Production method of electrolytic zinc

Abstract

The invention relates to the technical field of non-ferrous metal metallurgy and solid waste resource utilization, and discloses a production method of electrolytic zinc, which comprises the following steps: carrying out acid leaching on a copper-zinc-containing solid waste raw material, and directionally regulating and controlling the iron-silicon ratio and the sulfur content of leached residues to enable the leached residues to adapt to pyrogenic process smelting; the leaching residues are subjected to high-temperature reduction smelting to recover tin and lead, and high-activity pyrogenic process zinc-rich soot is prepared; the soot is used as a neutralizer to perform synergistic purification on the leachate, and iron, arsenic and antimony are deeply removed; and after the purified liquid is subjected to copper extraction to recover copper, the raffinate is subjected to deep purification and electrodeposition to produce electrolytic zinc. And when chlorine and fluorine impurities are accumulated in the system, partial raffinate is divided to prepare feed-grade zinc oxide so as to realize impurity discharge. According to the method, efficient coupling of a wet process and a pyrogenic process and multi-metal recovery of copper, zinc, tin and lead are achieved through slag property regulation and ash circulation, the problem of impurity accumulation is solved through a double-product-line mechanism, and the method has the advantages of being high in resource utilization rate, low in energy consumption and stable in system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of non-ferrous metallurgy and solid waste resource utilization, in particular to a production method of electrolytic zinc. BACKGROUND

[0002] With the increasing depletion of primary zinc sulfide ore resources, the use of secondary resources containing copper and zinc (such as copper smelting dust, electroplating sludge and other solid wastes) for the recovery of valuable metals such as zinc and copper has become an important trend in the industry. These complex solid waste raw materials usually have large composition fluctuations and contain iron, arsenic, antimony, lead, tin and various impurities such as chlorine and fluorine, posing a serious challenge to existing metallurgical processes.

[0003] Current processing technologies mostly use single wet leaching or pyrometallurgical volatilization processes, but there is often a lack of effective technical connection between the two. In the traditional zinc hydrometallurgy process, the leaching residue is usually not property-regulated for subsequent processing, resulting in leaching residue with an unsuitable iron-silicon ratio or sulfur content. If it is directly sent to the pyrometallurgical system, it will cause high viscosity and high melting point of the smelting process residue, not only greatly increasing the energy consumption and auxiliary material consumption, but also hindering the effective reduction and separation of associated metals such as lead and tin in the residue, resulting in resource waste.

[0004] In addition, in the purification link of the wet process system, in order to remove iron, arsenic, antimony and other impurities in the solution, a large amount of lime or industrial-grade zinc oxide is usually purchased as a neutralizing agent. However, conventional industrial zinc oxide usually has a dense crystal lattice due to high-temperature calcination, and has low chemical reaction activity, resulting in slow neutralization reaction kinetics, making it difficult to deeply remove trace amounts of arsenic and antimony impurities, and increasing production costs. At the same time, for halogen impurities such as chlorine and fluorine brought in by the raw material, the existing closed-loop process lacks an effective drainage mechanism, causing harmful elements to accumulate in the electrolyte, which can easily cause problems such as anode plate corrosion, cathode plate burning, and current efficiency reduction, severely restricting the long-term stable operation of the production system and the improvement of product quality. Therefore, it is urgent to develop a new method for producing electrolytic zinc that can efficiently couple wet and pyrometallurgical processes, achieve multi-metal co-recovery, and effectively control impurity balance. SUMMARY

[0005] In view of the deficiencies of the prior art, the present application provides a production method of electrolytic zinc, which solves the problems of low multi-metal recovery rate and high energy consumption caused by poor connection between wet and pyrometallurgical processes in existing copper and zinc-containing solid waste treatment processes, insufficient impurity removal depth of conventional neutralizing agents, and accumulation of halogen impurities in the closed-loop system, which destroys the stability of the electrolysis system.

[0006] To achieve the above purpose, the present application is implemented by the following technical scheme: a production method of electrolytic zinc, comprising the following steps: S1, raw material slurry and directional leaching: the solid waste raw material containing copper and zinc is slurried, sulfuric acid is added for acid leaching, the end point pH value of leaching is controlled, and solid-liquid separation is performed to obtain a copper and zinc containing leaching solution and a leaching residue; the leaching residue is sent to a pyrometallurgical system; S2, pyrometallurgical volatilization and ash preparation: the leaching residue obtained in step S1 is mixed with a reducing agent and then subjected to high-temperature reduction smelting, so that the zinc in the residue is volatilized into flue gas, and a pyrometallurgical zinc-rich ash is obtained by cooling and dust collection; S3, synergistic neutralization and purification: the copper and zinc containing leaching solution obtained in step S1 is heated, and the pyrometallurgical zinc-rich ash prepared in step S2 is added as a neutralizing agent to adjust the pH value of the solution to precipitate and remove iron, arsenic and antimony impurities, and a clean copper and zinc mixed solution is obtained by filtration; S4, copper extraction and recovery: the copper and zinc mixed solution obtained in step S3 is subjected to extraction separation using an organic extractant, and the loaded organic phase is subjected to stripping and electrodeposition to produce cathode copper, and the raffinate is a zinc containing solution; S5, zinc recovery: the raffinate of step S4 is subjected to deep purification and then sent to an electrodeposition system to produce electrolytic zinc.

[0007] By adopting the above technical scheme, the present application constructs a closed-loop material recycling system from wet leaching residue to pyrometallurgical volatilization and back to ash, solving the problems of low metal recovery rate, high difficulty in residue treatment and high consumption of auxiliary materials in traditional processes. The specific process principles and beneficial effects are described as follows: Firstly, directional regulation of residue components and self-adaptive matching of pyrometallurgical conditions are realized. In the wet leaching stage of step S1, the properties (iron-silicon ratio, sulfur content) of the leaching residue are pre-adjusted to the appropriate range of pyrometallurgical smelting by controlling the reaction end point and material ratio. This source control strategy enables the leaching residue to form a low eutectic point fayalite slag system in the high temperature environment of step S2, reducing the melt viscosity and improving the mass transfer conditions at the gas-liquid interface, thereby achieving efficient reduction and volatilization of zinc (volatilization rate can reach more than 94%) without adding a large amount of external flux, and significantly reducing the pyrometallurgical energy consumption.

