A method for atmospheric oxygen leaching of zinc sulphide concentrate and recovery of sulphur from the residue

Abstract

The present application relates to the technical field of hydrometallurgy, in particular to a method for atmospheric pressure oxygen leaching of zinc sulfide concentrate and sulfur recovery from slag. The method comprises the following steps: grinding the zinc sulfide concentrate to a target particle size; adding sulfuric acid and a leaching agent to the zinc sulfide concentrate to obtain a first reaction system, and performing low-acid first-stage atmospheric pressure oxygen leaching on the first reaction system to obtain a first-stage atmospheric pressure oxygen leaching solution and a first-stage atmospheric pressure oxygen leaching residue; the redox potential of the first reaction system is 280-380 mV; adding waste electrolyte to the first-stage atmospheric pressure oxygen leaching residue to obtain a second reaction system, and performing high-acid second-stage atmospheric pressure oxygen leaching on the second reaction system to obtain a second-stage atmospheric pressure oxygen leaching solution and a second-stage atmospheric pressure oxygen leaching residue; the redox potential of the second reaction system is 350-450 mV; adding water to the second-stage atmospheric pressure oxygen leaching residue to obtain a slurry; performing sulfur transformation treatment on the slurry to obtain a transformed residue; and recovering sulfur from the residue. The present application can improve the direct recovery rate of sulfur recovery at low cost and low energy consumption.

Description

Technical Field

[0001] The invention relates to the technical field of hydrometallurgy, and in particular to a method for oxygen leaching of zinc sulfide concentrate at normal pressure and recovering sulfur from slag. Background Art

[0002] Zinc sulfide concentrate contains significant amounts of zinc and sulfur, which can be converted into zinc and sulfur. Zinc is a key non-ferrous metal raw material, ranking third in consumption among non-ferrous metals, after copper and aluminum. Zinc possesses excellent ductility, wear resistance, and corrosion resistance, and can be combined with a variety of metals to form alloys with superior physical and chemical properties. Sulfur, as a basic chemical raw material, is widely used in the production of sulfuric acid, fertilizers, rubber, gunpowder, and pharmaceuticals.

[0003] Currently, the industry's primary method for separating zinc and sulfur from zinc sulfide concentrates is pressure leaching, a process that has been successfully applied in engineering applications. However, atmospheric pressure oxygen-enriched leaching (AOPLE) produces dispersed sulfur in the AOPLE leaching slag, resulting in incomplete crystal growth. Furthermore, the sulfur slag produced by AOPLE leaching of zinc concentrates contains high levels of impurities (such as iron). The sulfur content in the depleted sulfur slag cannot be recovered through hot sulfur filtration, making sulfur recovery difficult. Consequently, the process has not yet been successfully applied in engineering applications. Directly storing the incompletely recovered sulfur slag can lead to severe environmental pollution due to the natural oxidation of the sulfur in the slag, resulting in a waste of resources. Furthermore, the AOPLE leaching process requires the introduction of large amounts of oxygen, increasing industrial costs and energy consumption.

[0004] For example, Chinese invention patent application number 201310422340.9 discloses a method for recovering elemental sulfur from high-sulfur slag produced by atmospheric oxygen-enriched direct hydrometallurgy. The method comprises the following steps: 1) placing an oxygen leaching solution from atmospheric oxygen-enriched direct hydrometallurgy into a reactor, introducing oxygen and steam into the reactor to rapidly increase the temperature and pressure; the temperature is 110-150°C, the pressure is 450-1100 kPa, and the oxygen partial pressure is 250-800 kPa; 2) flashing the high-temperature, high-pressure oxygen leaching solution obtained in step 1) in a flash evaporation tank; 3) flotating the flashed oxygen leaching solution to produce high-sulfur slag; 4) melting the high-sulfur slag by introducing steam into a molten sulfur pool; 5) hot filtering the molten high-sulfur slag through a vane filter press to produce molten elemental sulfur; and 6) using a granulator to water-cool the molten elemental sulfur into granular solid elemental sulfur. This method requires a high-temperature, high-oxygen, high-pressure conversion process to achieve sulfur recovery, significantly increasing industrial costs and energy consumption.

[0005] In summary, it is necessary to provide a method for atmospheric pressure oxygen leaching of zinc sulfide concentrate and sulfur recovery in slag, which, on the one hand, solves the problems of incomplete sulfur conversion and incomplete sulfur recovery caused by the sulfur content in the depleted sulfur slag in the atmospheric pressure oxygen-enriched leaching process in the prior art, and on the other hand solves the problem that the atmospheric pressure oxygen-enriched leaching process in the prior art requires the introduction of a large amount of oxygen, which increases industrial costs and energy consumption. Summary of the Invention

[0006] The present invention aims to provide a method for atmospheric pressure oxygen leaching of zinc sulfide concentrate and sulfur recovery in slag. The specific technical scheme is as follows:

[0007] A method for atmospheric pressure oxygen leaching of zinc sulfide concentrate and sulfur recovery from slag, comprising:

[0008] Step S1, crushing and grinding the zinc sulfide concentrate to a target particle size; the zinc sulfide concentrate is composed of the following components in mass percentage: 43% to 48% zinc, 9% to 15% iron, 32% to 35% sulfur, and the remainder being impurities;

[0009] Step S2, adding sulfuric acid and a leaching agent to the zinc sulfide concentrate, mixing to obtain a first reaction system, and subjecting the first reaction system to a low-acid, one-stage atmospheric pressure oxygen leaching treatment to obtain a one-stage atmospheric pressure oxygen leaching liquid and a one-stage atmospheric pressure oxygen leaching residue; the low-acid, one-stage atmospheric pressure oxygen leaching treatment includes controlling the redox potential of the first reaction system to be 280-380 mV by passing oxygen; the low-acid, one-stage atmospheric pressure oxygen leaching treatment adopts a reaction temperature of 88-105° C. and a reaction time of 6-15 hours; in the mixed first reaction system, the mass concentration of sulfuric acid is 70-80 g / L, the mass concentration of iron is less than or equal to 15 g / L, and the mass concentration of zinc is greater than or equal to 105 g / L;

