Method for removing arsine from exhaust gas on the surface of copper electrowinning tank efficiently and environmentally

Abstract

The present application relates to copper electrolyte purification waste gas treatment technical field, especially to a kind of high-efficiency environmental protection removal method of arsine in copper electrodeposition tank surface waste gas.The method adds a certain concentration of waste electrolyte into flue gas spray liquor according to certain proportion, promotes arsine in copper electrodeposition tank surface waste gas and copper sulfate in spray liquor to react in spray tower, then the reaction product is clarified and separated in clarifier.Supernatant flows into clean water pool, after supplementing a certain amount of waste electrolyte, sulfuric acid and water, it is pumped into spray tower for recycling.The method effectively utilizes copper element in waste electrolyte, efficiently removes and recycles most of arsine in copper electrodeposition tank surface waste gas, and resources it as a semiconductor material, which not only solves the pollution of arsine to the environment, reduces the environmental protection risk of enterprise, but also greatly improves the economic and environmental protection benefit of enterprise.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of waste gas treatment, and particularly relates to a method for efficiently and environmentally removing arsine in waste gas on the surface of a copper electrodeposition tank. BACKGROUND

[0002] Copper electrolytic refining is a process in which anode copper is continuously dissolved and cathode copper is continuously deposited. However, with the dissolution of the anode, other non-copper chemical components in the anode will also be dissolved into the electrolyte along with the copper element, but not all elements will be deposited on the cathode. Some of the copper ions and some impurities such as arsenic, antimony and bismuth with similar potential to copper will continuously increase in concentration in the electrolyte. Therefore, in order to maintain the copper and impurity concentrations in the electrolyte, the clean liquid system needs to be started to reduce the copper and other impurity concentrations in the electrolyte to within the control range of the process parameters.

[0003] The main method currently used for removing impurities in clean liquid is induced arsenic removal. Induced arsenic removal is a process in which the electrolyte is periodically circulated through the electrodeposition tank to remove copper. The copper ions in the electrolyte are deposited on the cathode. As the concentration of copper ions decreases, the concentration of arsenic ions decreases. However, when the concentration of copper ions decreases to 2 g / L, arsenic hydride (AsH3) gas is generated on the cathode, which poses a safety problem for the on-site workers. The current method for treating this gas is to extract the arsenic hydride gas generated on the surface of the copper electrodeposition tank to a spray tower, use lye as the spray liquid, and spray and wash it in the spray tower by circulating it with a pump, thereby achieving absorption and treatment of the gas. This method is not effective in treating AsH3 gas, and the treated gas still contains some AsH3. AsH3 gas is denser than air and can easily deposit around the plant. When professional equipment is used to detect the gas around the production area, there are cases of AsH3 exceeding the standard, which affects the health of the workers. Therefore, it is necessary to find a method for removing AsH3 from the waste gas on the surface of the copper electrodeposition tank that is simple in process, easy to operate and low in cost. SUMMARY

[0004] The present application discloses a method for efficiently and environmentally removing arsine in waste gas on the surface of a copper electrodeposition tank, to solve any of the above and other potential problems in the prior art.

[0005] To address the aforementioned problems, the technical solution of this invention is: a highly efficient and environmentally friendly method for removing arsine from the exhaust gas of copper electrowinning cells. Arsenic has high solubility in copper sulfate solution and readily reacts with copper sulfate and sulfuric acid to form insoluble compounds, as shown in the reaction equation: 2AsH3 + 3CuSO4 = Cu3As2 + 3H2SO4, thereby achieving the effect of absorbing arsine gas. This method utilizes existing exhaust gas treatment processes and equipment, improving the addition structure of the spray reagent in the existing exhaust gas treatment process, reducing the amount of reagent added, reducing the generation of secondary pollutants, and recovering and utilizing the arsine in the flue gas as a resource. This method is simple to operate, easy to industrialize, environmentally friendly, and has significant economic, environmental, and social benefits.

[0006] A highly efficient and environmentally friendly method for removing arsine from waste gas from copper electrodeposition cells includes the following steps:

[0007] S1: Waste electrolyte, sulfuric acid and water are mixed in a certain proportion to obtain flue gas scrubbing liquid. The flue gas scrubbing liquid is pumped into the scrubbing tower to spray and wash the waste gas on the copper electrodeposition cell surface to obtain flue gas scrubbing mixed solution.

[0008] S2: The flue gas spray mixture is sent into a clarification tank for natural sedimentation to obtain supernatant and bottom sludge;

[0009] S3: The supernatant obtained in step S2 is sent to the clear water tank. After adding a certain amount of waste electrolyte, sulfuric acid and water to the clear water tank, it is pumped into the spray tower for recycling.

[0010] S4: Pump the bottom mud obtained in step S2 to a filter press, return the filtrate to the clarification tank for clarification, and send the filter cake to the copper arsenide refining process.

[0011] Preferably, the Cu in the flue gas scrubbing liquid in S1 2+ The concentration is 20-40 g / L, the acidity is 120-180 g / L, and the liquid-to-gas ratio is 2-6 L / m³. 3 .

[0012] Preferably, the arsine content in the flue gas after spraying is ≤0.3 mg / m³. 3 .

[0013] Preferably, the residence time of the exhaust gas from the copper electrodeposition tank surface in the spray tower in S1 is 1-3 seconds.

[0014] Preferably, the number of stages of the exhaust gas spray on the copper electrodeposition tank surface in S1 is one, two, or more.

[0015] Preferably, the natural settling time in S2 is 6-12 hours.

