A method and device for collecting and processing anode acid mist gas in a nickel-cobalt electrodeposition process

Abstract

The application discloses a device and method for collecting and processing anode acid mist gas in a nickel-cobalt electrodeposition process, and belongs to the technical field of hydrometallurgy. The device comprises an electrolytic cell, a diaphragm frame, a diaphragm bag, an anode frame, a gas collecting branch pipe, a converging main pipe, a gas-liquid separator, a liquid level sensor, a negative pressure regulating valve, a gas treatment unit and a degassing unit. The anode frame is sleeved outside the noble metal anode, an anode gas-liquid area is formed inside the anode frame, the gas collecting branch pipe is in communication with the anode frame and the converging main pipe respectively, and the gas-liquid separator is in communication with the converging main pipe. The liquid level sensor detects a liquid level signal in the gas-liquid separator, and the negative pressure regulating valve dynamically adjusts a vacuum degree in a range of -200 to -500 kPa according to the liquid level signal. The degassing unit is provided with a heating device, a stirring device and a negative pressure suction device. According to the method, the anode liquid and the gas are simultaneously introduced into the gas-liquid separator through negative pressure suction, gas-liquid separation is realized through dynamic negative pressure adjustment, the separated gas is treated and discharged or compressed for reuse, and the separated anode liquid is returned to the system for recycling after residual toxic gas is removed through the degassing unit.

Description

Technical Field

[0001] This invention belongs to the field of hydrometallurgical technology, specifically relating to a device and method for collecting and treating anolyte acid mist gas during the electrowinning process of nickel-cobalt hydrometallurgical processes. Background Technology

[0002] The electrowinning process in nickel-copper-cobalt hydrometallurgical processes mainly includes two forms: soluble anodes and insoluble anodes. Insoluble anode electrowinning can be further subdivided into sulfuric acid system and chloride system.

[0003] During the insoluble anodic electrodeposition process in a sulfuric acid system, oxygen evolution and acid formation reactions mainly occur on the anode surface. The acid formation reaction gradually increases the acidity of the electrodeposition solution, while the oxygen produced by the oxygen evolution reaction carries acidic vapors into the electrodeposition plant during its escape, causing a large amount of sulfuric acid mist to permeate the plant. When a large amount of acid mist enters the working environment, it not only affects the service life of the steel structure plant and equipment but also creates an extremely harsh operating environment, impacting worker performance.

[0004] To suppress acid mist, industrial processes typically employ the addition of surfactants such as sodium dodecyl sulfate and pore inhibitors to form a foam coating on the tank surface. However, the suppressive effect of these additives is limited, and the dosage is difficult to control consistently—excessive additives can cause a large amount of foam to permeate the electrolyte surface, leading to electrode short circuits and disrupting normal production; insufficient additives result in poor acid mist suppression. While commonly used ventilation methods can address the environmental problems caused by the large-scale volatilization of acid mist from the tank surface to some extent, they cannot fundamentally improve the working environment.

[0005] In the insoluble anodic electrowinning process of the chlorination system, due to the high concentration of Cl in the electrolyte... - During the electrodeposition process, the gas is anoly oxidized into chlorine gas. If the generated chlorine gas is not collected, it will not only seriously pollute the environment but also waste resources.

[0006] Existing acid mist absorption devices mainly fall into two categories: whole-tank electrolytic anode hoods and single-piece anode acid mist absorption hoods. For example, CN201148470Y discloses a nickel electrolytic acid mist absorption device that uses a long, open-ended hood fixed to the nickel electrolytic anode diaphragm frame to completely cover the entire anode. CN103409771A discloses an environmentally friendly continuous and stable production process device for electrolytic nickel or electrolytic cobalt, with a sealed anode frame and an acid mist absorption port connected to an acid mist recovery system. However, the aforementioned existing technologies generally suffer from poor absorption efficiency due to unstable negative pressure control, and the on-site environment is not significantly improved. Furthermore, the gas collection hood solution also has drawbacks such as acid mist condensing inside the hood and dripping down, corroding the copper busbars, and increased labor intensity due to difficult maintenance.

[0007] In summary, the existing technology lacks a technical solution that can be applied to both sulfuric acid and chlorination systems and can stably and efficiently collect and treat anodic acid mist / gas. In particular, there is an urgent need to propose an improved solution to address the problems of poor chlorine collection and reuse in chlorination systems and low acid mist absorption efficiency in sulfuric acid systems. Summary of the Invention

[0008] The purpose of this invention is to overcome the above-mentioned defects in the prior art and provide a device and method for collecting and treating anolyte acid mist / gas during nickel-cobalt electrowinning. It aims to solve the technical problems such as poor absorption effect of acid mist in the existing sulfuric acid system, poor collection and reuse effect of chlorine gas in the existing chlorine system, low absorption efficiency due to unstable negative pressure control in the existing device, and lack of a universal technical solution applicable to both systems.

