A zinc pressure leaching process incorporating a flash smelting process

Abstract

The present application relates to a kind of zinc oxygen pressure leaching method combined with flash smelting process, comprising the following steps: the slurry obtained by grinding zinc concentrate is carried out oxygen pressure leaching to obtain first stage leaching liquid and first stage leaching residue;Neutralizing agent is added to the first stage leaching liquid, and supernatant and neutralizing residue are obtained by separation;The neutralizing residue is carried out flash smelting, and fuming is obtained Multi-chamber furnace zinc oxide, and the multi-chamber furnace zinc oxide is added to neutralizing stirring tank to replace part of the neutralizing agent to react;Iron powder is added to the supernatant and copper precipitation and dechlorination are carried out, the pH of supernatant is adjusted to carry out fluorine precipitation, zinc powder is added to carry out displacement reaction, and displacement liquid and displacement residue are obtained by filtration, iron removal is carried out to the displacement liquid, and new liquid and purification residue are obtained by purification, and metal zinc is obtained by electrodeposition of the new liquid.The present application not only can improve oxygen pressure leaching processing capacity, but also can improve the direct recovery rate of various valuable metals, resource utilization rate, and reduce environmental pollution.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of metallurgy, in particular to a zinc oxygen pressure leaching method combined with a flash smelting process. BACKGROUND

[0002] The oxygen pressure leaching method is a modern metallurgical technology method, mainly applied to the smelting of metal ores such as zinc concentrate. The oxygen pressure leaching method does not require the construction of a supporting roasting workshop and an acid making system because the zinc concentrate does not need to be roasted, and has high leaching efficiency and strong adaptability to raw materials; compared with other smelting methods, it has great advantages in environmental protection and economy. The basic principle is to dissolve the metal elements in the ore under the action of high-pressure oxygen. The zinc oxygen pressure leaching process includes the following steps: first, the zinc concentrate is ground and slurried and then sent to a high-pressure autoclave for pressure leaching, then neutralized and solid-liquid separated to obtain a neutralized liquid and a neutralized residue, and then the neutralized liquid is purified with zinc powder, impurities are removed, purified, and electrodeposited to obtain zinc metal.

[0003] In order to improve the direct recovery rate of zinc, the existing zinc oxygen pressure leaching process usually puts the neutralized residue into the high-pressure autoclave again for oxygen pressure leaching, and then neutralizes and solid-liquid separates, which can cause the enrichment of arsenic and lead in the neutralized liquid. In the current oxygen pressure leaching process, arsenic can form insoluble compounds with many metals, which can cause the concentration of metals in the leaching solution to decrease, and the deposition of arsenic compounds on the surface of the solid product can also hinder the further leaching of zinc. Therefore, the presence of arsenic can affect the leaching rate and selectivity of zinc and other metals. In addition, arsenic compounds can have a corrosive effect on the reactor material, and the presence of arsenic can also increase the corrosion problem in the oxygen pressure leaching process, which can indirectly affect the leaching efficiency. Moreover, arsenic is a toxic element, and its increase in content can cause environmental pollution.

[0004] In addition, the neutralizing agent used in the existing zinc oxygen pressure leaching process is generally zinc oxide and calcine produced by traditional processes, but the zinc oxide and calcine produced by traditional roasting furnace and rotary kiln processes have high iron and silicon contents. Part of the iron and silicon enters the system solution during the neutralization process and exists in the form of silicates and iron oxides or hydrous iron alum, which has a great impact on the filtration or thickening clarification of the neutralized liquid. When iron precipitates, gallium and germanium will also precipitate with iron, which is not conducive to the recovery and impurity removal of valuable metals in the zinc sulfate solution. To solve this problem, the production is forced to increase the amount of neutralizing acid, which increases the amount of zinc powder used in the process of replacing valuable metals and removing impurities, increases the cost, and increases the amount of residue in the later stage. The valuable metal grade of gallium and germanium residue is low, which is not conducive to comprehensive recovery.

[0005] In summary, the existing zinc oxygen pressure leaching process has the problems of single process, difficulty in comprehensive recovery of resources, low direct recovery rate of valuable metals, environmental pollution, etc. SUMMARY

[0006] Based on this, the purpose of the present application is to provide a zinc pressure oxidation leaching method combined with a flash smelting process, which can not only effectively improve the direct recovery rate of valuable metals in zinc concentrates and resource utilization rate, but also improve the processing efficiency of pressure oxidation leaching and reduce environmental pollution.