[0008] Secondly, the in-situ prepared high-activity functional reagent is used to strengthen the depth of wet purification. The pyrometallurgical zinc-rich ash prepared in step S2 is a product formed by high-temperature gas phase rapid cooling, which has special lattice defects and large specific surface area. The ash is used as the neutralizing agent in step S3, and its reactivity is much higher than that of conventional commercially available zinc oxide. In the process of synergistic neutralization, the high-activity zinc oxide component rapidly neutralizes the acid solution, promotes the explosive hydrolysis of iron ions in the solution in a short time, and in-situ generates iron hydroxide or goethite colloid with high surface energy; the newly formed colloid has strong adsorption and co-precipitation effect on arsenate and antimonate ions in the solution, thereby achieving deep removal of impurities.

[0009] Thirdly, a multi-metal stepwise recovery and impurity balancing mechanism is constructed. The process not only recovers copper and zinc, but also utilizes the reduction smelting process in step S2 to promote the reduction and enrichment of tin and lead in the furnace bottom alloy phase in the raw material, eliminating the disadvantages of tin and lead loss with the slag in the traditional wet zinc smelting process. At the same time, in view of the problem that harmful impurities such as chlorine and fluorine in the complex raw material are easy to accumulate in the closed circuit, the impurities are guided to the byproduct production line for discharge through the subsequent shunting mechanism, maintaining the purity of the electrolyte in the main system and ensuring the current efficiency of the electrodeposition process and the product quality.

[0010] Preferably, in step S1, the solid waste raw material includes copper smelting fly ash and electroplating sludge, and the mass ratio of the copper smelting fly ash to the electroplating sludge is 1:(0.2-0.5); the process parameters of the acid leaching are as follows: initial acid concentration 150-180 g / L, temperature 75-90 ℃, and time 3.0-5.0 hours; an oxidizing agent is added after the reaction is performed for 1.0-2.5 hours, and the solution oxidation-reduction potential is controlled to be 350-450 mV.

[0011] By adopting the above technical solution, the reasonable raw material ratio utilizes the copper and zinc resources in the copper smelting fly ash and the valuable components in the electroplating sludge, and realizes waste treatment with waste. Controlling the oxidation-reduction potential interval on one hand ensures the efficient leaching of copper and zinc, and on the other hand inhibits the premature dissolution of a large amount of impurity iron, reducing the subsequent purification load.

[0012] Preferably, in step S1, the control of the leaching end point pH value is specifically to control the pH value to be between 1.5 and 2.0; and during or before the leaching process, the iron content in the material is adjusted by adding an iron source adjusting agent, so that the iron-silicon ratio of the leaching residue obtained finally is 1.2-1.8, and the sulfur content is 3%-6%.

[0013] By adopting the above technical solution, the accurate end point pH value control prevents the colloidization of silicates in the leaching residue, and improves the filter pressing performance. Locking the iron-silicon ratio of the residue to be 1.2-1.8 is to utilize the formation of 2FeO·SiO2 (fayalite) in the pyrometallurgical stage to reduce the melting point of the residue; controlling the sulfur content to be 3%-6% helps to form a low-melting-point matte phase or sulfide phase, promotes the separation of lead and tin from the residue, and enriches them in the furnace bottom.

[0014] Preferably, in step S2, the temperature of the high-temperature reduction smelting is 1150-1250 ℃, and the addition amount of the reducing agent is 12%-18% of the mass of the leaching residue; the pyrometallurgical zinc-rich fly ash has a hexagonal wurtzite structure, and the zinc oxide content is 55%-70%, and the specific surface area is ≥5 m 2 / g.

[0015] By adopting the technical scheme, the temperature and the reducing atmosphere ensure the reduction and volatilization rate of zinc, while inhibiting the reduction of iron (iron mainly forms slag). The obtained soot has a hexagonal wurtzite structure and a large specific surface area, which directly determines the dissolution kinetics and impurity removal activity when the soot is used as a neutralizing agent in a wet process section.

[0016] Preferably, in step S3, the synergistic neutralization and purification specifically includes two stages of reaction: in the first stage, the pH value is adjusted to 3.2-3.8 by adding the fire process zinc-rich soot, and air is blown or an oxidizing agent is added to oxidize and hydrolyze ferrous ions; in the second stage, the pH value is adjusted to 4.8-5.2 by continuously adding the fire process zinc-rich soot, and arsenic and antimony in the solution are adsorbed and co-precipitated by the in-situ generated iron hydroxide colloid, while lead components in the soot are used to remove sulfate.

[0017] By adopting the technical scheme, the staged purification strategy maximizes the impurity removal efficiency. In the first stage, the oxidation and preliminary hydrolysis of iron are mainly completed; in the second stage, under a higher pH value, the specific surface area of the newly generated iron hydroxide colloid is used to reduce the content of arsenic and antimony to a very low level (<1 mg / L) through physical adsorption and chemical co-precipitation. At the same time, trace lead in the soot forms lead sulfate precipitate, which plays a supplementary role in removing sulfur and assisting filtration.

[0018] Preferably, in step S4, the organic extractant is compounded from 2-hydroxy-5-nonyl phenylacetone oxime and 5-nonyl salicyl aldehyde oxime at a volume ratio of 1:(0.8-1.2), the diluent is sulfonated kerosene, and the volume concentration of the extractant is 15%-25%; the extraction separation adopts two-stage countercurrent extraction, and the phase ratio of O / A is 1:1-1.5:1.

[0019] By adopting the technical scheme, the compounded extractant combines the advantages of fast aldehyde oxime extraction speed and good ketone oxime phase separation, realizes high selectivity extraction of copper in a complex copper-zinc mixed solution system, and effectively separates copper and zinc.

[0020] Preferably, in step S5, the deep purification includes: adding zinc powder and an activator potassium antimonyl tartrate into the raffinate, reacting at 70-80°C for 40-60 minutes to remove cadmium, cobalt and nickel impurities by replacement; and the amount of zinc powder added is 1.2-1.5 times the total mass of impurity metals in the solution.

[0021] By adopting the technical scheme, potassium antimonyl tartrate as an activator can form a loose antimony metal layer on the surface of zinc powder, forming a micro-battery effect, thereby reducing the deposition overpotential of deep impurities such as cobalt and nickel, and ensuring that the solution after deep purification meets the production requirements of high-purity electrolytic zinc.

[0022] Preferably, in step S5, the process parameters of the electrodeposition system are as follows: the anode uses a lead-silver alloy plate, the cathode uses an aluminum plate, and the current density is 450-550 A / m2 The electrolyte temperature is 38-45 DEG C.

[0023] By adopting the technical scheme, the optimized electrodeposition parameters ensure the current efficiency under high current density, and the temperature control prevents the intensification of hydrogen evolution side reaction and anode corrosion.

[0024] Preferably, in step S2, the furnace bottom product generated by high-temperature reduction smelting is a crude tin-lead alloy; and in step S3, the filter residue generated by filtering is returned to the pyrometallurgical system of step S2 for recycling.