[0009] To achieve the above objectives, the present invention provides the following technical solution: I. Apparatus A device for collecting and treating anolyte acid mist / gas during nickel-cobalt electrowinning includes an electrolytic cell, a diaphragm frame, a diaphragm bag, a conductive copper busbar, a precious metal anode, an anode frame, a gas collecting branch pipe, a manifold, a gas-liquid separator, a liquid level sensor, a negative pressure regulating valve, a gas treatment unit, and a degassing unit.

[0010] The electrolytic cell is equipped with a diaphragm frame clip. The diaphragm frame is fixed inside the electrolytic cell by the diaphragm frame clip, and a diaphragm bag is fitted on the diaphragm frame, dividing the electrolytic cell into independent anode chambers. A conductive copper busbar is positioned above the electrolytic cell. The precious metal anode is fixedly suspended from the conductive copper busbar by a titanium screw and a titanium nut, and is located within the anode chamber. An anode frame is fitted outside the precious metal anode and located within the anode chamber. An anode gas-liquid region is formed inside the anode frame. The top of the anode frame is fixedly connected to the titanium screw, and a sealing structure is provided at the connection between the anode frame and the titanium screw. One end of the gas collecting branch pipe is connected to the upper part of the anode frame and communicates with the anode gas-liquid region, while the other end is connected to the manifold. The manifold is located outside the electrolytic cell, and each of the gas collecting branch pipes is connected to the manifold. The gas-liquid separator is connected to the outlet end of the manifold. The liquid level sensor is located at the front end or inside the gas-liquid separator to detect the liquid level signal of the gas-liquid mixture. The negative pressure regulating valve is located on the gas phase outlet pipe of the gas-liquid separator and is connected to the liquid level sensor. It dynamically adjusts the vacuum level within the gas-liquid separator within the range of -200 to -500 kPa based on the liquid level signal, allowing the anolyte to enter the gas-liquid separator intermittently and the gas to be continuously extracted. The gas processing unit is connected to the gas outlet of the gas-liquid separator. The degassing unit is connected to the liquid outlet of the gas-liquid separator and includes a heating device, a stirring device, and a negative pressure suction device.

[0011] Preferably, the sealing structure is a PVDF gasket.

[0012] Preferably, the system also includes a gas concentration sensor disposed on the surface of the electrolytic cell, the gas concentration sensor being signal-connected to the negative pressure regulating valve.

[0013] Preferably, the gas treatment unit includes an alkaline spray absorption tower and an exhaust pipe; the gas treatment unit also includes a drying tower and a chlorine compressor connected in parallel, and the inlet of the drying tower and the chlorine compressor is connected to the outlet of the gas-liquid separator through a switching valve.

[0014] II. Methods A method for collecting and treating anolyte acid mist / gas during nickel-cobalt electrowinning using the above-mentioned apparatus includes the following steps: (1) The diaphragm frame is fixed inside the electrolytic cell by the diaphragm frame clip, the diaphragm bag is placed outside the diaphragm frame to divide the electrolytic cell into independent anode chambers, the anode frame is placed outside the precious metal anode and placed inside the anode chamber, and the precious metal anode is fixed and suspended on the conductive copper busbar by the titanium screw and titanium nut, so that the anode frame forms an anode gas-liquid region. (2) During the electrowinning process, the acid mist / gas generated at the anode and the anolyte are collected in the anode gas-liquid region and simultaneously enter the main manifold through the gas collecting branch pipe; (3) The anolyte and gas in the manifold enter the gas-liquid separator. The liquid level signal in the gas-liquid separator is detected by the liquid level sensor. The controller sends a command to the negative pressure regulating valve set on the gas phase outlet pipeline of the gas-liquid separator according to the liquid level signal. The vacuum degree in the gas-liquid separator is dynamically adjusted within the range of -200 to -500 kPa, so that the anolyte enters the gas-liquid separator in an intermittent manner and the gas is extracted in a continuous manner, thereby realizing gas-liquid separation. (4) The separated gas enters the gas processing unit for processing; (5) The separated anolyte enters the degassing unit. Through the combined action of heating device to raise the temperature, stirring device to stir, and negative pressure suction device to draw out, the residual toxic gas in the anolyte is desorbed and overflowed. The degassed anolyte is returned to the system for recycling.

