Method for recovering indium and germanium from zinc smoke dust

Abstract

The invention discloses a method for recovering indium and germanium from zinc smoke dust, which comprises the following steps: mixing zinc oxide smoke dust with waste electrolyte, carrying out low-acid leaching, and filtering the obtained leaching mixture to obtain filtrate I and indium-containing filter residue I; extracting germanium from the filtrate I through an extraction process consisting of desilicication, extraction, washing, reverse extraction and hydrolysis, wherein organic phases, including an extracting agent, a T reagent and kerosene, need to be added during extraction; the filter residues I are subjected to high-acid leaching, purification, extraction and reverse extraction, sponge indium and zinc are obtained after a zinc plate is added for replacement, and then the sponge indium is subjected to a plurality of procedures to obtain indium ingots; and the raffinate obtained by extraction can be subjected to a plurality of procedures to obtain zinc ingots. According to the method disclosed by the invention, indium and germanium metals in the zinc oxide smoke dust produced by the zinc smelting plant are respectively recovered by adopting double processes, the problem that the content of silicon dioxide in indium and germanium products is too high can be avoided through the desilicication step, and efficient utilization of germanium and indium and comprehensive utilization of waste electrolyte and smoke dust in smelting production are smoothly realized.

Description

Technical Field

[0001] The invention belongs to the technical field of recovering indium and germanium from zinc oxide smoke, and specifically relates to a method for recovering indium and germanium from zinc oxide smoke. Background Art

[0002] Zinc smelting usually uses hydrometallurgy to recover zinc and other valuable metal elements. In the process of roasting-leaching-purification-electrodeposition of hydrometallurgical zinc smelting, indium germanium enters the zinc leaching slag in the conventional leaching process, and then volatilizes with lead and zinc in the pyrometallurgical volatilization process of the zinc leaching slag and is enriched in the zinc oxide smoke. Zinc oxide smoke contains high indium germanium content and has high recycling value. It is of great significance to recover indium germanium from zinc oxide smoke.

[0003] Zinc oxide dust is generally recovered by sulfuric acid leaching - tannin germanium precipitation - calcination - chlorination distillation process. Tannin germanium precipitation is a traditional process that has been used for many years. The process is simple and mature, but the amount of tannin used in this process is 20 to 25 times the mass of germanium, which is a large amount and cannot be recycled and reused, resulting in high costs for tannin germanium precipitation. In recent years, the price of tannin has risen sharply, making the cost of germanium recovery increasingly high. At the same time, because tannin is an organic matter, excessive tannin will stably exist in the hydrometallurgical zinc solution, resulting in problems such as reduced zinc electrolysis efficiency and poor zinc plate quality.

[0004] Chinese patent CN 107058751 A proposes a method for recovering zinc, copper and germanium from zinc oxide dust. The invention recovers germanium from zinc oxide dust by acid leaching, arsenic removal and germanium reduction precipitation, wherein arsenic removal is carried out by adding zinc, iron, zinc suboxide or zinc sulfite, and germanium is reduced and precipitated by iron powder or iron filings. The process does not consider the recovery of other valuable metals such as indium and copper, and is not suitable for the treatment of indium-containing zinc dust.

