A method for preparing high-purity ultrafine active zinc powder using zinc-containing waste

Abstract

The present invention relates to a method for preparing high-purity ultrafine active zinc powder using zinc-containing waste, and belongs to the technical field of metallic zinc recovery. The method comprises mechanically grinding and refining the zinc-containing waste in a closed grinding device and simultaneously subjecting the waste to a leaching reaction in an alkaline solution to obtain an alkaline leachate and an alkaline leachate residue; adding an oxidant to the alkaline leachate for oxidation and impurity removal to obtain an oxidation-removed solution; adding zinc powder to the oxidation-removed solution for reduction and impurity removal to obtain a purified solution; adjusting the concentrations of zinc ions and ammonium chloride in the purified solution, and adding a surfactant to obtain an electrolyte; electrolysis at a low current density to reduce and precipitate metal impurities with a more positive potential than zinc; then increasing the current density and continuing the electrolysis to deposit zinc powder on the cathode; transferring the zinc powder to a dilute acid solution for activation treatment, and then washing, filtering, surface treating, and drying to obtain high-purity ultrafine active zinc powder; and returning the electrolyte to a waste liquid tank for recycling in the leaching process when the zinc content in the electrolyte is low and the chloride ion concentration is enriched to 180 to 280 g / L.

Description

Technical Field

[0001] The invention relates to a method for preparing high-purity ultrafine active zinc powder by utilizing zinc-containing waste materials, and belongs to the technical field of metal zinc recovery. Background Art

[0002] Ultrafine zinc powder, defined as zinc powder with a particle size below 10 μm, has broad application prospects in chemical production, lubricant additives, coatings, and high-performance electrode materials due to its unique physical and chemical properties. Currently, the most common applications of ultrafine zinc powder are in coatings and anti-corrosion applications, where it can be used to create zinc-rich coatings or directly plated onto anti-corrosion coatings. The finer the zinc powder particle size, the greater its surface activity, which facilitates the formation of a coating.

[0003] Currently, the main methods for preparing zinc powder include distillation, atomization, high-energy ball milling, electrolysis, and vacuum evaporation and condensation. Industrial production primarily relies on airflow atomization and evaporation and condensation. Airflow atomization is primarily used to produce coarse zinc powder larger than 45 microns. The traditional evaporation and condensation method uses a horizontal zinc powder furnace to generate zinc vapor, which is then condensed into zinc powder using a conventional condenser. Because horizontal zinc powder furnaces only produce zinc vapor and lack refining capabilities, they cannot directly produce high-purity zinc powder with a total zinc content of 99.5% to 99.95% from crude zinc. Subsequent processing of the zinc powder (such as transportation, screening, grading, and packaging) occurs in an atmospheric environment, which can lead to oxidation and reduce its activity. Furthermore, the raw material used during processing must be zinc ingots; zinc-containing materials cannot be used. Furthermore, leakage of zinc powder deteriorates the production environment, endangers the health of operators, and poses a safety hazard.

[0004] In comparison, the advantages of the electrolytic method are lower cost, shorter production cycle, and higher product purity. However, the disadvantages are that the shape and size of the zinc powder are difficult to control, severe hydrogen evolution leads to low current efficiency, and product collection is difficult. In the method of producing high-purity metallic zinc from zinc oxide ore, the zinc and lead in the raw zinc oxide ore are first leached and dissolved into the filtrate with a strong alkaline solution, then the lead and zinc in the filtrate are separated with a separator, and finally the filtrate containing only zinc is electrolyzed to produce high-purity metallic zinc. In the method of producing high-purity metallic zinc from zinc oxide ore, the zinc oxide ore is leached with an alkaline solution, a sulfide separator is added to the leached filtrate, the lead-containing filter residue in the separated liquid is filtered, and the filtrate is subjected to zinc electrolysis. However, the zinc powder produced by the above two processes has a relatively large particle size and is uneven in coarseness and fineness. The preparation of ultrafine zinc powder requires grinding in a ball mill, which consumes a lot of energy and is complex. In the method of preparing ultrafine zinc powder by electrolysis with alkaline solution by adding lead-containing compounds, after the separator separates the lead ions, the lead-containing compounds are added as needed in the electrolysis step to better refine the zinc powder. However, there is the problem of trace lead precipitation.