[0015] Preferably, the method is applicable to the electrowinning of nickel in a sulfuric acid system. The separated gas enters the gas treatment unit, is neutralized by an alkaline spray absorption tower, and is then discharged. The separated anolyte is treated by a degassing unit to remove the acid mist entrained in the anolyte, and the degassed anolyte is returned to the system for recycling.

[0016] Preferably, the method is applicable to the electrowinning of nickel or cobalt in a chlorination system. The separated gas is monitored for chlorine concentration online. When the chlorine concentration is ≥ a set threshold, it enters a drying tower for drying and is then compressed by a chlorine compressor for reuse in the upstream process. When the chlorine concentration is < a set threshold, it is switched to an alkaline spray absorption tower for treatment before being discharged. The separated anolyte enters a degassing unit, where free chlorine is removed from the anolyte through the synergistic effect of heating, stirring, and negative pressure suction until the free chlorine content in the anolyte is ≤ 1 ppm. The dechlorinated anolyte is then returned to the system for recycling.

[0017] Preferably, a gas concentration sensor is installed on the surface of the electrolytic cell to detect the chlorine concentration on the surface of the cell in real time. When the detected concentration exceeds a set threshold, the gas concentration sensor sends a signal to the negative pressure regulating valve, and the negative pressure regulating valve automatically increases the pumping volume until the chlorine concentration on the surface of the cell drops below the set threshold.

[0018] The beneficial effects of this invention are as follows: (1) By interlocking the liquid level sensor and the negative pressure regulating valve, the vacuum degree inside the gas-liquid separator can be dynamically and accurately adjusted, avoiding the problem of mutual interference between the gas and liquid phases in the pipeline under conventional fixed negative pressure conditions. The anolyte enters intermittently and the gas is extracted continuously, resulting in good gas-liquid separation effect and greatly improving the collection efficiency of acid mist / gas.

[0019] (2) The same set of equipment can be used for acid mist absorption of electrolytic nickel in sulfuric acid system and chlorine collection and reuse of electrolytic nickel / cobalt in chloride system by switching the operating path of the gas treatment unit. The equipment utilization rate is high and the equipment investment cost is reduced.

[0020] (3) Through the synergistic effect of heating, stirring and negative pressure suction, the toxic gas remaining in the anolyte is fully desorbed and overflowed. The degassed anolyte is returned to the system for recycling, avoiding secondary pollution during the reuse of acid / chlorine-containing anolyte.

[0021] (4) By setting a gas concentration sensor on the surface of the electrolytic cell and interlocking it with the signal of the negative pressure regulating valve, the collection effect can be monitored in real time and automatically adjusted, ensuring that the gas concentration on the surface of the cell is always controlled below the safety threshold, thus protecting the health and safety of employees.

[0022] (5) The chlorine gas collected in the chlorination system is dried and compressed and then reused in the front-end process, which reduces production and operating costs and reduces tail gas emissions.

[0023] In summary, this invention effectively improves the on-site working environment, reduces production and operating costs, and significantly reduces exhaust gas and wastewater emissions. It not only meets the requirements for acid mist absorption during the electrowinning process of the existing sulfuric acid system, but also further improves the electrowinning technology of nickel / cobalt in the chloride system, resulting in significant economic and social benefits. Attached Figure Description

[0024] Figure 1 This is a side view of the electrolytic cell of the present invention.

[0025] Figure 2 This is a schematic diagram of the structure of the anodic acid mist gas absorption hood of the present invention.

[0026] Among them, 1-Electrolytic cell body; 2-Diaphragm holder clip; 3-Anode area; 4-Cell surface brick; 5-Electrolytic cell support leg; 6-Conductive copper busbar; 7-Anode frame; 8-Titanium screw; 9-Titanium nut; 10-Gas-liquid area of ​​anode frame; 11-Gas collecting branch pipe; 12-Main manifold; 13-Precious metal anode. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The following embodiments are for illustrative purposes only and should not be considered as limiting the scope of the invention.

[0028] See Figure 1 and Figure 2This invention provides a device for collecting and treating anode acid mist gas during nickel-cobalt electrowinning, which mainly includes an electrolytic cell 1, a diaphragm frame, a diaphragm bag, a conductive copper busbar 6, a precious metal anode 13, an anode frame 7, a gas collecting branch pipe 11, a manifold 12, a gas-liquid separator, a liquid level sensor, a negative pressure regulating valve, a gas treatment unit, and a degassing unit.

