CN114908364B - Method for continuously preparing copper sulfate crystals by ionic membrane electrolysis method - Google Patents

Abstract

The invention relates to a preparation method of copper sulfate crystals, in particular to a method for continuously preparing copper sulfate crystals by an ionic membrane electrolysis method. The method uses an ionic membrane to divide an electrolytic tank into an anode chamber and a cathode chamber, and sulfuric acid solution is introduced into the electrolytic tank, wherein a copper sheet is used as an anode, and insoluble materials are used as a cathode. At a temperature of 20-85 ℃ and a speed of 50A/m ² ~8000A/m ² The electrolysis is carried out according to the current density of the anode chamber, hydrogen ions in the cathode chamber are reduced into hydrogen gas for recovery, copper anodes are oxidized to generate copper ions for dissolution, copper sulfate solution is obtained in the anode chamber, and the tank voltage is 0.30V-2.00V. Filtering and impurity removing the copper sulfate solution, cooling to the temperature of minus 20-30 ℃ to separate out copper sulfate crystals, heating the filtered mother solution by a heat exchange device, and returning the mother solution to an anode chamber circulation tank to realize continuous electrolysis of the solution without waste liquid. The method solves the problems of complex process, higher cost, longer time consumption and the like of the existing high-purity copper sulfate preparation method, has simple process and can realize continuous production and large-scale industrial application.

Description

A method for continuously preparing copper sulfate crystals by ion membrane electrolysis

Technical field

The invention relates to a method for preparing copper sulfate crystals, and in particular to a method for continuously preparing copper sulfate crystals by ion membrane electrolysis.

Background technique

In recent years, the booming development of the lithium battery industry has driven the rapid growth of electrolytic copper foil. The electrolyte used in the production of lithium battery copper foil is a copper sulfate aqueous solution. It can be made by directly dissolving copper sulfate crystals in water, or a high-purity cathode can be used. Copper or standard cathode copper is prepared by oxidizing and dissolving in a sulfuric acid medium with air. The product quality standards on the market comply with HG/T 3592-2010, and the purity of copper sulfate for electroplating is greater than 98% by mass, which cannot meet the purity requirements in the production process of electrolytic copper foil. Therefore, in the actual production of electrolytic copper foil, the latter method mentioned above is generally used, but this method has problems such as slow copper dissolution speed, acid mist pollution, and low efficiency.

Currently, most of the copper sulfate on the market comes from the purification of crude copper sulfate. The crude copper sulfate produced from copper ore contains many impurities and needs further purification to prepare copper sulfate products that meet quality standards. The purification process mostly uses extraction methods, ion exchange methods, etc., which are complex, costly, and time-consuming. Therefore, it is of great significance to develop a low-cost, large-scale and high-purity copper sulfate crystal preparation method. It will not only revolutionize the traditional electrolytic copper foil dissolving copper solution making process, but also meet the demand for high-purity copper sulfate in other fields. .

Contents of the invention

In order to solve the above-mentioned shortcomings in the prior art, the object of the present invention is to provide a method for continuously preparing copper sulfate crystals by ion membrane electrolysis. The invention has a simple process and can be produced continuously and on a large scale.

The present invention is a method for continuously preparing copper sulfate crystals by ion membrane electrolysis. The ion membrane is used to separate an electrolytic cell into an anode chamber and a cathode chamber, and a sulfuric acid solution is passed through them. The copper sheet is used as the anode and the insoluble electrode material is used as the anode. cathode. After direct current is connected, the hydrogen ions in the cathode chamber are reduced to hydrogen gas and recycled; the copper anode is oxidized to generate copper ions that dissolve, and the ion membrane blocks the dissolved copper ions from entering the cathode chamber from the anode chamber to avoid precipitating on the cathode again. Chamber to obtain copper sulfate solution. The copper sulfate solution is filtered to remove impurities and cooled to precipitate copper sulfate crystals. The filtered mother liquor is heated by the heat exchange device and then returned to the anode chamber circulation tank, achieving continuous utilization of the solution without the generation of waste liquid. The electrode reaction formula is as follows:

anode: (1)

cathode: (2)

The technical solution of the present invention includes the following steps:

Step (1), heat the dilute sulfuric acid in the sulfuric acid storage tank to a certain temperature through the heat exchanger, pass it into the cathode chamber and anode chamber of the ion membrane electrolyzer through the cathode chamber circulation tank and the anode chamber circulation tank respectively, and then open them respectively. The electrolyte circulates between the cathode chamber, the anode chamber and the cathode chamber circulation tank. Direct current is connected and electrolysis occurs under a certain sulfuric acid concentration, temperature and current density. The anode chamber obtains copper sulfate solution, and the hydrogen generated in the cathode chamber passes through the gas collection device. carry out recycling;

Step (2), after the copper ions in the solution in the anode chamber circulation tank reach a certain concentration, they are filtered and impurities are removed and then passed into the copper solution storage tank;

Step (3), directly cool and crystallize the solution obtained in step (2), and filter to obtain the prepared copper sulfate crystals;

Step (4), the filtered mother liquor in step (3) is heated by the heat exchanger and returned to the anode chamber circulation tank; at the same time, the sulfuric acid in the sulfuric acid storage tank replenishes the anode chamber circulation tank at a certain flow rate to maintain the anode chamber circulation. The volume and concentration of the tank solution are stable.

In the described step (1), the ion membrane used in the ion membrane electrolytic cell separates the electrolytic cell into an anode chamber and a cathode chamber. Furthermore, the ion membrane used is any commercial ion membrane that is resistant to strong acid and does not allow copper ions to pass through. A sort of;

In the step (1), copper is used as the anode, and further, high-purity copper is used;

In the step (1), the insoluble material is the cathode, and further is any one or mixture of coated cathode materials such as copper, titanium, stainless steel, platinum, and precious metals;

In the described step (1), the sulfuric acid concentration is 30g/L~500g/L. Too low a concentration reduces the conductivity of the solution, and too high a concentration reduces the solubility of copper sulfate;

In the described step (1), the electrolysis temperature is 20°C to 85°C. Low temperature is not conducive to the conductivity of the electrolyte. Too high temperature can easily cause acid mist to evaporate, waste raw materials and increase energy consumption, and can easily cause damage to the ion membrane. ;

In the described step (1), the current density is 50A/m ² ~8000A/m ² . Too low current density slows down the dissolution rate of copper, and too high current density increases the cell voltage and energy consumption;

In the described step (1), the tank voltage is 0.30~2.00V;

In the described step (2), the concentration of copper ions is: 12g/L~180 g/L. Too low a concentration of copper ions is not conducive to cooling and crystallization. A too high concentration of copper ions increases the cell voltage and increases energy consumption. .

In the described step (3), the cooling temperature is -20°C~30°C, preferably 20°C~30°C. Low temperature is conducive to more precipitation of copper sulfate, but too low cooling temperature causes the mother liquor to return to the electrolyte. The energy required for heating increases;

In the step (4), the temperature of the solution heated by the heat exchanger is 20°C to 85°C.

Beneficial effects of the present invention:

(1) No impurity ions are introduced during the preparation process, which will not affect the purity and quality of the product.

(2) Hydrogen, a by-product of electrolysis, is green energy and can be recycled, achieving efficient use of resources; the filtered mother liquor can be returned to electrolysis, no waste liquid is produced, and it is environmentally friendly.

(3) The present invention has a simple process and low cost, can easily assemble the electrolytic cells of each unit, and can realize continuous production and large-scale industrial application.

Description of drawings

Figure 1 shows the ion membrane electrolysis device of the present invention;

Figure 2 is a schematic structural diagram of an ion membrane electrolyzer;

Figure 3 is the XRD pattern of the prepared copper sulfate pentahydrate crystal;

In the picture: 1-electrolytic cell, 2-cathode chamber, 3-anode chamber, 4-ion membrane, 5-sulfuric acid storage tank, 6-heat exchanger, 7-cathode chamber circulation tank, 8-anode chamber circulation tank, 9 -Circulation pump, 10-filtration device, 11-dissolved copper liquid storage tank, 12-crystallization device.

Detailed ways

The present invention will be further described below through specific embodiments and in conjunction with the accompanying drawings.

