A method for efficiently reducing ferric ions in a zinc leach solution

Abstract

This invention discloses a highly efficient method for reducing ferric ions in zinc leaching solution, belonging to the field of hydrometallurgical technology. The zinc leaching solution and zinc sulfide concentrate are placed in a closed reactor and subjected to a pressure-enhanced reduction reaction at a temperature of 100-120℃ and a pressure of 0.2-0.3 MPa to reduce the ferric ions in the leaching solution. Simultaneously, compressed air is introduced into the reaction system to prevent the generation of hydrogen sulfide gas. The reaction time is 0.5-2.0 h. The reduced reaction system is then settled and filtered to obtain the reduced solution and reduced sulfur residue. This technical solution innovatively proposes the use of compressed air for pressure-enhanced reduction of Fe in zinc leaching solution. 3+ This achieves the suppression of H2S gas generation while avoiding the reduction of Fe. 2+ It is oxidized again to Fe by a high concentration of O2. 3+ The pressurized reduction process within a closed container significantly improves reduction efficiency while enhancing the production environment. It achieves the cascade separation and enrichment of multiple metals, closed-loop circulation of the medium, and the reduction, resource recovery, and harmless treatment of slag.

Description

Technical Field

[0001] This invention belongs to the field of hydrometallurgical technology, specifically relating to a method for efficiently reducing ferric ions in zinc leaching solution. Background Technology

[0002] In the hydrometallurgical process of zinc, the acidic leachate produced after neutral leaching, low-acid leaching, and hot acid / high-acid leaching of zinc calcined sand, as well as the leachate used to treat zinc leaching residue, often contains high concentrations of ferric ions (Fe3+). 3+ Excessive Fe 3+ This not only increases the solution potential, inhibiting further leaching of valuable metals such as zinc and indium, but also creates difficulties for subsequent purification and electrolysis processes, and affects the settling and separation of iron slag. Therefore, Fe... 3+ Efficient and economical reduction to ferrous ions (Fe) 2+ This is a key step that connects the leaching and iron removal processes, ensures smooth flow, and improves metal recovery rate.

[0003] Currently, reduction methods used in industry and research are mainly based on the use of solid or gaseous reducing agents, the choice of which directly affects cost, efficiency, and operational complexity. The paper "Research on Reduction Leaching Process of Neutral Zinc Leaching Slag" (Fan Guang et al., Nonferrous Metals Engineering, September 2019) uses atmospheric pressure reduction leaching of zinc sulfide concentrate and SO2 pressure reduction leaching of neutral zinc leaching slag. Both processes achieve good leaching results and effectively remove Fe from the solution. 3+ Reduced to Fe 2+ While promoting the dissolution of zinc ferrite, this process also faces significant challenges. The reaction kinetics of atmospheric pressure reduction leaching of zinc sulfide concentrate are greatly affected by ore particle size and temperature, resulting in a slow reaction, low reduction efficiency, and a reaction time as long as 4-5 hours. Furthermore, the reaction produces H2S gas (especially at high acidity), posing safety and environmental risks. SO2 pressure reduction leaching introduces sulfate ions, requiring a large amount of lime for neutralization to clear excess SO4. 2– In addition, the SO2 pressurized reduction leaching process requires the establishment of an SO2 gas supply and recovery system, which places high demands on equipment sealing and corrosion prevention, and the exhaust gas must be strictly treated to prevent leakage.

[0004] The Chinese invention patent, "A Method for Reducing Ferric Ions to Ferrous Ions in Acid Leaching Solutions Containing Ge, In, and Zn" (Publication No.: CN105039697A), discloses the following technical solution: The acid leaching solution containing Ge, In, and Zn is placed in a reduction tank, and ZnSO3 is first used to stir the solution at a temperature of 60-70°C for 40-60 minutes. Then, iron filings are added, and the reaction is continued with stirring for at least 30 minutes, resulting in a ferric ion content in the Ge, In, and Zn acid leaching solution below 200 mg / L. This method utilizes metal (iron filings, zinc powder) reduction for displacement reduction. Although the reaction is thorough and the process is simple and intuitive, it faces challenges such as high cost (especially for zinc powder), higher reagent costs than zinc concentrate, potential introduction of new impurity ions, and large slag production from iron filings reduction, making it difficult to promote its use in the hydrometallurgical zinc smelting industry.