[0005] Furthermore, research on the recovery of zinc-containing waste residues is ongoing, but to date, no comprehensive method has been developed. Currently, there are three methods for treating zinc-containing waste residues: First, pyrometallurgical methods for recovering valuable metals from zinc electrolytic waste residues. However, these methods consume high energy, making them impractical for processing alone. They require blending with high-grade oxide ores for production. Furthermore, the resulting smoke and dust pose a significant environmental risk, requiring sophisticated dust removal equipment. Investment in both pyrometallurgical production and dust removal equipment is substantial. Second, flotation methods for recovering valuable metals from zinc electrolytic waste residues. However, this method consumes large amounts of reagents, results in low beneficiation yields, and struggles to meet the required concentrate grade. Most importantly, the drainage and slag removal processes still pose significant environmental risks and cause secondary pollution. Third, wet leaching methods for recovering zinc electrolytic leaching residues offer high recovery rates and can easily produce high-grade metal salt products. However, the current wet leaching process recovers zinc ingots, resulting in relatively high recovery costs and low added value. While wet leaching of waste residues is a promising development, further research and development of new processes and high-value-added products is needed. In the production of metallic zinc powder from zinc dust or zinc slag, zinc is leached with a strong alkaline solution, filtered, and lead is precipitated with sodium sulfide or other methods, and then electrolytically deposited to obtain zinc powder. This process is complex, and the lead separated from the zinc-containing material can only be used as lead waste and cannot be directly used as a product. In the recovery and preparation of ultrafine zinc powder from zinc-containing powder, zinc is leached with a strong alkaline solution, solid-liquid separation and electrolytic deposition are used to obtain zinc powder. The alkaline solution is then recycled as a raw material for leaching zinc slag. The resulting zinc powder is of insufficient purity and can only be used as a powder.

[0006] In summary, there are two main methods for preparing zinc powder: (1) atomizing metallic zinc liquid and rapidly cooling it; (2) heating metallic zinc into gas and rapidly cooling it. The above methods for producing zinc powder are difficult to produce zinc powder with a particle size of less than 20 microns, and the raw material requires metallic zinc. However, referring to the International Organization for Standardization's ultrafine high-activity zinc powder standard (ISO3549), ultrafine high-purity active zinc powder refers to zinc powder with a particle size of less than 10 μm and a powder content of more than 80%, and has the characteristics of high metallic zinc content (≥98%), low impurity content, smooth and clean surface, large specific surface area, high activity, low apparent density, low surface oxidation, and less melt deformation, adhesion, and platform-shaped particles. However, relying on existing preparation technology, it is impossible to achieve the relevant technical parameter indicators. Summary of the Invention

[0007] The present invention addresses the problem of preparing ultrafine active zinc powder and provides a method for preparing high-purity ultrafine active zinc powder using zinc-containing waste. The method comprises the following steps: using the zinc-containing waste as raw material, synergizing ball milling and leaching to promote particle refinement of the zinc-containing waste slag and improve the uniformity of the leaching process; utilizing the heat generated by ball milling friction to accelerate the leaching rate and effect; synergizing impurities between an oxidant and zinc powder, and further removing impurities at low current to ensure the purity of the zinc powder; and producing ultrafine zinc powder with the characteristics of small particle size, high activity and high purity by the method, with low production cost, low energy consumption and simple process control.

