Method for preparing copper sulfate feed liquid through ultrasonic oxidation and impurity removal of copper sponge leachate

Abstract

The invention discloses a method for preparing copper sulfate feed liquid through ultrasonic oxidation and impurity removal of copper sponge leachate, which specifically comprises the following steps: (1) pumping the copper sponge leachate into a circulating tank, adding ferrous sulfate according to the arsenic content in the copper sponge leachate, adjusting the iron-arsenic ratio to (1.2-1.5): 1, and then stirring for 15-35 minutes; (2) pumping into an ultrasonic oxidation reactor; (3) opening a gas supply valve of an oxygen station, adjusting a liquid outlet valve of the ultrasonic oxidation reactor, stabilizing the pressure in the kettle at 0.4-0.6 Mpa and the oxygen concentration of more than or equal to 90%, and introducing oxygen to circulate for 1.5-3 hours within the pressure range to obtain oxygen pressure leached liquid; and (4) adjusting the pH value of the liquid obtained after oxygen pressure leaching to 2.5-3.0, and carrying out filter pressing to obtain a copper sulfate feed liquid. The ultrasonic efficient oxidation technology is adopted for impurity removal, one-time investment is low, and the production and operation cost is lower. The process is simple in equipment, convenient to operate, economical, practical, safe, environmentally friendly, stable and reliable in equipment operation, low in loss rate of valuable metals such as copper and nickel, remarkable in comprehensive economic benefit and very high in popularization value.

Description

Technical Field

[0001] This invention relates to the field of hydrometallurgical technology, specifically to a method for preparing copper sulfate solution by ultrasonic oxidation and impurity removal from sponge copper leaching solution. Background Technology

[0002] Sponge copper leaching solution is produced by leaching sponge copper with a high-acid solution at a certain liquid-solid ratio, resulting in a high-acid copper-containing solution. This solution has high levels of Fe and As impurities, which does not meet the requirements for receiving copper sulfate solution in downstream processes. Chemical purification is necessary to ensure that Fe ≤ 0.3 g / L and As ≤ 0.2 g / L. Currently, sodium chlorate is used as an oxidant for room-temperature oxidation purification of the sponge copper leaching solution. Although this method can reduce the iron and arsenic content in the solution to the required range, the reagent consumption is large and expensive, leading to high production costs. Furthermore, this method makes it difficult to precisely control the amount of oxidant added.

[0003] Ultrasound refers to sound waves with frequencies higher than 20,000 Hz. It has good directionality and strong penetrating power, and its properties accelerate various reactions and increase reaction yields. When ultrasound of a certain intensity passes through a solution, the instantaneous closure and bursting of reactive oxygen micro- or nanobubbles or cavitation bubbles generated in the solution produces a series of high-pressure, high-heat kinetic processes. The movement of reactive oxygen micro- or nanobubbles is driven by the bubbles' own energy. During high-speed movement, the bubbles can reach critical states for chemical reactions at any time, rapidly converting Fe... 2＋ Oxidized to Fe 3＋ , will As 3+ Oxidized to As 5+ This allows for a rapid completion of the oxidation reaction, and then pH adjustment is used to allow Fe to... 3＋ As 5+ The reaction produces FeAsO4, which removes impurities from the copper sponge leachate in the form of solid slag. Summary of the Invention

[0004] The purpose of this invention is to solve the technical problems of high oxidant consumption, high cost, and difficulty in precise control in the leaching process of copper sulfate production. This invention provides a method for preparing copper sulfate solution by ultrasonic oxidation of sponge copper leaching solution.

[0005] To achieve its purpose, the present invention adopts the following technical solution: A method for preparing copper sulfate solution by ultrasonic oxidation and impurity removal of sponge copper leaching solution includes the following steps: Step 1: Pump the copper sponge leachate into the circulation tank. During this process, add ferrous sulfate according to the arsenic content in the copper sponge leachate to make the iron-arsenic ratio 1.2-1.5:1. Then stir for 15-35 minutes. Step 2: Pump the copper sponge leachate treated in Step 1 into the ultrasonic oxidation reactor; Step 3: Open the oxygen supply valve of the oxygen station and adjust the liquid outlet valve of the ultrasonic oxidation reactor to stabilize the pressure inside the reactor at 0.4-0.6 MPa and the oxygen concentration at ≥90%. Within this pressure range, circulate oxygen for 1.5-3 hours to obtain the oxygen pressure leachate. Step 4: Adjust the pH of the oxygen pressure leaching solution to 2.5-3.0, filter under pressure, and obtain a copper sulfate solution with As≤0.2g / l and Fe≤0.3g / l.

