阅读说明：本技术 一种电解置换结合的高纯硫酸铟制备方法 (Preparation method of high-purity indium sulfate by combination of electrolysis and replacement ) 是由 许哲源 李连捷 吴志鸿 王美玲 于 2021-10-27 设计创作，主要内容包括：本发明提出一种电解置换结合的高纯硫酸铟制备方法,包括以下步骤：以金属铟为阳极,配置阴极,以硫酸根高电位金属离子溶液为电解液,进行电解。电解过程中,阳极的金属铟被氧化溶解,变为铟离子,电解液中的高电位金属离子被还原成金属态沉积在阴极上。将电解后的电解液过滤,将滤液进行结晶,获得硫酸铟晶体。所述高电位金属离子选自钴离子、镍离子和铜离子中的一种或多种。以该硫酸根高电位金属离子溶液为电解液,采用电解置换结合的反应,阳极铟的溶解不受电解液的酸碱度及温度的影响,能在高电解效率下制备硫酸铟溶液,大幅降低操作成本及缩短反应时间,同时其副反应少,制备的硫酸铟溶液所含杂质少,提高了硫酸铟溶液的纯度。(The invention provides a preparation method of high-purity indium sulfate by combining electrolysis and replacement, which comprises the following steps: and (3) taking the metal indium as an anode, configuring a cathode, and taking a sulfate radical high-potential metal ion solution as an electrolyte to carry out electrolysis. During the electrolysis process, the metal indium at the anode is oxidized and dissolved to become indium ions, and the high potential metal ions in the electrolyte are reduced to be in a metal state and deposited on the cathode. And filtering the electrolyzed electrolyte, and crystallizing the filtrate to obtain the indium sulfate crystal. The high potential metal ions are selected from one or more of cobalt ions, nickel ions and copper ions. The sulfate radical high-potential metal ion solution is used as an electrolyte, an electrolysis and replacement combined reaction is adopted, the dissolution of anode indium is not influenced by the pH value and the temperature of the electrolyte, the indium sulfate solution can be prepared under high electrolysis efficiency, the operation cost is greatly reduced, the reaction time is shortened, meanwhile, the side reaction is less, the impurities contained in the prepared indium sulfate solution are less, and the purity of the indium sulfate solution is improved.)

1. The preparation method of the electrolytic-displacement-combined high-purity indium sulfate is characterized by comprising the following steps of: taking metal indium as an anode, configuring a cathode, and taking a sulfate radical high-potential metal ion solution as an electrolyte to carry out electrolysis; in the electrolytic process, the metal indium at the anode is oxidized and dissolved to become indium ions, and the high-potential metal ions in the electrolyte are reduced to be in a metal state and deposited on the cathode; filtering the electrolyzed electrolyte, and crystallizing the filtrate to obtain indium sulfate crystals;

the high potential metal ions are selected from one or more of cobalt ions, nickel ions and copper ions.

2. The method of producing high purity indium sulfate by electrolytic displacement bonding according to claim 1, further comprising the steps of: and refluxing the crystallized residual liquid to an electrolyte blending unit for use to form a closed circulation process.

3. The method for preparing high-purity indium sulfate by electrolytic displacement combination according to claim 1, characterized in that: an indium plate cast with indium having a purity of 99.99% or more is used as the anode.

4. The method for preparing high-purity indium sulfate by electrolytic displacement combination according to claim 1, characterized in that: a titanium plate, a titanium wire, or a copper plate is used as the cathode.

5. The method for preparing high-purity indium sulfate by electrolytic displacement combination according to any one of claims 1 to 4, characterized in that: the electrolyte is a nearly saturated copper sulfate solution.

6. The method for preparing high-purity indium sulfate by electrolytic displacement combination according to claim 5, characterized in that: in the electrolyte, the concentration of sulfate radicals is 1-2 mol/L.

7. The method for preparing high-purity indium sulfate by electrolytic displacement combination according to claim 6, characterized in that: the copper sulfate solution is prepared by adding copper sulfate pentahydrate into water and completely dissolving, wherein the sulfate radical concentration is 1.63 mol/L.

8. The method for preparing high-purity indium sulfate by electrolytic displacement combination according to any one of claims 1 to 4, characterized in that: in the electrolysis process, the temperature of the electrolyte is kept at 60-68 ℃.