[0007] A zinc pressure oxidation leaching method combined with a flash smelting process, comprising the following steps:

[0008] Step S1: oxygen pressure acid leaching: the ore slurry obtained by grinding zinc concentrate is sent to a first autoclave for first-stage pressure oxidation leaching, then sequentially subjected to instant flash evaporation in a first flash evaporation tank, temperature and pressure reduction in a first adjusting tank, and solid-liquid separation in a first thickening tank to obtain a first-stage leaching liquid and a first-stage leaching residue;

[0009] Step S2: neutralization reaction: the first-stage leaching liquid is sent to a neutralization stirring tank, a neutralizing agent is added and stirred for continuous neutralization reaction, and then sent to a neutralization thickening tank for separation to obtain a supernatant and a neutralization residue; the neutralizing agent comprises a neutralizing acid and zinc oxide;

[0010] Step S3: flash smelting and dechlorination and fluorine precipitation: the neutralization residue is sent to a flash smelting furnace for flash smelting and fuming after pressure filtration, crushing, drying and batching to obtain multi-tuyere furnace zinc oxide, and the multi-tuyere furnace zinc oxide is sent to the step S2 as the zinc oxide in the neutralizing agent; iron powder is added to the supernatant and pumped into a copper precipitation and dechlorination reaction tank for copper precipitation and dechlorination, and the pH is adjusted for fluorine precipitation to obtain a dechlorination and fluorine precipitation liquid;

[0011] Step S4: displacement reaction: the dechlorination and fluorine precipitation liquid in the step S3 is sent to a displacement stirring tank, the pH is adjusted, zinc powder is added for displacement continuous reaction, and then sent to a filter press for filtration to obtain a post-displacement liquid and a displacement residue;

[0012] Step S5: purification: the post-displacement liquid is subjected to iron removal and purification to obtain a new liquid and a purification residue;

[0013] Step S6: zinc electrowinning: the new liquid is subjected to zinc electrowinning to obtain metallic zinc.

[0014] In the oxygen pressure acid leaching process of step S1, the sulfur in zinc sulfide (ZnS) and the like in zinc concentrate is oxidized into elemental sulfur (S), and at the same time, zinc is converted into soluble zinc sulfate (ZnSO4); in addition, the first-stage leaching liquid contains a large amount of metal ions and acid radical ions, as well as part of fluoride ions (F-) and chloride ions (Cl-), and a small amount of arsenite (H3AsO3) and arsenate (H3AsO4); the metal ions in the first-stage leaching liquid include zinc ions (Zn 2+ ), lead ions (Pb 2+ ), copper ions (Cu 2+ ), gallium ions (Ga 3+ ), germanium ions (Ge4+ ), calcium ions (Ca 2+ ), etc. After the neutralizing agent is added in step S2, the zinc oxide undergoes a neutralization reaction with the acid in the first leaching solution to generate a salt and water; lead ions (Pb 2+ ) and gallium ions (Ga 3+ ) are converted into insoluble hydroxide precipitates by reacting with hydroxyl ions (OH-); arsenous acid (H3AsO3) and arsenic acid (H3AsO4) respectively combine with metal ions such as zinc ions (Zn 2+ ), calcium ions (Ca 2+ ), copper ions (Cu 2+ ), lead ions (Pb 2+ ), etc. to form precipitates; germanium ions (Ge 4+ ) react with hydroxyl ions (OH-) to generate water-insoluble germania (GeO2); fluorine ions (F-) and calcium ions (Ca 2+ )) and form chloridion type layered double metal hydroxide precipitate; thus, the neutralization slag contains hydroxide precipitate such as lead hydroxide precipitate (Pb(OH)2) and gallium hydroxide (Ga(OH)3), calcium arsenate (Ca3(AsO4)2) precipitate, calcium arsenite Ca3(AsO3)2 precipitate, germanium dioxide (GeO2), and the like. The lead in the neutralization slag produced in the neutralization step of the zinc oxygen pressure leaching process is removed by the flash smelting process of the present application, and after treatment such as arsenic removal by flue gas volatilization, the multi-hearth furnace zinc oxide with lower iron and silicon content than the zinc oxide produced by the traditional roaster and rotary kiln process is obtained; the substances in the neutralization slag are decomposed under the action of ultra-high temperature, among which the lead hydroxide (Pb(OH)2) precipitate is decomposed to generate lead oxide (PbO), which then reacts with coke to reduce the lead oxide (PbO) to metallic lead (Pb), and the metallic lead (Pb) is volatilized to form flue dust and is enriched and recovered; the arsenic in the neutralization slag is volatilized in the form of As2O3 into the flue gas under high temperature conditions, thereby achieving the effect of arsenic removal; in addition, after the calcium fluoride (CaF2) and chloridion type layered double metal hydroxide precipitate in the neutralization slag are decomposed, fluorine and chlorine are also volatilized into the flue dust for recovery treatment. The use of the multi-hearth furnace zinc oxide instead of part of the zinc oxide in the neutralizing agent added to the neutralization stirring tank can reduce the presence of silicates and iron oxides or hydrated iron alum in the system solution, on the one hand improving the effect of supernatant filtration or thickening clarification, and on the other hand further improving the direct recovery rate of valuable metals such as zinc, germanium, gallium, etc. through recycling of the multi-hearth furnace zinc oxide, improving resource utilization, and the low iron and silicon content can reduce the amount of neutralizing acid in subsequent step S2 and the amount of zinc powder in step S4, thereby reducing production costs and reducing the amount of displacement slag; in addition, the multi-hearth furnace zinc oxide contains a small amount of oxidized lead oxide, which reacts with sulfuric acid to form lead sulfate precipitate during the neutralization process, thereby reducing the sulfate ions in the system during the neutralization reaction process, solving the problem of high acidification rate in step S3 causing acid imbalance, avoiding the problems of decreased electrodeposition efficiency in subsequent step S6, increased viscosity of the new solution leading to deterioration of the electrodeposition process, and leaching of a large amount of impurity elements.