[0029] Electrolytic cell 1 is an open rectangular tank made of vinyl ester resin. Inside electrolytic cell 1 is a diaphragm holder 2, which is fixed to the side wall or bottom of electrolytic cell 1. The diaphragm holder has a rectangular frame structure and is fixed inside electrolytic cell 1 by the diaphragm holder 2. The diaphragm bag is made of acid- and chlorine-resistant filter cloth (such as polypropylene or polyester) and is fitted over the diaphragm holder. The diaphragm bag divides electrolytic cell 1 into independent anode chambers (i.e., anode zone 3). The anode chamber and cathode chamber are connected by the diaphragm bag, allowing for ion conduction and liquid isolation.

[0030] A conductive copper busbar 6 is positioned horizontally above the electrolytic cell 1. The precious metal anode 13 is either a titanium-coated lead dioxide anode (suitable for sulfuric acid systems) or a titanium-coated iridium-tantalum anode (suitable for chloride systems). The top of the precious metal anode 13 is equipped with a connecting lug, which is fixedly suspended from the conductive copper busbar 6 by a titanium screw 8 and a titanium nut 9. The precious metal anode 13 is located in the anode chamber, with its lower end extending below the anolyte surface.

[0031] The anode frame 7 is a rectangular cylindrical structure made of polypropylene or vinyl resin. The anode frame 7 is fitted outside the precious metal anode 13 and located within the anode chamber. The bottom of the anode frame 7 is open, and the top is closed, forming the anode gas-liquid region 10. The top of the anode frame 7 is threaded through a through-hole onto the titanium screw 8 and secured with a titanium nut 9. A PVDF gasket is provided at the connection between the anode frame 7 and the titanium screw 8 as a sealing structure to prevent gas leakage from the anode gas-liquid region 10. A DN25 interface is provided on the upper side wall or top wall of the anode frame 7.

[0032] The gas collecting branch pipe 11 is a DN25 PP flexible hose (polypropylene hose). One end of the gas collecting branch pipe 11 is connected to the DN25 interface on the upper part of the anode frame 7 via a quick connector and is connected to the anode gas-liquid area 10. The other end is connected to the manifold 12. The gas collecting branch pipe 11 is kept horizontal and slightly bent downwards in the direction of gravity (inclination angle of 5°~15°) so that the anolyte can flow smoothly into the manifold 12 under the action of gravity, while avoiding liquid seals or gas blockages in the pipeline.

[0033] The main manifold 12 is made of PP or PVC and is located outside the electrolytic cell 1, either to the side or below it. Each gas collecting branch pipe 11 is connected to the main manifold 12, and the outlet end of the main manifold 12 is connected to the inlet of the gas-liquid separator.

[0034] The gas-liquid separator is a vertical or horizontal gas-liquid separation tank made of PP or titanium. It has a gas outlet at the top, a liquid outlet at the bottom, and a gas-liquid mixture inlet in the middle or upper part. A wire mesh demister or cyclone separator can be installed inside the gas-liquid separator to enhance the gas-liquid separation effect.

[0035] The level sensor is installed on the front pipeline of the gas-liquid separator or inside the gas-liquid separator. The level sensor is a radar level gauge, differential pressure level gauge, or float level gauge, used to detect the liquid level height in the gas-liquid separator in real time and output a liquid level signal.

[0036] The negative pressure regulating valve is installed on the gas phase outlet pipeline of the gas-liquid separator. The negative pressure regulating valve is either an electrically operated butterfly valve or a pneumatically operated regulating valve. The negative pressure regulating valve is connected to the liquid level sensor via a controller (PLC controller or DCS control system). The controller receives the liquid level signal output by the liquid level sensor, performs internal calculations, and outputs a 4~20mA or 0~10V control signal to the negative pressure regulating valve to adjust the opening degree of the negative pressure regulating valve, thereby dynamically adjusting the vacuum degree in the gas-liquid separator within the range of -200~-500kPa.

[0037] The gas processing unit is connected to the outlet of the gas-liquid separator. The gas processing unit includes an alkaline spray absorption tower and a discharge pipe. The alkaline spray absorption tower is a packed tower or spray tower, filled with corrosion-resistant packing material (such as Pall rings or stepped rings). A spray device is installed at the top of the tower, and an alkaline circulation tank is located at the bottom. The tower body is made of PP or fiberglass. The gas processing unit also includes a drying tower and a chlorine compressor connected in parallel. The drying tower is a packed tower, filled with a desiccant (such as molecular sieves or silica gel). The chlorine compressor is a corrosion-resistant reciprocating compressor or centrifugal compressor. Its inlet is connected to the outlet of the gas-liquid separator via a switching valve, and the outlet is connected to the chlorine buffer tank in the upstream process.