A device for continuously preparing copper sulfate crystals by ion membrane electrolysis, including an electrolytic tank 1, an anion circulation tank 7, a cation circulation tank 8, a sulfuric acid storage tank 5, a filtering device 10, a copper solution storage tank 11, a crystallization device 12, and a Heater 6, circulation pump 9 and connecting pipelines.

Electrolytic tank 1, connected to the pipeline, uses ion membrane 4 to separate electrolytic tank 1 into a cathode chamber and an anode chamber, and places the insoluble material cathode and copper anode into cathode chamber 2 and anode chamber 3 respectively;

Dilute high-purity concentrated sulfuric acid with deionized water to prepare a dilute sulfuric acid solution, and store it in the sulfuric acid storage tank 5; heat the sulfuric acid solution in the sulfuric acid storage tank 5 to a certain electrolysis temperature through the heat exchanger 6, and then pass through the cathode through the pipeline. The circulation tank 7 and the anode chamber circulation tank 8 are connected to the cathode chamber 2 and the anode chamber 3 of the electrolytic tank 1; at the same time, the connections between the cathode chamber 2 and the anode chamber 3 and the cathode circulation tank 7 and the anode chamber circulation tank 8 are respectively started. Circulation pump 9 circulates the solution; under a certain current density, temperature, and sulfuric acid concentration, the electrolyte is subjected to DC electrolysis, the copper anode in the anode chamber 3 is dissolved, and the hydrogen generated in the cathode chamber 2 is recovered through the recovery device; the anode chamber circulates After the copper ion concentration in the solution in tank 8 reaches the target concentration, the solution is filtered and removed by the filtering device 10 and then flows into the copper-soluble liquid storage tank 11 at a certain flow rate; the solution in the copper-soluble liquid storage tank 11 is directly passed through the crystallization device 12 Cool and crystallize, and then filter through the filtration device 10 to obtain the prepared copper sulfate crystals in the solid phase, and the low-concentration mother liquor in the liquid phase. The mother liquor is heated to a certain temperature by the heat exchanger 6 and then returned to the anode chamber circulation tank 8. At the same time, the sulfuric acid in the sulfuric acid storage tank 5 replenishes the anode chamber circulation tank 8 at a certain flow rate to keep the anode chamber circulation tank 8 solution volume consistent with The concentration is stable.

Example 1 This example provides a method for continuously preparing copper sulfate crystals by ion membrane electrolysis, which includes the following steps:

Step 1: Pass 200g/L dilute sulfuric acid in the sulfuric acid storage tank into the ion membrane electrolyzer, use Cu-CATH-2 cathode copper as the anode, Cu-CATH-2 cathode copper as the cathode, the electrode spacing is 25mm, and use anion exchange The membrane is an ionic membrane, connected to direct current, controlling the current density to 500A/m ² , and performing electrolysis at a reaction temperature of 55°C. The hydrogen generated in the cathode chamber is recovered through the gas collection device, and the electrolytic cell voltage is 0.90V;

Step 2: When the copper ion concentration in the anode chamber circulation tank reaches 90g/L, the solution is filtered to remove impurities and then passed into the copper solution storage tank;

Step 3: Cool the solution in the copper solution storage tank to 20°C, precipitate copper sulfate crystals, filter, and prepare a copper sulfate crystal mass of 180g per liter of solution;

Step 4: After the mother liquor filtered in step 3 is heated to 55°C by the heat exchange device, it is returned to the anode chamber circulation tank; at the same time, the sulfuric acid in the sulfuric acid storage tank replenishes the anode chamber circulation tank at a certain flow rate to maintain the anode chamber circulation tank. The volume and concentration of the circulating tank solution are stable.