[0025] By adopting the technical scheme, the wet purification slag (rich in iron, arsenic and lead) is returned to the pyrometallurgical system, on the one hand to recover valuable metals therefrom, and on the other hand to solidify harmful elements such as arsenic in the high-temperature environment of pyrometallurgy, thereby avoiding secondary pollution and realizing closed-loop circulation of the whole system.

[0026] Preferably, in step S5, when the chloride ion concentration in the raffinate exceeds 100 mg / L or the fluoride ion concentration exceeds 50 mg / L, part of the raffinate is branched off to prepare feed-grade zinc oxide according to the following steps: the branched-off raffinate is heated to 80-90 DEG C, sodium carbonate solution is added to adjust the pH value to 6.8-7.2, and an alkali zinc carbonate precipitate is generated by reaction; the precipitate is filtered and washed with hot water until the sulfate content is qualified, and then dried and calcined at 450-550 DEG C to obtain the feed-grade zinc oxide product.

[0027] By adopting the technical scheme, a dynamic impurity discharge window is established. When the chlorine and fluorine in the system accumulate to the alarm value, the branched-off production line is started. In the precipitation and washing process of the alkali zinc carbonate, chlorine and fluorine ions mainly remain in the mother liquor and are discharged from the system, while zinc is recovered in the form of high-value zinc oxide product. This ingenious dual-product line design solves the technical problems of electrode corrosion and plate burning caused by halogen accumulation in closed-loop circulation, prolonging the service life of the electrolysis system.

[0028] The application provides a production method of electrolytic zinc. 1. The application improves the comprehensive utilization rate of resources by constructing a combined closed-loop system of wet process and pyrometallurgy and implementing directional regulation on leaching residue.

[0029] 2、The present application uses high-activity zinc-rich soot prepared in-situ by a pyrometallurgical system as a synergistic purifying agent for a wet system, achieving the dual effects of deep impurity removal and cost savings. Since the soot is a product formed by high-temperature reduction and volatilization followed by gas-phase rapid cooling, it has special lattice defects, a large specific surface area, and extremely high chemical reactivity. When used in the neutralization process of the wet method, it can promote the explosive hydrolysis of iron ions in the solution in a short time, generating freshly generated iron hydroxide or goethite colloid with high surface energy, and removing stubborn impurities such as arsenic and antimony in the solution to extremely low levels through adsorption and co-precipitation, effectively replacing expensive purchased neutralization reagents and strengthening the purification depth.

[0030] 3、The present application establishes a dual-product line diversion mechanism for electrolytic zinc and feed-grade zinc oxide, effectively solving the technical problem of halogen impurity accumulation in a closed-loop cycle. For harmful elements such as chlorine and fluorine brought in by complex solid waste raw materials, the process is provided with dynamic monitoring and diversion discharge channels. When the impurity concentration in the system approaches the warning threshold, part of the raffinate is switched to the zinc oxide preparation section, and chlorine and fluorine are removed from the circulation system by using the precipitation mother liquor separation method, thereby maintaining the cleanliness of the electrolyte in the main system at all times, avoiding anode corrosion and cathode plate burning caused by high-concentration halogens, and ensuring high current efficiency of the electrodeposition process and long-term operation stability of the system. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be described below in conjunction with the embodiments and comparative examples of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0032] The sources and specifications of the main raw materials and reagents used in the following examples and comparative examples are as follows: the reagents not specifically described are commercially available analytical pure or higher grade products.

[0033] Anionic polyacrylamide, CAS: 9003-05-8, molecular weight: 12-14 million.

[0034] Preparation Examples 1-3: Preparation Example 1: This preparation example provides a high-activity pyrometallurgical zinc-rich soot (labeled as soot A).

[0035] Take the tin-containing lead-containing acid leaching slag (dry basis moisture content 22%, iron-silicon ratio 1.45, sulfur content 4.2%) produced in the wet section of the process 1000 kg, and 150 kg of metallurgical coke powder with a particle size of less than 3 mm are mechanically mixed uniformly and sent into a rotary volatilization kiln for high-temperature reduction and volatilization. The temperature of the high-temperature constant temperature zone in the kiln is controlled at 1200°C to 1250°C, the material stays in the high-temperature zone for 120 minutes, and the CO volume concentration in the kiln atmosphere is controlled at 3% to 4%. The zinc-lead metal vapor volatilized at high temperature enters the surface cooler and is rapidly cooled to 180°C, and is captured in the bag dust collector to obtain a light gray powder-shaped high-activity pyrometallurgical zinc-rich soot A totaling 320 kg. Detection shows that the main chemical components of the soot A are: ZnO 68.5%, PbO 9.2%, Fe2O3 2.1%, S 0.6%, C 1.5%, and the rest is trace dust; physical property testing shows that its specific surface area (BET method) is 7.2 m 2 / g, and the average particle size D50 is 2.8 μm, showing extremely high chemical reaction activity.

[0036] Preparation Example 2: This preparation example provides a pyrometallurgical zinc-rich soot with a higher lead content (labeled as soot B), which is used to verify the purification ability of the wet process system for high-impurity circulating materials.

[0037] Take the same acid leaching slag as in Preparation Example 1 1000 kg, mix the reducing agent to 180 kg of anthracite powder, and send it into the rotary volatilization kiln. The temperature of the high-temperature constant temperature zone in the kiln is controlled to decrease to 1150°C to 1180°C, and the material stays for 140 minutes. Under this temperature condition, the reduction and volatilization of iron oxides in the slag is reduced, but the lead volatilization rate remains high. After cooling and dust collection, a dark gray powder-shaped pyrometallurgical zinc-rich soot B totaling 345 kg is obtained. Detection shows that the main chemical components of the soot B are: ZnO 58.4%, PbO 14.5%, Fe2O3 1.8%, S 1.1%, C 3.2%; physical property testing shows that its specific surface area (BET method) is 5.8 m 2 / g, and the average particle size D50 is 3.5 μm.

[0038] Preparation Example 3: This preparation example provides a pyrometallurgical zinc-rich soot prepared at medium temperature conditions (labeled as soot C).

[0039] Take the same source as preparation example 1 1000 kg of acid leaching residue, add 140 kg of coke powder, send into the fuming furnace for blowing treatment. Control the blowing temperature to be 1100 ℃ to 1150 ℃, and mix a small amount of secondary air before dust collection to strengthen oxidation. Finally, a total of 310 kg of ash white powder zinc-rich smoke ash C is collected. The detection shows that the main chemical components of the ash C are: ZnO 62.1%, PbO 8.5%, Fe2O3 1.5%, S 0.9%, SiO2 3.5% (mainly mechanical entrainment); the physical performance test shows that the specific surface area (BET method) is 6.4 m 2 / g, and the average particle size D50 is 3.1 μm.