[0015] The supernatant obtained after neutralization in step S2 contains a large amount of zinc ions (Zn 2+ ), sulfate ions, and a small amount of copper ions (Cu 2+) other metal ions and fluoride ions (F-), chloride ions (Cl-), if they cannot be effectively removed, will cause the subsequent electrodeposition process to burn the plate, while reducing the electrical efficiency of the electrolysis process and reducing the quality of the zinc product. Therefore, the supernatant in step S3 of the present application is pumped into a copper precipitation and dechlorination reaction tank and continuously added with reduced iron powder for copper precipitation and dechlorination, and the pH of the supernatant is adjusted for fluorine precipitation; the addition of iron powder reduces the copper ions in the supernatant to produce elemental copper, and during the copper precipitation process, the elemental copper, copper ions and chloride ions in the supernatant are reacted in an acidic environment to produce copper chloride precipitate, which is filtered to remove chloride ions; in addition, by controlling the pH of the supernatant, calcium ions in the supernatant form calcium fluoride and calcium chloride with fluoride and chloride ions, respectively, and iron ions in the solution form the same compound as natural goethite (alpha-FeOOH) and precipitate, and calcium fluoride (CaF2) and calcium chloride (CaCl2) are deposited with iron slag. The present application ingeniously combines the zinc oxygen pressure leaching process with the flash smelting slag treatment process, and converts the neutralization slag produced by the oxygen pressure leaching process into multi-hearth furnace zinc oxide with low iron and silicon content through the flash smelting process, while removing arsenic and lead in the neutralization slag of the oxygen pressure leaching process. Then, the multi-hearth furnace zinc oxide is reinserted into the neutralization step of the oxygen pressure leaching process instead of the oxygen pressure acid leaching step. On the one hand, it avoids the enrichment of arsenic and lead when the original neutralization slag reenters the oxygen pressure acid leaching step, which affects the leaching of zinc and other valuable metals, and causes environmental pollution due to arsenic. On the other hand, after the neutralization slag is subjected to flash smelting, the multi-hearth furnace zinc oxide obtained is rich in metals such as gallium and germanium and contains a small amount of lead oxide. Reinserting it into the neutralization step helps to avoid the loss of valuable metal elements such as gallium and germanium in this step, reduces the consumption of zinc powder in the displacement reaction, reduces production costs, and avoids the problem of reduced subsequent electrodeposition efficiency. After the displacement reaction, valuable metals such as germanium are concentrated in the displacement slag, and valuable metals can be obtained by recycling the displacement slag. Therefore, the present application can effectively improve the direct recovery rate of valuable metals from zinc concentrate and resource utilization rate, and can also improve the processing efficiency of the oxygen pressure leaching process and reduce environmental pollution.