[0005] Fu Weiqun and others adopted the "normal pressure leaching-oxygen pressure leaching" process. After one stage of normal pressure acid leaching and one stage of oxygen pressure acid leaching, the cumulative leaching rates of zinc, germanium and indium can reach 96.15%, 91.58% and 87.90% respectively; Peng Jinhui and others used ultrasound to directly enhance the neutral leaching of zinc oxide dust, and the leaching rate of zinc was >75%; Wang Wankun used microwave calcination-sulfuric acid leaching and microwave alkaline roasting-water solution neutral leaching to treat germanium-containing zinc oxide dust, and the leaching rates of germanium were 84.37% and 97.38% respectively. Although the leaching rate of this process is relatively high, it requires the use of new equipment and processes such as oxygen pressure acid leaching, and the problem of solution recycling is not investigated. There are problems such as complex equipment operation and difficult wastewater treatment. In addition, only a single-stage neutralization precipitation experiment was carried out, which makes it difficult to simultaneously meet the requirements of high germanium mass fraction in the slag and low germanium mass concentration in the liquid after germanium precipitation, and whether the neutralized germanium precipitation slag is easy to be subsequently treated has not been studied. The current treatment process of zinc oxide fume has problems such as high comprehensive cost of germanium and other valuable metals, long process, high equipment requirements and certain impact on subsequent production. Therefore, this paper proposes a method for recovering indium and germanium from zinc fume. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a method for recovering indium and germanium from zinc smoke. The method adopts a comprehensive process of atmospheric pressure hydrochloric acid leaching and two-stage leaching process. The process can effectively separate various metals in zinc smelting tailings, has the characteristics of high recovery rate, low production cost, meeting product quality requirements, and repeated use of acid solution, thus achieving low-pollution, low-carbon economic industrial production and the purpose of recycling rare and precious metals.

[0007] In order to achieve the above technical effects, the present invention is implemented by the following technical scheme: a method for recovering indium and germanium from zinc fume, specifically comprising the following steps: S1, mixing zinc oxide smoke and waste electrolyte, performing low-acid leaching, and filtering the obtained leached mixture to obtain filtrate I and indium-containing filter residue I; The mass percentage of each component of the zinc oxide smoke includes: 50-60% zinc, 20-25% lead, 2-4% iron, 0.01-0.02% indium, 1-2% silicon, 0.04-0.06% germanium, 0.7-1% arsenic, and the remainder is impurities; The filtrate I contains Zn: 120-150 g / L, Ge: 60-80 mg / L, Si: 800-850 mg / L, and Fe: 2-4.0 g / L; Preferably, the Zn mass concentration in the waste electrolyte in S1-S3 is 50-60 g / L, and the H2SO4 mass concentration is 160-180 g / L.

[0008] Preferably, the pH of the low-acid leaching solution in S1 is 5-6, the volume ratio of smoke mass to waste electrolyte is 1:(6-7), the leaching temperature is 80-85°C, and the leaching time is 2h.

[0009] S2, extracting germanium from the filtrate I in S1 through an extraction process consisting of desiliconization, extraction, washing, stripping and hydrolysis, and the extraction requires the addition of an organic phase including an extractant, T reagent and kerosene, and the kerosene is supplemented during the extraction process; Preferably, the extraction process in S2 specifically comprises the following steps: S201, desiliconization is performed by adding 0.2-0.4 g / L of cattle glue to the filtrate I; S202, after desiliconization, the solution is added with an organic phase including 25-30% 7815 extractant, 25-30% T reagent, and 40-50% kerosene, and the extraction ratio is O / A=1 / 3, and kerosene is supplemented during the process; S203, then add 0.2~0.25mol / L H2SO4 to the extract for washing, add 2~3mol / L NaOH to the extract after washing for stripping, and add 2~2.5mol / L H2SO4 to the stripping raffinate for regeneration; S204, the stripping solution is mixed with sulfuric acid in a ratio of 1:1-1.5 and hydrolyzed to obtain germanium concentrate.

[0010] S3, the filter residue I in S1 is subjected to high acid leaching, purification, extraction and stripping, and zinc plate replacement to obtain sponge indium and zinc, and then the sponge indium is subjected to briquetting, smelting, electrolysis, cadmium and thallium removal, and casting to obtain indium ingots; and the raffinate obtained by extraction can be subjected to iron removal, purification, electrolysis, and ingot casting to obtain zinc ingots.

[0011] Preferably, the specific steps of the high acid leaching process in S3 include: adding the filter residue I obtained in S1 to the waste electrolyte, adding sulfuric acid, and then acid leaching, and filtering the obtained leaching mixture to obtain filter residue II and filtrate II.