[0008] A method for preparing high-purity ultrafine active zinc powder using zinc-containing waste, comprising the following steps:

[0009] (1) The zinc-containing waste is mechanically ground into fine particles in a closed grinding device and simultaneously subjected to a leaching reaction in an alkaline solution, followed by solid-liquid separation to obtain an alkaline leachate and a leach residue; the alkaline solution is a mixed solution of ammonium chloride and aqueous ammonia;

[0010] (2) adding an oxidant to the alkaline leachate in step (1) for oxidative impurity removal, performing solid-liquid separation to obtain a de-impurity solution, and then adding zinc powder to the de-impurity solution for reduction and impurity removal to obtain a purified solution;

[0011] (3) adjusting the concentrations of zinc ions and ammonium chloride in the purified solution of step (2), adding a surfactant, and adjusting the pH value to obtain an electrolyte;

[0012] (4) inserting an anode plate and a cathode plate into the electrolyte obtained in step (3) to carry out an electrolytic reaction; depositing zinc powder on the cathode, and scraping the electrolytic zinc powder on the cathode;

[0013] (5) adding the electrolytic zinc powder obtained in step (4) to a dilute acid solution for activation treatment, washing and filtering to obtain active zinc powder, then adding the active zinc powder to a surface treatment solution for surface treatment, filtering, and drying to obtain high-purity ultrafine active zinc powder; preferably, the washing method is to use hot water at a temperature of 50 to 70° C. to wash away residual acid ions and adsorbed surfactants, and then use anhydrous ethanol to wash away residual water on the zinc powder;

[0014] (6) After the electrolyte in step (4) continues to be electrolyzed for several cycles, the zinc ion content in the electrolyte decreases and the chloride ion concentration increases. When the chloride ion concentration is enriched to 180-280 g / L, the electrolyte returns to step (1) for the leaching process.

[0015] The zinc-containing waste is one or more of zinc-containing smoke, zinc smelting waste slag, zinc dust, zinc scum, and high-chloride zinc-containing waste slag; the main components of the zinc-containing waste are one or more of Zn, ZnO, and ZnCl2, and contain impurities such as FeO, CuO, and lead compounds; the concentration of ammonium chloride solution in the alkaline solution is 20-80 g / L, and the concentration of ammonia water is 3-10 g / L.

[0016] In step (2), the oxidant is one or more of hydrogen peroxide, glucose, hydrazine hydrate, formaldehyde, and ascorbic acid, and the amount of the oxidant added is 5 to 20 g / L; the oxidant is preferably hydrogen peroxide.

[0017] The amount of zinc powder added in step (2) is 2-8 g / L.

[0018] In step (3), the zinc ion concentration is 20-30 g / L, the ammonium chloride concentration is 45-60 g / L, and the pH value of the electrolyte is 9-10.

[0019] The amount of surfactant added in step (3) is 10-30 mg / L, and the surfactant is one or more of Tween, sodium dodecylbenzenesulfonate, starch, and polyethylene glycol.

[0020] In step (4), the anode is a zinc plate anode, a lead alloy anode or a titanium-based coating anode, the cathode is a stainless steel cathode, an aluminum cathode or a zinc cathode, the inter-electrode distance is 5 to 15 cm, the entire electrolysis process is carried out in an electrolytic cell, and the electrolysis temperature is 40 to 60° C. The specific method of the electrolysis reaction is: at a low current density of 50 to 150 A / m 2 Electrolysis is carried out at a high current density of 550-800 A / m 2 Electrolyze for 20-40 minutes to deposit zinc powder on the cathode, and scrape the cathode zinc powder.

[0021] The dilute acid solution in step (5) is sulfuric acid, nitric acid or acetic acid, the mass concentration of the dilute acid solution is 0.5-1.5%, the activation temperature is room temperature, and the activation time is 30-90 minutes.

[0022] The surface treatment agent in step (5) is dodecanethiol or a silane coupling agent, the concentration of the surface treatment agent is 0.2 to 1 mg / L, and the treatment time is 3 to 10 minutes.

[0023] The drying method in step (6) is vacuum drying, nitrogen drying or freeze drying.