[0038] The degassing unit is connected to the liquid outlet of the gas-liquid separator. The degassing unit is a closed degassing tank, made of titanium or PP lined with titanium. The degassing unit is equipped with a heating device, a stirring device, and a negative pressure suction device. The heating device consists of a steam heating coil, electric heater, or heat exchanger installed on the inner or outer wall of the degassing tank, used to raise the anolyte temperature to 60-90℃. The stirring device is a mechanical stirring paddle installed inside the degassing tank, made of titanium, driven by a variable frequency motor located at the top of the degassing tank, with a stirring speed of 50-300 rpm, used to enhance the gas-liquid interface renewal of the anolyte and accelerate the desorption of toxic gases. The negative pressure suction device is a water ring vacuum pump or a Roots vacuum pump, connected to the gas phase port at the top of the degassing tank, used to promptly remove the desorbed toxic gases from the degassing tank, maintaining a negative pressure environment inside the degassing tank.

[0039] The bottom of the degassing unit is equipped with a degassed anolyte outlet, which is connected to the anolyte circulation tank of the electrolysis system through a pipeline, so that the degassed anolyte can be returned to the system for recycling.

[0040] As a preferred embodiment, the present invention further includes a gas concentration sensor disposed on the surface of the electrolytic cell 1. The gas concentration sensor is an electrochemical acid mist detector or a chlorine detector, used to detect the concentration of acid mist or chlorine on the surface of the cell in real time and output a concentration signal to the controller. The controller compares the concentration signal with a preset safety threshold (e.g., 1 mg / Nm³ for chlorine). 3 The controller compares the measured concentration with the safe threshold. When the measured concentration exceeds the safe threshold, the controller sends a command to the negative pressure regulating valve to automatically increase the opening of the negative pressure regulating valve and increase the pumping volume until the gas concentration on the tank surface drops below the safe threshold, thus forming a closed-loop feedback control.

[0041] Example 1 Electrowinning of nickel acid mist in sulfuric acid system This embodiment provides a method for collecting and treating anolyte acid mist during the electrowinning process of nickel in a sulfuric acid system.

[0042] The apparatus consists of: an electrolytic cell 1 made of vinyl ester resin, with a diaphragm holder 2 inside. The diaphragm holder is fixed inside the electrolytic cell 1 by the diaphragm holder 2, and a diaphragm bag is fitted onto the diaphragm holder, dividing the electrolytic cell 1 into independent anode chambers (anode areas 3). A conductive copper busbar 6 is positioned above the electrolytic cell 1. A precious metal anode (titanium-coated lead dioxide) 13 is fixedly suspended from the conductive copper busbar 6 by a titanium screw 8 and a titanium nut 9, and is located within the anode chamber. An anode frame 7 is fitted over the titanium-coated lead dioxide anode 13 and located within the anode chamber, forming an anode gas-liquid region 10 inside the anode frame 7. The top of the anode frame 7 is fixedly connected to the titanium screw 8, and the connection between the anode frame 7 and the titanium screw 8 is sealed with a PVDF gasket.

[0043] A DN25 interface is provided at the upper part of the anode frame 7. The gas collecting branch pipe 11 is a DN25 PP flexible hose. One end of the gas collecting branch pipe 11 is connected to the DN25 interface at the upper part of the anode frame 7 via a quick connector and communicates with the anode gas-liquid area 10. The other end is connected to the manifold 12. The gas collecting branch pipe 11 is kept horizontal and bent downward to facilitate the flow of anolyte and gas. The manifold 12 is located outside the electrolytic cell 1, and each gas collecting branch pipe 11 is connected to the manifold 12. The gas-liquid separator is connected to the outlet end of the manifold 12. A liquid level sensor is located at the front end of the gas-liquid separator to detect the liquid level signal of the gas-liquid mixture. A negative pressure regulating valve is located on the gas phase outlet pipe of the gas-liquid separator and is connected to the liquid level sensor signal. The gas treatment unit includes an alkaline spray absorption tower and a discharge pipe, which are connected to the gas outlet end of the gas-liquid separator. The degassing unit is connected to the liquid outlet of the gas-liquid separator. The degassing unit is equipped with a heating device, a stirring device, and a negative pressure suction device.

[0044] Operating instructions: (1) The diaphragm frame is fixed inside the electrolytic cell 1 by the diaphragm frame clip 2. The diaphragm bag is placed outside the diaphragm frame to divide the electrolytic cell 1 into an independent anode chamber. The anode frame 7 is placed outside the precious metal anode 13 and placed inside the anode chamber. The precious metal anode 13 is fixed and suspended on the conductive copper busbar 6 by the titanium screw 8 and titanium nut 9, so that the anode gas-liquid region 10 is formed inside the anode frame 7.

[0045] (2) During the electrowinning process, the acid mist oxygen generated at the anode and the anolyte are collected in the anode gas-liquid region (10) and simultaneously enter the main manifold (12) through the gas collecting branch pipe (11).