[0010] Step S3: adding a waste electrolyte to the first-stage atmospheric pressure oxygen leaching residue, mixing them to obtain a second reaction system, and subjecting the second reaction system to a high-acid second-stage atmospheric pressure oxygen leaching treatment to obtain a second-stage atmospheric pressure oxygen leaching liquid and a second-stage atmospheric pressure oxygen leaching residue; the second-stage atmospheric pressure oxygen leaching liquid is used as the leaching agent in the first reaction system; the high-acid second-stage atmospheric pressure oxygen leaching treatment includes controlling the redox potential of the second reaction system to be 350-450 mV by passing oxygen; the high-acid second-stage atmospheric pressure oxygen leaching treatment adopts a reaction temperature of 88-105° C. and a reaction time of 8-18 hours; the waste electrolyte comprises sulfuric acid and zinc sulfate; and the molar ratio of sulfuric acid to zinc in the mixed second reaction system is 1.5-2:1;

[0011] Step S4, adding water to the second-stage atmospheric pressure oxygen leaching residue and stirring to obtain a slurry; wherein the mass ratio of the added water to the second-stage atmospheric pressure oxygen leaching residue is 2-4:1; and the mass percentage of iron in the slurry is less than 5%;

[0012] Step S5: subjecting the slurry to sulfur conversion treatment to obtain conversion slag; if the total sulfur content in the conversion slag is greater than or equal to 75%, directly performing hot melt filtration to recover the sulfur in the slag; before the hot melt filtration, controlling the moisture content of the conversion slag to be less than 20%; if the total sulfur content in the conversion slag is less than 75%, first performing a flotation process and then performing hot melt filtration to recover the sulfur in the slag.

[0013] Optionally, in step S5, the sulfur conversion treatment includes sending the slurry into a conversion kettle, adding a surfactant, and blowing in gas; the pH value of the slurry is 0.5~5; the conversion temperature is controlled to be 130~160°C, the conversion time is 10~60min, and the pressure in the conversion kettle is 0.3~0.8MPa; the amount of the surfactant added is 1‰~5‰ of the solid mass in the slurry; the converted slurry is cooled to 80~90°C, and conversion slag is obtained by liquid-solid separation.

[0014] Optionally, the surfactant includes at least one of sodium lignin sulfonate, calcium lignin sulfonate and lignite.

[0015] Optionally, the gas includes at least one of air and nitrogen.

[0016] Optionally, the oxygen content of the gas in the transition reactor is controlled to be 0-21% by volume.

[0017] Optionally, the flotation process includes adding the transformation slag and water in a mass ratio of 1~2:10~15 into a flotation tank, and performing roughing, scavenging and cleaning in sequence to obtain flotation concentrate and flotation tailings; performing hot melt filtration on the flotation concentrate to recover sulfur in the slag; before the hot melt filtration, controlling the water content of the flotation concentrate to below 20%; and controlling the stirring rate to 1000~2000r / min and the aeration volume to 150~400L / h in the flotation process.

[0018] Optionally, the rough selection time is 10-15 minutes; the material residence time during the sweep selection is 15-25 minutes; and the material residence time during the fine selection is 5-10 minutes.

[0019] Optionally, the hot melt filtration adopts a hot melt temperature of 140-155° C. and a hot melt time of 10-30 min.

[0020] Optionally, in step S1, the target particle size is D90≤45 μm.

[0021] Optionally, the atmospheric pressure oxygen leaching solution is subjected to conventional iron removal, purification and zinc electrowinning treatment to obtain zinc.

[0022] The application of the technical solution of the present invention has at least the following beneficial effects:

[0023] (1) The present invention provides a method for atmospheric pressure oxygen leaching of zinc sulfide concentrate and sulfur recovery in slag, which solves the problems of incomplete sulfur conversion and incomplete sulfur recovery caused by the sulfur content in the depleted sulfur slag in the conventional atmospheric pressure oxygen-enriched leaching process, and solves the problem of increased industrial cost and energy consumption caused by the need to introduce a large amount of oxygen in the conventional atmospheric pressure oxygen-enriched leaching process. Specifically, the present invention first performs a low-acid one-stage atmospheric pressure oxygen leaching treatment on the zinc sulfide concentrate of a specific composition, and by controlling the composition of the first reaction system and using oxygen to control the redox potential to 280-380 mV, part of the zinc element and part of the iron element in the zinc sulfide concentrate are oxidized by oxygen into zinc sulfate and iron sulfate, respectively, and are separated out with the one-stage atmospheric pressure oxygen leaching liquid, while a large amount of sulfur element in the zinc sulfide concentrate is oxidized by oxygen into elemental sulfur and is separated out with the one-stage atmospheric pressure oxygen leaching residue; further, the present invention performs a high-acid two-stage atmospheric pressure oxygen leaching treatment on the one-stage atmospheric pressure oxygen leaching residue, and by controlling the composition of the second reaction system and using oxygen to control the redox potential to 350-450 mV, the zinc in the one-stage atmospheric pressure oxygen leaching residue is further oxidized by oxygen. The slag is oxidized to zinc sulfate and leached into the solution. The unoxidized sulfur element is further oxidized by oxygen to elemental sulfur and separated with the second-stage atmospheric pressure oxygen leaching residue. Subsequently, water is added to the second-stage atmospheric pressure oxygen leaching residue in step S4 to obtain a slurry with a specific water-slag ratio. The mass percentage of iron in the slurry is strictly controlled to be less than 5%, thereby avoiding the problem of incomplete sulfur recovery caused by the sulfur content in the iron-depleted sulfur slag. In addition, the addition of a specific amount of water in step S4 also helps to promote the sulfur conversion treatment in step S5, ensuring the smooth completion of the sulfur conversion. Finally, the sulfur conversion slag obtained by the sulfur conversion treatment in step S5 is then subjected to hot melt filtration, or after the flotation process, hot melt filtration is performed to recover the sulfur in the slag, achieving a direct sulfur product yield greater than 88% and a sulfur content of ≥99.6%. The present invention controls the appropriate redox potential by introducing an appropriate amount of oxygen during both the low-acid first-stage atmospheric pressure oxygen leaching treatment and the high-acid second-stage atmospheric pressure oxygen leaching treatment, thereby avoiding the problem of increased industrial costs and energy consumption caused by the introduction of a large amount of oxygen. In addition, the present invention uses the second-stage atmospheric pressure oxygen leaching liquid generated during the high-acid second-stage atmospheric pressure oxygen leaching treatment as a leaching agent in the first reaction system. During the low-acid first-stage atmospheric pressure oxygen leaching treatment, the zinc content in the first-stage atmospheric pressure oxygen leaching liquid is increased, providing a basic stock solution for subsequent zinc electrodeposition. The high-acid second-stage atmospheric pressure oxygen leaching treatment allows the unoxidized sulfur element and the residual zinc and iron elements in the first-stage atmospheric pressure oxygen leaching residue to be enriched and recovered again, thereby not only improving the recovery rates of sulfur, zinc and iron, but also reducing environmental pollution.

