Chlorine recovery system for chlorination electrodeposition nickel production

Abstract

The utility model provides a chlorine recovery system for production of chlorinated electrodeposited nickel, belongs to the technical field of hydrometallurgy, solves the problem of poor chlorine recovery effect in the production process of chlorinated electrodeposited nickel, and comprises a gas collection device, the gas collecting device is sequentially connected with a gas-liquid separator, a multi-stage cooler, a drying tower and a chlorine gas compressor; the chlorine gas compressor is respectively connected with a chlorine gas leaching device and an accident emergency treatment tank; wet chlorine and anolyte enter a gas collection device and then enter a gas-liquid separator; wet chlorine is subjected to water removal, impurity removal and drying through a multi-stage cooler and a drying tower, is compressed by a chlorine compressor, and enters a chlorine leaching device when the chlorine concentration meets the requirement; and the chlorine enters the accident emergency disposal tank when the chlorine concentration does not meet the requirement. The chlorine gas can be completely recycled, the unit processing cost is obviously reduced, the discharge amount of tail gas and sewage is greatly reduced, the working environment is improved, and the refining technology of the chlorinated electrodeposited nickel is further perfected.

Description

Technical Field

[0001] This utility model belongs to the field of hydrometallurgical technology, specifically relating to a chlorine recovery system for the production of nickel chloride electrowinning. Background Technology

[0002] The nickel chloride electrowinning technology is a domestic first, and the nickel chloride electrowinning product is also a domestic first. Nickel chloride electrowinning is a production process that utilizes a high-purity nickel chloride solution in a chlorination system. Through electrolysis, metal ions are deposited on the cathode, and chloride ions are deposited on the anode, releasing chlorine gas. This process is characterized by a short process flow, low cost, and high product quality.

[0003] Currently, the recovery and utilization of chlorine gas generated during the anode process is a core technology in the production of electrolytic nickel chloride. However, the following problems exist in the current production of electrolytic nickel chloride: poor chlorine gas recovery and utilization, lack of recovery technology, and chlorine gas easily escaping from the surface of the electrolytic cell into the air, causing environmental pollution; there is a lack of technology for utilizing low-concentration chlorine gas, and no mature recovery and utilization technology is available domestically. Therefore, a novel chlorine gas recovery and utilization system is needed to solve these problems. Utility Model Content

[0004] The purpose of this invention is to provide a chlorine recovery system for the production of electrolytic nickel chloride, in order to solve the problem of poor chlorine recovery and utilization in the electrolytic nickel chloride production process.

[0005] The technical solution of this utility model is: a chlorine recovery system for the production of nickel chloride electrowinning, including a gas collection device, which is connected in sequence to a gas-liquid separator, a multi-stage cooler, a drying tower and a chlorine compressor, and the chlorine compressor is connected to a chlorine leaching device and an emergency response tank.

[0006] As a further improvement of this utility model, the gas collection device includes an electrodeposition cell, insoluble anodes are suspended in the electrodeposition cell by conductive rods, an anode bag is provided on the insoluble anode, an anode cover is provided on the upper part of the insoluble anode, and a gas extraction pipe, a liquid extraction pipe and a gas collection pipe on the side of the cell are also provided on the electrodeposition cell.

[0007] As a further improvement of this utility model, the chlorine compressor is connected to the chlorine leaching device and the emergency response tank via a chlorine pressure stabilizing tank.

[0008] As a further improvement of this utility model, the multi-stage cooler includes a primary cooler and a secondary cooler. A circulating water machine is connected to the primary cooler, and a chilled water unit is also provided. The chilled water unit is fed into the secondary cooler.

[0009] As a further improvement of this utility model, the chlorine compressor is equipped with an automatically controlled vacuum regulation circuit.

[0010] The beneficial effects of this utility model are as follows: Chlorine gas and anolyte enter the gas collection device for effective collection of chlorine gas, and then pass through a gas-liquid separator for gas-liquid separation. After being cooled by a multi-stage cooler, most of the saturated water and entrained matter can be removed. Then, it is dried in a drying tower using concentrated sulfuric acid. If the dried chlorine gas meets the concentration requirements, it can be sent to a chlorine leaching device for leaching copper slag and raw materials. The composition of the leaching solution meets the production requirements. If the chlorine gas concentration is low and does not meet the concentration requirements, the chlorine gas cannot enter the chlorine leaching device, but is discharged into a chlorine gas emergency response tank, where it undergoes a neutralization reaction with sodium hydroxide to reach the standard before being discharged.