[0024] The high-purity ultrafine active zinc powder has an average particle size of 4 to 8 μm, a purity of 99.95 to 99.99%, and a shape of dendrites, flakes, fish scales, or spheres.

[0025] The principle of preparing high-purity ultrafine active zinc powder from zinc-containing waste:

[0026] 1. Basic principles of leaching process:

[0027] (1) Alkali leaching (sodium hydroxide, potassium hydroxide)

[0028] Zn+4OH - =ZnO2 2- +2H2O

[0029] ZnO+OH - =ZnO2 2- +H2O

[0030] Zn 2+ +4OH - =Zn(OH)4 2-

[0031] (2) Ammonia leaching

[0032] Zn+4OH - =ZnO2 2- +2H2O

[0033] ZnO+OH - =ZnO2 2- +H2O

[0034] ZnO+mNH3·H2O=Zn(NH3) m 2+ +mH2O

[0035] Zn 2+ +4OH - =Zn(OH)4 2-

[0036] (3) Ammonium salt leaching

[0037] ZnO+2NH4 + =Zn(NH3)2 2+ +H2O

[0038] Zn 2+ +2NH4 + =Zn(NH3)2 2+ +2H +

[0039] Leaching using synergistic reactions such as (1), (2) and (3);

[0040] 2. After leaching, oxidation and reduction are carried out to remove impurities. The specific reaction formula is:

[0041] (1) Oxidation and impurity removal:

[0042] Fe2+ +Oxidant+OH - =Fe(OH)3↓

[0043] (2) Zinc powder replacement and impurity removal:

[0044] Cu 2+ +Zn=Zn 2+ +Cu

[0045] Pb 2+ +Zn=Zn 2+ +Pb

[0046] Cd 2+ +Zn=Zn 2+ +Cd

[0047] 3. Electrode reaction process of electrolysis

[0048] (1) Anode reaction

[0049] 4OH - ↑→O2+2H2O+4e-

[0050] (2) Cathode reaction

[0051] Zn 2+ +2e→Zn↓

[0052] Cu 2+ +2e→Cu↓

[0053] Cd 2+ +2e→Cd↓

[0054] Pb 2+ +2e→Pb↓

[0055] 2H + +2e→H2↑

[0056] After the additives are added to the electrolyte, the cathode polarization curve test is carried out by taking Tween as an example. Figure 8 As shown in the figure, after the surfactant Tween is added to the electrolyte, the polarization is enhanced and the cathode deposition overpotential is increased, thereby increasing the nucleation rate, which is more significant at low current density, providing a guarantee for metal impurity removal by low current electrode reduction potential correction.

[0057] The beneficial effects of the present invention are:

[0058] (1) The present invention uses zinc-containing waste as raw material, promotes the refinement of zinc-containing waste slag particles and improves the uniformity of the leaching process through ball milling and leaching, and utilizes the heat generated by ball milling friction to accelerate the leaching rate and effect; impurities are removed by oxidizing agent and zinc powder, and further impurities are removed under low current to ensure the purity of zinc powder; the method has low energy consumption, high efficiency, easy process control and is convenient for large-scale production;

[0059] (2) The present invention uses zinc-containing waste with low recycling value as raw material to prepare high-purity ultrafine active zinc powder with high grade and high recycling added value;

[0060] (3) When the chloride ion concentration in the electrolytic wastewater of the present invention is 180-280 g / L, it can be returned for leaching reaction, so the process solution can be recycled and no waste liquid is discharged;

[0061] (4) The zinc powder prepared by the present invention has small particle size, large specific surface area, high activity, and meets the requirements for electronic grade use. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 It is a process flow chart of the present invention;

[0063] Figure 2 Phase analysis diagram of high-purity ultrafine active zinc powder in Example 1

[0064] Figure 3 This is the particle size distribution diagram of the high-purity ultrafine active zinc powder in Example 1;

[0065] Figure 4 This is a microscopic morphology of the high-purity ultrafine active zinc powder of Example 2;