[0024] (2) The present invention adopts step S5 to control the pH value, transition temperature, transition time and pressure in the transition kettle of the slurry. On the one hand, the transition of the two-stage atmospheric pressure oxygen leaching slag under low acid and low pressure is achieved, thereby reducing the erosion of the transition kettle. On the other hand, the obtained transition slag can promote the aggregation and growth of sulfur, presenting a better crystal form, which is convenient for hot melting filtration to recover sulfur in the slag.

[0025] (3) The present invention crushes and grinds the zinc sulfide concentrate to a target particle size of D90≤45μm, which facilitates the leaching of zinc and iron elements and improves the subsequent sulfur recovery. If a smaller target particle size is used, the sulfur recovery rate will not be significantly improved, but the cost of crushing and grinding will be significantly increased. If a larger target particle size is used, the leaching of zinc and iron elements will be insufficient, and the sulfur recovery rate will also decrease.

[0026] In addition to the above-described objects, features and advantages, the present invention has other objects, features and advantages. The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0028] Figure 1 This is a schematic flow chart of a method for atmospheric pressure oxygen leaching of zinc sulfide concentrate and sulfur recovery from slag in Example 2. DETAILED DESCRIPTION

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention are within the scope of protection of the present invention.

[0030] Example 1:

[0031] A method for atmospheric pressure oxygen leaching of zinc sulfide concentrate and sulfur recovery from slag, comprising:

[0032] Step S1, crushing and grinding the zinc sulfide concentrate to a target particle size; the target particle size is D90≤45 μm; the zinc sulfide concentrate is composed of the following components in mass percentage: 46.68% zinc, 10.21% iron, 34.52% sulfur, and the remainder is impurities;

[0033] Step S2, adding sulfuric acid (mass percentage of 98%, amount of 50g) and a leaching agent to 500g of the zinc sulfide concentrate, mixing to obtain a first reaction system, and subjecting the first reaction system to a low-acid one-stage atmospheric pressure oxygen leaching treatment to obtain a one-stage atmospheric pressure oxygen leaching liquid (the volume of the one-stage atmospheric pressure oxygen leaching liquid is 2.5L, wherein the mass concentration of zinc is 147.5g / L, the mass concentration of iron is 10.78g / L, and the mass concentration of sulfuric acid is 15 g / L) and a first-stage atmospheric pressure oxygen leaching residue (the mass of the first-stage atmospheric pressure oxygen leaching residue is 385g, wherein the mass percentage of zinc is 35.8%, the mass percentage of iron is 13.89%, the mass percentage of sulfur is 44.2%, and the balance is impurities); the low-acid first-stage atmospheric pressure oxygen leaching treatment includes controlling the redox potential of the first reaction system to 360mV by passing oxygen; the reaction temperature used in the low-acid first-stage atmospheric pressure oxygen leaching treatment is 95°C and the reaction time is 12h; in the mixed first reaction system, the mass concentration of sulfuric acid is 75g / L, the mass concentration of iron is 11.7g / L, and the mass concentration of zinc is 109g / L;

[0034] Step S3, performing conventional iron removal, purification and zinc electrowinning treatment on the first-stage atmospheric pressure oxygen leaching solution to obtain zinc; adding waste electrolyte to the first-stage atmospheric pressure oxygen leaching residue (the waste electrolyte comprises sulfuric acid and zinc sulfate; the volume of the waste electrolyte is 2.5 L, wherein the mass concentration of zinc sulfate is 135.7 g / L, and the mass concentration of sulfuric acid is 160 g / L), mixing to obtain a second reaction system, and performing high-acid two-stage atmospheric pressure oxygen leaching on the second reaction system to obtain a two-stage atmospheric pressure oxygen leaching solution (the volume of the two-stage atmospheric pressure oxygen leaching solution is 2.5 L, wherein the mass concentration of zinc is 109.2 g / L, the mass concentration of iron is 11.75 g / L, and the mass concentration of sulfuric acid is 55 g / L) and second-stage atmospheric pressure oxygen leaching residue (the mass of the second-stage atmospheric pressure oxygen leaching residue is 195g, wherein the mass percentage of zinc is 1.15%, the mass percentage of iron is 12.36%, the mass percentage of sulfur is 82.95%, and the balance is impurities); the second-stage atmospheric pressure oxygen leaching liquid is the leaching agent in the first reaction system; the high-acid second-stage atmospheric pressure oxygen leaching treatment includes controlling the redox potential of the second reaction system to 420mV by passing oxygen; the reaction temperature used in the high-acid second-stage atmospheric pressure oxygen leaching treatment is 95°C and the reaction time is 12h; the molar ratio of sulfuric acid to zinc in the mixed second reaction system is 1.92:1;

[0035] Step S4, adding water to the second-stage atmospheric pressure oxygen leaching residue and stirring to obtain a slurry; wherein the mass ratio of the added water to the second-stage atmospheric pressure oxygen leaching residue is 3:1; and the mass percentage of iron in the slurry is less than 5%, specifically 3.09%;

[0036] Step S5: subjecting the slurry to sulfur conversion treatment to obtain conversion slag; if the mass percentage of total sulfur in the conversion slag is greater than or equal to 75%, directly performing hot melt filtration to recover the sulfur in the slag; before the hot melt filtration, controlling the water content of the conversion slag to be less than 20%.