[0046] (3) The anolyte and gas in the manifold (12) enter the gas-liquid separator. The liquid level signal in the gas-liquid separator is detected by the liquid level sensor. The controller sends a command to the negative pressure regulating valve set on the gas phase outlet pipeline of the gas-liquid separator according to the liquid level signal, and dynamically adjusts the vacuum degree in the gas-liquid separator within the range of -200~-500kPa. When the liquid level rises, the negative pressure regulating valve is closed to reduce the vacuum degree and reduce the amount of gas pumped out, preventing the anolyte from being pumped into the gas phase pipeline in excess. When the liquid level falls, the negative pressure regulating valve is opened to increase the vacuum degree and increase the amount of gas pumped out, ensuring that the gas is continuously pumped out. Thus, the anolyte enters the gas-liquid separator in an intermittent manner and the gas is pumped out in a continuous manner, realizing gas-liquid separation.

[0047] (4) The separated gas enters the gas treatment unit and is neutralized by the alkaline spray absorption tower before being discharged in compliance with standards.

[0048] (5) The separated anolyte enters the degassing unit. Through the combined action of heating device to raise the temperature, stirring device to stir, and negative pressure suction device to suction, the acid mist entrained in the anolyte is desorbed and overflowed. The degassed anolyte is returned to the system for recycling.

[0049] After treatment using the method described in this embodiment, the efficiency of anolyte acid mist collection during the electrowinning process of the sulfuric acid system is significantly improved, the working environment of the electrowinning tank surface is significantly improved, and the corrosion of the plant and equipment is greatly reduced.

[0050] Example 2 Chlorination system for nickel / cobalt electrowinning, chlorine gas collection and reuse This embodiment provides a method for collecting and reusing anolyte chlorine gas during the electrowinning of nickel or cobalt in a chlorination system.

[0051] The apparatus consists of: an electrolytic cell 1 made of vinyl ester resin, with a diaphragm holder 2 inside. The diaphragm holder is fixed inside the electrolytic cell 1 by the diaphragm holder 2, and a diaphragm bag is fitted onto the diaphragm holder, dividing the electrolytic cell 1 into independent anode chambers (anode areas 3). A conductive copper busbar 6 is positioned above the electrolytic cell 1. A precious metal anode 13 is fixedly suspended from the conductive copper busbar 6 by a titanium screw 8 and a titanium nut 9, and is located within the anode chamber. An anode frame 7 is fitted over the precious metal anode 13 and located within the anode chamber, forming an anode gas-liquid region 10 inside the anode frame 7. The top of the anode frame 7 is fixedly connected to the titanium screw 8, and the connection between the anode frame 7 and the titanium screw 8 is sealed with a PVDF gasket.

[0052] A DN25 interface is provided at the upper part of the anode frame 7. The gas collecting branch pipe 11 is a DN25 PP hose. One end of the gas collecting branch pipe 11 is connected to the DN25 interface at the upper part of the anode frame 7 via a quick connector and is connected to the anode gas-liquid area 10. The other end is connected to the manifold 12. The gas collecting branch pipe 11 is kept horizontal and bent downward to facilitate the flow of anode liquid and gas. The manifold 12 is located outside the electrolytic cell 1, and each gas collecting branch pipe 11 is connected to the manifold 12. The gas-liquid separator is connected to the outlet end of the manifold 12. The liquid level sensor is located at the front end of the gas-liquid separator to detect the liquid level signal of the gas-liquid mixture. The negative pressure regulating valve is located on the gas phase outlet pipe of the gas-liquid separator and is connected to the liquid level sensor signal. The gas treatment unit includes an online chlorine concentration detection device, a drying tower, a chlorine compressor, and an alkaline spray absorption tower. The outlet of the online chlorine concentration detection device is connected to the drying tower and the alkaline spray absorption tower, respectively. The degassing unit is connected to the liquid outlet of the gas-liquid separator. The degassing unit is equipped with a heating device, a stirring device, and a negative pressure suction device.

[0053] Operating instructions: (1) The diaphragm frame is fixed inside the electrolytic cell 1 by the diaphragm frame clip 2. The diaphragm bag is placed outside the diaphragm frame to divide the electrolytic cell 1 into an independent anode chamber. The anode frame 7 is placed outside the precious metal anode 13 and placed inside the anode chamber. The precious metal anode 13 is fixed and suspended on the conductive copper busbar 6 by the titanium screw 8 and titanium nut 9, so that the anode gas-liquid region 10 is formed inside the anode frame 7.