[0066] Figure 5 This is the particle size distribution diagram of the high-purity ultrafine active zinc powder in Example 2;

[0067] Figure 6 This is a microscopic morphology of the high-purity ultrafine active zinc powder of Example 3;

[0068] Figure 7 This is the particle size distribution diagram of the high-purity ultrafine active zinc powder of Example 3;

[0069] Figure 8 These are the cathodic polarization curves when different concentrations of Tween are added as surfactant in the electrolyte. DETAILED DESCRIPTION

[0070] The present invention will be further described in detail below in conjunction with specific embodiments, but the protection scope of the present invention is not limited to the contents described above.

[0071] Example 1: The composition of the zinc-containing waste in this example is shown in Table 1.

[0072] Table 1 Composition of zinc-containing waste (metal element content)

[0073]

[0074] A method for preparing high-purity ultrafine active zinc powder using zinc-containing waste (see Figure 1 ), the specific steps are as follows:

[0075] (1) 1000 g of zinc-containing waste is added to a closed grinding device for mechanical grinding to refine particles and then subjected to a leaching reaction simultaneously with an alkaline mixed solution of ammonium chloride and ammonia water, followed by solid-liquid separation to obtain an alkaline zinc leachate and a leaching residue; wherein the concentration of the ammonium chloride solution in the alkaline mixed solution is 20 g / L, the concentration of the ammonia water is 10 g / L, and the leaching reaction temperature is room temperature;

[0076] (2) adding the alkaline leaching solution in step (1) to a purification tank, adding hydrogen peroxide as an oxidant, performing oxidation decontamination at room temperature for 10 minutes, performing solid-liquid separation to obtain a decontamination solution, adding zinc powder to the decontamination solution, performing reduction decontamination at room temperature to obtain a purified solution; wherein the amount of the oxidant hydrogen peroxide added is 5 g / L, and the amount of the zinc powder added is 8 g / L;

[0077] (3) adding deionized water and ammonium chloride to adjust the concentration of zinc ions in the purified solution of step (2) to 20 g / L and the concentration of ammonium chloride to 45 g / L, adjusting the pH value to 10, and adding a surfactant Tween to obtain an electrolyte; wherein the amount of the surfactant Tween added is 10 mg / L;

[0078] (4) Using the titanium-based coating anode as the electrolytic anode and the zinc plate as the cathode with an inter-electrode distance of 5 cm, electrolysis is carried out in the electrolyte of step (3), and the zinc powder on the cathode plate is scraped off; after the electrolyte continues to be electrolyzed for several cycles, the zinc ion content in the electrolyte decreases, and when the chloride ion concentration in the electrolytic waste liquid is 180 g / L, return to step (1) for leaching reaction; wherein, the electrolysis temperature is 40°C, and the current density is 100 A / m 2 Electrolyze for 5 minutes to reduce and remove the impurity metals with more positive electrophoresis than zinc in the solution, and then increase the current density to 550A / m 2 Electrolyze for 40 minutes to deposit zinc powder on the cathode;

[0079] (5) The cathode zinc powder is added to a sulfuric acid solution with a concentration of 0.5%, and activated at room temperature for 30 minutes. Then, hot water with a temperature of 70°C is used to rinse the residual acid ions and adsorbed surfactants until the hot water is neutral. Then, the residual water on the zinc powder is rinsed with anhydrous ethanol, and the aged zinc powder is filtered to obtain an aged zinc powder. The aged zinc powder is then added to a surfactant treatment solution containing dodecyl mercaptan for surface treatment for 3 minutes, and then freeze-dried to obtain a high-purity ultrafine active zinc powder; wherein the concentration of the dodecyl mercaptan surfactant is 0.2 mg / L;

[0080] The phase analysis diagram of the high-purity ultrafine active zinc powder of this embodiment is shown in FIG. Figure 2 , particle size distribution diagram see Figure 3 ,from Figure 2 and Figure 3It can be seen that the purity of the high-purity ultrafine active zinc powder of this embodiment is 99.96%, the average particle size is 6.309 microns, the morphology is spherical, and the zinc recovery rate is 95%.

