one of the following characteristics (1) to (4): (1) The mesoporous silica includes at least one of SBA-15 and MCM-41; (2) The specific surface area of ​​the mesoporous silica is >500 m². 2 / g; (3) The average pore size of the mesoporous silica is 4 nm to 8 nm; (4) The mercaptosilane includes 3-mercaptopropyltrimethoxysilane.

3. A method for preparing the modified indium ion adsorbent as described in claim 1 or 2, characterized in that, Includes the following steps: Mesoporous silica and mercaptosilane are grafted together to obtain mercapto-modified mesoporous silica. The thiolized mesoporous silica and diphenylphosphine chloride are mixed and treated to obtain the modified indium ion adsorbent.

4. The method for preparing the modified indium ion adsorbent according to claim 3, characterized in that, The grafting process includes the following steps: Under an inert atmosphere, a mixture of mesoporous silica-toluene and mercaptosilane is refluxed.

5. The method for preparing the modified indium ion adsorbent according to claim 4, characterized in that, It satisfies at least one of the following characteristics (1) to (4): (1) The inert atmosphere includes at least one of nitrogen atmosphere, argon atmosphere, and helium atmosphere; (2) In the mesoporous silica-toluene mixture, the mass-volume ratio of mesoporous silica to toluene is 1g:40ml~50ml; (3) The reflux temperature is 110℃~120℃; (4) The reflux time is 12h~24h.

6. The method for preparing the modified indium ion adsorbent according to any one of claims 3 to 5, characterized in that, The mixing process includes the following steps: After the reaction solution was subjected to the first stirring reaction under an inert atmosphere and an ice-water bath, the second stirring reaction was carried out at room temperature in the dark. The reaction solution contains mercapto-modified mesoporous silica, diphenylphosphine chloride, a catalyst, and a solvent.

7. The method for preparing the modified indium ion adsorbent according to claim 6, characterized in that, It satisfies at least one of the following characteristics (1) to (6): (1) The catalyst includes triethylamine; (2) The solvent includes dichloromethane; (3) The mass-to-volume ratio of the mesoporous silica, triethylamine and dichloromethane is 1g:0.35ml~0.4ml:45ml~55ml; (4) The temperature of the ice water bath is 0℃~5℃; (5) The first stirring reaction time is 1h~2h; (6) The second stirring reaction time is 12h~24h.

8. A method for recovering indium from indium waste, characterized in that, Includes the following steps: The indium waste leachate is subjected to adsorption and desorption treatment with an adsorbent to obtain a desorbed solution; wherein the adsorbent includes the modified indium ion adsorbent as described in claim 1 or 2. The desorption solution is subjected to electrolytic refining to obtain indium.

9. The method for recovering indium from indium waste according to claim 8, characterized in that, The adsorption-desorption treatment includes the following steps: After adjusting the pH of the indium waste leachate to 1.5-2.5, it is adsorbed using an adsorption column containing modified indium ion adsorbent, and then desorbed using sulfuric acid to obtain the desorbed solution.

10. The method for recovering indium from indium waste according to claim 9, characterized in that, It satisfies at least one of the following characteristics (1) to (5): (1) The flow rate of the indium waste leachate entering the adsorption column is 4 mL / min to 6 mL / min; (2) The mass ratio of the modified indium ion adsorbent to the indium waste is 2~3:1; (3) The concentration of the sulfuric acid is 1 mol / L to 2 mol / L; (4) The preparation of the indium waste leachate includes the following steps: Under stirring, indium waste and nitric acid undergo a first mixing reaction, followed by a second mixing reaction with hydrogen peroxide. The filtrate is then collected to obtain indium waste leachate. (5) The electrolytic refining process includes the following steps: Electrolysis is performed using titanium-based IrO2 as the anode, stainless steel as the cathode, and an electrolyte containing desorption solution and additives.

Images