[0005] The zinc sulfide concentrate reduction method and the SO2 reduction method are currently the main methods for treating Fe in zinc leaching solutions or residues. 3+ These are the two most promising processes. Both can effectively promote the decomposition of zinc ferrite, increase zinc leaching rate, and create favorable conditions for subsequent iron removal processes such as the hematite method and the potassium ferrite method. Among them, the SO2 method has a slight advantage in reduction efficiency and leaching rate, but the zinc concentrate method, due to its readily available raw materials and high integration, remains the focus of research and optimization. Technological development of the zinc sulfide concentrate reduction method focuses on overcoming its inherent defects and improving its economic efficiency and safety.

[0006] The paper "Reduction of Ferric Ion from Zinc Hydrometallurgy Acid-LeachingSolution Using Zinc Sulfide Concentrate" (Sun, P., et al. In JOM 76, 4608–4616 (2024), increasing the reaction temperature from 80℃ to 120℃ can make Fe 3+ The reduction rate increased from 93.3% to 98%, while the reaction time was significantly reduced from 180 minutes to 60 minutes. Under optimized conditions, zinc concentrate consumption was close to 1.1 to 1.2 times the theoretical amount, significantly better than the 2 to 3 times level observed in earlier studies. Using a pressurized process to further increase the reaction temperature proved to be an effective strategy for improving zinc concentrate utilization and reduction rate while reducing residue. However, one of the core challenges of this process is the risk of generating the byproduct hydrogen sulfide (H2S). In an acidic environment, ZnS, besides being directly converted by Fe... 3+Besides oxidation, it may also react with acid to generate H2S, posing safety and environmental hazards due to highly toxic and corrosive gases, and potentially causing ineffective consumption of reducing agents. These challenges have not been addressed in existing patents and published papers. Therefore, this application must prioritize the inhibition of H2S formation and its safe disposal. By controlling the oxygen potential of the system, the reduction reaction can be controlled, both inhibiting H2S gas formation and avoiding Fe... 2+ Re-oxidation makes the risks manageable, improves the production environment, and significantly increases reduction efficiency. Summary of the Invention

[0007] The purpose of this invention is to provide a method for efficiently reducing ferric ions in zinc leaching solution.

[0008] The objective of this invention is achieved as follows: the method for efficiently reducing ferric ions in zinc leaching solution includes the following steps: The zinc leaching solution and zinc sulfide concentrate are placed in a closed reactor and subjected to a pressure-enhanced reduction reaction at a temperature of 100~120℃ and a pressure of 0.2~0.3 MPa to reduce the ferric ions in the leaching solution. At the same time, compressed air is introduced into the reaction system to prevent the generation of hydrogen sulfide gas. The reaction time is 0.5~2.0h. The reduced reaction system was settled and filtered to obtain the reduced liquid and reduced sulfur residue.

[0009] Compared with the prior art, the technical solution described in this invention has the following advantages: 1. The iron in the hot acid / high acid leaching solution of zinc roasted sand is mainly in the form of ferric ions (Fe3+). 3+ In zinc sulfide concentrate, zinc, iron, lead, and copper exist primarily as sulfides. During pressure-enhanced reduction, ferric ions in the hot acid / high-acid leaching solution of zinc roasted sand are reduced to ferrous ions (Fe3+). 2+ When ferrous ions are reduced by zinc sulfide concentrate, sulfuric acid is not generated. At the same time, zinc, iron, copper and germanium in zinc sulfide concentrate are leached by sulfuric acid, which can consume excess sulfuric acid in the system.

[0010] 2. Reduction of Fe in zinc leaching solution with zinc sulfide concentrate (ZnS) under normal pressure. 3+ When H2SO4 is present, ZnS inevitably reacts with it to produce H2S gas. H2S is an acutely toxic gas that seriously endangers life and health. Furthermore, H2S is also a corrosive gas; it dissolves in water to form a weak acid, causing various forms of corrosion to equipment and pipelines. Additionally, under normal pressure, the reduction of Fe in the zinc leaching solution by zinc sulfide concentrate... 3+ At that time, due to the low reaction temperature (<95℃), the reaction was slow and the reduction efficiency was low.