[0011] The gas collection device features a specific design: the insoluble anode is suspended within the electrowinning cell by conductive rods, primarily serving a conductive function. This allows for the transfer of current, ensuring stable current transmission during electrolysis and guaranteeing the normal progress of the electrolytic reaction. It also enables the insoluble anode to effectively precipitate metal ions during electrolysis, helping to maintain electrolyte balance and thus ensuring the stability and efficiency of the production process. The anode sleeve on the insoluble anode forms a gas collection cavity with the upper anode cover, effectively preventing chlorine gas escape and improving chlorine recovery. The electrowinning cell is equipped with extraction pipes, liquid extraction pipes, and side gas collection pipes to ensure effective gas collection, stable gas flow, and optimized gas distribution.

[0012] To stabilize the tank level, prevent air from entering the chlorine system, improve chlorine purity, and facilitate chlorine recovery and reuse, a vacuum regulation loop was added to the chlorine compressor, and automatic control technology was employed to ensure the stability and adjustability of the system vacuum. Finally, the chlorine concentration is selected for either the chlorine leaching unit or the emergency response tank, providing different options for subsequent treatment in different situations. This increases the effective recovery and utilization of chlorine, thereby effectively recovering and utilizing chlorine during the nickel chlorination electrowinning process, reducing production costs and environmental pollution.

[0013] This invention addresses the issue that during the production of electrolytic nickel chloride, the mixture of chlorine gas and anolyte generated is processed through electrolytic gas collection devices, gas-liquid separation, multi-stage cooling, drying, compression, chlorine leaching, or emergency response tanks. This allows for the complete recovery and reuse of chlorine gas, significantly reducing unit processing costs, greatly decreasing exhaust gas and wastewater emissions, improving the working environment, and further refining the electrolytic nickel chloride refining technology. It yields significant economic and social benefits and further improves the electrolytic nickel chloride production process technology. Attached Figure Description

[0014] Figure 1 This is a diagram showing the connection structure of the system of this utility model;

[0015] Figure 2 This is a structural diagram of the gas collection device in this utility model.

[0016] In the diagram: 1-Gas collection device; 2-Gas-liquid separator; 3-First-stage cooler; 4-Second-stage cooler; 5-Drying tower; 6-Chlorine compressor; 7-Chlorine pressure stabilizing tank; 8-Chlorine leaching device; 9-Emergency response tank; 10-Circulating water machine; 11-Chiller unit; 12-Electrowinning tank; 13-Insoluble anode; 14-Anode bag; 15-Anode cover; 16-Extraction pipe; 17-Liquid extraction pipe; 18-Gas collection pipe at the side of the tank; 19-Conductive rod. Detailed Implementation

[0017] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] like Figures 1-2 As shown, a chlorine recovery system for nickel chloride electrowinning production includes a gas collection device 1, which is sequentially connected to a gas-liquid separator 2, a multi-stage cooler, a drying tower 5, and a chlorine compressor 6. The chlorine compressor 6 is connected to a chlorine leaching device 8 and an emergency response tank 9.

[0019] The gas collection device 1 includes an electrodeposition cell 12, in which an insoluble anode 13 is suspended by a conductive rod 19. An anode bag 14 is provided on the insoluble anode 13, and an anode cover 15 is provided on the upper part of the insoluble anode 13. The electrodeposition cell 12 is also provided with a gas extraction pipe 16, a liquid extraction pipe 17, and a gas collection pipe 18 on the side of the cell.

[0020] The chlorine compressor 6 is connected to the chlorine leaching device 8 and the emergency response tank 9 via the chlorine pressure stabilizing tank 7. The multi-stage cooler includes a primary cooler 3 and a secondary cooler 4. A circulating water pump 10 is connected to the primary cooler 3, and a chilled water unit 11 is also provided, which is fed into the secondary cooler 4. The chlorine compressor 6 is equipped with an automatically controlled vacuum regulation circuit.

[0021] This system includes the following steps:

[0022] Step 1: Wet chlorine gas and anolyte enter the gas collection device 1 for chlorine gas collection, and then enter the gas-liquid separator 2 to separate the wet chlorine gas and anolyte. The anolyte is returned to the production system for reuse.

