Method for producing cuprous oxide by utilizing low-grade purified copper slag in zinc hydrometallurgy process

Abstract

The invention discloses a method for producing cuprous oxide by utilizing low-grade purified copper slag in a zinc hydrometallurgy process, and belongs to the technical field of purified copper slag. The invention relates to a method for producing cuprous oxide by utilizing low-grade purified copper slag in a zinc hydrometallurgy process. The method mainly comprises the following steps: acid leaching and impurity removal; the pre-leached filter residues are mixed with dilute sulphuric acid, air is introduced to serve as an oxidizing agent for oxidation leaching, after leaching, the pH is adjusted to 4.0-5.0 through CaCO3, and copper-containing leaching liquid is obtained through filtering; adding dextrose monohydrate into the copper-containing leachate, and adjusting the pH value by using NaOH; according to the method, through the closed-loop process of acid presoaking impurity removal, air oxidation leaching, glucose reduction and cuprous oxide Cl <-> removal, conversion from harmless treatment to resource high-value utilization of the low-grade copper slag is achieved, air is used for replacing KMnO4, MnO2 and other chemical oxidants, the cost is reduced, no harmful by-product exists, the green metallurgy requirement is met, and the method is suitable for industrial production. The prepared cuprous oxide is directly used for removing Cl <-> from a supernatant in electrolytic zinc, and the double contradiction of copper slag dilution and high cost of a Cl <-> removing agent in the industry is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of purifying copper residue, and particularly relates to a method for producing cuprous oxide by using low-grade purified copper residue in a zinc hydrometallurgy process. BACKGROUND

[0002] When a zinc hydrometallurgy enterprise processes zinc oxide ore, a large amount of low-grade purified copper residue (an intermediate product) is generated, which is characterized by low copper content (Cu≤8%), high impurity content (Zn 10-15%, Fe 1-3%, Al 2-5%, H2O 40-50%), and large composition fluctuation. At present, this type of copper residue is mostly disposed of by a rotary kiln, but copper cannot be vaporized into flue dust because the normal pressure boiling point of copper is as high as 2567 DEG C, which is much higher than the working temperature (900-1200 DEG C) of the rotary kiln, and is finally discarded with water-quenched residue, resulting in serious waste of copper resources.

[0003] The existing copper residue copper extraction technology has many defects: 1) Conventional dilute sulfuric acid leaching can only dissolve a small amount of copper in the oxidation state, and the copper leaching rate is only 12-16%; 2) Although KMnO4 or MnO2 can be used as an oxidizing agent to improve the leaching rate, KMnO4 is expensive and has a large dosage, and MnO2 causes difficulty in liquid-solid separation due to high Fe content, and the leaching rate of both is less than 90%; 3) After the preparation of cuprous oxide, the existing Cl-removal technology has the problems of large feeding amount and low copper utilization rate; 4) The cuprous chloride residue produced by Cl-removal has a long process, high energy consumption (900-1000 DEG C), large three-waste pollution, and low economic value of the product. SUMMARY

[0004] The purpose of the present application is to solve the problems raised in the background art, and a method for producing cuprous oxide by using low-grade purified copper residue in a zinc hydrometallurgy process is provided.

[0005] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0006] The method for producing cuprous oxide by using low-grade purified copper residue in a zinc hydrometallurgy process mainly comprises the following steps:

[0007] Step 1: Acid leaching and impurity removal

[0008] The low-grade purified copper residue is mixed with dilute sulfuric acid for acid pre-leaching to remove Zn, Al, Fe, and Cd impurities in the residue; the pre-leaching filtrate is used for an electrolytic zinc solution system, and the pre-leaching residue is reserved;

[0009] Step 2: Air oxidation leaching and copper extraction

[0010] The pre-leaching residue of step one is mixed with dilute sulfuric acid, and air is introduced as oxidant for oxidative leaching. After leaching, the pH is adjusted to 4.0-5.0 with CaCO3, and the copper-containing leaching solution is obtained by filtration;

[0011] Step three, preparation of cuprous oxide by glucose reduction

[0012] To the copper-containing leaching solution of step two, add one water glucose, adjust the pH with NaOH, filter and wash after heating reaction to obtain cuprous oxide product and reduced solution;

[0013] Step four, removal of Cl- from cuprous oxide

[0014] Add the cuprous oxide of step three to the supernatant of electrolytic zinc, and remove Cl- by stirring reaction. The cuprous chloride residue is obtained by filtration.

