Zinc hydrometallurgy electrolyte cost control method

Abstract

The invention relates to the technical field of non-ferrous metallurgy, and aims to provide a zinc hydrometallurgy electrolyte cost control method which comprises the following steps: purifying and removing impurities from a middle supernatant; cooling, thickening and settling the electrolytic waste liquid; automatically stripping cathode zinc and cleaning an anode plate; and casting cathode zinc. By optimizing the purification, electrolysis and casting processes, the problems of high energy consumption and low efficiency of the traditional process are systematically solved, the zinc electrodeposition efficiency is improved by 2%-3%, the direct current unit consumption is reduced by 50 kWh / t.Zn, and the cost is saved by 50-60 yuan / t.Zn. And meanwhile, the method has economical efficiency and environmental friendliness, and an innovative solution is provided for the zinc hydrometallurgy industry.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of non-ferrous metallurgy, and particularly relates to a zinc hydrometallurgy electrolyte cost control method. BACKGROUND

[0002] As the mainstream process of global zinc smelting (capacity share over 80%), the core process of zinc electrowinning accounts for more than 39% of the whole process. However, under the market price fluctuation, rising energy costs and environmental pressure, the industry's profit margin continues to shrink. Traditional processes generally use the "purified new liquid cooling sedimentation" or "new liquid-waste liquid mixing" mode, and some enterprises add a waste liquid cooling calcium and magnesium removal process, but there are still three technical bottlenecks: first, the impurities such as manganese, magnesium and calcium in the electrolytic waste liquid are enriched (Mg 2+ concentration often exceeds 15g / L, Mn 2+ accelerating the deposition of anode mud by more than 30%), resulting in anode passivation, cell voltage rising to 3.4-3.6V, and current efficiency falling below 88%; second, the electrolytic liquid temperature control precision is low (fluctuation ±3℃ or more), resulting in increased electrolyte resistance, direct current consumption per ton of zinc exceeding 3100kWh, which is 20% higher than the advanced level; third, zinc stripping and anode cleaning rely on manual operation, with a processing capacity of less than 5 tons per shift, and there are safety risks and high labor costs. The above problems lead to the dilemma of shrinking profit margin for the zinc hydrometallurgy industry. Although some enterprises have tried to improve (such as waste liquid cooling calcium and magnesium removal), they have not systematically solved the core contradictions of high energy consumption, low efficiency and difficult cost control. SUMMARY

[0003] The purpose of the present application is to provide a zinc hydrometallurgy electrolyte cost control method to solve the problems raised in the background art.

[0004] In order to achieve the above-mentioned purpose, the technical solution adopted by the present application is: A zinc hydrometallurgy electrolyte cost control method, comprising the following steps: S1: removing impurities from the supernatant; S2: cooling and thickening sedimentation of electrolytic waste liquid; S3: automatic stripping of cathode zinc and cleaning of anode plate; S4: cathode zinc smelting.

[0005] In the step S1, a three-stage or four-stage purification process is used to achieve deep removal of impurities through zinc powder replacement, cobalt removal agent and activated carbon adsorption.

[0006] In the step S2, the mixing ratio of electrolytic waste liquid to new liquid is 3.2:1-3.8:1, and the sedimentation temperature is controlled at 38-39℃.

[0007] In the step S3, both the stripping of cathode zinc and the cleaning of anode mud use automatic equipment to reduce the dependence on manual operation.

[0008] The melting and casting process in the step S4 uses the waste heat steam of the calcination furnace for heat supply.

[0009] Therefore, by means of the technical solutions described above, the present application has the following beneficial effects: By optimizing the process flow, the present application can significantly improve the zinc electrowinning efficiency, realize comprehensive utilization and efficient recovery of anode manganese, and provide a more economically efficient and environmentally friendly solution for the zinc hydrometallurgy industry. At the same time, the present application is simple and reliable to operate, is very suitable for industrial production, has significant economic potential, and has a close process flow connection, so that it can realize rapid industrialization application without the need for large-scale equipment updating. The present application can effectively solve the problems of high energy consumption, low efficiency, and difficult cost control in the traditional zinc hydrometallurgy industry, and has broad industry popularization value. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1 The process flow chart of the present application is shown. DETAILED DESCRIPTION

[0011] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0012] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative labor are within the scope of protection of the present application.