Example 2 This example provides a method for continuously preparing copper sulfate crystals by ion membrane electrolysis, which includes the following steps:

Step 1: Pass 200g/L dilute sulfuric acid in the sulfuric acid storage tank into the ion membrane electrolyzer, use Cu-CATH-2 cathode copper as the anode, iridium-tantalum-titanium-based coating material as the cathode, the electrode spacing is 25mm, and use anion exchange The membrane is an ionic membrane, connected to direct current, controlling the current density to 500A/m ² , and performing electrolysis at a reaction temperature of 85°C. The hydrogen generated in the cathode chamber is recovered through the gas collection device, and the electrolytic cell voltage is 0.79V;

Step 2: When the copper ion concentration in the anode chamber circulation tank reaches 140g/L, the solution is filtered and impurities are removed and then passed into the copper solution storage tank;

Step 3: Cool the solution in the copper solution storage tank to 30°C, precipitate copper sulfate crystals, filter, and prepare a copper sulfate crystal mass of 320g per liter of solution;

Step 4: After the mother liquor filtered in step 3 is heated to 85°C by the heat exchange device, it is returned to the anode chamber circulation tank; at the same time, the sulfuric acid in the sulfuric acid storage tank replenishes the anode chamber circulation tank at a certain flow rate to maintain the anode chamber circulation tank. The volume and concentration of the circulating tank solution are stable.

Example 3 This example provides a method for continuously preparing copper sulfate crystals by ion membrane electrolysis, which includes the following steps:

Step 1: Pass 500g/L dilute sulfuric acid in the sulfuric acid storage tank into the ion membrane electrolyzer, use Cu-CATH-2 cathode copper as the anode, Cu-CATH-2 cathode copper as the cathode, the electrode spacing is 25mm, and use anion exchange The membrane is an ionic membrane, connected to direct current, controlling the current density to 500A/m ² , and performing electrolysis at a reaction temperature of 55°C. The hydrogen generated in the cathode chamber is recovered through the gas collection device, and the electrolytic cell voltage is 0.78V;

Step 2: When the copper ion concentration in the anode chamber circulation tank reaches 40g/L, the solution is filtered and impurities are removed and then passed into the copper solution storage tank;

Step 3: Cool the solution in the copper solution storage tank to 10°C, precipitate copper sulfate crystals, filter, and prepare a copper sulfate crystal mass of 130g per liter of solution;

Step 4: After the mother liquor filtered in step 3 is heated to 55°C by the heat exchange device, it is returned to the anode chamber circulation tank; at the same time, the sulfuric acid in the sulfuric acid storage tank replenishes the anode chamber circulation tank at a certain flow rate to maintain the anode chamber circulation tank. The volume and concentration of the circulating tank solution are stable.

Example 4 This example provides a method for continuously preparing copper sulfate crystals by ion membrane electrolysis, which includes the following steps:

Step 1: Pass 500g/L dilute sulfuric acid in the sulfuric acid storage tank into the ion membrane electrolyzer, use Cu-CATH-2 cathode copper as the anode, Cu-CATH-2 cathode copper as the cathode, the electrode spacing is 25mm, and use anion exchange The membrane is an ionic membrane, connected to direct current, controlling the current density to 8000A/m ² , and performing electrolysis at a reaction temperature of 55°C. The hydrogen generated in the cathode chamber is recovered through the gas collection device, and the electrolytic cell voltage is 1.28V;

Step 2: When the copper ion concentration in the anode chamber circulation tank reaches 40g/L, the solution is filtered and impurities are removed and then passed into the copper solution storage tank;

Step 3: Cool the solution in the copper solution storage tank to 10°C, precipitate copper sulfate crystals, filter, and prepare a copper sulfate crystal mass of 130g per liter of solution;

Step 4: After the mother liquor filtered in step 3 is heated to 55°C by the heat exchange device, it is returned to the anode chamber circulation tank; at the same time, the sulfuric acid in the sulfuric acid storage tank replenishes the anode chamber circulation tank at a certain flow rate to maintain the anode chamber circulation tank. The volume and concentration of the circulating tank solution are stable.

Example 5 This example provides a method for continuously preparing copper sulfate crystals by ion membrane electrolysis, which includes the following steps:

Step 1: Pass 500g/L dilute sulfuric acid in the sulfuric acid storage tank into the ion membrane electrolyzer, use Cu-CATH-2 cathode copper as the anode, Cu-CATH-2 cathode copper as the cathode, the electrode spacing is 25mm, and use anion exchange The membrane is an ionic membrane, connected to direct current, controlling the current density to 500A/m ² , and performing electrolysis at a reaction temperature of 20°C. The hydrogen generated in the cathode chamber is recovered through the gas collection device, and the electrolytic cell voltage is 0.95V;