9. The method for preparing high-purity indium sulfate by electrolytic displacement combination according to any one of claims 1 to 4, characterized in that: before the electrolytic reaction, the electrolyte is deoxidized, and the electrolytic reaction is carried out in an oxygen-free environment.

10. The method for preparing high-purity indium sulfate by electrolytic displacement combination according to any one of claims 1 to 4, characterized in that: and controlling the residual anode indium after the electrolysis to be 18-22% of the original mass.

Technical Field

The invention relates to the technical field of indium sulfate preparation, in particular to a preparation method of high-purity indium sulfate by combining electrolysis and replacement.

Background

The transparent electrode has excellent conductivity and high visible light transmittance, so that the transparent electrode is an indispensable photoelectric material for preparing a plurality of high-demand electronic devices, such as touch screens, liquid crystal display screens and the like. There are many materials used for manufacturing transparent electrodes, and among them, ITO thin films prepared from indium sulfate are most widely used.

Patent application publication No. CN101235508A discloses a method for preparing high-purity indium sulfate, the first step is to prepare indium sulfate solution: casting 4N high-purity metal indium into a metal anode plate, electrolyzing in 20-70% of analytically pure sulfuric acid solution to prepare an indium sulfate solution, and then filtering the indium sulfate solution; the second step is the concentration and crystallization of the indium sulfate solution: heating the high-purity indium sulfate solution purified in the first step under the condition of stirring until a large amount of crystals appear, completely discharging the mixture, and continuously crystallizing at room temperature; the third step is vacuum crystallization of indium sulfate: and (3) fully and uniformly stirring the indium sulfate produced in the second step, and heating and preserving the temperature of the mixture under the vacuum condition to directly obtain a powdery indium sulfate product. The method can be used for removing impurities and purifying while preparing the indium sulfate solution, so that the purity of the indium sulfate solution is improved; by adopting the technical scheme of secondary crystallization, the indium sulfate solution is ensured to be fully crystallized, so that the indium sulfate solution is completely converted into indium sulfate crystals as far as possible, and the conversion rate reaches 70%; the process flow is shortened, the loss of indium in the production process is reduced, and the indium resource is saved. However, this method has problems of low electrolysis efficiency, slow speed of preparing the indium sulfate solution, and the like.

Disclosure of Invention

In order to solve the problems of low electrolysis efficiency and low speed of preparing indium sulfate solution in the existing method for preparing high-purity indium sulfate, the invention provides a method for preparing high-purity indium sulfate by combining electrolysis and replacement, which aims to solve the technical problem. The preparation method of the high-purity indium sulfate is as follows.

A preparation method of high-purity indium sulfate by electrolytic replacement combination comprises the following steps: taking metal indium as an anode, configuring a cathode, and taking a sulfate radical high-potential metal ion solution as an electrolyte to carry out electrolysis; in the electrolytic process, the metal indium at the anode is oxidized and dissolved to become indium ions, and the high-potential metal ions in the electrolyte are reduced to be in a metal state and deposited on the cathode; and filtering the electrolyzed electrolyte, and crystallizing the filtrate to obtain the indium sulfate crystal. Wherein the high potential metal ions are selected from one or more of cobalt ions, nickel ions and copper ions. The metal activity of cobalt, nickel and copper is excluded after indium, so that cobalt ions, nickel ions and copper ions can be replaced by metal indium and reduced to a zero valence state.

As a further improvement of the electrolytic displacement combined high-purity indium sulfate preparation method, the preparation method also comprises the following steps: and refluxing the crystallized residual liquid to an electrolyte blending unit for use to form a closed circulation process.

In a further improvement of the method for producing high-purity indium sulfate by electrolytic displacement combination according to the present invention, an indium plate cast with indium having a purity of 99.99% or more is used as the anode.

As a further improvement of the electrolytic displacement bonded high purity indium sulfate production method of the present invention, a titanium plate, a titanium wire or a copper plate is used as the cathode.

As a further improvement of the electrolytic displacement combined high-purity indium sulfate preparation method, the electrolyte is a near-saturated copper sulfate solution.

As a further improvement of the electrolytic displacement combined high-purity indium sulfate preparation method, the sulfate radical concentration in the electrolyte is 1-2 mol/L.