[0016] The beneficial effects of this invention are:

[0017] 1. The method of the present application can greatly reduce the addition of basic absorbent, and reduce the generation of high-salinity wastewater in the waste gas treatment process;

[0018] 2. By introducing waste electrolyte, replacing the existing basic absorbent, the arsine is removed from the system in the form of copper arsenide precipitation, the arsine is converted into copper arsenide for resource recycling, and the waste liquid is recycled by simple sedimentation and waste electrolyte supplement, thereby reducing the pressure and cost of wastewater treatment;

[0019] 3. The process flow is simple and reliable, easy to industrialize, and has important economic and social benefits. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 The process flow chart of the method for removing arsine from copper electrodeposition tank surface waste gas in a high-efficiency and environmentally friendly manner. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present application will be clearly and completely described below, obviously, the described embodiments are only part of the embodiments of the present application, not all. Any equivalent changes and improvements made within the scope of the present application should still belong to the patent coverage range of the present application.

[0022] Example 1

[0023] The waste electrolyte A (Cu 2+ with a concentration of 43.79 g / L and an acidity of 162.58 g / L), sulfuric acid and a certain amount of water are prepared into Cu 2+ The concentration of the smoke spraying solution is 20 g / L, the acidity is 120 g / L, and the smoke is sprayed into the spraying tower, the liquid-gas ratio is 2 L / m 3 , and the smoke spraying mixed solution is obtained. Among them, the copper electrodeposition tank surface waste gas stays in the spraying tower for 2s, and the smoke is treated by two-stage spraying. The smoke washing mixed solution is introduced into the clarifier for natural sedimentation, and after natural sedimentation for 6h, the supernatant flows into the clean water tank, and after supplementing a certain amount of waste electrolyte, sulfuric acid and water, it is pumped into the spraying tower for recycling. The lower sludge is pumped into the filter press, the filtrate is returned to the clarifier for clarification, and the filter cake is sent to the copper arsenide refining process.

[0024] The initial arsine gas concentration in the waste gas is 0.892 mg / m 3 , and after the method for removing arsine from copper electrodeposition tank surface waste gas is used, the arsine gas concentration is 0.188 mg / m 3 , and the removal rate is 78.92%.

[0025] Example 2

[0026] The waste electrolyte B (Cu 2+ The concentration of the waste electrolyte B (Cu 2+ The concentration of the waste electrolyte B (Cu 3 The concentration of the waste electrolyte B (Cu 3 The concentration of the waste electrolyte B (Cu 3 The concentration of the waste electrolyte B (Cu 2+ The concentration of the waste electrolyte B (Cu 2+ The concentration of the waste electrolyte B (Cu 3 The concentration of the waste electrolyte B (Cu 3 The concentration of the waste electrolyte B (Cu 3 The concentration of the waste electrolyte B (Cu

[0027] The concentration of the waste electrolyte B (Cu 3 The concentration of the waste electrolyte B (Cu 3 The concentration of the waste electrolyte B (Cu

[0028] Example 3

[0029] The waste electrolyte B (Cu 2+ The concentration of the waste electrolyte B (Cu 2+ The concentration of the waste electrolyte B (Cu 3 The concentration of the waste electrolyte B (Cu 3 The concentration of the waste electrolyte B (Cu 3 The concentration of the waste electrolyte B (Cu

[0030] The concentration of the waste electrolyte B (Cu 3 The concentration of the waste electrolyte B (Cu 3 The concentration of the waste electrolyte B (Cu

[0031] Finally, it should be noted that the above only describes the preferred embodiments of the present application and is not intended to limit the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art will appreciate that the technical solutions described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalent features, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A highly efficient and environmentally friendly method for removing arsine from waste gas from copper electrodeposition tanks, characterized in that, Specifically, the following steps are included: S1: Waste electrolyte, sulfuric acid, and water are mixed to obtain flue gas scrubbing liquid. This liquid is pumped into a scrubbing tower to spray and wash the waste gas from the copper electrodeposition cell surface, resulting in a flue gas scrubbing mixed solution. The Cu in the flue gas scrubbing liquid... 2+ The concentration is 20-40 g / L, the acidity is 120-180 g / L, and the liquid-to-gas ratio is 2-6 L / m³. 3 ; S2: The flue gas spray mixture is sent into a clarification tank for natural sedimentation to obtain supernatant and bottom sludge; S3: The supernatant obtained in step S2 is sent to the clear water tank. After adding a certain amount of waste electrolyte, sulfuric acid and water to the clear water tank, it is pumped into the spray tower for recycling. S4: Pump the bottom mud obtained in step S2 to a filter press, return the filtrate to the clarification tank for clarification, and send the filter cake to the copper arsenide refining process.

2. The method for efficiently and environmentally friendly removal of arsine from waste gas from copper electrodeposition cells according to claim 1, characterized in that, The arsine content in the flue gas after spraying is ≤0.3 mg / m³. 3 .

3. The method for efficiently and environmentally friendly removal of arsine from waste gas from copper electrodeposition tanks according to claim 1, characterized in that, The residence time of the exhaust gas from the copper electrodeposition tank surface in the spray tower in S1 is 1-3 seconds.

4. The method for efficiently and environmentally friendly removal of arsine from waste gas from copper electrodeposition tanks according to claim 1, characterized in that, The number of stages for the exhaust gas spray on the copper electrodeposition tank surface in S1 can be one, two, or more.

5. The method for efficiently and environmentally friendly removal of arsine from waste gas from copper electrodeposition tanks according to claim 1, characterized in that, The natural settling time in S2 is 6-12 hours.

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