[0054] (2) During the electrowinning process, the chlorine gas generated at the anode and the anolyte are collected in the anode gas-liquid region 10 and simultaneously enter the main manifold 12 through the gas collecting branch pipe 11.

[0055] (3) The anolyte and gas in the manifold 12 enter the gas-liquid separator. The liquid level signal in the gas-liquid separator is detected by the liquid level sensor. The controller sends a command to the negative pressure regulating valve installed on the gas phase outlet pipeline of the gas-liquid separator according to the liquid level signal, and dynamically adjusts the vacuum degree in the gas-liquid separator within the range of -200 to -500 kPa. When the liquid level rises, the negative pressure regulating valve is closed to reduce the vacuum degree and reduce the amount of gas pumped out, preventing the anolyte from being pumped into the gas phase pipeline in excess. When the liquid level falls, the negative pressure regulating valve is opened to increase the vacuum degree and increase the amount of gas pumped out, ensuring that the gas is continuously pumped out. Thus, the anolyte enters the gas-liquid separator intermittently and the gas is pumped out continuously, realizing gas-liquid separation.

[0056] (4) The separated gas is tested for chlorine concentration online. When the chlorine concentration is ≥90%, it enters the drying tower for drying and is then compressed by the chlorine compressor and reused in the front-end process. When the chlorine concentration is <90%, it is switched to the alkaline spray absorption tower for treatment and then discharged.

[0057] (5) The separated anolyte enters the degassing unit, where it is heated to 60~90℃ by a heating device, stirred by a stirring device and sucked by a negative pressure suction device to remove free chlorine from the anolyte until the free chlorine content in the anolyte is ≤1ppm. The dechlorinated anolyte is then returned to the system for recycling.

[0058] After treatment using the method described in this embodiment, the chlorine content in the air above the electrowinning tank at a distance of 1m from the edge of the nickel electrowinning cell is ≤1mg / Nm³. 3 The efficiency of chlorine collection and reuse has been significantly improved, production and operating costs have been greatly reduced, the on-site working environment has been fundamentally improved, and the health and safety of employees have been effectively protected.

[0059] In summary, the device and method for collecting and treating anolyte acid mist / gas during nickel-cobalt electrowinning provided by this invention are suitable for the absorption and treatment of anolyte acid mist during nickel electrowinning in a sulfuric acid system, as well as the collection and reuse of anolyte chlorine gas during nickel or cobalt electrowinning in a chloride system, and have broad industrial application prospects.

[0060] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention, and the specific embodiments described above can enable those skilled in the art to more fully understand the present invention. Those skilled in the art, under the guidance of the present invention, can make various similar representations without departing from the spirit and claims of the present invention, and all of these should be covered within the protection scope of the present invention. In particular, this relates to sulfuric acid system electrowinning acid mist absorption technology, and chlorine gas collection and reuse technology for chlorine system electrowinning nickel and cobalt.

Claims

1. A device for collecting and treating anolyte acid mist gas during nickel-cobalt electrowinning, characterized in that, include: Electrolytic cell (1), wherein the electrolytic cell (1) is provided with a diaphragm holder (2); The diaphragm frame is fixed inside the electrolytic cell (1) by the diaphragm frame clip (2). The diaphragm frame is fitted with a diaphragm bag, which divides the electrolytic cell (1) into independent anode chambers. A conductive copper busbar (6) is disposed above the electrolytic cell (1); The precious metal anode (13) is fixedly suspended on the conductive copper busbar (6) by a titanium screw (8) and a titanium nut (9), and the precious metal anode (13) is disposed in the anode chamber; An anode frame (7) is fitted outside the precious metal anode (13) and located inside the anode chamber. An anode gas-liquid region (10) is formed inside the anode frame (7). The top of the anode frame (7) is fixedly connected to the titanium screw (8). A sealing structure is provided at the connection between the anode frame (7) and the titanium screw (8). Gas collecting branch pipe (11), one end of which is connected to the upper part of the anode frame (7) and communicates with the anode gas-liquid region (10), and the other end is connected to the main pipe (12); The main manifold (12) is located outside the electrolytic cell (1), and each of the gas collecting branch pipes (11) is connected to the main manifold (12); The gas-liquid separator is connected to the outlet end of the manifold (12); A liquid level sensor is installed at the front end or inside the gas-liquid separator to detect the liquid level signal of the gas-liquid mixture; A negative pressure regulating valve is installed on the gas phase outlet pipe of the gas-liquid separator and is connected to the liquid level sensor signal. It is used to dynamically adjust the vacuum degree in the gas-liquid separator within the range of -200~-500kPa according to the liquid level signal, so that the anolyte enters the gas-liquid separator intermittently and the gas is extracted continuously. A gas processing unit is connected to the gas outlet of the gas-liquid separator; The degassing unit is connected to the liquid outlet of the gas-liquid separator. The degassing unit is equipped with a heating device, a stirring device, and a negative pressure suction device.