[0037] In step S5, the sulfur conversion treatment includes feeding the slurry into a conversion kettle, adding a surfactant, and blowing in gas; the water added in step S4 helps to promote the foaming of the surfactant under the action of the blown gas, promotes the enrichment of the conversion slag during the conversion, and ensures the smooth completion of the sulfur conversion; the pH value of the slurry is 3; the conversion temperature is controlled to 145°C, the conversion time is 40 minutes, and the conversion pressure is 0.4 MPa; the surfactant is calcium lignin sulfonate, and its addition amount is 3‰ of the solid mass in the slurry; the converted slurry is cooled to 85°C, and liquid-solid separation is performed to obtain a conversion slag (the mass of the conversion slag is 194g, wherein the mass percentage of zinc is 1.13%, the mass percentage of iron is 12.34%, the mass percentage of sulfur is 82.93%, and the remainder is impurities) and a conversion liquid (585mL, the mass concentration of Zn is 0.086g / L, and the mass concentration of Fe is 0.28g / L); the conversion liquid can replace the water in step S4 and be reused in the sulfur conversion treatment.

[0038] The gas is a mixture of air and nitrogen, and the oxygen content of the gas in the transformation kettle is controlled to 15%, thereby avoiding the problem that the iron in the solution is oxidized to form iron oxide during the transformation process, and the sulfur content in the depleted sulfur slag leads to a significant reduction in sulfur recovery.

[0039] The hot melt filtration adopts a hot melt temperature of 145° C. and a hot melt time of 20 minutes to obtain hot sulfur and hot filter residue; the hot sulfur is kept at 145° C. for 20 minutes and then pumped into granules to obtain sulfur with a sulfur content of 99.8% and a direct sulfur recovery rate of 90%.

[0040] Example 2:

[0041] See also Figure 1 A method for atmospheric pressure oxygen leaching of zinc sulfide concentrate and recovery of sulfur from slag, comprising:

[0042] Step S1, crushing and grinding the zinc sulfide concentrate to a target particle size; the target particle size is D90≤45 μm; the zinc sulfide concentrate is composed of the following components in mass percentage: 46.68% zinc, 10.21% iron, 34.52% sulfur, and the remainder is impurities;

[0043] Step S2, adding sulfuric acid (98% by mass, 30g in amount) and a leaching agent to 500g of the zinc sulfide concentrate, mixing to obtain a first reaction system, and subjecting the first reaction system to a low-acid one-stage atmospheric pressure oxygen leaching treatment to obtain a one-stage atmospheric pressure oxygen leaching solution (the volume of the one-stage atmospheric pressure oxygen leaching solution is 2.5 L, wherein the mass concentration of zinc is 145.55g / L, the mass concentration of iron is 8.21g / L, and the mass concentration of sulfuric acid is 13.8 g / L) and a first-stage atmospheric pressure oxygen leaching residue (the mass of the first-stage atmospheric pressure oxygen leaching residue is 396g, wherein the mass percentage of zinc is 36.2%, the mass percentage of iron is 8.8%, the mass percentage of sulfur is 45.6%, and the balance is impurities); the low-acid first-stage atmospheric pressure oxygen leaching treatment includes controlling the redox potential of the first reaction system to 320mV by passing oxygen; the reaction temperature used in the low-acid first-stage atmospheric pressure oxygen leaching treatment is 89°C and the reaction time is 12h; in the mixed first reaction system, the mass concentration of sulfuric acid is 77g / L, the mass concentration of iron is 1.7g / L, and the mass concentration of zinc is 109g / L;

[0044] Step S3, performing conventional iron removal, purification and zinc electrowinning treatment on the first-stage atmospheric pressure oxygen leaching solution to obtain zinc; adding waste electrolyte (same as in Example 1) to the first-stage atmospheric pressure oxygen leaching residue, mixing to obtain a second reaction system, and performing high-acid two-stage atmospheric pressure oxygen leaching on the second reaction system to obtain a two-stage atmospheric pressure oxygen leaching solution (the volume of the second-stage atmospheric pressure oxygen leaching solution is 2.5 L, wherein the mass concentration of zinc is 109.53 g / L, the mass concentration of iron is 1.73 g / L, and the mass concentration of sulfuric acid is 65 g / L) and a two-stage atmospheric pressure oxygen leaching residue (the mass concentration of the second-stage atmospheric pressure oxygen leaching residue is The amount is 215g, of which the mass percentage of zinc is 3.27%, the mass percentage of iron is 14.2%, the mass percentage of sulfur is 68.77%, and the balance is impurities); the second-stage atmospheric pressure oxygen leaching liquid is the leaching agent in the first reaction system; the high-acid second-stage atmospheric pressure oxygen leaching treatment includes controlling the redox potential of the second reaction system to be 400mV by passing oxygen; the reaction temperature used in the high-acid second-stage atmospheric pressure oxygen leaching treatment is 95°C and the reaction time is 12h; the molar ratio of sulfuric acid to zinc in the mixed second reaction system is 1.85:1;

[0045] Step S4, adding water to the second-stage atmospheric pressure oxygen leaching residue and stirring to obtain a slurry; wherein the mass ratio of the added water to the second-stage atmospheric pressure oxygen leaching residue is 3:1; and the mass percentage of iron in the slurry is 3.55%;

[0046] Step S5: subjecting the slurry to sulfur conversion treatment to obtain conversion slag; if the total sulfur content in the conversion slag is less than 75%, a flotation process is first performed, followed by hot melt filtration to recover the sulfur in the slag.

[0047] In step S5, the sulfur conversion treatment includes feeding the slurry into a conversion kettle, adding a surfactant, and blowing in gas; the pH value of the slurry is 2; controlling the conversion temperature to 150°C, the conversion time to 30 minutes, and the conversion gas pressure to 0.5 MPa; the surfactant is sodium lignin sulfonate, and the addition amount thereof is 3‰ of the solid mass in the slurry; cooling the converted slurry to 85°C, and obtaining a conversion slag (the mass of the conversion slag is 214 g, wherein the mass percentage of zinc is 3.26%, the mass percentage of iron is 14.1%, the mass percentage of sulfur is 68.75%, and the remainder is impurities) and a conversion liquid (645 mL, the mass concentration of Zn is 0.084 g / L, and the mass concentration of Fe is 0.55 g / L) through liquid-solid separation; the conversion liquid can replace the water in step S4 and be reused in the sulfur conversion treatment.