[0011] 3. The technical solution described above is based on thermodynamic and kinetic analysis, and innovatively proposes the use of compressed air to pressurize and enhance the reduction of Fe in zinc leaching solution. 3+ During pressurized reduction, compressed air with an O2 concentration of 20-22% is introduced into a sealed container. H2S gas reacts with O2 to produce elemental sulfur (S). 0 This achieves the goal of suppressing H2S gas generation while avoiding the reduction of Fe. 2+ It is oxidized again to Fe by a high concentration of O2. 3+ Pressure-enhanced reduction within a sealed container improves the production environment while significantly increasing reduction efficiency.

[0012] 4. The technical solution described above uses pressurized enhanced reduction in a sealed container, which can make the reaction temperature greater than 100°C. Increasing the reaction temperature can accelerate the reaction rate and even shorten the reduction time to 0.5~1.0 h. Furthermore, by controlling the opening of the exhaust valve of the sealed container, the heat carried away by the exhaust gas can be reduced. Therefore, the power and steam consumption is lower than that of atmospheric pressure reduction.

[0013] 5. After the reduced liquid undergoes displacement precipitation of copper, pre-neutralization, neutralization precipitation of indium, germanium, and hematite, it can be returned to the neutral leaching and / or low-acid leaching section of the zinc roasted sand. The reduced sulfur slag can be subjected to high-acid / ultra-high-acid leaching to further leach zinc, copper, indium, germanium, etc., while further enriching lead, silver, sulfur, etc. Therefore, the above technical solution is not a simple iron removal, but uses iron as a medium to achieve the stepwise separation and enrichment of multiple metals, closed-loop circulation of the medium, and reduction, resource utilization, and harmless treatment of slag.

[0014] In summary, the technical solution described in this invention has the presence of trivalent iron ions (Fe). 3+ It features high reduction efficiency and produces no H2S gas, thus avoiding pollution of the operating environment. It is a clean and efficient technical solution with great value for promotion and application. Detailed Implementation

[0015] The present invention will be further described below, but this is not intended to limit the invention in any way. Any modifications or substitutions made based on the teachings of the present invention shall fall within the scope of protection of the present invention.

[0016] The method for efficiently reducing ferric ions in zinc leaching solution includes the following steps: The zinc leaching solution and zinc sulfide concentrate are placed in a closed reactor and subjected to a pressure-enhanced reduction reaction at a temperature of 100~120℃ and a pressure of 0.2~0.3 MPa to reduce the ferric ions in the leaching solution. At the same time, compressed air is introduced into the reaction system to prevent the generation of hydrogen sulfide gas. The reaction time is 0.5~2.0h. The reduced reaction system was settled and filtered to obtain the reduced liquid and reduced sulfur residue.

[0017] In the zinc leaching solution and zinc sulfide concentrate reaction system, based on the Fe content of the zinc leaching solution... 3+ The excess coefficient of zinc sulfide concentrate is 1.2~1.8.

[0018] The zinc leaching solution is obtained by neutral leaching, low acid leaching, and hot acid / high acid leaching of zinc calcined sand.

[0019] The zinc leaching solution is preferably the leaching solution obtained by hot acid / high acid leaching of zinc calcined sand.

[0020] The zinc sulfide concentrate is any one or both of high-lead, high-silicon zinc concentrate or high-silicon zinc concentrate.

[0021] The zinc sulfide concentrate is preferably composed of high-lead, high-silicon zinc concentrate and high-silicon zinc concentrate in a mass ratio of 1:1.

[0022] The oxygen concentration of the compressed air is 20-22%, preferably 21%.

[0023] The preferred reaction time is 1.0 h.

[0024] The pressurized reduction process can be either intermittent or continuous. That is, it can involve intermittent feeding, intermittent leaching followed by discharging, or continuous feeding, continuous leaching, and continuous discharging. The feeding unit and the operating method do not affect the Fe content in the reduced solution. 3+ Concentration control does not affect the slag ratio of reduced sulfur slag, nor the leaching rates of zinc, copper, iron, sulfur, and germanium.

[0025] During the pressurized reduction process, the H2S content in the exhaust gas emitted by the pressurized reduction was simultaneously detected using lead acetate test paper and an H2S gas detector.

[0026] Fe in the reduced solution 3+ The concentration is ≤1.5g / L, or even ≤1.0g / L.

[0027] The slag ratio of the reduced sulfur slag is ≤60%.

[0028] After the solution reduced by ferric ions is replaced with copper and neutralized to precipitate indium and germanium, hematite is precipitated as iron.

[0029] The resulting reduced sulfur slag is then subjected to high-acid / ultra-high-acid leaching to further leach zinc, copper, indium, germanium, etc., while simultaneously enriching lead, silver, sulfur, etc.