[0016] Further, the leaching temperature in the autoclave of step S1 is 145-155℃, and the leaching pressure is 1300-1400KPa; the acid concentration of the first-stage leaching solution is 15-25g / L. The above leaching environment is conducive to improving the entry of valuable metals into the first-stage leaching solution.

[0017] Further, the zinc oxygen pressure leaching method combined with the flash smelting process further comprises between step S1 and step S2:

[0018] Step S11: grinding the first-stage leaching residue and sending it to a second-stage autoclave for second-stage oxygen pressure leaching, then sending it through a second-stage flash tank for instant flash, a second-stage adjusting tank for temperature and pressure reduction, and a second-stage thickening tank for solid-liquid separation to obtain second-stage leaching liquid and second-stage leaching residue; adding the second-stage leaching liquid to the ore slurry in step S1.

[0019] Further, the acid concentration in the neutralization stirring tank in step S3 is 5-7 g / L.

[0020] Further, the pH value of the supernatant in the displacement stirring tank in step S4 is adjusted to 4.5-4.7. In the above pH value range, the displacement reaction is more complete, which helps to improve the recovery rate of metals and gradually remove impurities in the supernatant, making the solution clearer and purer. This not only helps to improve product quality, but also provides better conditions for subsequent processing and treatment.

[0021] Further, step S4 further comprises adding calcium carbonate to the post-displacement liquid for secondary fluorine precipitation.

[0022] Further, between step S4 and step S5 of the zinc oxygen pressure leaching method combined with the flash smelting process, there further comprises:

[0023] Step S41: slurry the displacement residue, wash it with weak acid, filter under pressure, and then send it to a comprehensive recovery workshop for comprehensive recovery.

[0024] For better understanding and implementation, the present application is described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 Flowchart of the zinc oxygen pressure leaching method combined with the flash smelting process. DETAILED DESCRIPTION

[0026] It should be clear that the described embodiments are only part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0027] The terms used in the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0028] Zinc in zinc concentrate is usually in the form of zinc oxide (ZnO) and zinc sulfide (ZnS), in addition to which the zinc concentrate also contains compounds of various metals, silicon dioxide and germanium ions (Ge 2 + ) and gallium ions (Ga 3+ ) in the form of isomorphism in zinc sulfide (ZnS); usually the metal compounds include various combinations of the following components:

[0029] Metal oxides: such as iron oxides (FeO, Fe2O3, Fe3O4), magnesium oxide (MgO), copper oxide (CuO), chromium trioxide (Cr2O3), antimony oxides (Sb2O5, Sb2O3), As2O5, etc.;

[0030] Metal sulfides: such as sodium sulfide (Na2S), iron sulfide (FeS2), lead sulfide (PbS), copper sulfide (CuS), cadmium sulfide (CdS), nickel sulfide (NiS), cobalt sulfide (CoS), antimony sulfide (Sb2S3), As2S3, FeAsS, etc.;

[0031] Metal fluorides: such as zinc fluoride (ZnF2), etc.;

[0032] Metal salts: such as sodium chloride (NaCl), sodium carbonate (NaCO3), sodium sulfate (Na2SO4), etc.;

[0033] Other inorganic salts: orthoarsenate, silicate, etc.

[0034] Please refer to Figure 1 , a zinc oxygen pressure leaching method combined with a flash smelting process, comprising the following steps:

[0035] Step S1: oxygen pressure acid leaching: the ore slurry obtained by grinding the zinc concentrate is sent to a first autoclave for first oxygen pressure leaching, then sequentially subjected to instant flash evaporation in a first flash evaporation tank, temperature and pressure reduction in a first adjusting tank, and solid-liquid separation in a first thickening tank to obtain a first leaching liquid and a first leaching residue.