[0013] In order to better understand the present application, the following description is made, and the present application aims to achieve the following objectives through process optimization: 1. Reduce the direct current power consumption and anode crystallization amount; 2. Improve the zinc electrowinning efficiency and electrolyte stability; 3. Reduce the dependence on manual work and improve production safety; 4. Reduce the processing cost per ton of zinc, and enhance the competitiveness of enterprises.

[0014] As shown in the drawings, Figure 1 The innovative zinc hydrometallurgy electrolysis process cost control method of the present application is mainly realized through the following steps: S1. Purification of supernatant: adopt three or four purification processes, through zinc powder replacement, cobalt removal agent (thiophos) and activated carbon adsorption, deep removal of copper, cadmium, cobalt and other impurities; the first and second stage purification slag is ground by ball mill or slurry tank to recover valuable metals, the third and fourth stage purification slag is enriched with cobalt resources, realizing resource recycling; control the purification reaction temperature (65-85℃), pH value (4.8-5.2) and stirring speed (80-85r / min) to ensure that the impurity content of the purified liquid is controlled to Cu<0.3mg / L, Co<0.5mg / L, Cd<0.5mg / L, Ge<0.04mg / L and other indicators. Among them, the electrolytic circulating waste liquid cooling and sedimentation equipment is implemented for the original process purification new liquid cooling and sedimentation equipment, without the need to increase new equipment, and the first and second stage zinc powder replacement is zinc powder (60-80 mesh) blown by electric furnace, or alloy zinc powder is purchased or prepared by enterprise zinc powder workshop.

[0015] S2. Cooling and thickening sedimentation of electrolytic waste liquid: use the original purification new liquid cooling tower and thickener to cool and thicken the electrolytic circulating waste liquid, mix the supernatant with the new liquid at a ratio of 3.2:1-3.8:1, and then reuse, control the waste liquid temperature (38-39℃), acid content (175-190g / L) and zinc content (39-48g / L), and ensure the sedimentation efficiency; the underflow is discharged to the leaching and oxidation tank to replace manganese powder and realize comprehensive utilization of manganese resources.

[0016] S3. Cathode zinc stripping and anode plate cleaning: based on the automatic stripping of cathode zinc according to the precipitation period, the anode mud is cleaned synchronously, and the stripped zinc is directly sent to the melting process; the anode mud is sent to the leaching and oxidation tank for recycling, reducing manual intervention and safety risk, wherein the cathode zinc is stripped according to the size of the cathode plate and the precipitation period.

[0017] S4. Melting of cathode zinc: high-efficiency melting furnace is used for melting of cathode zinc, and the cathode zinc ingot is sold as standard zinc ingot; the melting process uses the waste heat steam of the calcination furnace for heating, further reducing energy consumption.

[0018] The above waste liquid is the product of electrolysis of zinc hydrometallurgy, without the need to purchase; the heating source of the above purification and melting process can be provided by the waste heat steam of the calcination furnace of the zinc hydrometallurgy enterprise, without the need to purchase. Embodiment

[0019] 1. Middle supernatant purification impurity removal: middle supernatant, Zn 152.26 g / L, Cd 504.66 mg / L, Cu 890.82 mg / L, Ge 0.12 mg / L, Ni 24.86 mg / L, pH 5.0. A three-stage purification process is adopted, the stirring speed is 83 r / min, zinc powder (alloy, blowing) is used in the first and second stages to remove copper and cadmium at low temperature (65-75°C), and a cobalt removal agent (sodium formate) is used in the third stage to remove copper, cadmium, cobalt and other impurities at high temperature (80-85°C); the impurity content of the purified new solution is Cu 0.032 mg / L, Co 0.23 mg / L, Cd 0.16 mg / L, Ge 0.014 mg / L, and Ni 0.05 mg / L. The first and second stage purification residues are ground by a ball mill or a slurry tank and then sent to a comprehensive recovery process to recover valuable metals such as copper, cadmium and zinc, and the third stage purification residue is sent to a comprehensive recovery process to enrich cobalt (Co 8.5%), producing high-cobalt residue and realizing resource recycling; 2. Cooling and thickening settlement of electrolytic waste solution: the original purified new solution cooling tower and thickener are used to cool and thicken the electrolytic circulating waste solution (acid content 189.34 g / L, Zn 45 g / L, Mn 9.4 g / L, Mg 15.8 g / L), and the temperature of the settled supernatant waste solution is controlled at 39.5°C. After mixing the acid and zinc in a ratio of 3.5:1, it is sent to the electrolytic distribution tank for zinc electrodeposition; the underflow is discharged to the leaching and oxidation tank to replace manganese powder and realize comprehensive utilization of manganese resources.