[0012] Based on the previous step, preferably, the initial sulfuric acid mass concentration of the acid leaching solution is 60-80 g / L, the mass ratio of filter residue I to waste electrolyte is 1:3-5, the leaching temperature is 80-85°C, the reaction time is 2h, and the final acidity of the filtrate II obtained after the reaction is <35 g / L.

[0013] Preferably, the specific steps of the purification process in S3 include: the filter residue II is recovered by using a lead smelting system of a pyrometallurgical lead smelting process to finally obtain valuable metallic lead; the filtrate II can be added with a flocculant solution and a gelatin solution, clarified for 4 to 6 hours, and filtered through a double-layer filter cloth to obtain a filter residue III and a filtrate III; the filtrate II can also be neutralized with zinc oxide smoke to precipitate indium, thereby enriching the indium element.

[0014] Based on the above step, the flocculant is preferably 3 # (polyacrylamide), the addition amount is 0.03~5kg / mol / L 3 ; The amount of gelatin added is 0.02~0.03 kg / mol / L 3 ; The filter residue III is a slag containing silica, which is stored.

[0015] Based on the above step, the neutralization and precipitation of indium specifically includes the following steps: S301, adding zinc oxide smoke to the obtained filtrate II for pre-neutralization, and filtering to obtain filtrate IV and filter residue IV; S302, zinc oxide fume is added to the filtrate IV to neutralize and precipitate indium, and the filter residue V and the filtrate V are filtered to obtain the filter residue IV and the filtrate V, and the filter residue IV and the filtrate V are returned to the low-acid leaching step, and the final acidity of the filtrate IV is 0-5g / L H2SO4, the neutralization reaction temperature is 70-80°C, and the neutralization time is 0.5-1h; S303, the filter residue V is mixed with the waste electrolyte for acid leaching and then filtered to obtain the filtrate VI and the filter residue VI, the filter residue VI is recycled in the lead smelting system of the pyrometallurgical lead smelting, the filtrate VI is returned to the desiliconization extraction step, and the acid leaching temperature is 70-80°C, the leaching time is 2h, the liquid-solid ratio is 3-5:1, the end point pH value of the filtrate V is 4.4-4.8, and the final acidity of the filtrate VI is 60-65g / L.

[0016] As a preferred embodiment, the reaction conditions of extraction and stripping in S3 are: the extraction of filtrate III is 15-20% P204 + 80-85% 260 # The stripping is carried out in a kerosene system, with an extraction phase ratio O / A of 1 / 5-6, a mixing time of 5-10 min, and an extraction temperature of 40-45°C; the stripping is carried out in a 3mol / LHCl+2mol / LZnCl2 system, with an O / A ratio of 20-25 / 1, a mixing time of 10-15 min, and an extraction temperature of 40-45°C, and an ammonium fluoride solution is added to the lean organic phase obtained by stripping to wash iron to obtain a regenerated organic phase, which is returned to the extraction.

[0017] The beneficial effects of the present invention are: 1. Realize low-cost and efficient utilization of germanium in zinc oxide dust. Zinc oxide dust is leached with low acid at normal pressure to obtain germanium concentrate through impurity removal, extraction and hydrolysis, thus realizing efficient recovery of germanium. Overcome the difficulties of silicon dioxide impurity removal technology and composite germanium extraction technology, solve the problems of high cost, long process, high equipment requirements and certain impact on subsequent production in the current germanium processing technology, and realize low-cost and efficient recovery of germanium; 2. Realize efficient recovery of indium from zinc oxide dust. Zinc oxide dust is leached at normal pressure and low acid, and then subjected to impurity removal, extraction, reduction and replacement to obtain crude indium; 3. Clean production process. All wastewater is returned to the process for recycling, achieving zero wastewater discharge; no waste gas is generated during the process; except for the storage of silicon dioxide waste residue, all other products are output in the form of products; 4. Adopt the method of "waste treatment with waste" to achieve the goal of reducing and harmless waste. Using electrolytic waste liquid to leach zinc oxide smoke not only achieves the disposal of electrolytic waste liquid, but also utilizes the acid and valuable metals in the electrolytic waste liquid.