[0036] In step S1 of the embodiment, the waste liquid containing dilute sulfuric acid is used for leaching, the acid concentration is 100 g / L, the leaching temperature in the autoclave is 155°C, the leaching pressure is 1400 KPa, and in order to improve the valuable metals into zinc sulfate solution, the acid concentration of the first-stage leaching liquid is controlled to be more than 15 g / L, preferably 15-25 g / L; the zinc concentrate contains about 30 wt% of sulfur, part of the sulfur element is acidified during the reaction process to generate sulfuric acid, the acidification rate is about 10%, and the system can maintain the balance of acid. The first-stage leaching liquid contains a large amount of metal ions and sulfate ions, part of fluoride ions (F-) and chloride ions (Cl-), and a small amount of arsenite (H3AsO3) and arsenate (H3AsO4); the metal ions in the first-stage leaching liquid include zinc ions (Zn 2+ ), lead ions (Pb 2 + ), iron ions (Fe 3+ ), magnesium ions (Mg 2+ ), sodium ions (Na + ), copper ions (Cu 2+ ), cadmium ions (Cd 2+ ), antimony ions (Sb 3+ ), gallium ions (Ga 3+ ), germanium ions (Ge 4+ ), chromium ions (Cr 3+ ), cobalt ions (Co 2+ ), nickel ions (Ni 2+ ), calcium ions (Ca 2+ ), etc.

[0037] Step S11: The first-stage leaching residue is ground and sent to a second-stage autoclave for second-stage oxygen pressure leaching, then instantaneously flashed through a second-stage flash tank, cooled and depressurized through a second-stage adjusting tank, and solid-liquid separated through a second-stage thickening tank to obtain a second-stage leaching liquid and a second-stage leaching residue; the second-stage leaching liquid is added to the ore slurry in step S1.

[0038] Step S2: neutralization reaction: the first-stage leaching liquid is sent to a neutralization stirring tank, a neutralizing agent is added and stirred for neutralization continuous reaction, and then sent to a thickening tank for separation to obtain supernatant and neutralization residue; the neutralizing agent includes neutralizing acid, zinc oxide or calcine.

[0039] In step S2 of the embodiment, after the neutralizing agent is added, the zinc oxide reacts with the acid in the first-stage leaching liquid to generate salt and water; lead ions (Pb 2+ ) and gallium ions (Ga 3+ ) are converted into difficultly soluble hydroxide precipitates by reacting with hydroxyl ions (OH-); arsenite (H3AsO3) and arsenate (H3AsO4) react with zinc ions (Zn 2+ ), calcium ions (Ca 2+copper ions (Cu 2 + lead ions (Pb 2+ ) and other metal ions combine to form precipitates; germanium ions (Ge 4+ ) react with hydroxyl ions (OH-) to form germania (GeO2) which is insoluble in water; fluorine ions (F-) and calcium ions (Ca 2+ ) combine to form calcium fluoride (CaF2) precipitates; chlorine ions (Cl-) combine with various metal cations to form chloride-type layered double hydroxide precipitates; thus, the neutralization residue contains hydroxides such as lead hydroxide (Pb(OH)2) and gallium hydroxide (Ga(OH)3), calcium arsenate (CaAsO4), calcium arsenite Ca3(AsO3)2, germania (GeO2), calcium fluoride (CaF2), chloride-type layered double hydroxide, and the like. The supernatant contains, in addition to a large amount of zinc ions (Zn 2+ ), sulfate ions (SO4 2- ), a small amount of copper ions (Cu 2+ ), iron ions (Fe 3+ ), magnesium ions (Mg 2+ ), sodium ions (Na + ), cadmium ions (Cd 2+ ), antimony ions (Sb 3+ ), chromium ions (Cr 3+ ), cobalt ions (Co 2+ ), nickel ions (Ni 2+ ), calcium ions (Ca 2+ ), gallium ions (Ga 3+ ), germanium ions (Ge 4+ ), and other metal ions, and a small amount of fluorine ions (F-) and chlorine ions (Cl-).