[0020] 3. Cathode zinc stripping and anode plate cleaning: a 1.6 m² aluminum cathode plate is used, and after 24 h of electrodeposition period, the zinc sheet (thickness 6-8 mm) is mechanically stripped, and the zinc stripping rate is ≥99.5%; anode mud cleaning: periodically use high-pressure water gun or vacuum trenching to remove Pb-Ag anode mud (containing Zn 9.8%, Mn 16.6%), return to the leaching process to recover metals; 4. Cathode zinc casting: the temperature of the induction furnace is controlled at 680-720°C, a certain amount of ammonium chloride is added to remove impurities, and 99.995% grade zinc ingots are cast and sold.

[0021] The results show that by using the above method, the direct current consumption is reduced to 3025 kWh / t.Zn (reduction of 1.8%), the anode crystallization amount is reduced by 30%, the current efficiency is increased to 92.3% (+2.1%), the electrolyte stability is enhanced, and the production cost is saved by 50-55 yuan / t.Zn. Example

[0022] 1. Middle supernatant purification impurity removal: middle supernatant, Zn 156.93 g / L, Cd 627.00 mg / L, Cu 647.00 mg / L, Ge 0.06 mg / L, Ni 13.10 mg / L, pH 5.0. A three-stage purification process is adopted, the stirring speed is 83 r / min, zinc powder (alloy, blowing) is used in the first and second stages to remove copper and cadmium at low temperature (65-75°C), and a cobalt removal agent (sodium formate) is used in the third stage to remove copper, cadmium, cobalt and other impurities at high temperature (80-85°C); the impurity content of the purified new solution is Cu 0.038 mg / L, Co 0.10 mg / L, Cd 0.12 mg / L, Ge 0.012 mg / L, and Ni 0.04 mg / L. The first and second stage purification slag is ground by a ball mill or a slurry tank and then sent to the comprehensive recovery process to recover valuable metals such as copper, cadmium and zinc, and the third stage purification slag is sent to the comprehensive recovery process to enrich cobalt (Co 8.8%), producing high-cobalt slag and realizing resource recycling; 2. Cooling and thickening settlement of electrolytic waste solution: the original purified new solution cooling tower and thickener are used to cool and thicken the electrolytic circulating waste solution (acid content 185 g / L, Zn 46 g / L, Mn 8.6 g / L, Mg 15.3 g / L), and the temperature of the supernatant waste solution is controlled at 39.5°C. After mixing the acid and zinc in a ratio of 3.6:1, it is sent to the electrolytic distribution tank for zinc electrodeposition; the underflow is discharged to the leaching oxidation tank to replace manganese powder and realize comprehensive utilization of manganese resources.

[0023] 3. Cathode zinc stripping and anode plate cleaning: 1.6 m² aluminum cathode plate is used, and after 24 h of electrodeposition period, the zinc sheet (thickness 6-8 mm) is mechanically stripped, and the zinc stripping rate is ≥99.5%; anode mud cleaning: periodically use high-pressure water gun or vacuum trenching to remove Pb-Ag anode mud (containing Zn 9.8%, Mn 16.2%), and return to the leaching process for metal recovery; 4. Cathode zinc casting: the induction furnace temperature is controlled at 680-720°C, ammonium chloride is added for impurity removal, and 99.995% grade zinc ingots are cast and sold.

[0024] The results show that by using the above method, the direct current consumption is reduced to 3023 kWh / t.Zn (reduction of 1.82%), the anode crystallization amount is reduced by 28.5%, the current efficiency is increased to 92.1% (+1.9%), the electrolyte stability is enhanced, and the production cost is saved by 53 yuan / t.Zn. Example