[0030] Example 1

[0031] Reaction materials: The zinc leaching solution is the leaching solution obtained by hot acid / high acid leaching of zinc calcined sand.

[0032] Zinc leaching solution: Zn 2+ 93.72 g / L, Fe 3+ 28.58 g / L, H2SO4 51.94 g / L, Cu 2+ 890.1 mg / L, As 30.12 mg / L, Ge 25.87 mg / L, In 9.34 mg / L, Mg 2+ 23.98 g / L, Mn 2+ 17.28 g / L.

[0033] Zinc sulfide concentrate is a high-silver, high-silicon zinc concentrate.

[0034] High-silver, high-silicon zinc concentrate: Zn 50.69wt%, Fe 4.26wt%, Cu 0.092wt%, As 0.11wt%, Ge 130g / t, In 10 g / t, Mg 0.25wt%, SiO2 6.90wt%, S 26.32wt%, Pb 1.57wt%, Cd 0.46wt%, Ag 306g / t.

[0035] Restoration method: A hot acid / high acid leaching solution of zinc roasted sand and a high-silver, high-silicon zinc concentrate were added to a closed reactor at an excess ratio of 1.4. Simultaneously, compressed air with an oxygen concentration of 21% was introduced into the reaction system. A pressure-enhanced reduction reaction was carried out for 1.0 h at 110℃ and 0.3 MPa to reduce the ferric ions in the leaching solution. Testing showed that the hydrogen sulfide content in the exhaust gas during the pressure-enhanced reduction process was 0%. The reduced reaction system was then settled and filtered to obtain the reduced liquid and reduced sulfur slag.

[0036] Among them, Fe in the reduced solution 3+ The concentration is 0.5 g / L, Fe 3+ The reduction rate was 98.3%, Fe 3+ The concentration meets the requirements for copper plating by displacement. After copper plating, pre-neutralization and neutralization are carried out to precipitate indium and germanium. The slag rate of the reduced sulfur slag is 59.41%, containing 34.63wt% Zn, 0.030wt% Cu, 3.37wt% Fe, 45.54wt% S, and 152.4g / t Ge. The zinc leaching rate is 59.41%, the copper leaching rate is 80.63%, the iron leaching rate is 53.00%, the sulfur leaching rate is 2.80%, and the germanium leaching rate is 30.35%.

[0037] Example 2

[0038] Reactant materials: Same as in Example 1. The excess coefficient of high-silver, high-silicon zinc concentrate is the same as in Example 1.

[0039] Reduction method: During pressurized intensified reduction, all conditions were the same as in Example 1, except for the reaction temperature, which was 120°C. Testing showed that the hydrogen sulfide content in the exhaust gas during the pressurized intensified reduction process was 0. The reduced slurry was settled and filtered to obtain the reduced liquid and reduced sulfur slag.

[0040] Among them, Fe in the reduced solution 3+ The concentration is 0.7 g / L, Fe 3+ The reduction rate was 97.7%, Fe 3+ The concentration meets the requirements for copper plating by displacement. After copper plating, pre-neutralization and neutralization are carried out to precipitate indium and germanium. The slag rate of the reduced sulfur slag is 56.98%, containing 32.05wt% Zn, 0.035wt% Cu, 3.31wt% Fe, 46.19wt% S, 158.9g / t Ge, with a zinc leaching rate of 63.97%, a copper leaching rate of 78.32%, an iron leaching rate of 55.73%, a sulfur leaching rate of 0.01%, and a germanium leaching rate of 30.36%.

[0041] Example 3

[0042] Reactant materials: Same as in Example 1. The excess coefficient of high-silver, high-silicon zinc concentrate is the same as in Example 1.

[0043] Reduction method: During pressurized enhanced reduction, all conditions were the same as in Example 1, except for the reaction time, which was 2.0 h. Testing showed that the hydrogen sulfide content in the exhaust gas was 0 during the pressurized enhanced reduction process. The reduced slurry was settled and filtered to obtain the reduced liquid and reduced sulfur slag.

[0044] Among them, Fe in the reduced solution 3+ The concentration is 1.5 g / L, Fe 3+ The reduction rate was 95.0%, Fe 3+ The concentration is high, but still meets the requirements for copper replacement leaching; the slag rate of the reduced sulfur slag is 57.55%, containing 34.03wt% Zn, 0.038wt% Cu, 3.49wt% Fe, 45.77wt% S, 146.5g / t Ge, with zinc leaching rate of 61.37%, copper leaching rate of 76.23%, iron leaching rate of 52.86%, sulfur leaching rate of 0.07%, and germanium leaching rate of 35.15%.