[0040] Example 1-4: Example 1

[0041] The embodiment provides a production method of electrolytic zinc, and specifically comprises the following steps: (1) Raw material slurry and directional leaching: 1000 kg of copper smelting smoke ash and 300 kg of electroplating sludge are uniformly mixed and added into an acid-resistant reaction kettle, industrial water is added to adjust the liquid-solid ratio to 5:1 for slurry. Concentrated sulfuric acid is slowly added, the initial acid concentration is controlled at 160 g / L, and the temperature is increased to 85 ℃ for stirring reaction. After 1.5 hours of reaction, 20 kg of soft manganite powder is added as an oxidizing agent, and the solution oxidation-reduction potential is controlled at 420 mV. Continue to react for 2.5 hours, and finely adjust the amount of sulfuric acid added to control the leaching end point pH value to be 1.8. At this time, most of the copper and zinc enter the solution, while the tin, lead and most of the iron remain in the slag. Pressure filtration separation is performed to obtain a copper-zinc-containing leaching solution and a filter cake-shaped leaching residue. The detection shows that the moisture content of the leaching residue is 24%, the iron-silicon ratio (Fe / SiO2) is 1.4, and the sulfur content is 3.8%, which is directly sent to the pyrometallurgical system as high-quality raw material for tin and lead recovery.

[0042] (2) Synergistic neutralization and purification: the copper-zinc-containing leaching solution obtained in step (1) is pumped into a purification tank and heated to 70 ℃. 45 kg of high-activity zinc-rich smoke ash A prepared in preparation example 1 is weighed as a neutralization and purification agent, and slowly added into the leaching solution. The active zinc oxide in the smoke ash is used to neutralize the free acid in the solution, and the pH value of the solution is gradually adjusted to 5.0. In this process, compressed air is blown in to assist oxidation, promote the hydrolysis of iron ions in the solution to form hydroxyl iron / hematite precipitate, and remove arsenic and antimony impurities in the solution by using the in-situ generated precipitate. After 2 hours of reaction, filtration is performed, the filter residue is returned to the pyrometallurgical system, and the filtrate is a clean copper-zinc mixed solution, the iron content of which is reduced to below 3 mg / L.

[0043] (3) Copper extraction and recovery: The copper-zinc mixed solution obtained in step (2) is sent to a mixing and clarification tank, and two-stage countercurrent extraction is performed using an aldoxime / ketoxime mixed extractant (diluted with sulfonated kerosene) with a concentration of 20%. The phase ratio (O / A) is controlled to be 1.2:1. After extraction, the loaded organic phase is washed with acid and then stripped with electrolytic waste liquid to produce high-purity copper sulfate solution for electrodeposition to obtain cathode copper product. The raffinate is a solution rich in zinc sulfate, which enters the zinc recovery system.

[0044] (4) Deep purification and zinc electrolysis: zinc powder (added in an amount of 1.5 times the total amount of cadmium and nickel in the solution) and 1.5 mg / L potassium antimony tartrate are added to the raffinate of step (3), and deep displacement impurity removal is performed at 75°C for 45 minutes. The purified zinc sulfate solution is sent to the zinc electrolysis workshop, and electrodeposition is performed using a lead-silver alloy anode and an aluminum cathode at a current density of 500 A / m 2 , electrolyte temperature 38°C, to finally produce electrolytic zinc ingots with a purity of ≥99.995%. Example 2

[0045] The present embodiment provides a production method of electrolytic zinc, which specifically comprises the following steps: (1) Raw material slurrying and directional leaching: 1000 kg of copper smelting ash and 500 kg of electroplating sludge are mixed and added to an acid-resistant reaction kettle, with a liquid-solid ratio controlled to be 4:1. Concentrated sulfuric acid is added, with an initial acid concentration of 180 g / L, and the reaction is carried out at 90°C. 30 kg of hydrogen peroxide is added as an oxidizing agent, and the redox potential is controlled to be 400 mV. The leaching endpoint pH value is controlled to be 1.5 to maximize the metal leaching rate. Pressure filtration is performed to obtain a leaching solution and a leaching residue. By adjusting during the batching stage, the iron-silicon ratio (Fe / SiO2) of the leaching residue is 1.25, and the sulfur content is 4.5%, meeting the requirements of the feed of the pyrometallurgical fuming furnace, which is sent to the pyrometallurgical system for treatment.

[0046] (2) Simultaneous neutralization and purification: The copper-zinc leaching solution is heated to 65°C. The pyrometallurgical zinc-rich ash B with a high lead content prepared in Preparation Example 2 is used as a neutralizing agent and is added to the solution in batches. The pH value of the solution is adjusted to 4.8 by using the alkaline components thereof. During the reaction, the lead oxide in the ash is converted into lead sulfate precipitate into the residue phase, and the iron and arsenic in the solution are deeply removed. After 1.5 hours of reaction, filtration is performed to obtain a copper-zinc mixed solution.

[0047] (3) Copper extraction and recovery: The same extraction system as in Example 1 is used, but the phase ratio (O / A) is adjusted to 1.5:1, and copper is separated by three-stage countercurrent extraction to produce cathode copper.

[0048] (4) Preparation of electrolytic zinc and zinc oxide by diversion: After copper extraction, the raffinate is purified by deep displacement with zinc powder. The solution is detected and found that the concentration of chloride ions accumulates to 120 mg / L. To protect the electrolysis system, 70% of the solution flow is sent to the electrolysis tank to produce electrolytic zinc under the condition of current density 480 A / m 2 The remaining 30% of the solution is diverted to the zinc precipitation kettle, heated to 85°C, and 25% concentrated sodium carbonate solution is added. The final pH value is controlled at 7.0, and the basic zinc carbonate precipitate is generated by reaction. The precipitate is filtered, washed with multiple hot water (to remove chloride, fluorine and sulfate), dried at 110°C, and calcined in a rotary kiln at 500°C for 1.5 hours to produce zinc oxide products that meet the feed grade standard. Example 3

[0049] This example provides a method for producing electrolytic zinc, which specifically includes the following steps: (1) Raw material slurry and directional leaching: 1000 kg of copper smelting ash, 200 kg of electroplating sludge, and 50 kg of pyrite cinder (as an iron regulator) are mixed with a liquid-solid ratio of 6:1. Sulfuric acid leaching is carried out at 80°C, with an initial acid concentration of 150 g / L and the addition of 15 kg of soft mica powder. The leaching end point pH value is strictly controlled at 2.0. Under this higher pH condition, part of the dissolved silicate ions re-polymerize and precipitate, and the hydrolysis rate of iron increases. After pressure filtration, the Fe / SiO2 ratio of the obtained leaching residue is accurately regulated to 1.65, and the residue is loose and porous, which is extremely beneficial to the gas-solid reaction in the subsequent pyrovolatilization kiln. It is sent to the pyro-system.