As a further improvement of the electrolytic displacement combined high-purity indium sulfate production method of the present invention, the copper sulfate solution is configured such that copper sulfate pentahydrate is added to water and completely dissolved, and the sulfate radical concentration is 1.63 mol/L.

The electrolytic displacement combined high-purity indium sulfate preparation method is further improved, the temperature of the electrolyte is kept at 60-68 ℃ in the electrolytic process, so that complete dissolution of copper sulfate and indium sulfate is guaranteed, the fluid resistance and osmotic pressure are reduced, and the higher electrolytic reaction rate is kept.

As a further improvement of the electrolytic displacement combined high-purity indium sulfate preparation method, the electrolyte is deoxidized before the electrolytic reaction, and the electrolytic reaction is carried out in an oxygen-free environment.

As a further improvement of the electrolytic displacement combined high-purity indium sulfate preparation method, residual anode indium after electrolysis is controlled to be 18-22% of the original mass. If the percentage of the residual amount to the mass of the whole anode plate is too small, this ratio too small results in a cell voltage change of the anode in the electrolytic cell during the reaction during the continuous progress of the reaction in the electrolytic cell, and the change is very rapid, and the cell voltage rapidly increases in a short time.

The invention has the advantages that: the method takes a sulfate radical high-potential metal ion solution as an electrolyte, adopts an electrolytic displacement combined reaction method, ensures that the dissolution of anode indium is not influenced by the pH value and the temperature of the electrolyte, can prepare an indium sulfate solution at high electrolytic efficiency, greatly reduces the operation cost, shortens the reaction time, improves the speed of preparing the indium sulfate solution, has less side reactions, contains less impurities and improves the purity of the indium sulfate solution. In the process of concentration and crystallization, the precipitation critical concentration of impurity metal is controlled, the ultra-high purity indium sulfate crystal can be produced, the concentrated residual liquid can be recycled, the loss of indium resources in the production process is reduced, and the economic benefit of the preparation method is greatly improved.

Drawings

In order to more clearly illustrate the technical solution of the embodiments of the present invention, the drawings used in the embodiments will be briefly described below. It is appreciated that the following drawings depict only some embodiments of the invention and are therefore not to be considered limiting of its scope, for those skilled in the art will be able to derive additional related drawings therefrom without the benefit of the inventive faculty.

FIG. 1 is a graph showing the cumulative dissolution of indium in anodes versus the cumulative dissolution of indium in electrolytes under the same voltage.

FIG. 2 is a graph showing the cumulative dissolution of indium in anodes versus the cumulative dissolution of indium in electrolytes under the same current.

Fig. 3 is a graph comparing the power consumed by different electrolytes for each gram of indium dissolved.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

First, experiment medicine and instrument

The main drugs used in this experiment were: 4N-grade indium, copper sulfate pentahydrate (99.99%), concentrated sulfuric acid (98%) and ultrapure water (analytically pure).

The main experimental instruments used in this experiment and their uses are shown in table 1-1:

TABLE 1-1 Experimental instruments and uses thereof

Serial number	Name of instrument	Use of
			1	Electrolytic cell	Carrying out an electrolytic replacement reaction
2	Electronic balance	Weighing solids
			3	Multipurpose electric meter	Measuring potential difference between cathode and anode
4	Volumetric flask	Preparing standard solution
			5	Beaker	Dissolving solids, diluting liquids
6	Measuring cylinder	Measuring liquid
			7	Glass rod	Stirring the solution and draining

Second, design of experiment

2.1 preparation of high-purity indium sulfate by electrolytic displacement combination method

The preparation of the indium sulfate solution is carried out in an electrolytic cell by a combination of an electrolytic method and a displacement method. The specific method comprises the following steps: in an electrolytic bath, 4N-grade indium is taken as an anode, a titanium plate is taken as a cathode, high-purity copper sulfate solution is taken as electrolyte, the bath voltage and the electrolysis time are controlled, and electrolytic replacement is carried out. The electrolytic reaction in the electrolytic cell is as follows:

anode: in → In³⁺+3e^-

Cathode: cu²⁺+2e^-→Cu

The high-purity indium sulfate electrolyte is obtained, and indium sulfate crystals are obtained by evaporating, concentrating and drying the electrolyte and other steps.