[0045] As can be seen from the above three examples, controlling the reaction time to 1.0 h is a better choice when performing pressure-enhanced reduction. Pressure-enhanced reduction was performed at 120°C, and the Fe content of the reduced solution... 3+ The concentration still meets the requirements for copper displacement plating.

[0046] Example 4

[0047] Reaction raw materials: Zinc leaching solution as in Example 1.

[0048] Zinc sulfide concentrate is a high-lead, high-silicon zinc concentrate.

[0049] High-lead, high-silicon zinc concentrate: Zn 44.00wt%, Fe 3.96wt%, Cu 0.42wt%, As 0.034wt%, Ge 65 g / t, In 9 g / t, Mg 0.093wt%, SiO2 7.19wt%, S 28.88wt%, Pb 5.56wt%, Cd 0.09wt%, Ag 174g / t.

[0050] Restoration method: A hot acid / high acid leaching solution of zinc roasted sand and a high-lead, high-silicon zinc concentrate were added to a closed reactor at an excess ratio of 1.2. Simultaneously, compressed air with an oxygen concentration of 21% was introduced into the reaction system. A pressure-enhanced reduction reaction was carried out for 1.0 h at 110℃ and 0.3 MPa to reduce the ferric ions in the leaching solution. Testing showed that the hydrogen sulfide content in the exhaust gas during the pressure-enhanced reduction process was 0%. The reduced reaction system was then settled and filtered to obtain the reduced liquid and reduced sulfur slag.

[0051] Among them, Fe in the reduced solution 3+ The concentration is 0.4 g / L, Fe 3+ The reduction rate was 98.6%, Fe 3+ The concentration meets the requirements for copper plating by displacement. After copper plating, pre-neutralization and neutralization are performed to precipitate indium and germanium. The slag rate of the reduced sulfur slag is 57.02%, containing 10.63wt% Zn, 0.33wt% Cu, 6.20wt% Fe, 44.63wt% S, 113.9 g / t Ge, with a zinc leaching rate of 86.23%, a copper leaching rate of 55.20%, an iron leaching rate of 10.73%, a sulfur leaching rate of 11.89%, and a germanium leaching rate of 0.09%.

[0052] Example 5

[0053] Reaction raw materials: Zinc leaching solution as in Example 1.

[0054] The zinc sulfide concentrate is composed of high-lead, high-silicon zinc concentrate and high-silicon zinc concentrate in a mass ratio of 1:1.

[0055] High-silver, high-silicon zinc concentrate: Same as Example 1.

[0056] High-lead, high-silicon zinc concentrate: Same as Example 4.

[0057] Restoration method: A hot acid / high acid leaching solution of zinc roasted sand and a mixture of high-lead, high-silicon zinc concentrate and high-silicon zinc concentrate at a mass ratio of 1:1 were added to a closed reactor with an excess coefficient of 1.5. Simultaneously, compressed air with an oxygen concentration of 21% was introduced into the reaction system, and a pressure-enhanced reduction reaction was carried out at 110℃ and 0.3MPa for 1.0 h to reduce the ferric ions in the leaching solution. Testing showed that the hydrogen sulfide content in the exhaust gas during the pressure-enhanced reduction process was 0%. The reduced reaction system was then settled and filtered to obtain the reduced liquid and reduced sulfur slag.

[0058] Among them, Fe in the reduced solution 3+ The concentration is 1.0 g / L, Fe 3+ The reduction rate was 96.6%, Fe 3+ The concentration meets the requirements for copper plating by displacement. After copper plating, pre-neutralization and neutralization are carried out to precipitate indium and germanium. The slag rate of the reduced sulfur slag is 60.00%, containing 24.47wt% Zn, 0.090wt% Cu, 5.29wt% Fe, 45.99wt% S, 139.4 g / t Ge, with a zinc leaching rate of 68.99%, a copper leaching rate of 78.91%, an iron leaching rate of 22.77%, a sulfur leaching rate of 0.02%, and a germanium leaching rate of 14.21%.

[0059] Example 6

[0060] Reaction materials: Same as in Example 5.