2. The anode acid mist gas collection and treatment device according to claim 1 during nickel-cobalt electrowinning is characterized in that, The sealing structure is a PVDF gasket.

3. The anode acid mist gas collection and treatment device according to claim 1 during nickel-cobalt electrowinning is characterized in that, The vacuum degree of the gas-liquid separator is -200~-500kPa.

4. The anode acid mist gas collection and treatment device during nickel-cobalt electrowinning according to claim 1, characterized in that, It also includes a gas concentration sensor disposed on the surface of the electrolytic cell, the gas concentration sensor being signal-connected to the negative pressure regulating valve.

5. The anode acid mist gas collection and treatment device according to claim 1 during nickel-cobalt electrowinning, characterized in that, The gas treatment unit includes an alkaline spray absorption tower and an exhaust pipe connected in series.

6. The anode acid mist gas collection and treatment device according to claim 5 during nickel-cobalt electrowinning, characterized in that, The gas processing unit also includes a drying tower and a chlorine compressor connected in parallel. The inlet of the drying tower and the chlorine compressor is connected to the outlet of the gas-liquid separator through a switching valve.

7. A method for collecting and treating anolyte acid mist gas during nickel-cobalt electrowinning using the apparatus described in any one of claims 1-6, characterized in that, Includes the following steps: The diaphragm frame is fixed inside the electrolytic cell (1) by the diaphragm frame clip (2). The diaphragm bag is placed outside the diaphragm frame to divide the electrolytic cell (1) into independent anode chambers. The anode frame (7) is placed outside the precious metal anode (13) and placed inside the anode chamber. The precious metal anode (13) is fixed and suspended on the conductive copper busbar (6) by the titanium screw (8) and titanium nut (9) so that an anode gas-liquid region (10) is formed inside the anode frame (7). During the electrowinning process, the acid mist / gas generated at the anode and the anolyte are collected in the anode gas-liquid region (10) and simultaneously enter the main manifold (12) through the gas collecting branch pipe (11). The anolyte and gas in the manifold (12) enter the gas-liquid separator. The liquid level signal in the gas-liquid separator is detected by the liquid level sensor. The controller sends a command to the negative pressure regulating valve set on the gas phase outlet pipeline of the gas-liquid separator according to the liquid level signal. The vacuum degree in the gas-liquid separator is dynamically adjusted in the range of -200~-500kPa, so that the anolyte enters the gas-liquid separator in an intermittent manner and the gas is extracted in a continuous manner, thereby realizing gas-liquid separation. The separated gas enters the gas processing unit for further processing. After separation, the anolyte enters the degassing unit. Through the combined action of heating, stirring, and suction, the residual toxic gases in the anolyte are desorbed and released. The degassed anolyte is then returned to the system for recycling.

8. The method for collecting and treating anolyte acid mist gas during nickel-cobalt electrowinning according to claim 7, characterized in that, The method is applicable to nickel electrowinning in a sulfuric acid system. The separated gas enters the gas treatment unit, is neutralized by an alkaline spray absorption tower, and is discharged through the discharge pipe. The separated anolyte is treated by a degassing unit to remove the acid mist entrained in the anolyte. The degassed anolyte is returned to the system for recycling.

9. The method for collecting and treating anolyte acid mist gas during nickel-cobalt electrowinning according to claim 7, characterized in that, The method is applicable to the electrowinning of nickel or cobalt in a chlorination system. The separated gas is monitored for chlorine concentration online. When the chlorine concentration is ≥ a set threshold, it enters a drying tower for drying and is then compressed by a chlorine compressor for reuse in the upstream process. When the chlorine concentration is < a set threshold, it is switched to an alkaline spray absorption tower for treatment before being discharged. The separated anolyte enters a degassing unit, where free chlorine is removed from the anolyte through the synergistic effect of heating, stirring, and negative pressure suction until the free chlorine content in the anolyte is ≤ 1 ppm. The dechlorinated anolyte is then returned to the system for recycling.

10. The method for collecting and treating anolyte acid mist / gas during nickel-cobalt electrowinning according to claim 9, characterized in that, A gas concentration sensor is installed on the surface of the electrolytic cell to detect the chlorine concentration on the surface of the cell in real time. When the detected concentration exceeds a set threshold, the gas concentration sensor sends a signal to the negative pressure regulating valve, which automatically increases the pumping volume until the chlorine concentration on the surface of the cell drops below the set threshold.

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