[0040] Step S3: flash smelting and dechlorination and fluorine precipitation: the neutralization residue is subjected to pressure filtration, crushing, drying, and batching, and then is fed into a flash smelting furnace for flash smelting and fuming to obtain a multi-hearth furnace zinc oxide, which is fed to the step S2 as the zinc oxide in the neutralizing agent; iron powder is added to the supernatant and is pumped into a copper precipitation and dechlorination reaction tank for copper precipitation and dechlorination, and the pH is adjusted for fluorine precipitation, to obtain a dechlorination and fluorine precipitation liquid. The multi-hearth furnace zinc oxide is added until the acid concentration in the neutralization and stirring tank is reduced from 15 g / L to about 5 g / L, preferably 5-7 g / L.

[0041] In step S3 of the embodiment, the substances in the neutralized residue are decomposed under the action of super-high temperature, in which the lead hydroxide (Pb(OH)2) precipitate is decomposed by heat to generate lead oxide (PbO), which then reacts with coke to reduce the lead oxide (PbO) into metallic lead (Pb), the metallic lead (Pb) is fumed to form smoke dust and is enriched and recovered; the calcium arsenate (Ca3(AsO4)2) precipitate and calcium arsenite Ca3(AsO3)2 precipitate are decomposed by heat to generate arsenic oxide (As2O3) and calcium oxide (CaO), and the arsenic oxide (As2O3) is volatilized by the smoke gas to remove the arsenic in the neutralized residue. In addition, after the calcium fluoride (CaF2) and chloride-type layered double hydroxide precipitate in the neutralized residue are decomposed by heat, the fluorine and chlorine are also volatilized into the smoke dust for recovery treatment.

[0042] Step S4: displacement reaction: the dechlorination and fluorination liquid in step S3 is sent to a displacement stirring tank, the pH of the supernatant is gradually adjusted to 4.5-4.7, zinc powder is added for displacement continuous reaction, precipitates of gallium and germanium metals, and then is sent to a filter press for filtration to obtain a post-displacement liquid and a displacement residue; the displacement residue is slurried and washed with a weak acid, is sent to a filter press, and then is sent to a comprehensive recovery workshop for comprehensive recovery. The copper ions (Cu 2+ ), iron ions (Fe 3+ ), gallium ions (Ga 3+ ), and germanium ions (Ge 4+ ) in the supernatant are respectively reduced to generate elemental metals.

[0043] As a further improvement of the above scheme, calcium carbonate is added for secondary fluorination while zinc powder is added to the post-displacement liquid. The calcium ions form calcium fluoride (CaF2) with the fluorine ions in the post-displacement liquid, and the iron ions (Fe 3 + ) in the post-displacement liquid are hydrolyzed into goethite crystal precipitate, and the calcium fluoride (CaF2) is deposited with the iron residue.

[0044] Step S41: the displacement residue is slurried and washed with a weak acid, is filtered, and then is sent to a comprehensive recovery workshop for comprehensive recovery.

[0045] Step S5: purification: the post-displacement liquid is de-ironed and purified to obtain a new liquid and a purification residue;

[0046] Step S6: zinc electrowinning: the new liquid is electrowon to obtain metallic zinc.

[0047] The zinc content of the multiple hearth furnace zinc oxide obtained in step S3 of the embodiment is about 50wt%, the germanium content is about 0.5wt%, and the lead oxide content is about 15-20wt%. After the multiple hearth furnace zinc oxide is added to the neutralization stirring tank, the leaching rate of zinc in the multiple hearth furnace zinc oxide is 85%, the leaching rate of gallium and germanium is as high as 90%, the germanium content of the supernatant increases from 15mg / L to about 30mg / L, the neutralization slag contains about 7wt% of zinc and about 0.04wt% of germanium, and it can be seen that the zinc and germanium in the slag are recovered again by using the neutralization slag as a neutralizing agent after flash smelting, thereby improving the resource utilization rate. The fluorine precipitation rate of the supernatant in step S3 reaches 60%. The germanium concentration in the liquid after displacement in step S4 is lower than 2mg / L, the average germanium content in the displacement slag increases from 4.5kg / t to 6.2kg / t, the direct recovery rate of germanium metal increases from 65% to 90%, and the germanium metal recovery rate is significantly improved. In addition, since the neutralization slag is treated by using the flash smelting process in the embodiment, the channel for returning the neutralization slag to the oxygen leaching in the existing zinc oxide pressure leaching process is omitted, so that the zinc concentrate processing efficiency is improved from 42t / h to 50t / h, the zinc ingot production capacity is improved from 148,000 tons to 152,000 tons, the average zinc content of the new liquid in step S6 is reduced from 200g / L to 180g / L, the oxygen pressure leaching processing efficiency is improved, and the direct recovery rate of zinc, gallium, germanium and other valuable metals is improved. The embodiment also reduces the dependence on the purchase of high-quality zinc oxide, improves the production stability, reduces the cost input, improves the production efficiency of the factory, reduces the environmental pollution problem, realizes the green circular economy, has considerable economic, safety and social benefits, and has important significance for promoting the sustainable development of the industry.