[0018] As described above, the present invention aims at the characteristics of zinc oxide fume for recovering valuable metals, and uses green economic technology to recover various valuable metals, thereby achieving the purpose of comprehensive recovery and utilization of valuable metals such as lead, germanium, and indium, providing ideas for the recovery and utilization of zinc oxide fume and valuable metals, and also providing guidance for the process design of valuable metal recovery, thereby promoting the sustainable development of green recovery of valuable metals. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solution of the embodiment of the present invention, the drawings required for describing the embodiment are briefly introduced below. Those skilled in the art can also obtain other drawings based on these drawings without paying any creative work.

[0020] Figure 1 is a flow chart of the method of the present invention; Figure 2 is a schematic diagram of germanium extraction of the present invention; Figure 3 This is a process flow chart of extracting germanium according to the present invention; Figure 4 The process flow chart of the present invention is as follows: neutralization precipitation indium, extraction extraction indium, and preparation of indium DETAILED DESCRIPTION

[0021] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention. Example 1

[0022] like Figure 1~Figure 4 As shown, in this embodiment, the inventors provide a method for recovering indium and germanium from zinc fume in order to recover valuable metals in zinc oxide fume while reducing the recovery cost and pollution to the environment. The method specifically comprises the following steps: S1, mixing zinc oxide smoke and waste electrolyte, performing low-acid leaching, and filtering the obtained leached mixture to obtain filtrate I and indium-containing filter residue I; The mass percentage of each component of zinc oxide smoke includes: zinc 50-60%, lead 20-25%, iron 2-4%, indium 0.01-0.02%, silicon 1-2%, germanium 0.04-0.06%, arsenic 0.7-1%, and the remainder is impurities; Filtrate I contains Zn: 120~150g / L, Ge: 60~80mg / L, Si: 800~850mg / L, Fe: 2~4.0g / L; Furthermore, the mass concentration of Zn in the spent electrolyte in S1~S3 is 50~60 g / L, and the mass concentration of H2SO4 is 160~180 g / L.

[0023] Furthermore, the pH of the low-acid leaching solution in S1 is 5-6, the ratio of the smoke mass to the volume of the spent electrolyte is 1:(6-7), the leaching temperature is 80-85°C, and the leaching time is 2h.

[0024] S2, extracting germanium from the filtrate I in S1 through an extraction process consisting of desiliconization, extraction, washing, stripping and hydrolysis, and the extraction requires the addition of an organic phase including an extractant, T reagent and kerosene, and the kerosene is supplemented during the extraction process; Furthermore, the extraction process in S2 specifically includes the following steps: S201, desiliconization is performed by adding 0.2-0.4 g / L of cattle glue to the filtrate I; S202, after desiliconization, the solution is added with an organic phase including 25-30% 7815 extractant, 25-30% T reagent, and 40-50% kerosene, and the extraction ratio is O / A=1 / 3, and kerosene is supplemented during the process; S203, then add 0.2~0.25mol / L H2SO4 to the extract for washing, add 2~3mol / L NaOH to the extract after washing for stripping, and add 2~2.5mol / L H2SO4 to the stripping raffinate for regeneration; S204, the stripping solution is mixed with sulfuric acid in a ratio of 1:1-1.5 and hydrolyzed to obtain germanium concentrate.

[0025] S3. The filter residue I in S1 is subjected to high acid leaching, purification, extraction and stripping, and zinc plate replacement to obtain sponge indium and zinc. The sponge indium is then subjected to briquetting, smelting, electrolysis, cadmium and thallium removal, and casting to obtain indium ingots. The raffinate obtained by extraction can be subjected to iron removal, purification, electrolysis, and ingot casting to obtain zinc ingots.

[0026] Furthermore, the specific steps of the high acid leaching process in S3 include: adding the filter residue I obtained in S1 to the waste electrolyte, adding sulfuric acid, and then acid leaching, and filtering the obtained leaching mixture to obtain filter residue II and filtrate II.