[0048] The gas is air, and the oxygen content of the gas in the transition kettle is controlled to be 21% to avoid the problem of iron being oxidized into iron oxide and the sulfur content in the depleted sulfur slag resulting in incomplete sulfur recovery.

[0049] The flotation process includes adding the transformation slag and water in a mass ratio of 1.5:12 into a flotation cell, and sequentially performing roughing, scavenging, and cleaning to obtain a flotation concentrate (the mass of the flotation concentrate is 171.2 g, wherein the mass percentage of zinc is 3.76%, the mass percentage of iron is 9.63%, the mass percentage of sulfur is 82.94%, and the remainder is impurities) and a flotation tailing (the mass of the flotation tailing is 42.8 g, wherein the mass percentage of zinc is 1.25%, the mass percentage of iron is 32%, the mass percentage of sulfur is 12%, and the remainder is impurities); performing hot melt filtration on the flotation concentrate to recover sulfur in the slag; before the hot melt filtration, controlling the water content of the flotation concentrate to be below 20%; and controlling the stirring rate to be 1500 r / min and the aeration volume to be 200 L / h during the flotation process.

[0050] The roughing time is 12 minutes; the material residence time during the sweeping selection is 18 minutes; and the material residence time during the fine selection is 8 minutes.

[0051] The hot melt filtration adopts a hot melt temperature of 145° C. and a hot melt time of 20 minutes to obtain hot sulfur and hot filter residue; the hot sulfur is kept at 145° C. for 20 minutes and then pumped into granules to obtain sulfur with a sulfur content of 99.8% and a sulfur direct recovery rate of 89%.

[0052] Comparative Example 1:

[0053] Different from Example 1, in step S2, the low-acid, one-stage atmospheric-pressure oxygen leaching treatment includes controlling the redox potential of the first reaction system to 200 mV by passing oxygen; the first reaction system is subjected to the low-acid, one-stage atmospheric-pressure oxygen leaching treatment to obtain a one-stage atmospheric-pressure oxygen leaching solution (the volume of the one-stage atmospheric-pressure oxygen leaching solution is 2.5 L (same as Example 1), wherein the mass concentration of zinc is 138.51 g / L, the mass concentration of iron is 6.70 g / L, and the mass concentration of sulfuric acid is 30 g / L) and a one-stage atmospheric-pressure oxygen leaching residue (the mass of the one-stage atmospheric-pressure oxygen leaching residue is 412 g, wherein the mass percentage of zinc is 38.9%, the mass percentage of iron is 12.58%, the mass percentage of sulfur is 35.2%, and the remainder is impurities); in the uniformly mixed first reaction system, the mass concentration of sulfuric acid is 88 g / L, the mass concentration of iron is 7 g / L, and the mass concentration of zinc is 109 g / L (same as Example 1);

[0054] In step S3, the molar ratio of sulfuric acid to zinc in the mixed second reaction system is 1.66:1; the second reaction system is subjected to a high-acid two-stage atmospheric pressure oxygen leaching treatment to obtain a two-stage atmospheric pressure oxygen leaching liquid (the volume of the two-stage atmospheric pressure oxygen leaching liquid is 2.5 L (same as in Example 1), wherein the mass concentration of zinc is 109.2 g / L (same as in Example 1), the mass concentration of iron is 7.01 g / L, and the mass concentration of sulfuric acid is 68 g / L) and a two-stage atmospheric pressure oxygen leaching residue (the mass of the two-stage atmospheric pressure oxygen leaching residue is 302 g, wherein the mass percentage of zinc is 8.15%, the mass percentage of iron is 11.35%, the mass percentage of sulfur is 76.8%, and the remainder is impurities);

[0055] In step S5, liquid-solid separation was performed to obtain transition slag (the mass of the transition slag was 302 g, wherein the mass percentage of zinc was 8.14%, the mass percentage of iron was 11.35%, the mass percentage of sulfur was 76.7%, and the remainder was impurities) and transition liquid (906 mL, Zn 0.123 g / L, Fe 0.16 g / L).

[0056] The sulfur content is 99.5% and the direct sulfur recovery rate is 82%.

[0057] Comparative Example 2:

[0058] Different from Example 1, in step S2, the low-acid, one-stage atmospheric-pressure oxygen leaching treatment includes controlling the redox potential of the first reaction system to 450 mV by passing oxygen; the first reaction system is subjected to the low-acid, one-stage atmospheric-pressure oxygen leaching treatment to obtain a one-stage atmospheric-pressure oxygen leaching solution (the volume of the one-stage atmospheric-pressure oxygen leaching solution is 2.5 L (same as Example 1), wherein the mass concentration of zinc is 147.47 g / L, the mass concentration of iron is 15.62 g / L, and the mass concentration of sulfuric acid is 55 g / L) and a one-stage atmospheric-pressure oxygen leaching residue (the mass of the one-stage atmospheric-pressure oxygen leaching residue is 326 g, wherein the mass percentage of zinc is 22.8%, the mass percentage of iron is 6.23%, the mass percentage of sulfur is 48.5%, and the remainder is impurities); in the uniformly mixed first reaction system, the mass concentration of sulfuric acid is 105 g / L, the mass concentration of iron is 3 g / L, and the mass concentration of zinc is 83.8 g / L;

[0059] In step S3, the molar ratio of sulfuric acid to zinc in the mixed second reaction system is 3.57:1; the second reaction system is subjected to a high-acid two-stage atmospheric pressure oxygen leaching treatment to obtain a two-stage atmospheric pressure oxygen leaching liquid (the volume of the two-stage atmospheric pressure oxygen leaching liquid is 2.5 L (same as in Example 1), wherein the mass concentration of zinc is 83.84 g / L, the mass concentration of iron is 3.32 g / L, and the mass concentration of sulfuric acid is 85 g / L) and a two-stage atmospheric pressure oxygen leaching residue (the mass of the two-stage atmospheric pressure oxygen leaching residue is 192 g, wherein the mass percentage of zinc is 1.16%, the mass percentage of iron is 6.25%, the mass percentage of sulfur is 80.38%, and the remainder is impurities);

[0060] In step S5, liquid-solid separation is performed to obtain a transition slag (the mass of the transition slag is 191 g, wherein the mass percentage of zinc is 1.15%, the mass percentage of iron is 6.24%, the mass percentage of sulfur is 80.37%, and the remainder is impurities) and a transition liquid (576 mL, the mass concentration of Zn is 0.053 g / L, and the mass concentration of Fe is 0.14 g / L);

[0061] The sulfur content is 99.5%, and the direct sulfur recovery rate is 80%.