[0081] Example 2: The composition of the zinc-containing waste in this example is shown in Table 2.

[0082] Table 2 Composition of zinc-containing waste (metal element content)

[0083]

[0084] A method for preparing high-purity ultrafine active zinc powder using zinc-containing waste (see Figure 1 ), the specific steps are as follows:

[0085] (1) 1000 g of zinc-containing waste was added to a closed grinding device for mechanical grinding to refine particles and then subjected to a leaching reaction in an alkaline mixed solution of ammonium chloride and ammonia water, followed by solid-liquid separation to obtain an alkaline leachate and a leached residue; wherein the concentration of ammonium chloride solution in the alkaline mixed solution was 50 g / L, the concentration of ammonia water was 3 g / L, and the leaching reaction temperature was room temperature;

[0086] (2) adding the alkaline leaching solution in step (1) to a purification tank, adding glucose as an oxidant, performing oxidation decontamination at room temperature for 30 minutes, performing solid-liquid separation to obtain a decontamination solution, adding zinc powder to the decontamination solution, performing reduction decontamination at room temperature to obtain a purified solution; wherein the amount of glucose added as the oxidant is 10 g / L, and the amount of zinc powder added is 5 g / L;

[0087] (3) adjusting the concentration of zinc ions in the purified solution of step (2) to 25 g / L and the concentration of ammonium chloride to 50 g / L by adding deionized water and ammonium chloride, adjusting the pH value to 9, and adding a surfactant, sodium dodecylbenzenesulfonate, to obtain an electrolyte; wherein the amount of the surfactant sodium dodecylbenzenesulfonate added is 20 mg / L;

[0088] (4) Using the zinc plate as the electrolytic anode and the aluminum plate as the cathode, with an inter-electrode distance of 10 cm, electrolyze in the electrolyte of step (3), and scrape the zinc powder on the cathode plate; after the electrolyte continues to electrolyze for several cycles, the zinc ion content in the electrolyte decreases, and when the chloride ion concentration in the electrolytic waste liquid is 280 g / L, return to step (1) for leaching reaction; wherein the electrolysis method is: the electrolysis temperature is 45 ° C, the current density is 50 A / m 2 Electrolyze for 10 minutes to reduce and remove the impurity metals with more positive electrophoresis than zinc in the solution, and then increase the current density to 700A / m 2 Electrolyze for 30 minutes to deposit zinc powder on the cathode;

[0089] (5) The cathode zinc powder is added to a dilute acetic acid solution with a concentration of 1%, and activated at room temperature for 50 minutes. Then, hot water with a temperature of 60°C is used to wash away the residual acid ions and adsorbed surfactants. The hot water is washed until the hot water is neutral. Then, the residual water on the zinc powder is washed with anhydrous ethanol, and the aged zinc powder is filtered to obtain an aged zinc powder. The aged zinc powder is then added to a surface active treatment solution containing a surfactant silane coupling agent for surface treatment for 10 minutes, and then dried in a vacuum manner to obtain a high-purity ultrafine active zinc powder; wherein the concentration of the surfactant silane coupling agent is 0.5 mg / L;

[0090] The surface morphology of the high-purity ultrafine active zinc powder of this embodiment is shown in FIG. Figure 4 , laser particle size see Figure 5 ,from Figure 4 and Figure 5 It can be seen that the purity of the high-purity ultrafine active zinc powder of this embodiment is 99.97%, the average particle size is 6.464 μm, the morphology is dendritic, and the zinc recovery rate is 94.5%.

[0091] Example 3: The composition of the zinc-containing waste in this example is shown in Table 3.