[0027] Based on the previous step, preferably, the initial sulfuric acid mass concentration of the acid leaching solution is 60-80 g / L, the mass ratio of filter residue I to waste electrolyte is 1:3-5, the leaching temperature is 80-85°C, the reaction time is 2h, and the final acidity of the filtrate II obtained after the reaction is <35 g / L.

[0028] Furthermore, the specific steps of the purification process in S3 include: the filter residue II is recovered by using the lead smelting system of the pyrometallurgical lead smelting process, and valuable metallic lead can be finally obtained; the filtrate II can be added with flocculant solution and gelatin solution, clarified for 4 to 6 hours, and filtered through a double-layer filter cloth to obtain the filter residue III and the filtrate III, and the filtrate II can also be neutralized with zinc oxide smoke to precipitate indium, thereby enriching the indium element.

[0029] Based on the previous step, preferably, the flocculant is 3 # (polyacrylamide), the addition amount is 0.03~5kg / mol / L 3 ; Gelatin addition amount is 0.02~0.03 kg / mol / L 3 ; The filter residue III is a slag containing silica, which is stored.

[0030] Based on the above step, preferably, neutralizing the precipitated indium specifically includes the following steps: S301, adding zinc oxide smoke to the obtained filtrate II for pre-neutralization, and filtering to obtain filtrate IV and filter residue IV; S302, zinc oxide fume is added to the filtrate IV to neutralize and precipitate indium, and the filter residue V and the filtrate V are filtered to obtain the filter residue IV and the filtrate V, and the filter residue IV and the filtrate V are returned to the low-acid leaching step, and the final acidity of the filtrate IV is 0-5g / L H2SO4, the neutralization reaction temperature is 70-80°C, and the neutralization time is 0.5-1h; S303, the filter residue V is mixed with the waste electrolyte for acid leaching and then filtered to obtain the filtrate VI and the filter residue VI, the filter residue VI is recycled in the lead smelting system of the pyrometallurgical lead smelting, the filtrate VI is returned to the desiliconization extraction step, and the acid leaching temperature is 70-80°C, the leaching time is 2h, the liquid-solid ratio is 3-5:1, the end point pH value of the filtrate V is 4.4-4.8, and the final acidity of the filtrate VI is 60-65g / L.

[0031] Furthermore, the reaction conditions of extraction and stripping in S3 are: the extraction of filtrate III is 15~20% P204+80~85% 260 # The stripping is carried out in a kerosene system, with an extraction phase ratio O / A of 1 / 5-6, a mixing time of 5-10 min, and an extraction temperature of 40-45°C; the stripping is carried out in a 3mol / LHCl+2mol / LZnCl2 system, with an O / A ratio of 20-25 / 1, a mixing time of 10-15 min, and an extraction temperature of 40-45°C, and an ammonium fluoride solution is added to the lean organic phase obtained by stripping to wash iron to obtain a regenerated organic phase, which is returned to the extraction. Example 2

[0032] Based on the above Example 1, the inventors conducted a chemical composition analysis of the zinc oxide fume selected in Example 1 as shown in Table 1 below: The main chemical composition analysis results are listed in Table 1.

[0033]

[0034] The conclusion is: the main elements of the zinc oxide fume are lead and zinc, with the lead and zinc content reaching 72-73%, followed by iron content of about 2%. The indium and germanium content is relatively high, accounting for about 0.05%. From the composition point of view, the zinc oxide fume has a great recycling value; At the same time, the inventors also analyzed the waste electrolyte selected in Example 1: The conclusion is: the waste electrolyte used was taken from the production site of Chi Zinc Plant, with a Zn concentration of 53.2 g / L and a H2SO4 concentration of 161.0 g / L. Example 3

[0035] Based on the above Example 1, leaching experiments were carried out on metals such as zinc, germanium, and indium under the conditions of a smoke dust to waste electrolyte ratio of 1:5, a reaction temperature of 80°C, and a reaction time of 2h. The leaching test results are shown in Table 2.