[0050] (2) Simultaneous neutralization and purification: The leaching solution is heated to 75°C, and the pyro-zinc-rich ash C prepared in Preparation Example 3 is added. Since the ash is prepared at medium temperature, the specific surface area is moderate, and the addition speed is controlled at 8 kg / min. The solution pH value is adjusted to 5.2, and the reaction is carried out for 2.5 hours to ensure that iron, arsenic and antimony are completely precipitated. The copper-zinc mixed solution is obtained by filtration.

[0051] (3) Copper extraction and recovery: The conventional LIX984N extraction system is used to separate copper, and cathode copper is produced.

[0052] (4) Zinc recovery: After deep purification, the raffinate is sent to the electrodeposition system. Due to the complete front-end purification and appropriate residue regulation, the impurity cycle accumulates slowly in the system, and electrolytic zinc is stably produced under the condition of current density 520 A / m 2 without burning the plate. Example 4

[0053] This example provides a method for producing electrolytic zinc, which specifically includes the following steps: (1) Raw material slurrying and directional leaching: 1000 kg of copper smelting dust was mixed with 400 kg of electroplating sludge, with a liquid to solid ratio of 4.5:1. Sulfuric acid leaching was carried out at 75°C (lower temperature), with a reaction time of 5.0 hours. An oxidizing agent was added to maintain an electric potential of 380 mV. The leaching end point pH was controlled at 1.6. The leaching residue (Fe / SiO2=1.3, sent to pyrometallurgical process) and leaching solution were separated.

[0054] (2) Simultaneous neutralization and purification: the leaching solution was maintained at 60°C, and the dust prepared in Preparation Example 1 and Preparation Example 2 were mixed (mass ratio 1:1) as the neutralizing agent. The solution pH was adjusted to 4.5 (lower pH boundary). The reaction time was extended to 3.0 hours to ensure reaction equilibrium. The precipitate was removed by filtration, and a copper-zinc mixed solution was obtained.

[0055] (3) Copper extraction and recovery: copper was separated by extraction according to the conventional process, and cathode copper was produced.

[0056] (4) Zinc recovery: after purification, the raffinate was subjected to electrowinning to produce electrolytic zinc. Although the purification pH was low, due to the extended reaction time and high activity of the dust, the impurity indicators of the solution entering the tank still met the requirements of electrowinning, and qualified electrolytic zinc products were produced. Comparative Examples 1-4: Comparative Example 1: Compared with Example 1, the difference is that in step (2) of simultaneous neutralization and purification, instead of using the high-activity zinc-rich dust A prepared in Preparation Example 1 as the neutralizing agent for pH adjustment and impurity removal, an equivalent amount of commercially available industrial-grade zinc oxide powder (a product of high-temperature calcination with a small specific surface area) was used. The remaining steps and parameters were the same.

[0057] Comparative Example 2: Compared with Example 3, the difference is that in step (1) of raw material slurrying and directional leaching, the properties of the leaching residue were not directionally controlled for the subsequent pyrometallurgical process. Specifically, pyrite cinder was not added to adjust the iron to silicon ratio, and in order to pursue the ultimate leaching speed, the leaching end point pH was controlled at 0.8 (strongly acidic environment), resulting in high residual acid content, low iron content, and severe silicon gelation in the residue. The remaining steps and parameters were the same.

[0058] Comparative Example 3: Compared with Example 2, the difference is that in step (4), the process route for preparing zinc oxide was not adopted. Specifically, the raffinate containing high levels of chlorine and fluorine was sent in full amount to the zinc electrowinning system for electrolysis, and no zinc oxide bypass was set up as an impurity discharge port. The remaining steps and parameters were the same.

[0059] Comparative Example 4: Compared with Example 1, the difference is that the material closed loop of wet process and pyrometallurgical process is broken. Specifically, the leaching residue generated in step (1) is not sent to the pyrometallurgical system for recovery, but is stored as ordinary solid waste; all reagents required for purification in step (2) are purchased (limeslurry is used to adjust pH), and no zinc-containing material is introduced; that is, there is no tin-lead recovery and zinc return process, and the remaining process parameters are the same.

[0060] Test Example 1-5: Test Example 1: Process feasibility and product quality detection Experimental description: This test example aims to verify the stability and compliance of the product quality produced by the process described in the present application under different implementation conditions. The cathode copper, electrolytic zinc ingot and feed-grade zinc oxide produced by Examples 1 to 4 are selected as the detection objects.

[0061] The specific detection methods are as follows: Cathode copper detection: According to the national standard GB / T467-2010 "Cathode Copper", the copper content is determined by electrolytic gravimetric method, and the impurity element content is determined by inductively coupled plasma atomic emission spectrometry (ICP-OES, model: Agilent5110).

[0062] Electrolytic zinc detection: According to the national standard GB / T470-2008 "Zinc Ingot", ICP-OES is used to determine the main grade and impurity contents such as lead, iron and cadmium.

[0063] Feed-grade zinc oxide detection: According to the national standard GB / T3494-2012 "Feed-grade Zinc Oxide", ethylenediaminetetraacetic acid disodium (EDTA) complexometric titration method is used to determine the zinc oxide content, atomic fluorescence spectrometry (AFS) is used to determine the arsenic content, and atomic absorption spectrometry (AAS) is used to determine the lead and cadmium contents.

[0064] Test results: Table 1. Detection results of key chemical components and quality indicators of products produced by each example

[0065] Note: " / " indicates that the example does not start the zinc oxide shunt production line and does not involve product detection.

[0066] Result analysis: Based on the above detection data, the feasibility analysis of the technical scheme of the present application is as follows: The purity of the cathode copper produced by Examples 1 to 4 under different raw material ratios, leaching pH values and types of purification agents is maintained at more than 99.95%, and the purity of the electrolytic zinc is more than 99.995%, indicating that the wet process and pyrometallurgical process coupling system constructed by the present application has good process adaptability.

[0067] The data particularly show that, in Example 2, although the impurity contents of the cathode copper and the electrolytic zinc slightly increase, the impurity contents still meet the requirements of the national standards when treating raw materials with high impurity contents. Meanwhile, the zinc oxide content of the zinc oxide product produced by the shunt production of this example reaches 96.4%, and the heavy metal indicators such as lead, arsenic, and cadmium are far below the upper limit of the feed grade standard.