[0023] Step 2: The wet chlorine gas separated by the gas-liquid separator 2 passes through a multi-stage cooler and drying tower 5 to remove water and impurities and dry the wet chlorine gas;

[0024] Step 3: After drying, the chlorine gas is compressed by the chlorine compressor 6. When the chlorine concentration meets the requirements, it enters the chlorine leaching device 8 for further recycling. When the chlorine concentration does not meet the requirements, it enters the emergency response tank 9 for treatment and is then discharged in compliance with standards.

[0025] In step two, the multi-stage cooler includes a primary cooler 3 and a secondary cooler 4. In the secondary cooler 4, the temperature of the wet chlorine gas drops to below 15°C. In step two, 98% concentrated sulfuric acid is introduced into the drying tower 5. In step three, the inlet vacuum of the chlorine compressor 6 is -0.02 to -0.05 MPa, and the outlet pressure of the chlorine compressor 6 is 0.35 to 0.45 MPa. In step three, when the chlorine concentration is below 50%, it enters the emergency response tank 9.

[0026] Example 1

[0027] The mixture of wet chlorine gas and anolyte enters the gas collection device 1 for gas collection, and then enters the gas-liquid separator 2 in sequence through the gas extraction pipe 16, the liquid extraction pipe 17, and the tank-side gas collection pipe 18. The gas collection device 1 mainly collects the wet chlorine gas generated during the production process to ensure that it does not escape into the environment, thereby reducing environmental pollution. During the wet chlorine gas recovery process, the vacuum generated at the compressor inlet can prevent backflow and ensure that the liquid does not flow back into the system.

[0028] The mixture of wet chlorine gas and anolyte enters the gas-liquid separator 2. The anolyte is discharged from the lower drain pipe by gravity, while the wet chlorine gas exits from the top of the gas-liquid separator 2 and enters the primary cooler 3. The primary cooler 3 is a shell-and-tube cooler, with the wet chlorine gas flowing from the bottom to the top. After cooling, it enters the secondary cooler 4. The temperature of the chlorine gas cooled by the primary cooler 3 is <30℃. The shell of the primary cooler 3 contains circulating cooling water supplied by the circulating water unit 10. The primary cooler 3 is equipped with a temperature detection and regulation device, which can realize the detection and automatic adjustment of the titanium tube cooler temperature. The wet chlorine gas cooled by the primary cooler 3 enters the secondary cooler 4, with the wet chlorine gas flowing from the bottom to the top. The shell of the secondary cooler 4 contains chilled water supplied by the chilled water unit 11. The temperature of the wet chlorine gas is reduced to below 15℃ by the secondary cooler 4, thereby removing more than 90% of the saturated water and entrained substances.

[0029] The circulating water from the primary cooler 3 and the chilled water from the secondary cooler 4 can be reused, increasing the resource recovery rate. The main reasons for setting up multi-stage coolers are to improve cooling efficiency, enhance system flexibility, adapt to different environmental conditions, improve system reliability, and minimize energy consumption.

[0030] The humid chlorine gas cooled by the secondary cooler 4 enters the drying tower 5 from the side and flows upwards. 98% concentrated sulfuric acid is introduced into the drying tower 5 as a desiccant. 98% concentrated sulfuric acid is characterized by its resistance to dilution, maintaining acidity and oxidizing properties, and its ability to continuously dry humid chlorine gas. The 98% concentrated sulfuric acid is sprayed downwards in a uniform mist from the top of the drying tower 5, drying in a counter-current manner. The moisture content of the gas entering the drying tower 5 is 0.4%, and the moisture content of the dried chlorine gas is <0.05%. The extremely low moisture content of the dried chlorine gas facilitates the selection of materials for chlorine compression, storage equipment, and pipelines, resulting in high economic efficiency. The concentrated sulfuric acid introduced from the drying tower 5 after use has a concentration reduced to below 93%, and its hygroscopic and oxidizing properties have changed. It can no longer be used for drying gas but can be recycled for reuse. Concentrated sulfuric acid flows back to the sulfuric acid circulation tank from the bottom of drying tower 5 by gravity, while dry chlorine gas is discharged from the top of drying tower 5 from bottom to top and enters chlorine compressor 6. Pressure and temperature sensors are installed at the outlet of the chlorine pipeline at the top of drying tower 5 to detect the chlorine pressure and temperature at the outlet of drying tower 5.