2.2 comparison of the conductivity of copper sulfate electrolyte and sulfuric acid electrolyte

Two electrolytic cells were prepared: the electrolyte in one electrolytic tank is a sulfuric acid solution diluted by ultrapure water (analytically pure), 4N-grade indium (the indium purity reaches more than 99.99%) is used as an anode, and a titanium plate is used as a cathode; the electrolyte used by the other electrolytic cell is copper sulfate solution, 4N-grade indium is also used as an anode, and a titanium plate is used as a cathode; the volumes of the electrolyte in the two electrolytic tanks are equal.

By comparing the copper sulfate solution as the electrolyte with the sulfuric acid solution as the electrolyte, when the power supply is not connected, the voltage difference between the two electrode plates of the two electrolytic tanks is larger, and the electrolyte has more excellent conductive capability.

2.3 comparison of electrolytic rates

Two electrolytic cells were prepared: the electrolyte in one electrolytic cell is sulfuric acid solution diluted by ultrapure water (analytically pure), 4N-grade indium is used as an anode, and a titanium plate is used as a cathode; the electrolyte used by the other electrolytic cell is copper sulfate solution, 4N-grade indium is also used as an anode, and a titanium plate is used as a cathode; the volumes of the electrolyte in the two electrolytic tanks are the same. When the two electrolytic tanks are controlled to carry out electrolysis, the voltage and the reaction time of the electrolysis replacement reaction are the same, and the dissolving amount of the anode indium ingot is compared. In an equal time period, the electrolysis bath with more indium dissolved amount needs shorter time for preparing indium sulfate solution with the same concentration, and the rate for preparing the indium sulfate solution is faster.

2.4 comparison of Power losses

Two electrolytic cells were prepared: the electrolyte in one electrolytic cell is sulfuric acid solution diluted by ultrapure water (analytically pure), 4N-grade indium is used as an anode, and a titanium plate is used as a cathode; the electrolyte used by the other electrolytic cell is copper sulfate solution, 4N-grade indium is also used as an anode, and a titanium plate is used as a cathode; the volumes of the electrolyte in the two electrolytic tanks are the same. When the two electrolytic tanks are controlled to carry out electrolytic work, the current of the electrolytic replacement reaction is the same, and the dissolving amount of the anode indium ingots after the same time of the reaction is compared. In the same time period, the electrolysis bath with more indium dissolution consumes less electric energy for preparing the indium sulfate solution with the same concentration, thereby saving more energy.

Third, the experimental procedure

3.1 preparation of two electrolytes containing sulfate ions

Preparing a sulfuric acid electrolyte: 255ml of 98% concentrated sulfuric acid (analytically pure) is taken, a certain amount of ultrapure water is added, and the volume is fixed to one liter.

Preparing a copper sulfate electrolyte: 406.98g of high-purity copper sulfate pentahydrate (99.99%) was weighed, and a certain amount of ultrapure water was added to completely dissolve the copper sulfate pentahydrate and to make a volume of one liter.

3.2 measurement of the Voltage between the two plates of the two electrolyte tanks

Two electrolytic cells were prepared: the electrolyte in one electrolytic cell is the sulfuric acid electrolyte prepared in the step 3.1, and the electrolytic cell takes 4N-grade indium as an anode and a titanium plate as a cathode; the electrolyte used by the other electrolytic cell is the copper sulfate electrolyte prepared in the step 3.1, and the electrolytic cell takes 4N-grade indium as an anode and a titanium plate as a cathode; the volumes of the electrolytes in the two electrolytic tanks are the same; the two cells were identical except for the type of electrolyte. The two electrolytic tanks are not connected with an external voltage, the voltages between the anode and the cathode which take a copper sulfate solution and a sulfuric acid solution as electrolyte are respectively measured by a multipurpose ammeter, and relevant data records are made.

3.3 determination of the electrolytic reaction rates of the different electrolytes

An electrolytic bath, a power supply (capable of providing constant voltage) and a plurality of leads are prepared, and then 4N-pole indium is used as an anode and a titanium plate is used as a cathode in the electrolytic bath. And (3) adjusting the voltage of the electrolytic cell, testing that 200ml of copper sulfate electrolyte prepared in the step (3.1) is added under the condition of room temperature when the constant direct current voltage is 0.4v, electrolyzing for 4 hours, and recording the residual mass of the dried anode indium ingot every other hour.