[0036]

[0037] As shown in Table 2, as long as the conditions are properly controlled during the intermediate leaching process, the leaching rate of zinc can reach more than 88% when calculated based on slag; the leaching rate of germanium can reach more than 75%; and the leaching rate of germanium can reach more than 83% when calculated based on solution. Example 4

[0038] Based on the above Example 1, two-stage acid leaching experiments were carried out on metals such as iron, antimony, zinc, germanium, indium, and arsenic under the conditions of a ratio of zinc oxide fume to waste electrolyte of 1:3, 1:5, a reaction temperature of 85°C, and a reaction time of 1, 2, and 3 h. The leaching test results are shown in Table 3.

[0039]

[0040] As shown in Table 3, the suitable conditions for the two-stage acid leaching are temperature 85°C, liquid-to-solid ratio 3:1, time 2h, and initial acid concentration of about 60g / L. Under this condition, the leaching rates of zinc, germanium, and indium can reach more than 50%, 70%, and 85%; the total leaching rate of zinc calculated based on slag in the first-stage low-acid leaching and the second-stage acid leaching can reach more than 94%; the leaching rate of germanium in the two stages can reach more than 91%; and the efficient leaching of valuable metals such as Ge and In in zinc oxide dust is achieved. Example 5

[0041] Based on the above Example 4, the mixed solution obtained by the two-stage acid leaching test under various conditions was used as the extraction stock solution. According to the concentration of indium in the solution, the composition of the extracted organic phase was determined to be 15% P204 + 85% 260# kerosene, compared with O / A = 1 / 5, the mixing time was 5-10 mol / Lin, and single-stage extraction and two-stage simulated countercurrent extraction tests were carried out respectively. Considering that the temperature of the output solution of the acid leaching process in actual production is 70°C, and the minimum cooling temperature in actual production is 40°C, the temperature is mainly controlled at about 40°C during the extraction test.

[0042]

[0043] The results in Table 4 show that when the free H2SO4 concentration of the extraction stock solution is controlled at about 45g / L, the temperature is 40℃, and the mixing time is 5mol / L, the solution does not undergo clarification and silicon removal treatment, the phase separation is good during extraction, no emulsification occurs, and the extraction rate of indium can reach more than 96%; when the free H2SO4 concentration of the extraction stock solution is reduced to about 35g / L, it must be clarified and silicon removed, and the extraction temperature must be around 40℃, the phase separation is good during extraction, and no emulsified phase and bubbles are generated. The above extraction test also shows that the addition of reagent B can eliminate the generation of extraction bubbles and accelerate the speed of phase separation.

[0044] For the stripping of indium loaded in organic phase, 3mol / LHCl+2mol / LZnCl2 solution is usually used as stripping agent in industry. Based on this, we conducted a verification test of stripping indium. The stripping test was carried out at room temperature (25℃), with O / A=20 / 1 and time of 15min. The primary stripping rates of indium and antimony were 98.32% and 93.11%, respectively. Example 6

[0045] Based on the above Example 4, the second-stage acid leaching solution contains valuable metal ions Zn 2+ ,Ge 4+ (Mainly HGeO3 ~ and GeO3 2~ Form existence), In 3+ , also contains As 5+ (AsO4 3~ morphological existence), Sb 3+ , Fe 3+ , Fe 2+ The concentration of free H2SO4 is ~45g / L. Therefore, the neutralization precipitation indium method is adopted, which utilizes the difference in pH value of indium and zinc hydrolysis, and controls the pH value of the solution to precipitate indium in the form of In(OH)3, so as to achieve the purpose of separating indium.

[0046] Since the final acid of the solution produced by the second-stage acid leaching is ~45g / L and the residual acid is high, in order to improve the indium grade of the neutralized indium precipitation slag, zinc oxide fume is used for pre-neutralization before neutralization and precipitation of indium. The pre-neutralization temperature is 80℃ and the time is 40mol / Lin. The acidity of the solution is neutralized to H2SO4~5g / L. After filtration, the pre-neutralized liquid is used for neutralization and precipitation of indium. The process temperature is controlled at 80℃. Each test uses 500mol / LL of pre-neutralized liquid and produces 500mol / LL of indium precipitation liquid. The test conditions and results are listed in Table 5.