[0006] As a further preferred embodiment of the technical solution of the present invention, in step 1, the iron-arsenic ratio in the copper sponge leachate is 1.2:1.

[0007] Furthermore, in step 1, the stirring speed is 50-100 r / min.

[0008] Furthermore, in step 1, the pH of the sponge copper leaching solution is 1.5-2.0, and the copper concentration is 45g / L-60g / L.

[0009] Compared with the prior art, the present invention has the following beneficial effects: This invention discloses a method for preparing copper sulfate solution by removing impurities from sponge copper leaching solution using an ultrasonic oxidation reactor. Employing high-efficiency ultrasonic oxidation technology, it features low initial investment and lower production and operating costs. Compared to the sodium chlorate oxidation process for iron removal, production and operating costs can be reduced by 50%. This process is characterized by simple equipment, convenient operation, economic efficiency, safety, and environmental friendliness. The equipment operates stably and reliably, with low losses of valuable metals such as copper and nickel, resulting in significant overall economic benefits. It solves the long-standing technical problem of impurity removal in hydrometallurgical processes and has high potential for widespread application. Detailed Implementation

[0010] The present invention will be further described below with reference to specific embodiments.

[0011] Example 1 A method for preparing copper sulfate solution by ultrasonic oxidation and impurity removal of sponge copper leaching solution includes the following steps: Step 1: Prepare 20 ml of sponge copper leaching solution with pH 1.5 and copper concentration of 45.37 g / L. 3 The solution was pumped into a circulation tank. The arsenic concentration of the sponge copper leaching solution was 3.0 g / L and the iron concentration was 1.2 g / L. 240 kg of ferrous sulfate heptahydrate containing 20% ​​iron was added and stirred at 60 r / min for 20 min. Step 2: Pump the copper sponge leachate treated in Step 1 into the ultrasonic oxidation reactor; Step 3: Open the oxygen supply valve of the oxygen station and adjust the liquid outlet valve of the ultrasonic oxidation reactor to stabilize the pressure inside the reactor at 0.5 MPa and the oxygen concentration at 92%. Circulate oxygen within this pressure range for 2 hours to obtain the oxygen pressure leachate. Step 4: Adjust the pH of the oxygen pressure leaching solution to 2.5, filter under pressure, and obtain copper sulfate solution. The composition of the copper sulfate solution is shown in Table 1.

[0012] Table 1. Elemental content analysis of copper sulfate solution in Example 1 Table 1 shows that the Fe content in the copper sulfate solution is ≤0.3 g / L and the As content is ≤0.2 g / L, meeting the usage requirements. However, due to mechanical entrainment of impurities and analytical errors, the copper content in the copper sulfate solution is lower than that in the sponge copper leaching solution. The specific analysis is as follows: (1) The impurity removal process adopts chemical precipitation method, that is, high-valence arsenic and iron form ferric arsenate precipitate under specific pH conditions. However, if the iron-arsenic ratio in the sponge copper leaching solution does not reach 1.2-1.5:1, that is, the iron content is low (iron-arsenic ratio is in the range of 0.1-1.1), the excess high-valence arsenic cannot form precipitate with iron. At this time, the high-valence arsenic reacts with copper to form copper arsenate precipitate, thus causing copper loss.

[0013] (2) During the impurity removal process, sodium carbonate is needed to adjust the pH of the sponge copper leaching solution. After all the arsenic and iron have formed precipitates, the excess alkali will form insoluble copper hydroxide, which will adhere to the filter cloth of the filter press during the filter press, resulting in copper loss.