[0092] Table 3 Composition of zinc-containing waste (metal element content)

[0093]

[0094] A method for preparing high-purity ultrafine active zinc powder using zinc-containing waste (see Figure 1 ), the specific steps are as follows:

[0095] (1) 1000 g of zinc-containing waste is added to a closed grinding device for mechanical grinding to refine particles and simultaneously subjected to leaching reaction in an alkaline mixed solution of ammonium chloride and ammonia water until the pH value is 8.0-8.5, followed by solid-liquid separation to obtain an alkaline leaching solution and an alkaline leaching residue; wherein the concentration of the ammonium chloride solution in the alkaline mixed solution is 80 g / L, the concentration of the ammonia water is 6 g / L, and the leaching reaction temperature is room temperature;

[0096] (2) adding the alkaline leaching solution in step (1) to a purification tank, then adding hydrazine hydrate as an oxidant, performing oxidation removal at room temperature for 30 minutes, performing solid-liquid separation to obtain a de-impurity solution, adding zinc powder to the de-impurity solution, performing reduction removal at room temperature to obtain a purified solution; wherein the amount of hydrazine hydrate added as an oxidant is 20 g / L, and the amount of zinc powder added is 2 g / L;

[0097] (3) adjusting the concentration of zinc ions in the purified solution of step (2) to 30 g / L and the concentration of ammonium chloride to 60 g / L by adding deionized water and ammonium chloride, adjusting the pH value to 9.5, and adding a surfactant polyethylene glycol to obtain an electrolyte; wherein the amount of the surfactant polyethylene glycol added is 30 mg / L;

[0098] (4) Using a lead plate as an electrolytic anode and a stainless steel plate as a cathode with an inter-electrode distance of 15 cm, electrolysis is performed in the electrolyte of step (3), and zinc powder on the cathode plate is scraped off; after the electrolyte continues to be electrolyzed for several cycles, the zinc ion content in the electrolyte decreases, and when the chloride ion concentration in the electrolytic waste liquid is 250 g / L, return to step (1) for leaching reaction; wherein the electrolysis method is: the electrolysis temperature is 50°C, the current density is 150 A / m 2 Electrolyze for 3 minutes to reduce and remove the impurity metals with more positive electrophoresis than zinc in the solution, and then increase the current density to 800A / m 2 Electrolyze for 20 minutes to deposit zinc powder on the cathode;

[0099] (5) The cathode zinc powder is added to a dilute nitric acid solution with a concentration of 1.5%, and activated at room temperature for 90 minutes. Then, hot water with a temperature of 70°C is used to rinse the residual acid ions and adsorbed surfactants until the hot water is neutral. Then, the residual water on the zinc powder is rinsed with anhydrous ethanol, and the aged zinc powder is filtered to obtain an aged zinc powder. The aged zinc powder is then added to a surface active treatment solution containing a surfactant, dodecanethiol, for surface treatment for 10 minutes. The powder is dried by blowing nitrogen to obtain a high-purity ultrafine active zinc powder; wherein the concentration of the surfactant, dodecanethiol, is 1 mg / L.

[0100] The surface morphology of the high-purity ultrafine active zinc powder of this embodiment is shown in FIG. Figure 6 , particle size distribution see Figure 7 ,from Figure 6 and Figure 7 It can be seen that the purity of the high-purity ultrafine active zinc powder of this embodiment is 99.93%, the average particle size is 6.57 μm, the morphology is thick flakes, and the zinc recovery rate is 93.8%.

[0101] The above describes the specific embodiments of the present invention in detail, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in this field without departing from the scope of the present invention.