[0062] Comparative Example 3:

[0063] A method for atmospheric pressure oxygen leaching of zinc sulfide concentrate and sulfur recovery from slag, comprising:

[0064] Step S1, crushing and grinding the zinc sulfide concentrate to a target particle size; the target particle size is D90≤45 μm; the zinc sulfide concentrate is composed of the following components by mass percentage: 46.68% zinc, 10.21% iron, and 34.52% sulfur, with the remainder being impurities;

[0065] Step S2: Sulfuric acid (98% by mass, 50 g) and a leaching agent are added to 500 g of the zinc sulfide concentrate, and the mixture is mixed to obtain a first reaction system. The first reaction system is subjected to a low-acid one-stage atmospheric pressure oxygen leaching treatment to obtain a one-stage atmospheric pressure oxygen leaching solution (the volume of the one-stage atmospheric pressure oxygen leaching solution is 2.5 L, wherein the mass concentration of zinc is 140.08 g / L, the mass concentration of iron is 8.69 g / L, the mass concentration of sulfuric acid is 72g / L) and a first-stage atmospheric pressure oxygen leaching residue (the mass of the first-stage atmospheric pressure oxygen leaching residue is 376g, wherein the mass percentage of zinc is 35.2%, the mass percentage of iron is 13.89%, the mass percentage of sulfur is 43.9%, and the balance is impurities); the low-acid first-stage atmospheric pressure oxygen leaching treatment includes controlling the redox potential of the first reaction system to 360mV by passing oxygen; the reaction temperature used in the low-acid first-stage atmospheric pressure oxygen leaching treatment is 95°C, and the reaction time is 12h; in the mixed first reaction system, the mass concentration of sulfuric acid is 122g / L, the mass concentration of iron is 9g / L, and the mass concentration of zinc is 99g / L;

[0066] Step S3, performing conventional iron removal, purification and zinc electrowinning treatment on the first-stage atmospheric pressure oxygen leaching solution to obtain zinc; adding the spent electrolyte (same as in Example 1) to the first-stage atmospheric pressure oxygen leaching residue, mixing to obtain a second reaction system, and performing high-acid second-stage atmospheric pressure oxygen leaching on the second reaction system to obtain a second-stage atmospheric pressure oxygen leaching solution (the volume of the second-stage atmospheric pressure oxygen leaching solution is 2.5 L, wherein the mass concentration of zinc is 99.66 g / L, the mass concentration of iron is 9.16 g / L, and the mass concentration of sulfuric acid is 102 g / L) and second-stage atmospheric pressure oxygen leaching residue (the mass of the second-stage atmospheric pressure oxygen leaching residue is 223g, wherein the mass percentage of zinc is 9.28%, the mass percentage of iron is 13.15%, the mass percentage of sulfur is 65.8%, and the balance is impurities); the second-stage atmospheric pressure oxygen leaching liquid is the leaching agent in the first reaction system; the high-acid second-stage atmospheric pressure oxygen leaching treatment includes controlling the redox potential of the second reaction system to be 300mV by passing oxygen; the reaction temperature used in the high-acid second-stage atmospheric pressure oxygen leaching treatment is 95°C and the reaction time is 12h; the components of the electrolyte include sulfuric acid and zinc sulfate; the molar ratio of sulfuric acid to zinc in the mixed second reaction system is 2:1;

[0067] Step S4, adding water to the second-stage atmospheric pressure oxygen leaching residue and stirring to obtain a slurry; wherein the mass ratio of the added water to the second-stage atmospheric pressure oxygen leaching residue is 3:1; and the mass percentage of iron in the slurry is 3.29%;

[0068] Step S5: subjecting the slurry to sulfur conversion treatment to obtain conversion slag; if the mass percentage of total sulfur in the conversion slag is less than 75%, a flotation process (same as in Example 2) is first performed, followed by hot melt filtration (same as in Example 2) to recover the sulfur in the slag.

[0069] In step S5, liquid-solid separation was performed to obtain transition slag (the mass of the transition slag was 222 g, wherein the mass percentage of zinc was 9.27%, the mass percentage of iron was 13.15%, the mass percentage of sulfur was 65.7%, and the remainder was impurities) and transition liquid (669 mL, the mass concentration of Zn was 0.17 g / L, and the mass concentration of Fe was 0.20 g / L).

[0070] The flotation process obtains flotation concentrate (the mass of the flotation concentrate is 177.6 g, of which the mass percentage of zinc is 11.02%, the mass percentage of iron is 8.94%, the mass percentage of sulfur is 77.63%, and the balance is impurities) and flotation tailings (the mass of the flotation tailings is 44.4 g, of which the mass percentage of zinc is 2.28%, the mass percentage of iron is 30%, the mass percentage of sulfur is 18%, and the balance is impurities).

[0071] The sulfur content is 99.3%, and the direct sulfur recovery rate is 82.5%.