Preparing an electrolytic tank, a power supply (capable of providing constant voltage) and a plurality of leads, then taking 4N-pole indium as an anode in the electrolytic tank, taking a titanium plate as a cathode, adjusting the voltage of the electrolytic tank, testing that 200ml of sulfuric acid electrolyte prepared in the step 3.1 is added under the room temperature condition when the constant direct current voltage is 0.4v, electrolyzing for 4 hours, and recording the residual mass of the anode indium ingot after being dried every other hour.

Experimental data were recorded and the reaction rates for the two different electrolytes were calculated under otherwise identical conditions.

3.4 determination of the electrolytic energy losses of the different electrolytes

Two electrolyzers, a power supply (which can supply constant current) and a plurality of leads are prepared.

In one of the electrolyzers, a 4N-pole indium plate is used as an anode, and a titanium plate is used as a cathode. Regulating the current of the electrolytic cell, testing that 200ml of copper sulfate electrolyte prepared in the step 3.1 is added under the condition of room temperature when the constant direct current is 0.3A, electrolyzing for 3 hours in total, recording the voltage at two ends of the electrolytic cell every half hour, and weighing the residual mass of the dried anode indium ingot.

In another electrolytic cell, a 4N-pole indium plate is used as an anode, and a titanium plate is used as a cathode. Regulating the current of the electrolytic cell and keeping the current constant, testing that 200ml of sulfuric acid electrolyte prepared in the step 3.1 is added under the condition of room temperature when the constant direct current is 0.3A, electrolyzing for 3 hours in total, recording the voltage at two ends of the electrolytic cell every half hour, and weighing the mass of the anode indium ingot left after being dried.

The areas of the anode plates and the cathode plates used in the two electrolytic tanks are controlled to be the same.

Making an experimental data record, and calculating according to the experimental data: (1) current densities of the cathode plate and the anode plate; (2) under the conditions of the same current density and the same other conditions, the copper sulfate electrolyte and the sulfuric acid electrolyte respectively dissolve one gram of indium, so that the consumed electric energy is saved.

3.5 purification by crystallization

Stirring and heating the electrolyte after the electrolytic reaction to evaporate water, evaporating and concentrating to separate out a large amount of indium sulfate crystals, cooling to room temperature to continue crystallization, and cleaning and drying crystals to obtain powdery indium sulfate crystals.

In the crystallization and purification process, in order to produce the ultra-high purity indium sulfate product, the influence of the concentration of impurity metals (such as copper) on the product purity must be mastered, the heating and concentration operation should be stopped when the critical precipitation concentration of the impurity metals is close, and the residual liquid and the cleaning liquid can both flow back to the front end copper sulfate electrolyte blending unit for use, so as to form a closed circulation process. However, the content ratio of the part of the reflux liquid needs to be controlled within a range, and the content ratio is too high, so that a large amount of sludge is easily formed at the anode, the electrolytic reaction is not facilitated, and the short circuit phenomenon is easily caused. However, the proportion of the recycled return liquid is not too low, and is too low, the temperature in the electrolyte is not high enough due to less return liquid, the electrolysis efficiency is reduced due to too low temperature, and the fluid resistance in the electrolyte is increased and the osmotic pressure is increased partially. Through research, the proportion of the indium electrolyte recycled is controlled to be about 30L/min/tank, the electrode reaction is ensured to be carried out smoothly, meanwhile, the current efficiency is higher, and impurities such as mud and the like are less produced at the anode.

Fourth, data analysis

4.1 measurement of the Voltage between two plates of different electrolytes

In this section, the results of the experimental step 3.2 are illustrated, and before the experiment of preparing the indium sulfate solution by electrolytic displacement, the electric meter is used to measure that the bipolar voltage of the sulfuric acid solution as the indium electrolyte is 0.001v, and the bipolar voltage of the electrolytic cell as the copper sulfate solution as the indium electrolyte is 0.418 v. It can be seen that the internal voltage of the copper sulfate solution as an electrolyte is significantly higher than that of the sulfuric acid solution as an electrolyte. This can result in: under the same conditions, the conductivity of the copper sulfate solution as an electrolyte is higher than that of the sulfuric acid solution as an electrolyte. It was concluded that, under the same conditions, the reaction rate of the copper sulfate solution as an electrolyte solution was faster than that of the sulfuric acid solution as an electrolyte solution.