[0047]

[0048] It can be seen from the data listed in Table 5 that when the neutralization endpoint pH value is controlled in the range of 4.4~4.8, the precipitation rate of indium is 97.00%~98.64%, that is, the concentration of liquid In after precipitation of indium can reach below 1mol / L; the second-stage acid leaching solution is first pre-neutralized with zinc oxide fume to about 5.0g / L with H2SO4, and then the zinc oxide fume is neutralized to precipitate indium, and the neutralized precipitation indium slag In can be enriched to more than 0.32%. At a fixed temperature of 70℃~80℃, the leaching time is 2h, the liquid-solid ratio is 3.0:1, and the initial acid concentration is 60g / L. The metal leaching rate (%) is calculated to be In95.10 and Ge93.75. It can be seen that indium and germanium have been effectively enriched, but iron, antimony and arsenic also enter the precipitation indium slag leaching solution, and indium must be separated by extraction.

[0049] Based on Examples 2 to 6, the inventors found that the valuable metals in zinc oxide fume can be effectively recovered through one-stage neutralization leaching, two-stage acid leaching and extraction displacement electrolysis, and the recovery rates of metal indium and germanium are as high as over 90%, and the purity of the valuable metals after electrolysis is high, meeting the quality requirements of the product.

[0050] In summary, the present invention is based on the understanding of zinc oxide dust and uses low-carbon economic technology to recover valuable metals in zinc oxide dust, which provides a new idea for the recycling of zinc oxide dust and promotes the sustainable development of green valuable metals in the future.

[0051] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0052] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for recovering indium and germanium from zinc fume, characterized in that: The specific steps include: S1, mixing zinc oxide smoke and waste electrolyte, performing low-acid leaching, and filtering the obtained leached mixture to obtain filtrate I and indium-containing filter residue I; The mass percentage of each component of the zinc oxide smoke includes: 50-60% zinc, 20-25% lead, 2-4% iron, 0.01-0.02% indium, 1-2% silicon, 0.04-0.06% germanium, 0.7-1% arsenic, and the remainder is impurities; The filtrate I contains Zn: 120-150 g / L, Ge: 60-80 mg / L, Si: 800-850 mg / L, and Fe: 2-4.0 g / L; S2, extracting germanium from the filtrate I in S1 through an extraction process consisting of desiliconization, extraction, washing, stripping and hydrolysis, and the extraction requires the addition of an organic phase including an extractant, T reagent and kerosene, and the kerosene is supplemented during the extraction process; S3, the filter residue I in S1 is subjected to high acid leaching, purification, extraction and stripping, and zinc plate replacement to obtain sponge indium and zinc, and then the sponge indium is subjected to briquetting, smelting, electrolysis, cadmium and thallium removal, and casting to obtain indium ingots; and the raffinate obtained by extraction can be subjected to iron removal, purification, electrolysis, and ingot casting to obtain zinc ingots.

2. The method for recovering indium and germanium from zinc fume according to claim 1, characterized in that: The waste electrolyte in S1-S3 has a Zn mass concentration of 50-60 g / L and a H2SO4 mass concentration of 160-180 g / L.

3. The method for recovering indium and germanium from zinc fume according to claim 1, characterized in that: The pH of the low-acid leaching solution in S1 is 5-6, the volume ratio of smoke mass to waste electrolyte is 1:(6-7), the leaching temperature is 80-85°C, and the leaching time is 2h.