Step 2: When the copper ion concentration in the anode chamber circulation tank reaches 12g/L, the solution is filtered and impurities are removed and then passed into the copper solution storage tank;

Step 3: Cool the solution in the copper solution storage tank to -20°C, precipitate copper sulfate crystals, filter, and prepare a copper sulfate crystal mass of 40g per liter of solution;

Step 4: After the mother liquor filtered in step 3 is heated to 20°C by the heat exchange device, it is returned to the anode chamber circulation tank; at the same time, the sulfuric acid in the sulfuric acid storage tank replenishes the anode chamber circulation tank at a certain flow rate to maintain the anode chamber circulation tank. The volume and concentration of the circulating tank solution are stable.

Example 6 This example provides a method for continuously preparing copper sulfate crystals by ion membrane electrolysis, which includes the following steps:

Step 1: Pass 30g/L dilute sulfuric acid in the sulfuric acid storage tank into the ion membrane electrolyzer, use Cu-CATH-2 cathode copper as the anode, Cu-CATH-2 cathode copper as the cathode, the electrode spacing is 25mm, and use anion exchange The membrane is an ionic membrane, connect to direct current, control the current density to 50A/m ² , and perform electrolysis at a reaction temperature of 55°C. The hydrogen generated in the cathode chamber is recovered through the gas collection device, and the electrolytic cell voltage is 2.00V;

Step 2: When the copper ion concentration in the anode chamber circulation tank reaches 120g/L, the solution is filtered and impurities are removed and then passed into the copper solution storage tank;

Step 3: Cool the solution in the copper solution storage tank to 20°C, precipitate copper sulfate crystals, filter, and prepare a copper sulfate crystal mass of 195g per liter of solution;

Step 4: After the mother liquor filtered in step 3 is heated to 55°C by the heat exchange device, it is returned to the anode chamber circulation tank; at the same time, the sulfuric acid in the sulfuric acid storage tank replenishes the anode chamber circulation tank at a certain flow rate to maintain the anode chamber circulation tank. The volume and concentration of the circulating tank solution are stable.

Example 7 This example provides a method for continuously preparing copper sulfate crystals by ion membrane electrolysis, which includes the following steps:

Step 1: Pass 30g/L dilute sulfuric acid in the sulfuric acid storage tank into the ion membrane electrolyzer, use Cu-CATH-2 cathode copper as the anode, commercial platinum electrode as the cathode, the electrode spacing is 25mm, and use an anion exchange membrane as the ion membrane , connect the direct current, control the current density to 50A/m ² , perform electrolysis at a reaction temperature of 85°C, the hydrogen generated in the cathode chamber is recovered through the gas collection device, and the electrolytic cell voltage is 1.15V;

Step 2: When the copper ion concentration in the anode chamber circulation tank reaches 180g/L, the solution is filtered and impurities are removed and then passed into the copper solution storage tank;

Step 3: Cool the solution in the copper solution storage tank to 30°C, precipitate copper sulfate crystals, filter, and prepare a copper sulfate crystal mass of 350g per liter of solution;

Step 4: After the mother liquor filtered in step 3 is heated to 85°C by the heat exchange device, it is returned to the anode chamber circulation tank; at the same time, the sulfuric acid in the sulfuric acid storage tank replenishes the anode chamber circulation tank at a certain flow rate to maintain the anode chamber circulation tank. The volume and concentration of the circulating tank solution are stable.

Example 8 This example provides a method for continuously preparing copper sulfate crystals by ion membrane electrolysis, which includes the following steps:

Step 1: Pass 400g/L dilute sulfuric acid in the sulfuric acid storage tank into the ion membrane electrolyzer, use Cu-CATH-2 cathode copper as the anode, commercial platinum electrode as the cathode, the electrode spacing is 25mm, and use an anion exchange membrane as the ion membrane , connect the direct current, control the current density to 50A/m ² , perform electrolysis at a reaction temperature of 85°C, the hydrogen generated in the cathode chamber is recovered through the gas collection device, and the electrolytic cell voltage is 0.30V;

Step 2: When the copper ion concentration in the anode chamber circulation tank reaches 100g/L, the solution is filtered and impurities are removed and then passed into the copper solution storage tank;

Step 3: Cool the solution in the copper solution storage tank to 30°C, precipitate copper sulfate crystals, filter, and prepare a copper sulfate crystal mass of 220g per liter of solution;

Step 4: After the mother liquor filtered in step 3 is heated to 85°C by the heat exchange device, it is returned to the anode chamber circulation tank; at the same time, the sulfuric acid in the sulfuric acid storage tank replenishes the anode chamber circulation tank at a certain flow rate to maintain the anode chamber circulation tank. The volume and concentration of the circulating tank solution are stable.