[0068] The above results prove that, by using the high-activity zinc-rich fly ash in the gradient purification, the impurities such as arsenic and antimony can be effectively blocked from entering the electrodeposition system. Meanwhile, through the shunt mechanism of the zinc oxide production line, the accumulation problems of chlorine, fluorine, and heavy metals in the complex solid waste raw materials are effectively solved, and the quality of multiple product lines is ensured to meet the standards. This process route realizes the comprehensive recovery of multiple metals while ensuring the commercial quality of the final products.

[0069] Test Example 2: Comparison test of wet purification effect and reaction kinetics Test description: This test aims to compare the reaction efficiency and impurity removal depth of Example 1 (using self-produced high-activity zinc-rich fly ash) and Comparative Example 1 (using commercially available industrial-grade zinc oxide powder) in the wet purification process.

[0070] The same batch of acid leaching solution was selected as the raw material, and the initial pH value of the leaching solution was 1.8, the concentration of iron (Fe) was 2150 mg / L, the concentration of arsenic (As) was 145 mg / L, and the concentration of antimony (Sb) was 38 mg / L.

[0071] The experimental steps are as follows: The above leaching solution was evenly divided into two groups, each with a volume of 1000 L, and was placed in two constant-temperature stirred reaction kettles with the same configuration. The temperature was heated and maintained at 70±2°C, and the stirring speed was set at 120 r / min.

[0072] Experimental group (corresponding to Example 1): According to 1.1 times the theoretical acid consumption, the high-activity zinc-rich fly ash obtained in Preparation Example 1 was slowly added.

[0073] Control group (corresponding to Comparative Example 1): According to 1.1 times the theoretical acid consumption, commercially available industrial-grade zinc oxide powder (produced by high-temperature calcination process, purity 99%) was slowly added.

[0074] If the control group does not reach the target pH value (pH=5.0) within the specified time, additional zinc oxide powder is added until the standard is met, and the actual total consumption is recorded.

[0075] During the reaction, the pH value was detected every 30 minutes. After the reaction was completed (set as 2.5 hours), the supernatant was analyzed for residual impurity concentration, and the vacuum filtration rate of the slurry was measured (filter cake thickness 20 mm, vacuum degree -0.08 MPa).

[0076] Test results: Table 2. Comparison data of wet system purifying agent efficiency and impurity removal end point indicators

[0077] Result analysis: Based on the principles of material properties and chemical reaction kinetics, the analysis of the above data is as follows: The experimental group is superior to the control group in terms of purification efficiency and impurity removal depth. The data shows that the actual consumption of the purifying agent used in Example 1 is close to the theoretical value (1.12 times), and the reaction reaches the standard time (85 minutes); while the purchased zinc oxide used in Comparative Example 1 is calcined at high temperature, the crystal lattice structure is dense, and the specific surface area is small, which leads to slow dissolution and neutralization reaction kinetics in weak acidic environment, and needs to be added in excess (1.45 times) to reach the target pH value, and the reaction time is greatly extended.

[0078] In terms of impurity removal, the residual iron, arsenic and antimony concentrations in the filtrate of the experimental group are all reduced to very low levels (Fe < 2 mg / L, As < 0.5 mg / L). The mechanism lies in: the pyrometallurgical zinc-rich soot prepared by the invention is a gas-phase rapid cooling product with high specific surface area and many lattice defects, and has very high chemical activity. This highly active component rapidly neutralizes the acid solution, promotes the explosive hydrolysis of iron ions in the solution in a short time, and forms a large amount of colloidal iron hydroxide / goethite with high surface energy. These newly formed precipitates have strong adsorption and co-precipitation effects on arsenate and antimonate ions.

[0079] In contrast, due to the slow neutralization reaction, the hydrolysis process of iron ions is prolonged, the formed precipitate is highly crystallized and aged, the adsorption active sites are reduced, leading to incomplete removal of arsenic and antimony. In addition, the higher filtration rate of the experimental group indicates that the fine lead salt particles introduced by the pyrometallurgical ash play the role of filter aid in the precipitation process, improving the pore structure of the filter cake. In summary, the use of pyrometallurgical zinc-rich soot in the system as a purifying agent shows obvious technical advantages in chemical reaction activity and impurity removal effect.

[0080] Test Example 3: Comparison test of pyrometallurgical smelting working condition adaptability and energy efficiency Experimental description: This test aims to verify the difference in thermal performance and metallurgical efficiency of the pyrometallurgical recovery stage between the directionally controlled slag (Example 3) and the non-controlled acid leaching slag (Comparative Example 2).

[0081] The pyrometallurgical adapted leaching slag produced by Example 3 and the conventional acid leaching slag produced by Comparative Example 2 were selected as raw materials. Both groups of raw materials were tested for composition before entering the furnace. The iron-silicon ratio (Fe / SiO2) of the slag sample of Example 3 was 1.65, and the moisture content was 22%; the iron-silicon ratio of the slag sample of Comparative Example 2 was 0.65 (high silicon and low iron), and the moisture content was 38%.

[0082] The experimental procedure is as follows: Proportioning calculation: For the high-silicon slag of Comparative Example 2, in order to avoid slagging in the furnace, limestone and iron ore powder are added as fluxing agents according to the theory of pyrometallurgical smelting to make the final slag basicity and iron-silicon ratio meet the smelting requirements; while the slag sample of Example 3 only adds reducing coal, without additional or only a small amount of fluxing agent.

[0083] Smelting operation: The two groups of materials are respectively put into the same specification of pilot-scale rotary volatilization kiln. The feeding speed is controlled constant, and the slag layer in the furnace is maintained in a molten and flowing state by adjusting the burner power and the amount of reducing coal added (by observing the slag turning in the furnace).

[0084] Parameter recording: Record the furnace temperature required to maintain normal smelting, total consumption of reducing coal and fuel gas, and processing capacity per unit time.

[0085] Product analysis: After stable operation for 4 hours, the water-quenched slag (waste slag) discharged from the kiln tail is analyzed for residual zinc and lead content, and the metal volatilization rate is calculated.

[0086] Experimental results: Table 3. Comparison of thermal energy consumption and metal recovery indicators of pyrometallurgical smelting system

[0087] Result analysis: The technical analysis of the above thermal and metallurgical data is as follows: The data intuitively reflects the decisive influence of front-end wet process control on the back-end pyrometallurgical process. The control group (Comparative Example 2) did not manage the slag type in the wet process section, resulting in a low iron-silicon ratio (high-silicon slag) entering the furnace. The increase in SiO2 content leads to an increase in the liquidus temperature of the slag system and the formation of a complex silicate network structure, resulting in an increase in melt viscosity. In order to maintain smelting, the furnace temperature must be increased significantly (about 130°C higher on average) and up to 18.4% of fluxing agent must be added, which directly leads to a significant increase in energy consumption and a decrease in effective processing capacity. At the same time, high-viscosity slag hinders the diffusion and volatilization of zinc vapor from the interior of the melt to the gas-liquid interface, resulting in a high residual zinc content of 4.87% in the tail slag, causing serious resource loss.