Claims

1. A method for preparing high-purity ultrafine active zinc powder using zinc-containing waste, characterized in that: The specific steps are as follows: (1) The zinc-containing waste is mechanically ground into fine particles in a closed grinding device and simultaneously leached in an alkaline solution, followed by solid-liquid separation to obtain an alkaline leachate and leach residue; The alkaline solution is a mixed solution of ammonium chloride and ammonia water; the zinc-containing waste contains impurities of FeO, CuO and lead compounds; the concentration of ammonium chloride solution in the alkaline solution is 20-80 g / L, and the concentration of ammonia water is 3-10 g / L; (2) adding an oxidant to the alkaline leachate in step (1) to perform oxidation removal, separating the solid and liquid to obtain a decontaminated solution, and then adding zinc powder to the decontaminated solution to perform reduction removal to obtain a purified solution; (3) adjusting the concentrations of zinc ions and ammonium chloride in the solution purified in step (2), adding a surfactant, and adjusting the pH value to obtain an electrolyte; the surfactant is one or more of Tween, sodium dodecylbenzenesulfonate, starch, and polyethylene glycol; the zinc ion concentration in the electrolyte is 20-30 g / L, the ammonium chloride concentration is 45-60 g / L, and the pH value of the electrolyte is 9-10; (4) inserting an anode plate and a cathode plate into the electrolyte obtained in step (3) to carry out electrolytic reaction; depositing zinc powder on the cathode, and scraping the electrolytic zinc powder on the cathode; the specific method of the electrolytic reaction is: at a low current density of 50~150 A / m 2 Electrolyze for 5-15 minutes at a high current density of 550-800 A / m 2 Electrolysis is carried out for 20-40 minutes; the distance between the anode plate and the cathode plate is 5-15 cm, and the electrolysis temperature is 40-60°C; (5) adding the electrolytic zinc powder obtained in step (4) into a dilute acid solution for activation treatment, washing and filtering to obtain active zinc powder, then adding the active zinc powder into a surface treatment solution for surface treatment, filtering and drying to obtain high-purity ultrafine active zinc powder; (6) After the electrolyte in step (4) continues to be electrolyzed for several cycles, the zinc ion content in the electrolyte decreases and the chloride ion concentration gradually enriches. When the chloride ion concentration is enriched to 180~280g / L, the electrolyte returns to step (1) for the leaching process.

2. The method for preparing high-purity ultrafine active zinc powder from zinc-containing waste according to claim 1, wherein: The zinc-containing waste material is one or more of zinc-containing smoke, zinc smelting waste slag, zinc dust, zinc dross, and high-chloride zinc-containing waste slag.

3. The method for preparing high-purity ultrafine active zinc powder from zinc-containing waste according to claim 1, wherein: In step (2), the oxidant is one or more of hydrogen peroxide, glucose, hydrazine hydrate, formaldehyde, and ascorbic acid, and the amount of the oxidant added is 5-20 g / L.

4. The method for preparing high-purity ultrafine active zinc powder from zinc-containing waste according to claim 1 or 3, characterized in that: The amount of zinc powder added in step (2) is 2-8 g / L.

5. The method for preparing high-purity ultrafine active zinc powder from zinc-containing waste according to claim 1, wherein: The amount of surfactant added in step (3) is 10~30 mg / L.

6. The method for preparing high-purity ultrafine active zinc powder from zinc-containing waste according to claim 1, characterized in that: In step (4), the anode is a zinc plate anode, a lead alloy anode or a titanium-based coating anode, and the cathode is a stainless steel cathode, an aluminum cathode or a zinc cathode.

7. The method for preparing high-purity ultrafine active zinc powder from zinc-containing waste according to claim 1, characterized in that: In step (5), the dilute acid solution is sulfuric acid, nitric acid or acetic acid, the mass concentration of the dilute acid solution is 0.5-1.5%, and the activation time is 30-90 min.

8. The method for preparing high-purity ultrafine active zinc powder from zinc-containing waste according to claim 1, characterized in that: In step (5), the surface treatment agent is dodecanethiol or a silane coupling agent, the concentration of the surface treatment agent is 0.2-1 mg / L, and the treatment time is 3-10 min.

9. The method for preparing high-purity ultrafine active zinc powder from zinc-containing waste according to claim 1, characterized in that: The drying method in step (5) is vacuum drying, nitrogen drying or freeze drying.

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