[0014] Example 2 A method for preparing copper sulfate solution by ultrasonic oxidation and impurity removal of sponge copper leaching solution includes the following steps: Step 1: Prepare 15 ml of sponge copper leaching solution with pH 2 and copper concentration of 50.19 g / L. 3 The solution was pumped into a circulation tank. The arsenic concentration of the sponge copper leaching solution was 2.0 g / L and the iron concentration was 1.4 g / L. 75 kg of ferrous sulfate heptahydrate containing 20% ​​iron was added and stirred at 100 r / min for 15 min. Step 2: Pump the copper sponge leachate treated in Step 1 into the ultrasonic oxidation reactor; Step 3: Open the oxygen supply valve of the oxygen station and adjust the liquid outlet valve of the ultrasonic oxidation reactor to stabilize the pressure inside the reactor at 0.6 MPa and the oxygen concentration at 91%. Within this pressure range, circulate oxygen for 1.5 hours to obtain the oxygen pressure leachate. Step 4: Adjust the pH of the oxygen pressure leaching solution to 3.0, filter under pressure, and obtain copper sulfate solution. The composition of the copper sulfate solution is shown in Table 2.

[0015] The composition of the copper sulfate solution is shown in Table 2.

[0016] Table 2. Elemental content analysis of copper sulfate solution in Example 2 Table 2 shows that the Fe content in the copper sulfate solution is ≤0.3g / l and the As content is ≤0.2g / l, which meets the usage requirements. The reason for the decrease in copper content in the copper sulfate solution compared to the sponge copper leaching solution is the same as in Example 1.

[0017] Example 3 A method for preparing copper sulfate solution by ultrasonic oxidation and impurity removal of sponge copper leaching solution includes the following steps: Step 1: Prepare 20 ml of sponge copper leaching solution with pH 2.0 and copper concentration of 59.66 g / L. 3 The solution was pumped into a circulation tank. The arsenic concentration of the sponge copper leaching solution was 3.53 g / L and the iron concentration was 0.85 g / L. 340 kg of ferrous sulfate heptahydrate containing 20% ​​iron was added and stirred at 50 r / min for 35 min. Step 2: Pump the copper sponge leachate treated in Step 1 into the ultrasonic oxidation reactor; Step 3: Open the oxygen supply valve of the oxygen station and adjust the liquid outlet valve of the ultrasonic oxidation reactor to stabilize the pressure inside the reactor at 0.4 MPa and the oxygen concentration at 91%. Circulate oxygen within this pressure range for 3 hours to obtain the oxygen pressure leachate. Step 4: Adjust the pH of the oxygen pressure leaching solution to 3.0, filter under pressure, and obtain copper sulfate solution. The composition of the copper sulfate solution is shown in Table 3.

[0018] Table 3. Elemental content analysis of copper sulfate solution in Example 3 Table 3 shows that the Fe content in the copper sulfate solution is ≤0.3g / l and the As content is ≤0.2g / l, which meets the usage requirements. The reason for the decrease in copper content in the copper sulfate solution compared to the sponge copper leaching solution is the same as in Example 1.

Claims

1. A method for preparing copper sulfate solution by ultrasonic oxidation and impurity removal of sponge copper leaching solution, characterized in that, Includes the following steps: Step 1: Pump the copper sponge leachate into the circulation tank. During this process, add ferrous sulfate according to the arsenic content in the copper sponge leachate to make the iron-arsenic ratio 1.2-1.5:

1. Then stir for 15-35 minutes. Step 2: Pump the copper sponge leachate treated in Step 1 into the ultrasonic oxidation reactor; Step 3: Open the oxygen supply valve of the oxygen station and adjust the liquid outlet valve of the ultrasonic oxidation reactor to stabilize the pressure inside the reactor at 0.4-0.6 MPa and the oxygen concentration at ≥90%. Within this pressure range, circulate oxygen for 1.5-3 hours to obtain the oxygen pressure leachate. Step 4: Adjust the pH of the oxygen pressure leaching solution to 2.5-3.0, filter under pressure to obtain a copper sulfate solution with As≤0.2g / l and Fe≤0.3g / l.

2. The method for preparing copper sulfate solution by ultrasonic oxidation and impurity removal of sponge copper leaching solution as described in claim 1, characterized in that, In step 1, the iron-arsenic ratio in the copper sponge leachate is 1.2:

1.

3. The method for preparing copper sulfate solution by ultrasonic oxidation and impurity removal of sponge copper leaching solution as described in claim 2, characterized in that, In step 1, the stirring speed is 50-100 r / min.

4. The method for preparing copper sulfate solution by ultrasonic oxidation and impurity removal of sponge copper leaching solution as described in any one of claims 1-3, characterized in that, In step 1, the pH of the sponge copper leaching solution is 1.5-2.0 and the copper concentration is 45g / L-60g / L.

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