[0088] On the contrary, the experimental group (Example 3) pre-set a suitable Fe / SiO2 ratio through directional regulation of the wet section, so that the leaching residue showed excellent self-fluxing property under the fire process. The formation of fayalite (2FeO·SiO2) eutectic phase effectively reduced the melting point and slag viscosity, improved the mass and heat transfer conditions in the furnace. This not only reduced fuel consumption, but also strengthened the kinetics of reduction and volatilization, so that the zinc volatilization rate reached 94.6%. The results confirmed that the whole-process slag property regulation strategy proposed in the present application eliminated the technical gap between the wet process and the fire process in the traditional process, and realized the optimization of the overall energy efficiency of the system.

[0089] Test Example 4: Long-term running stability and impurity balance monitoring of the electrolysis system Experimental description: This test aims to investigate the impurity regulation ability and the influence on the stability of the electrolysis system when the electrolytic zinc / zinc oxide dual-product line diversion strategy proposed in Example 2 is used to treat high-halogen raw materials. The comparison object is Comparative Example 3 (full-amount electrolysis without zinc oxide diversion branch).

[0090] Two sets of micro closed-loop systems were constructed, both using the same leaching solution containing 0.05% chlorine (Cl) and 0.03% fluorine (F) as the starting raw material. The cycle running period was set to 20 days, and a fixed amount of raw material was treated and product was produced every day. The electrolysis waste liquid was returned to the leaching section for recycling.

[0091] The experimental control strategy is as follows: Experimental group (Example 2): The chlorine ion warning threshold of the system is set to 100 mg / L. The electrolyte composition is detected daily, and if the chlorine ion concentration is below the threshold, full-amount electrolysis is carried out; if the threshold is exceeded, 30% of the purified liquid is diverted to the zinc oxide preparation section, and the remaining 70% continues to be electrolyzed. The washing water (containing chlorine and fluorine) produced in the zinc oxide section is discharged open-loop and not returned to the system.

[0092] Control group (Comparative Example 3): Regardless of the impurity concentration, the purified liquid is always sent to the electrolysis system in full amount, and the electrolysis waste liquid is recycled in full amount.

[0093] Monitoring index: The fluorine and chlorine ion concentrations in the electrolyte are recorded daily, the current efficiency of the shift (according to the ratio of actual zinc production to theoretical zinc production) is calculated, and the direct current consumption is monitored.

[0094] Experimental results: Table 4. Impurity accumulation and electrolysis technical index evolution data of the closed-loop system

[0095] Result analysis: The technical analysis of the system running data is as follows: The data of the control group (Comparative Example 3) presents a typical impurity accumulation effect. Due to the lack of effective halogen exhaust channels, the chlorides and fluorides brought in by the raw materials are continuously enriched with the closed-loop circulation of the solution. By the 10th day, the chloride ion concentration has broken through 300 mg / L, leading to the accelerated corrosion of the anode lead plate, the lead entering the solution in the form of ions and being deposited at the cathode, and the reduction of product purity. By the 20th day, the chloride ion concentration exceeds 1000 mg / L, triggering serious plate burning, the acid dissolution of the cathode zinc, the sharp drop of the current efficiency to 52.6%, the abnormal increase of the power consumption, and the collapse of the production system.

[0096] The experimental group (Example 2) establishes a dynamic impurity balance mechanism by introducing a zinc oxide shunt branch. The data show that when the chloride ion accumulates to the warning line, the shunt operation effectively removes part of the high-impurity solution from the electrolysis circulation. In the preparation process of zinc oxide, chlorides and fluorides are mainly removed into the precipitation mother liquor and washing water, while zinc is recovered in the form of basic carbonate precipitate. This mechanism enables the chloride ion concentration in the electrolyte to be maintained in a controllable range of 90-110 mg / L, ensuring that the electrowinning process operates in a low-impurity interference environment, and the current efficiency is stably maintained at about 90% for a long time. The results confirm that the dual-product line design is not only an increase in product types, but also a key technical means to maintain the material balance of the whole hydrometallurgical system and prevent impurity poisoning.

[0097] Test Example 5: Comprehensive metal recovery rate accounting of the whole process Experimental description: This test aims to compare the differences in the utilization efficiency of valuable metal resources between Example 1 (two-way coupled closed-loop process of wet and pyrometallurgical methods) and Comparative Example 4 (traditional single-way open-loop process of wet method) through material balance calculation.

[0098] The experiment selects a mixture of 5.00 tons of uniform composition as the reference for the raw material (a mixture of copper smelting dust and electroplating sludge). The measured values of the mass content of the main metal elements in the raw material are: copper 11.45%, zinc 18.62%, lead 5.84%, and tin 1.95%.

[0099] The experimental operation and accounting boundary are as follows: Experimental group (Example 1): The whole process is processed according to the process of the present application. The wet leaching slag is sent to the pyrometallurgical system, the crude tin-lead alloy produced by the pyrometallurgical method is counted as a recovered product, the pyrometallurgical dust returns to the wet system, and the cathode copper and electrolytic zinc produced by the wet method are counted as recovered products. The final system discharge is only the pyrometallurgical water quenching slag and the wet purification open-loop slag.

[0100] Control group (Comparative Example 4): According to the traditional wet process. The raw material is treated by acid leaching, conventional lime neutralization and purification, extraction and electrodeposition to produce cathode copper and electrolytic zinc. The leaching residue is high in sulfur and heavy metals and is treated as hazardous waste by solidification and landfill, without subsequent metal extraction; the purification residue is also stored and disposed of.

[0101] Calculation method: Collect the final qualified products from each section, weigh and test the main element content, calculate the total recovery mass of each metal element, and divide the total mass of the metal in the raw material to obtain the overall recovery rate of the whole process.

[0102] Experimental results: Table 5. Comparison data of key metal element flow and overall recovery rate of the whole process

[0103] Result analysis: Data analysis reveals the technical advantages of the two-way coupled process in resource utilization depth: In terms of zinc recovery, there is a gap between the experimental group and the control group (96.52% vs 82.19%). In the control group, about 15%-18% of zinc exists in the form of insoluble zinc ferrite (ZnFe2O4) and cannot be dissolved under atmospheric acid leaching conditions, eventually being lost with the leaching residue. In the experimental group, this part of zinc-containing leaching residue enters the high-temperature reduction environment of pyrometallurgy, the structure of zinc ferrite is destroyed, zinc is reduced to metal vapor and oxidized to collect as soot, and returns to the wet process system. This mechanism of wet process, pyrometallurgical bottom-up, and gas phase circulation actually changes the zinc recovery path from single pass to closed loop, thereby greatly improving the overall recovery rate.