4.2 electrolytic reaction rates of different electrolytes

In the experimental step, as described in the above 3.3, in the electrolytic replacement experiment for preparing the indium sulfate solution, the electrolytes are respectively a sulfuric acid solution and a copper sulfate solution, and both a 4N-grade indium ingot is used as an anode and a titanium plate is used as a cathode; the reaction times were the same at the same direct voltage (0.4 v). The electrolytic replacement experiment process is carried out in an electrolytic bath, and the total electrolytic process is 4 hours. The amount of dissolved anodic indium ingots during electrolysis is shown in tables 4-1 and 4-2 below:

TABLE 4-1 indium electrode quality data for copper sulfate electrolyte systems

Time	Indium ingot quality/g	Cumulative mass/g of indium dissolved
			0h	81.3998	0
1h	73.2302	8.1696
			2h	67.6594	13.7404
3h	65.8474	15.5524
			4h	64.3239	17.0759

TABLE 4-2 indium electrode quality data for sulfuric acid electrolyte system

Time	Indium ingot quality/g	Cumulative mass/g of indium dissolved
			0h	64.2695	0
1h	63.8494	0.4201
			2h	63.6102	0.6593
3h	63.5281	0.7412
			4h	63.2176	1.0517

As can be seen by comparing the anode indium cumulative dissolution quality data of the two electrolyte systems in tables 4-1 and 4-2, the difference between the two dissolution amounts is large, and the indium dissolution quality of the copper sulfate electrolyte is significantly higher than that of the sulfuric acid electrolyte, indicating that the indium dissolution rate of the copper sulfate solution as the electrolyte is significantly higher than that of the sulfuric acid solution as the electrolyte after the same reaction time.

The data in tables 4-1 and 4-2 were extracted and used to create a graph, giving the fold line graph of FIG. 1. The results of fig. 1 show that the slope of the indium dissolution mass curve using the high purity copper sulfate solution as the electrolyte was always larger than that of the indium dissolution mass curve using the diluted sulfuric acid solution as the electrolyte, indicating that the indium dissolution rate using the high purity copper sulfate solution as the electrolyte was always higher than that of the diluted sulfuric acid solution as the electrolyte at the same time of the reaction.

From the data in tables 4-1 and 4-2, the average dissolution rate of indium for two electrolyte adjustments, i.e., the average hourly production rate of indium dissolved in the electrolyte, can be calculated as shown in tables 4-3:

TABLE 4-3 comparison of production rates

Production rate of sulfuric acid electrolyte (g/h)	4.27
		Copper sulfate electrolyte production Rate (g/h)	0.2625

Therefore, as can be seen from the comparison of the production rates of the two electrolytes in tables 4-3, the production rate when the high-purity copper sulfate solution is used as the electrolyte is significantly higher than that when the diluted sulfuric acid solution is used as the electrolyte, which is greatly increased from 0.2625g/h to 4.27 g/h.

Therefore, in the actual production, when the indium sulfate solution is prepared by electrolysis, the copper sulfate solution as the electrolyte has faster reaction efficiency than the sulfuric acid solution as the electrolyte, so that a large amount of reaction time can be reduced, and the production rate is improved.

4.3 energy loss

Experimental procedure as described above in 3.4, set current 0.3A; the anode current density was calculated to be 172.5A/m²(ii) a Cathode current density is 480.8A/m²。

In an electrolytic replacement experiment for preparing an indium sulfate solution, electrolytes are respectively a sulfuric acid solution and a copper sulfate solution, a 4N-grade indium ingot is used as an anode, and a titanium plate is used as a cathode; the reaction time was the same under the same direct current (0.3A). The electrolytic replacement experiment process is carried out in an electrolytic bath, and the total electrolytic process is 3 hours. The data of the amount of dissolution of anodic indium ingots during electrolysis are shown in the following tables 4-4 and 4-5:

TABLE 4-4 Electrolysis parameters of copper sulfate electrolyte systems

Time/h	current/A	voltage/V	Weight/g of anode indium ingot	Cumulative indium dissolution/g
					0	0.3	0.5	61.2551	0
0.5	0.3	0.5	59.02	2.2351
					1	0.3	0.9	57.0999	4.1552
1.5	0.3	0.9	55.6494	5.6057
					2	0.3	0.9	54.269	6.9861
2.5	0.3	0.9	53.5186	7.7365
					3	0.3	0.9	52.4537	8.8014

TABLE 4-5 Electrolysis parameters of sulfuric acid electrolyte systems

Time/h	current/A	voltage/V	Weight/g of anode indium ingot	Cumulative indium dissolution/g
					0	0.3	0.1	62.8419	0
0.5	0.3	0.3	62.5523	0.2896
					1	0.3	0.5	62.3055	0.5364
1.5	0.3	0.5	62.0513	0.7906
					2	0.3	0.5	61.815	1.0269
2.5	0.3	0.5	61.5741	1.2678
					3	0.3	0.5	61.3485	1.4934

The data in tables 4-4 and 4-5 were extracted and used to create a graph, resulting in the broken line graph of FIG. 2. As shown in the results of fig. 2, the slope of the indium dissolution mass curve when the high purity copper sulfate solution was used as the electrolyte was always larger than that when the diluted sulfuric acid solution was used as the electrolyte, indicating that the indium dissolution rate when the high purity copper sulfate solution was used as the electrolyte was always higher than that when the diluted sulfuric acid solution was used as the electrolyte at the same time of the reaction.

According to the data of tables 4-4 and 4-5, the electric energy consumed for dissolving each gram of indium can be calculated according to W (cumulative electric energy consumed)/m (cumulative amount of indium dissolved), and tables 4-6 and 4-7 are obtained.

TABLE 4-6 energy consumption parameters of sulfuric acid electrolytes

TABLE 4-7 energy consumption parameters of copper sulfate electrolyte

The data results of tables 4-8 can be calculated from the data results of tables 4-6 and tables 4-7.

TABLE 4-8 energy saving parameters for copper sulfate electrolytes

From the data in tables 4-8, the energy losses for two electrolyte conditions, i.e. the average power consumed per gram of indium dissolved, can be derived, as shown in tables 4-9:

TABLE 4-9 energy consumption comparison

Average power consumed by sulfuric acid electrolyte system to dissolve indium per gram (J)	865.22
		Average power consumed by copper sulfate electrolyte system to dissolve indium per gram (J)	227.43

As can be seen from tables 4-9, under the same other conditions, the average energy consumption is reduced from 856.22J/g to 227.43J/g when copper sulfate solution is used as electrolyte, compared with the average energy consumption when sulfuric acid is used as electrolyte, and the energy is saved by about 73% when copper sulfate is used as electrolyte. Therefore, when the high-purity indium sulfate product is actually produced, the copper sulfate solution serving as the electrolyte can save energy more and reduce the production cost than sulfuric acid serving as the electrolyte.

The data from tables 4-8 were extracted to produce a comparative plot of the power consumed by the different electrolytes to dissolve each gram of indium, yielding figure 3. It is evident from fig. 3 that the difference in the power consumed for dissolution of indium per gram is large in the two electrolyte conditions, and the power required for dissolution of indium per gram in the copper sulfate electrolyte is much less than that in the sulfuric acid electrolyte.

In addition, in the experiment for preparing high-purity indium sulfate by copper sulfate electrolytic replacement, attention is paid to improve the following experimental conditions:

(1) the equipment area is ensured not to be conductive with the outside, and the low humidity of the electrolysis operation area is kept, so that the loss of electric energy is prevented.

(2) Before the electrolytic reaction, the electrolyte can be deoxidized, and the electrolytic reaction is carried out in an oxygen-free environment to reduce the side reaction Cu + H₂SO₄+1/2O₂→CuSO₄+H₂O, etc.

(3) A shorter distance between the anode and cathode plates is provided to reduce voltage drop.

Fifth, conclusion

The copper sulfate electrolyte is used for replacing the sulfuric acid electrolyte in the prior art, the indium production rate is increased to 4.7g/h from 0.2625g/h, the energy loss is reduced to 227.43J/g from 856.22J/g, and the energy is saved by about 73%.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.