[0048] The above-described embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it cannot be understood as limiting the scope of the patent. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, several modifications and improvements can be made, and the present application also intends to include these modifications and improvements.

Claims

1. A zinc pressure leaching process incorporating a flash smelting process characterised in that: It comprises the following steps: Step S1: oxygen pressure acid leaching: the ore slurry obtained by grinding zinc concentrate is sent to a first autoclave for first-stage oxygen pressure leaching, then sequentially subjected to first-stage flash tank for instantaneous flash, first-stage adjusting tank for temperature and pressure reduction, and first-stage thickening tank for solid-liquid separation to obtain first-stage leaching liquid and first-stage leaching residue; Step S2: neutralization reaction: the first-stage leaching liquid is sent to a neutralization stirring tank, a neutralizing agent is added and stirred for continuous neutralization reaction, and then sent to a neutralization thickening tank for separation to obtain supernatant and neutralization residue; the neutralizing agent comprises neutralizing acid and zinc oxide; Step S3: flash smelting and dechlorination and fluorine precipitation: the neutralization residue is sent to a flash smelting furnace for flash smelting and fuming after being subjected to pressure filtration, crushing, drying and batching, to obtain multi-hearth furnace zinc oxide, which is used as zinc oxide in the neutralizing agent in the step S2; iron powder is added to the supernatant and pumped into a copper precipitation and dechlorination reaction tank for copper precipitation and dechlorination, and the pH is adjusted for fluorine precipitation, to obtain dechlorination and fluorine precipitation liquid; Step S4: displacement reaction: the dechlorination and fluorine precipitation liquid in the step S3 is sent to a displacement stirring tank, the pH is adjusted, and zinc powder is added for displacement continuous reaction, and then sent to a filter press for filtration to obtain displacement liquid and displacement residue; Step S5: purification: the displacement liquid is subjected to iron removal and purification to obtain new liquid and purification residue; Step S6: zinc electrowinning: the new liquid is subjected to zinc electrowinning to obtain metallic zinc.

2. The zinc pressure leaching process in combination with a flash smelting process according to claim 1, characterized in that: The leaching temperature in the autoclave of the step S1 is 145-155℃, and the leaching pressure is 1300-1400Kpa; the acid concentration of the first-stage leaching liquid is 15-25g / L.

3. The zinc pressure leaching process in combination with a flash smelting process according to claim 1, characterized in that: Between the step S1 and the step S2, there is further: Step S11: the first-stage leaching residue is ground and sent to a second autoclave for second-stage oxygen pressure leaching, then subjected to second-stage flash tank for instantaneous flash, second-stage adjusting tank for temperature and pressure reduction, and second-stage thickening tank for solid-liquid separation to obtain second-stage leaching liquid and second-stage leaching residue; the second-stage leaching liquid is added to the ore slurry in the step S1.

4. The zinc pressure leaching process integrated with flash smelting process as claimed in claim 1, wherein: The acid concentration in the neutralization stirring tank of the step S2 is 5-7g / L.

5. The zinc pressure leaching process in combination with a flash smelting process according to claim 1, characterized in that: The pH of the supernatant in the displacement stirring tank of the step S4 is adjusted to 4.5-4.

7.

6. The zinc pressure leaching process in combination with a flash smelting process according to claim 1, characterized in that: The step S4 further comprises: adding calcium carbonate to the dechlorination and fluorine precipitation liquid for secondary fluorine precipitation.

7. The zinc pressure leaching process in combination with a flash smelting process according to claim 1, characterized in that: Between the step S4 and the step S5, there is further: Step S41: the displacement residue is slurried and washed with weak acid, filtered, and then sent to a comprehensive recovery workshop for comprehensive recovery.

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