The copper sulfate crystals prepared in Examples 1 to 8 were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The typical metal impurity element test results of ultra-pure copper sulfate crystals are as shown in Table 1. As can be seen from Table 1, the elemental contents of As, Pb, Sb and Zn were not detected, while the contents of Bi, Fe, Sn and Ni were 16ppm, 4ppm, 2ppm and 2ppm respectively, indicating that through our ion membrane electrolysis method The purity of the continuously prepared copper sulfate crystals is very high, which is better than the current national copper sulfate standard for electroplating HG/T3592-2010, and is suitable for the demand for high-purity copper sulfate solution for lithium battery copper foil.

Table 1 element As Bi Fe Pb sb Sn Ni Zn content(%) not detected 0.0016 0.0004 not detected not detected 0.0002 0.0002 not detected

Figure 3 shows the XRD pattern of the prepared copper sulfate pentahydrate and the spectrum of the standard card PDF#72-2355. By comparison, the main peaks basically correspond one to one and there are no impurity peaks, indicating that the prepared product is high-purity copper sulfate pentahydrate. The X-ray diffraction peaks in the spectrum are quite sharp, indicating that the crystallinity of copper sulfate after cooling and crystallization is very high.

The above are only examples of the embodiments of the present invention. Within the scope of knowledge possessed by those of ordinary skill in the art, several improvements and deformations can also be made without departing from the technical principles of the present invention. These improvements and deformations are also should be regarded as the protection scope of the present invention.

Claims (2)

1. The method for continuously preparing the copper sulfate crystal by the ionic membrane electrolysis method is characterized by comprising the following steps of:

heating dilute sulfuric acid in a sulfuric acid storage tank to a certain temperature through a heat exchanger, respectively introducing a cathode chamber and an anode chamber of an ion membrane electrolytic tank through a cathode chamber circulation tank and an anode chamber circulation tank, respectively starting electrolyte circulation among the cathode chamber, the anode chamber, the cathode chamber circulation tank and the anode chamber circulation tank, switching on direct current, electrolyzing the dilute sulfuric acid under a certain sulfuric acid concentration, a certain temperature and a certain current density, obtaining a copper sulfate solution in the anode chamber, and recovering hydrogen generated in the cathode chamber through a gas collecting device, wherein the sulfuric acid concentration is 30-500 g/L;

step (2), filtering and impurity removing after copper ions of the solution in the anode chamber circulation tank reach a certain concentration, and then introducing the solution into a copper-dissolving solution storage tank;

step (3), directly cooling and crystallizing the solution obtained in the step (2), and filtering to obtain a prepared copper sulfate crystal;

step (4), heating the mother liquor filtered in the step (3) by a heat exchanger and returning the mother liquor to the anode chamber circulation tank; meanwhile, sulfuric acid in the sulfuric acid storage tank supplements liquid for the anode chamber circulation tank at a certain flow rate, so that the volume and concentration of the anode chamber circulation tank solution are kept stable, the anode material in the anode chamber is high-purity copper, and the cathode in the cathode chamber is insoluble;

in the step (1), the electrolysis temperature is 20-85 ℃ and the current density is 50A/m ² ~8000A/m ² ；

The cooling temperature in the step (3) is-20-30 ℃, and the tank voltage in the step (1) is 0.30-2.00V;

the ionic membrane adopted in the ionic membrane electrolytic tank is a strong acid resistant commercial ionic membrane which does not allow copper ions to pass through;

the concentration of copper ions in the step (2) is 12 g/L-180 g/L.

2. The method of claim 1, wherein the temperature of the heat exchanger heating solution in step (4) is 20 ℃ to 85 ℃.