[0025] 1. Middle supernatant purification impurity removal: middle supernatant, Zn 156.39 g / L, Cd 595.00 mg / L, Cu 587.00 mg / L, Ge 0.05 mg / L, Ni 11.6 mg / L, pH 5.0. A three-stage purification process is adopted, the stirring speed is 83 r / min, zinc powder (alloy, blowing) is used in the first and second stages to remove copper and cadmium at low temperature (65-75 DEG C), and a cobalt removal agent (sodium formate) is used in the third stage to remove copper, cadmium, cobalt and other impurities at high temperature (80-85 DEG C); the impurity content of the purified new solution is Cu 0.026 mg / L, Co 0.20 mg / L, Cd 0.11 mg / L, Ge 0.010 mg / L, and Ni 0.05 mg / L. The first and second stage purification residues are ground by a ball mill or a slurry tank and then sent to a comprehensive recovery process to recover valuable metals such as copper, cadmium and zinc, and the third stage purification residue is sent to a comprehensive recovery process to enrich cobalt (Co 8.9%), producing high-cobalt residue and realizing resource recycling; 2. Electrolytic waste liquid cooling thickening and sedimentation: the original purified new solution cooling tower and thickener are used to cool, thicken and settle the electrolytic circulating waste liquid (containing 188 g / L of acid, 47 g / L of Zn, 9.2 g / L of Mn and 15.5 g / L of Mg), the supernatant waste liquid is controlled at a temperature of 39.5 DEG C, the acid and zinc are mixed at a ratio of 3.7:1, and then sent to an electrolysis distribution tank for zinc electrodeposition; the underflow is discharged to an leaching and oxidation tank to replace manganese powder to realize comprehensive utilization of manganese resources.

[0026] 3. Cathode zinc stripping and anode plate cleaning: a 1.6 m² aluminum cathode plate is used, the zinc sheet (thickness 6-8 mm) is mechanically stripped after 24 h electrodeposition cycle, and the zinc stripping rate is ≥99.5%; anode mud cleaning: periodically use high-pressure water gun or vacuum slotting to remove Pb-Ag anode mud (containing 9.5% of Zn and 16% of Mn), and return to the leaching process to recover metals; 4. Cathode zinc casting: the induction furnace temperature is controlled at 680-720 DEG C, ammonium chloride is added for impurity removal, and 99.995% grade zinc ingots are cast and sold.

[0027] The results show that by using the above method, the direct current power consumption is reduced to 3005 kWh / t.Zn (decrease of 1.86%), the anode crystallization amount is reduced by 29.2%, the current efficiency is increased to 92.0% (+1.8%), the electrolyte stability is enhanced, and the production cost is saved by 55 yuan / t.Zn.

[0028] The above experiments show that the technical advantages of the present application are: 1. Energy saving: the direct current power consumption is reduced by 50 kWh / t·Zn, the anode crystallization amount is reduced by 39%, and the cost is saved by 50-60 yuan / t·Zn; 2. Efficiency improvement: the zinc electrodeposition efficiency is improved by 2-3 percentage points, the electrolyte stability is enhanced (temperature fluctuation ±1 DEG C), and the safety risk level is reduced; 3. Resource recycling: high-efficiency recovery of valuable metals such as zinc, cobalt, and manganese in waste liquid, anode mud, and purification residue; 4. Low-cost transformation: modular design compatible with original equipment, investment intensity reduced by 30%, and no need for large-scale update for rapid industrialization.

Claims

1. A method for controlling the cost of a hydrometallurgical zinc electrolyte, characterized in that: The steps include: S1: purification and removal of impurities from the supernatant; S2: cooling and thickening of electrolytic wastewater; S3: Automatic cathode zinc stripping and anode plate cleaning; S4: Cathode zinc casting.

2. The method for controlling the cost of zinc hydrometallurgy electrolyte according to claim 1, wherein: In step S1, a three-stage or four-stage purification process is adopted to achieve deep removal of impurities through zinc powder replacement, cobalt removal agent and activated carbon adsorption.

3. The method for controlling the cost of zinc hydrometallurgy electrolyte according to claim 1, wherein: In step S2, the mixing ratio of electrolytic waste liquid and new liquid is 3.2:1-3.8:1, and the sedimentation temperature is controlled at 38-39°C.

4. The method for controlling the cost of zinc hydrometallurgy electrolyte according to claim 1, wherein: In step S3, cathode zinc stripping and anode mud cleaning are both performed using automated equipment to reduce manual labor dependence.

5. The method for controlling the cost of zinc hydrometallurgy electrolyte according to claim 1, wherein: In step S4, the melting and casting process utilizes waste heat steam from the roasting furnace for heating.

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