[0015] Preferably, in step one, the conditions for acid pre-leaching of low-grade purified copper residue with dilute sulfuric acid are as follows:

[0016] pH is 1.0-2.0;

[0017] Temperature is 40-60℃;

[0018] Liquid-solid ratio is 2-4 to 1;

[0019] Reaction time is 40-80min.

[0020] Preferably, in step two, the conditions for oxidative leaching by introducing air as oxidant are as follows:

[0021] pH is 2.0-3.0;

[0022] Temperature is 50-80℃;

[0023] Reaction time is 3-5h;

[0024] Air flow is 150-250L / h.

[0025] Preferably, in step two, the pH for oxidative leaching by introducing air as oxidant is 2.5.

[0026] Preferably, in step two, the conditions for washing the residue with dilute sulfuric acid are as follows:

[0027] pH is 1.0-2.0;

[0028] Temperature is 40-60℃;

[0029] Washing time is 20-40min.

[0030] Preferably, in step three, the conditions for reduction of copper-containing leaching solution by adding one water glucose are as follows:

[0031] The mass ratio of the glucose monohydrate to Cu2+ is 1.2 to 1.8;

[0032] The pH is adjusted by NaOH to 9-11;

[0033] The reaction temperature is 70-90 DEG C, and the reaction time is 70-90 min.

[0034] Preferably, the conditions for removing Cl- from cuprous oxide in step four are as follows:

[0035] The mass ratio of the cuprous oxide to Cl- is 1.8 to 2.2;

[0036] The temperature is 40-60 DEG C;

[0037] The pH is 2.0-3.0;

[0038] The reaction time is 50-70 min.

[0039] Preferably, the filter residue in step two is washed with dilute sulfuric acid at 50 DEG C for 30 min, and then neutralized with CaCO3 to a pH of 4.5, and after filtration, the washing liquid is returned to step two for recycling.

[0040] Preferably, the reduced liquid in step three is introduced into the air oxidation leaching copper process in step two.

[0041] Compared with the prior art, the present application provides a method for producing cuprous oxide from low-grade purified copper residue in a zinc hydrometallurgy process, which has the following beneficial effects:

[0042] The parts not involved in the device are the same as or can be realized by the prior art. The present application realizes the transformation of low-grade copper residue from harmless disposal to resource high-value utilization through the closed-loop process of acid pre-leaching, air oxidation leaching, glucose reduction, and cuprous oxide Cl-removal. The air is used to replace chemical oxidants such as KMnO4 and MnO2, which reduces the cost and has no harmful by-products, in line with the requirements of green metallurgy. The prepared cuprous oxide is directly used for Cl-removal in electrolytic zinc supernatant, solving the dual contradiction of copper residue depletion and high cost of Cl-removal reagent in the industry. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present application will be described below. Obviously, the described embodiments are only a part of the embodiments of the present application, not all.

[0044] Embodiment:

[0045] The method for producing cuprous oxide from low-grade purified copper residue in a zinc hydrometallurgy process mainly includes the following steps:

[0046] Step one, acid leaching and impurity removal:

[0047] The low-grade purified wet copper residue from zinc hydrometallurgy is added with tap water at a liquid-solid ratio of 3:1, 98% dilute sulfuric acid is added dropwise to adjust the pH to 1.5, the temperature is raised to 50°C, and the leaching is carried out at 250 r / min for 40-80 min, then the acid leaching solution and the acid leaching residue are obtained after filtration, the acid leaching solution contains Zn≥45 g / L and Cu≤5 g / L; the acid leaching solution is sent to the electrolytic zinc solution preparation system, and the acid leaching residue is reserved;

[0048] It should be noted that the leaching rate of Zn and Al is slow when it is lower than 50°C, and the energy consumption increases when it is higher than 50°C, and the impurities can be removed deeply when the leaching is carried out at 50°C for 60 min; the liquid-solid ratio is 3:1, which can ensure that the impurities are fully dissolved, and at the same time, the subsequent solution volume is not too large to cause the increase of treatment cost; the pH range is 1.0-2.0, in which range, the solubility of Zn, Al and Fe sulfates is high, and Cu mainly exists in the form of elemental substance or insoluble sulfide, which is beneficial to the preferential removal of impurities and the retention of copper;