4. The method for recovering indium and germanium from zinc fume according to claim 1, characterized in that: The extraction process in S2 specifically comprises the following steps: S201, desiliconization is performed by adding 0.2-0.4 g / L of cattle glue to the filtrate I; S202, after desiliconization, the solution is added with an organic phase including 25-30% 7815 extractant, 25-30% T reagent, and 40-50% kerosene, and the extraction ratio is O / A=1 / 3, and kerosene is supplemented during the process; S203, then add 0.2~0.25mol / L H2SO4 to the extract for washing, add 2~3mol / L NaOH to the extract after washing for stripping, and add 2~2.5mol / L H2SO4 to the stripping raffinate for regeneration; S204, the stripping solution is mixed with sulfuric acid in a ratio of 1:1-1.5 and hydrolyzed to obtain germanium concentrate.

5. The method for recovering indium and germanium from zinc fume according to claim 1, characterized in that: The specific steps of the high acid leaching process in S3 include: adding the filter residue I obtained in S1 to the waste electrolyte, adding sulfuric acid, and then acid leaching, and filtering the obtained leaching mixture to obtain filter residue II and filtrate II.

6. The method for recovering indium and germanium from zinc fume according to claim 5, characterized in that: The initial sulfuric acid mass concentration of the acid leaching solution is 60-80 g / L, the mass ratio of the filter residue I to the waste electrolyte is 1:3-5, the leaching temperature is 80-85°C, the reaction time is 2h, and the final acidity of the filtrate II obtained after the reaction is <35 g / L.

7. The method for recovering indium and germanium from zinc fume according to claim 1, characterized in that: The specific steps of the purification process in S3 include: the filter residue II is recovered by using the lead smelting system of the pyrometallurgical lead smelting process to finally obtain valuable metallic lead; the filtrate II can be added with a flocculant solution and a gelatin solution, clarified for 4 to 6 hours, and filtered through a double-layer filter cloth to obtain the filter residue III and the filtrate III; the filtrate II can also be used together with zinc oxide smoke to neutralize and precipitate indium, thereby enriching the indium element.

8. The method for recovering indium and germanium from zinc fume according to claim 7, characterized in that: The flocculant is 3 # (polyacrylamide), the addition amount is 0.03~5kg / mol / L 3 ; The amount of gelatin added is 0.02~0.03 kg / mol / L 3 ; The filter residue III is a slag containing silica, which is stored.

9. The method for recovering indium and germanium from zinc fume according to claim 7, characterized in that: The neutralization and precipitation of indium specifically comprises the following steps: S301, adding zinc oxide smoke to the obtained filtrate II for pre-neutralization, and filtering to obtain filtrate IV and filter residue IV; S302, zinc oxide smoke is added to the filtrate IV to neutralize and precipitate indium, and the filter residue V and the filtrate V are filtered to obtain the filter residue IV and the filtrate V, and the filter residue IV and the filtrate V are returned to the low-acid leaching step, and the final acidity of the filtrate IV is 0-5g / L H2SO4, the neutralization reaction temperature is 70-80°C, and the neutralization time is 0.5-1h; S303, the filter residue V is mixed with the waste electrolyte for acid leaching and then filtered to obtain the filtrate VI and the filter residue VI, the filter residue VI is recycled in the lead smelting system of the pyrometallurgical lead smelting, the filtrate VI is returned to the desiliconization extraction step, and the acid leaching temperature is 70-80°C, the leaching time is 2h, the liquid-solid ratio is 3-5:1, the end point pH value of the filtrate V is 4.4-4.8, and the final acidity of the filtrate VI is 60-65g / L.

10. The method for recovering indium and germanium from zinc fume according to claim 1, characterized in that: The reaction conditions of extraction and stripping in S3 are as follows: the extraction of filtrate III is 15-20% P204 + 80-85% 260 # The stripping is carried out in a kerosene system, with an extraction phase ratio O / A of 1 / 5-6, a mixing time of 5-10 min, and an extraction temperature of 40-45°C; the stripping is carried out in a 3mol / LHCl+2mol / LZnCl2 system, with an O / A ratio of 20-25 / 1, a mixing time of 10-15 min, and an extraction temperature of 40-45°C, and an ammonium fluoride solution is added to the lean organic phase obtained by stripping to wash iron to obtain a regenerated organic phase, which is returned to the extraction.

Images