[0072] Comparative Example 4:

[0073] A method for atmospheric pressure oxygen leaching of zinc sulfide concentrate and sulfur recovery from slag, comprising:

[0074] Step S1, crushing and grinding the zinc sulfide concentrate to a target particle size; the target particle size is D90≤45 μm; the zinc sulfide concentrate is composed of the following components by mass percentage: 46.68% zinc, 10.21% iron, and 34.52% sulfur, with the remainder being impurities;

[0075] Step S2, adding sulfuric acid (mass percentage of 98%, amount of 50g) and a leaching agent to 500g of the zinc sulfide concentrate, mixing to obtain a first reaction system, and subjecting the first reaction system to a low-acid one-stage atmospheric pressure oxygen leaching treatment to obtain a one-stage atmospheric pressure oxygen leaching liquid (the volume of the one-stage atmospheric pressure oxygen leaching liquid is 2.5L, wherein the mass concentration of zinc is 147.5g / L, the mass concentration of iron is 15.35g / L, and the mass concentration of sulfuric acid is 28 g / L) and a first-stage atmospheric pressure oxygen leaching residue (the mass of the first-stage atmospheric pressure oxygen leaching residue is 385g, wherein the mass percentage of zinc is 35.6%, the mass percentage of iron is 12.89%, the mass percentage of sulfur is 44.3%, and the balance is impurities); the low-acid first-stage atmospheric pressure oxygen leaching treatment includes controlling the redox potential of the first reaction system to 360mV by passing oxygen; the reaction temperature used in the low-acid first-stage atmospheric pressure oxygen leaching treatment is 95°C and the reaction time is 12h; in the mixed first reaction system, the mass concentration of sulfuric acid is 85g / L, the mass concentration of iron is 14.6g / L, and the mass concentration of zinc is 108g / L;

[0076] Step S3, performing conventional iron removal, purification and zinc electrowinning treatment on the first-stage atmospheric pressure oxygen leaching solution to obtain zinc; adding the spent electrolyte (same as in Example 1) to the first-stage atmospheric pressure oxygen leaching residue, mixing to obtain a second reaction system, and performing high-acid two-stage atmospheric pressure oxygen leaching on the second reaction system to obtain a two-stage atmospheric pressure oxygen leaching solution (the volume of the second-stage atmospheric pressure oxygen leaching solution is 2.5 L, wherein the mass concentration of zinc is 108.7 g / L, the mass concentration of iron is 14.68 g / L, and the mass concentration of sulfuric acid is 65 g / L) and second-stage atmospheric pressure oxygen leaching residue (the mass of the second-stage atmospheric pressure oxygen leaching residue is 192g, wherein the mass percentage of zinc is 1.15%, the mass percentage of iron is 6.6%, the mass percentage of sulfur is 78.5%, and the balance is impurities); the second-stage atmospheric pressure oxygen leaching liquid is the leaching agent in the first reaction system; the high-acid second-stage atmospheric pressure oxygen leaching treatment includes controlling the redox potential of the second reaction system to be 500mV by passing oxygen; the reaction temperature used in the high-acid second-stage atmospheric pressure oxygen leaching treatment is 95°C and the reaction time is 12h; the components of the electrolyte include sulfuric acid and zinc sulfate; the molar ratio of sulfuric acid to zinc in the mixed second reaction system is 1.95:1;

[0077] Step S4, adding water to the second-stage atmospheric pressure oxygen leaching residue and stirring to obtain a slurry; wherein the mass ratio of the added water to the second-stage atmospheric pressure oxygen leaching residue is 3:1; and the mass percentage of iron in the slurry is 1.65%;

[0078] Step S5: subjecting the slurry to sulfur conversion treatment to obtain conversion slag; if the mass percentage of total sulfur in the conversion slag is greater than or equal to 75%, directly performing hot melt filtration (same as in Example 1) to recover the sulfur in the slag; before the hot melt filtration, controlling the moisture content of the conversion slag to be less than 20%.

[0079] In step S5, the sulfur conversion treatment is the same as in Example 1, and liquid-solid separation is performed to obtain conversion slag (the mass of the conversion slag is 194 g, wherein the mass percentage of zinc is 1.14%, the mass percentage of iron is 6.5%, and the mass percentage of sulfur is 78.4%) and conversion liquid (576 mL, the mass concentration of Zn is 0.053 g / L, and the mass concentration of Fe is 0.45 g / L); the conversion liquid can replace the water in step S4 and be reused in the sulfur conversion treatment.

[0080] The sulfur content is 99.7% and the direct sulfur recovery rate is 76%.

[0081] Comparative Example 5:

[0082] A method for atmospheric pressure oxygen leaching of zinc sulfide concentrate and sulfur recovery from slag, comprising:

[0083] Step S1, crushing and grinding the zinc sulfide concentrate to a target particle size; the target particle size is D90≤65μm; the zinc sulfide concentrate is composed of the following components in mass percentage: 46.68% zinc, 10.21% iron, and 34.52% sulfur, with the remainder being impurities;

[0084] Step S2: Sulfuric acid (98% by mass, 30 g) and a leaching agent are added to 500 g of the zinc sulfide concentrate, and the mixture is mixed to obtain a first reaction system, and the first reaction system is subjected to a low-acid one-stage atmospheric pressure oxygen leaching treatment to obtain a one-stage atmospheric pressure oxygen leaching liquid (the volume of the one-stage atmospheric pressure oxygen leaching liquid is 2.5 L, wherein the mass concentration of zinc is 137.55 g / L, the mass concentration of iron is 10.19 g / L, and the mass concentration of sulfuric acid is 56.8 g / L) and a first-stage atmospheric pressure oxygen leaching residue (the mass of the first-stage atmospheric pressure oxygen leaching residue is 433 g, wherein the mass percentage of zinc is 39.9%, the mass percentage of iron is 9.7%, and the mass percentage of sulfur is 40.3%); the low-acid first-stage atmospheric pressure oxygen leaching treatment includes controlling the redox potential of the first reaction system to 320 mV by passing oxygen; the reaction temperature used in the low-acid first-stage atmospheric pressure oxygen leaching treatment is 89° C. and the reaction time is 12 hours; in the mixed first reaction system, the mass concentration of sulfuric acid is 99.2 g / L, the mass concentration of iron is 6.6 g / L, and the mass concentration of zinc is 113 g / L;