[0049] Step two, air oxidation leaching for copper extraction:

[0050] The acid leaching residue is added with tap water at a liquid-solid ratio of 11:1 and put into a reaction kettle, a gas disperser is installed, air is introduced, the air flow is 200 L / h, 98% dilute sulfuric acid is added dropwise to adjust the pH to 2.5, the temperature is raised to 70°C, and the leaching is carried out at 300 r / min for 4 h.

[0051] After the leaching is completed, CaCO3 powder is added to adjust the pH to 4.5, the stirring is continued for 30 min, and the copper-containing leaching solution and the leaching residue are obtained after filtration, the leaching solution contains Cu 10-15 g / L and Zn≤0.2 g / L.

[0052] The leaching residue is added with tap water at a liquid-solid ratio of 3:1, dilute sulfuric acid is added dropwise to adjust the pH to 1.5, the temperature is raised to 50°C, the stirring is carried out for 30 min, CaCO3 is added to neutralize to pH 4.5, and the washing solution and the washing residue are obtained after filtration, the washing solution contains Cu 0.5-2 g / L; the washing solution is returned to the air oxidation leaching process, and the washing residue is sent to the precious metal recovery process;

[0053] In this step, the oxidation potential of oxygen (O2 / H2O electrode potential 1.229 V) is higher than the oxidation potential of copper (Cu 2+ / Cu electrode potential 0.3419 V), in the dilute sulfuric acid system, the air oxidizes copper into Cu 2+ in the solution, and the specific reaction formula is:

[0054] 2Cu+O2+2H2SO4→2CuSO4+2H2O

[0055] Step three, preparation of cuprous oxide by glucose reduction:

[0056] Take the above copper-containing leaching solution, add one water glucose, stir at 350 r / min, add 500 g / L NaOH solution to adjust pH to 10, heat to 70°C, and react for 90 min.

[0057] After the reaction is completed, stand for 30 min, filter to obtain cuprous oxide filter residue and reduced liquid, the reduced liquid contains Cu≤1 mg / L and Zn≤20 mg / L.

[0058] The cuprous oxide filter residue is washed with water for 3 times, dried, and detected: Cu2O content≥81%, Cu≥81%, Zn≤0.9%, and Fe≤0.08%, which meets the requirement of industrial cuprous oxide (Cu2O≥80%), and the reduced liquid is returned to the acid pre-leaching process;

[0059] In this step, under weak alkaline conditions, Cu 2+ First reacts with NaOH to form Cu(OH)2, and then forms [Cu(OH)4] 2- Complex ion; the aldehyde group (-CHO) of glucose ionizes [Cu(OH)4] 2- Cu 2+ Into Cu2O, and the reaction formula is:

[0060] 2Cu 2+ +4OH - +CH2OH(CHOH)4CHO→Cu2O↓+2H2O+CH2OH(CHOH)4COOH

[0061] Step four, cuprous oxide removes Cl - :

[0062] Take the above cuprous oxide product, add supernatant of electrolytic zinc, the supernatant contains Cl - 1000-1100 mg / L and Zn 110-115 g / L, control the mass ratio of Cu + and Cl - to be 2, adjust pH to 2.5, heat to 50°C, stir at 280 r / min, react for 60 min, filter to obtain CuCl residue and Cl - removed liquid, wherein the CuCl residue contains Cl - ≥33%, Cu≥65%, the Cl - removed liquid contains Cl - ≤310 mg / L and Zn 105-110 g / L.

[0063] The Cl - removed liquid is returned to the electrolytic zinc system, and the CuCl residue recovers metal copper according to the existing process;

[0064] In this step, cuprous oxide reacts with Cl -The reaction produces CuCl precipitate, thus achieving Cl removal. - The reaction formula is:

[0065] Cu₂O + 2HCl → 2CuCl↓ + H₂O

[0066] This invention employs acidic pre-soaking for impurity removal, air oxidation leaching, glucose reduction, and cuprous oxide dechlorination. - This closed-loop process transforms low-grade copper slag from harmless disposal to high-value resource utilization. It uses air instead of chemical oxidants such as KMnO4 and MnO2, reducing costs and eliminating harmful byproducts, thus meeting green metallurgy requirements. The prepared cuprous oxide is directly used in the supernatant of electrolytic zinc for Cl removal. - Solving the problems of copper slag depletion and Cl removal in the industry - The dual contradiction of high drug costs.