[0031] To stabilize the tank level, prevent air from entering the chlorine system, improve chlorine purity, and facilitate chlorine recovery and reuse, a vacuum regulation loop is added to the chlorine compressor 6, employing automatic control technology to ensure stable and adjustable system vacuum. The inlet vacuum of the chlorine compressor 6 is -0.02 to -0.05 MPa, and the outlet pressure is 0.35 to 0.45 MPa. A return pipe is installed on the outlet pipe of the chlorine compressor 6, connected to the inlet pipe. A vacuum gauge is installed on the inlet pipe, and an automatic regulating valve is installed on the connecting pipe. This valve is interlocked with the vacuum gauge, and the system vacuum is balanced by adjusting the valve opening. This allows for the detection and automatic adjustment of the inlet and outlet pressures of the chlorine compressor 6. The chlorine compressor 6 supplies compressed chlorine to the chlorine pressure stabilizing tank 7. The chlorine pressure stabilizing tank 7 maintains stable system pressure and regulates the chlorine flow rate to ensure stable system operation and safe supply. The inlet pipe of the chlorine compressor 6 and the anode cover 15 of the electrowinning tank 12 are all welded, which further prevents air from entering the vacuum pipe.

[0032] When the chlorine concentration exceeds 50%, the compressed dry chlorine gas enters the chlorine leaching unit 8. A measured amount of copper-nickel concentrate slurry is added to the chlorine leaching unit 8, and the leaching potential is strictly controlled to achieve the purification of valuable metals such as nickel, copper, and cobalt. By recovering and utilizing the chlorine gas generated during the electrowinning process of this system, and using chlorine gas to leach copper slag and nickel concentrate, not only is the consumption of sodium hydroxide absorbent reduced, but the supply of fresh chlorine gas from external plants is also saved, resulting in significant economic benefits.

[0033] In the event of an accident or low chlorine concentration (below 50%), chlorine cannot enter the chlorine leaching device. Instead, it is discharged into the emergency response tank 9 where it is neutralized with sodium hydroxide until it reaches the required standard before being released. An automatic regulating valve connecting the chlorine compressor 6 to the emergency response tank 9 is interlocked with the chlorine concentration detection device on the compressor 6, achieving interlocked control between the compressor 6 and the emergency response tank 9. If the pressure in the main chlorine pipe suddenly changes drastically, potentially causing a chlorine leak, the automatic regulating valve to the emergency response tank 9 immediately opens, sending the chlorine to the tank. After absorption by the alkaline solution, the chlorine is released only after reaching the required standard.

Claims

1. A chlorine recovery system for nickel chloride electrowinning production, characterized in that: It includes a gas collection device (1), which is connected in sequence to a gas-liquid separator (2), a multi-stage cooler, a drying tower (5) and a chlorine compressor (6). The chlorine compressor (6) is connected to a chlorine leaching device (8) and an emergency response tank (9). The gas collection device (1) includes an electrodeposition cell (12), insoluble anode (13) is suspended in the electrodeposition cell (12) by a conductive rod (19), an anode sleeve (14) is provided on the insoluble anode (13), an anode cover (15) is provided on the upper part of the insoluble anode (13), and a gas extraction pipe (16), a liquid extraction pipe (17) and a gas collection pipe (18) on the side of the cell are also provided on the electrodeposition cell (12).

2. The chlorine recovery system for nickel chloride electrowinning production according to claim 1, characterized in that: The chlorine compressor (6) is connected to the chlorine leaching device (8) and the emergency response tank (9) via the chlorine pressure stabilizing tank (7).

3. A chlorine recovery system for nickel chloride electrowinning production according to claim 1 or 2, characterized in that: The multi-stage cooler includes a primary cooler (3) and a secondary cooler (4). A circulating water machine (10) is connected to the primary cooler (3), and a chilled water unit (11) is also provided. The chilled water unit (11) is fed into the secondary cooler (4).

4. A chlorine recovery system for nickel chloride electrowinning production according to claim 3, characterized in that: The chlorine compressor (6) is equipped with an automatically controlled vacuum regulation circuit.

Images