[0104] In terms of tin and lead recovery, the control group has a recovery rate of zero because the traditional wet process cannot handle the slag phase components in the form of lead sulfate and tin oxide. The experimental group uses the directional regulation characteristics of the leaching residue to convert it into high-quality raw material for pyrometallurgical smelting, successfully extracting the tin and lead components in the raw material, and achieving a transition from single copper-zinc recovery to copper-zinc-tin-lead multi-metal collaborative recovery.

[0105] In addition, the slight increase in copper recovery rate (98.48% vs 93.69%) is mainly due to the capture of a small amount of unwashed copper components in the slag into the matte or alloy phase during the pyrometallurgical process, which is recovered, while in the control group, this part of copper is lost with the slag landfill. In summary, the technical solution of the present application eliminates the metal loss breakpoints in the traditional process through process reconstruction, and realizes the maximization of the resource value of complex multi-metal solid waste.

Claims

1. A method for the production of electrolytic zinc, characterized in that, The method comprises the following steps: S1, raw material slurry and directional leaching: the solid waste raw material containing copper and zinc is slurried, sulfuric acid is added for acid leaching, the leaching end point pH value is controlled, and solid-liquid separation is performed to obtain a copper and zinc containing leaching solution and a leaching residue; the leaching residue is sent to a pyrometallurgical system; S2, pyrometallurgical volatilization and ash preparation: the leaching residue obtained in step S1 is mixed with a reducing agent and then subjected to high-temperature reduction smelting, so that the zinc in the residue is volatilized into flue gas, and a pyrometallurgical zinc-rich ash is obtained by cooling and dust collection; S3, synergistic neutralization and purification: the copper and zinc containing leaching solution obtained in step S1 is heated, and the pyrometallurgical zinc-rich ash prepared in step S2 is added as a neutralizing agent to adjust the pH value of the solution to precipitate and remove iron, arsenic and antimony impurities, and a clean copper and zinc mixed solution is obtained by filtration; S4, copper extraction and recovery: an organic extractant is used to extract and separate the copper and zinc mixed solution obtained in step S3, the loaded organic phase is subjected to stripping and electrodeposition to produce cathode copper, and the raffinate is a zinc containing solution; S5, zinc recovery: after deep purification, the raffinate of step S4 is sent to an electrodeposition system to produce electrolytic zinc.

2. A process for the production of electrolytic zinc as claimed in claim 1 wherein, In step S1, the solid waste raw material comprises copper smelting ash and electroplating sludge, and the mass ratio of the copper smelting ash to the electroplating sludge is 1:(0.2-0.5); The process parameters of the acid leaching are as follows: initial acid concentration 150-180 g / L, temperature 75-90℃, and time 3.0-5.0 hours; An oxidizing agent is added after 1.0-2.5 hours of reaction, and the solution oxidation-reduction potential is controlled at 350-450 mV.

3. A process for the production of electrolytic zinc as claimed in claim 1 wherein, In step S1, the control of the leaching end point pH value is specifically controlling the pH value to be between 1.5 and 2.0; And during or before the leaching process, the iron content in the material is adjusted by adding an iron source, so that the iron to silicon ratio of the obtained leaching residue is 1.2-1.8, and the sulfur content is 3%-6%.

4. A process for the production of electrolytic zinc as claimed in claim 1 wherein, In step S2, the temperature of the high-temperature reduction smelting is 1150-1250℃, and the addition amount of the reducing agent is 12%-18% of the mass of the leaching residue; The zinc-rich smoke dust by pyrogenic process has a hexagonal wurtzite structure, the content of zinc oxide is 55-70%, and the specific surface area is ≥5 m 2 / g.

5. A process for the production of electrolytic zinc as claimed in claim 1 wherein, In step S3, the synergistic neutralization and purification specifically comprises two stages of reactions: First stage: the pyrometallurgical zinc-rich ash is added to adjust the pH value to 3.2-3.8, and air is blown in or an oxidizing agent is added to oxidize and hydrolyze ferrous ions; Second stage: the pyrometallurgical zinc-rich ash is continuously added to adjust the pH value to 4.8-5.2, and the in-situ generated iron hydroxide colloid is used to adsorb and co-precipitate arsenic and antimony in the solution, and the lead component in the ash is used to remove sulfate ions.

6. A process for the production of electrolytic zinc as claimed in claim 1 wherein, In step S4, the organic extractant is compounded by 2-hydroxy-5-nonyl phenylacetone oxime and 5-nonyl salicyl aldehyde oxime at a volume ratio of 1:(0.8-1.2), the diluent is sulfonated kerosene, and the volume concentration of the extractant is 15%-25%; The extraction separation adopts two-stage countercurrent extraction, and the phase ratio O / A is 1:1-1.5:

1.

7. A process for the production of electrolytic zinc as claimed in claim 1 wherein, In step S5, the deep purification comprises: Zinc powder and an activator potassium antimonyl tartrate are added to the raffinate, and the solution is reacted at 70-80℃ for 40-60 minutes to replace and remove cadmium, cobalt and nickel impurities; The addition amount of the zinc powder is 1.2-1.5 times the total mass of the impurity metals in the solution.

8. A process for the production of electrolytic zinc as claimed in claim 1 wherein, In step S5, the process parameters of the electrodeposition system are as follows: The anode is made of lead-silver alloy plate, the cathode is made of aluminum plate, the current density is 450-550 A / m 2 , and the electrolyte temperature is 38-45℃.

9. A process for the production of electrolytic zinc as claimed in claim 1 wherein, In step S2, the furnace bottom product generated by high-temperature reduction smelting is a crude tin-lead alloy; In step S3, the filter residue generated is returned to the pyrometallurgical system in step S2 for recycling.

10. A process for the production of electrolytic zinc as claimed in claim 1 wherein, In step S5, when the chloride ion concentration in the raffinate exceeds 100 mg / L or the fluoride ion concentration exceeds 50 mg / L, part of the raffinate is branched off to prepare feed-grade zinc oxide according to the following steps: The branched-off raffinate is heated to 80-90℃, and sodium carbonate solution is added to adjust the pH value to 6.8-7.2, and an alkali zinc carbonate precipitate is generated by reaction; The precipitate is filtered and washed with hot water until the sulfate content is qualified, and after drying, feed-grade zinc oxide product is obtained by calcination at 450-550℃.

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