[0061] Reduction method: During pressurized enhanced reduction, the conditions were the same as in Example 5, except for the excess coefficient, which was 1.7. Testing showed that the hydrogen sulfide content in the exhaust gas was 0 during the pressurized enhanced reduction process. The reduced slurry was settled and filtered to obtain the reduced liquid and reduced sulfur slag.

[0062] Among them, Fe in the reduced solution 3+ The concentration is 0.7 g / L, Fe 3+ The reduction rate was 97.6%, Fe 3+ The concentration meets the requirements for copper plating by displacement. After copper plating, pre-neutralization and neutralization are performed to precipitate indium and germanium. The slag ratio of the reduced sulfur slag is 63.28%, containing 27.56wt% Zn, 0.085wt% Cu, 5.00wt% Fe, 44.16wt% S, and 133.0 g / t Ge. The zinc leaching rate is 63.16%, the copper leaching rate is 78.99%, the iron leaching rate is 23.01%, the sulfur leaching rate is 1.26%, and the germanium leaching rate is 13.67%.

[0063] As can be seen from the above embodiments, the technical solution of the present invention can use high-lead, high-silicon / high-silicon, high-zinc concentrate alone or in combination, so that the Fe in the reduced solution is reduced. 3+The concentration is below 1.5 g / L, or even below 1.0 g / L, making Fe... 3+ The reduction rate is greater than 95%, Fe 3+ The concentration meets the requirements for copper precipitation. After copper precipitation, pre-neutralization, neutralization to precipitate indium and germanium, and hematite to precipitate iron are carried out. In addition, zinc, copper, iron, and germanium in the zinc concentrate are partially leached, while lead, silver, and sulfur are enriched in the reducing sulfur slag. The reducing sulfur slag then undergoes high-acid / ultra-high-acid leaching to further leach zinc, copper, indium, and germanium, while further enriching lead, silver, and sulfur. This process achieves the cascade separation and enrichment of multiple metals, closed-loop circulation of the medium, and the reduction, resource utilization, and harmless treatment of the slag.

Claims

1. A method for efficiently reducing ferric ions in zinc leaching solution, characterized in that, The process includes the following steps: The zinc leaching solution and zinc sulfide concentrate are placed in a closed reactor and subjected to a pressure-enhanced reduction reaction at a temperature of 100~120℃ and a pressure of 0.2~0.3MPa to reduce the ferric ions in the leaching solution. At the same time, compressed air is introduced into the reaction system to prevent the generation of hydrogen sulfide gas. The reaction time is 0.5~2.0h. The reduced reaction system was settled and filtered to obtain the reduced liquid and reduced sulfur residue.

2. The method for efficiently reducing ferric ions in zinc leaching solution according to claim 1, characterized in that, In the zinc leaching solution and zinc sulfide concentrate reaction system, based on the Fe content of the zinc leaching solution... 3+ The excess coefficient of zinc sulfide concentrate is 1.2~1.

8.

3. The method for efficiently reducing ferric ions in zinc leaching solution according to any one of claims 1 to 2, characterized in that, The zinc leaching solution is obtained by neutral leaching, low acid leaching, and hot acid / high acid leaching of zinc calcined sand.

4. The method for efficiently reducing ferric ions in zinc leaching solution according to claim 3, characterized in that, The zinc leaching solution is obtained by hot acid / high acid leaching of zinc calcined sand.

5. The method for efficiently reducing ferric ions in zinc leaching solution according to claim 1, characterized in that, The zinc sulfide concentrate is any one or both of high-lead, high-silicon zinc concentrate or high-silicon zinc concentrate.

6. The method for efficiently reducing ferric ions in zinc leaching solution according to claim 5, characterized in that, The zinc sulfide concentrate is composed of high-lead, high-silicon zinc concentrate and high-silicon zinc concentrate in a mass ratio of 1:

1.

7. The method for efficiently reducing ferric ions in zinc leaching solution according to claim 1, characterized in that, The oxygen concentration of the compressed air is 20-22%.

8. The method for efficiently reducing ferric ions in zinc leaching solution according to claim 1, characterized in that, The reaction time is 1.0 h.

9. The method for efficiently reducing ferric ions in zinc leaching solution according to claim 1, characterized in that, Fe in the reduced solution 3+ The concentration is ≤1.5g / L.

10. The method for efficiently reducing ferric ions in zinc leaching solution according to claim 1, characterized in that, The slag ratio of the reduced sulfur slag is ≤60%.