[0067] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for producing cuprous oxide from low-grade purified copper slag during a hydrometallurgical zinc smelting process, characterized in that, The main steps include: Step 1: Acid leaching to remove impurities Low-grade purified copper slag is mixed with dilute sulfuric acid for acidic pre-leaching to remove Zn, Al, Fe, and Cd impurities from the slag. The pre-leaching filtrate is used in the electrolytic zinc solution production system, and the pre-leaching residue is kept for later use. Step 2: Air oxidation leaching for copper extraction The pre-leaching filter residue from step one is mixed with dilute sulfuric acid, and air is introduced as an oxidant for oxidative leaching. After leaching, the pH is adjusted to 4.0-5.0 with CaCO3, and the solution containing copper is obtained by filtration. Step 3: Preparation of cuprous oxide by glucose reduction Add glucose monohydrate to the copper-containing leaching solution from step two, adjust the pH with NaOH, heat the reaction, filter and wash to obtain cuprous oxide product and reduced solution; Step 4: Dechlorination of cuprous oxide - Add cuprous oxide from step three to the supernatant of the electrolytic zinc, and stir the reaction to achieve Cl removal. - The filtration yielded cuprous chloride slag.

2. The method for producing cuprous oxide from low-grade purified copper slag in a hydrometallurgical zinc smelting process according to claim 1, characterized in that, The conditions for acidic pre-leaching of low-grade purified copper slag mixed with dilute sulfuric acid in step one are as follows: pH is 1.0-2.0; The temperature is 40-60℃; Liquid-to-solid ratio 2-4:1; The reaction time is 40-80 minutes.

3. The method for producing cuprous oxide from low-grade purified copper slag in a hydrometallurgical zinc smelting process according to claim 1, characterized in that, The conditions for oxidative leaching in step two, where air is introduced as an oxidant, are as follows: pH is 2.0-3.0; The temperature is 50-80℃; The reaction time is 3-5 hours; The air flow rate is 150-250L / h.

4. The method for producing cuprous oxide from low-grade purified copper slag in a wet zinc smelting process according to claim 3, characterized in that, In step two, air is introduced as an oxidant for oxidative leaching, and the pH is 2.

5.

5. The method for producing cuprous oxide from low-grade purified copper slag in a hydrometallurgical zinc smelting process according to claim 3, characterized in that, The conditions for washing the filter residue with dilute sulfuric acid in step two are as follows: pH is 1.0-2.0; The temperature is 40-60℃; Washing time is 20-40 minutes.

6. The method for producing cuprous oxide from low-grade purified copper slag in a hydrometallurgical zinc smelting process according to claim 1, characterized in that, The conditions for adding glucose monohydrate to the copper-containing leachate in step three are as follows: glucose monohydrate and Cu 2+ The mass ratio is 1.2 to 1.8; The pH was adjusted to 9-11 using NaOH. The reaction temperature is 70-90℃ and the reaction time is 70-90min.

7. The method for producing cuprous oxide from low-grade purified copper slag in a hydrometallurgical zinc smelting process according to claim 1, characterized in that, In step four, cuprous oxide undergoes Cl removal. - The conditions are: Cuprous oxide and Cl - The mass ratio is 1.8 to 2.2; The temperature is 40-60℃; pH is 2.0-3.0; The reaction time is 50-70 minutes.

8. The method for producing cuprous oxide from low-grade purified copper slag in a hydrometallurgical zinc smelting process according to claim 1, characterized in that, The filter residue from step two is washed with dilute sulfuric acid at 50°C for 30 minutes, then neutralized with CaCO3 to pH 4.

5. After filtration, the washing liquid is returned to step two for recycling.

9. The method for producing cuprous oxide from low-grade purified copper slag in a hydrometallurgical zinc smelting process according to claim 8, characterized in that, The reduced solution from step three enters the air oxidation leaching copper extraction process in step two.