[0085] Step S3: performing conventional iron removal, purification, and zinc electrowinning treatment on the first-stage atmospheric pressure oxygen leaching solution to obtain zinc; adding the spent electrolyte (same as in Example 1) to the first-stage atmospheric pressure oxygen leaching residue, mixing to obtain a second reaction system, and performing high-acid two-stage atmospheric pressure oxygen leaching on the second reaction system to obtain a two-stage atmospheric pressure oxygen leaching solution (the volume of the second-stage atmospheric pressure oxygen leaching solution is 2.5 L, wherein the mass concentration of zinc is 113.29 g / L, the mass concentration of iron is 6.57 g / L, and the mass concentration of sulfuric acid is 87.2 g / L) and a two-stage atmospheric pressure oxygen leaching residue (the mass of the second-stage atmospheric pressure oxygen leaching residue is 281 g). , wherein the mass percentage of zinc is 9.62%, the mass percentage of iron is 9.1%, the mass percentage of sulfur is 58.23%, and the remainder is impurities); the second-stage atmospheric pressure oxygen leaching liquid is the leaching agent in the first reaction system; the high-acid second-stage atmospheric pressure oxygen leaching treatment includes controlling the redox potential of the second reaction system to 400 mV by passing oxygen; the reaction temperature used in the high-acid second-stage atmospheric pressure oxygen leaching treatment is 95°C and the reaction time is 12 hours; the components of the electrolyte include sulfuric acid and zinc sulfate; the molar ratio of sulfuric acid to zinc in the second reaction system is 1.54:1;

[0086] Step S4, adding water to the second-stage atmospheric pressure oxygen leaching residue and stirring to obtain a slurry; wherein the mass ratio of the added water to the second-stage atmospheric pressure oxygen leaching residue is 3:1; and the mass percentage of iron in the slurry is 2.28%;

[0087] Step S5: subjecting the slurry to sulfur conversion treatment to obtain conversion slag; if the total sulfur content in the conversion slag is less than 75%, a flotation process is first performed, followed by hot melt filtration to recover the sulfur in the slag.

[0088] In step S5, the sulfur conversion treatment is the same as in Example 2, and liquid-solid separation is performed to obtain conversion slag (the mass of the conversion slag is 280 g, wherein the mass percentage of zinc is 9.61%, the mass percentage of iron is 9%, the mass percentage of sulfur is 58.22%, and the remainder is impurities) and conversion liquid (843 mL, the mass concentration of Zn is 0.15 g / L, and the mass concentration of Fe is 0.44 g / L); the conversion liquid can replace the water in step S4 and be reused in the sulfur conversion treatment.

[0089] The flotation process was the same as that in Example 2, to obtain a flotation concentrate (the mass of the flotation concentrate was 224 g, wherein the mass percentage of zinc was 10.45%, the mass percentage of iron was 4.25%, the mass percentage of sulfur was 67.03%, and the balance was impurities) and a flotation tailing (the mass of the flotation tailing was 56 g, wherein the mass percentage of zinc was 6.25%, the mass percentage of iron was 28%, the mass percentage of sulfur was 23%, and the balance was impurities). The flotation concentrate was subjected to hot melt filtration to recover sulfur in the slag.

[0090] Since the sulfur content in the flotation concentrate is too low, below 75%, hot melt filtration cannot be performed and sulfur products cannot be produced.

[0091] The zinc sulfide concentrates processed in Examples 1-2 and Comparative Examples 1-5 were zinc sulfide concentrates of the same composition. Table 1 summarizes the changes in the core parameters and sulfur recovery data of the sulfur recovery methods in Examples 1-2 and Comparative Examples 1-5.

[0092] Table 1 Changes in sulfur recovery core parameters and sulfur recovery data

[0093]

[0094] As shown in Table 1, compared with Comparative Examples 1 to 5, the present invention can provide a direct yield of sulfur recovery using Examples 1 to 2. The reasons are analyzed as follows:

[0095] In Comparative Example 1, the redox potential of the first reaction system was too low, resulting in partial sulfur in the zinc sulfide concentrate not being fully oxidized to form elemental sulfur, which reduced the sulfur content in the first-stage atmospheric pressure oxygen leaching residue and the second-stage atmospheric pressure oxygen leaching residue, thereby reducing the direct recovery rate of sulfur.

[0096] In Comparative Example 2, the redox potential of the first reaction system was too high, causing part of the sulfur in the zinc sulfide concentrate to be over-oxidized to form sulfuric acid, which reduced the sulfur content in the first and second stage atmospheric pressure oxygen leaching residues, thereby reducing the direct sulfur recovery rate.

[0097] In Comparative Example 3, the redox potential of the second reaction system was too low, resulting in partial sulfur in the zinc sulfide concentrate not being fully oxidized to form elemental sulfur, which reduced the sulfur content in the first-stage atmospheric pressure oxygen leaching residue and the second-stage atmospheric pressure oxygen leaching residue, thereby reducing the direct recovery rate of sulfur.

[0098] In Comparative Example 4, the redox potential of the second reaction system was too high, causing part of the sulfur in the zinc sulfide concentrate to be over-oxidized to form sulfuric acid, resulting in a decrease in the sulfur content in the first-stage atmospheric pressure oxygen leaching residue and the second-stage atmospheric pressure oxygen leaching residue, thereby reducing the direct sulfur recovery rate;

[0099] The target particle size D90 used in Comparative Example 5 was too high, i.e., the particle size of the crushed and ground zinc sulfide concentrate was too large, resulting in a large amount of unleached zinc in the first-stage atmospheric pressure oxygen leaching residue and the second-stage atmospheric pressure oxygen leaching residue. This resulted in a relatively low sulfur content, i.e., the sulfur content in the flotation concentrate was too low, below 75%, making hot melt filtration impossible and no sulfur product produced.

[0100] In Examples 1 and 2, controlling the appropriate redox potentials of the first reaction system and the second reaction system can promote the complete oxidation of sulfur in the zinc sulfide concentrate into elemental sulfur. Controlling the appropriate target particle size allows zinc in the first-stage atmospheric pressure oxygen leaching residue and the second-stage atmospheric pressure oxygen leaching residue to be fully leached, thereby avoiding a reduction in sulfur content and thereby improving the direct yield of sulfur recovery.

[0101] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for atmospheric pressure oxygen leaching of zinc sulfide concentrate and recovery of sulfur from slag, characterized in that: include: Step S1, grinding the zinc sulfide concentrate to a target particle size; The zinc sulfide concentrate is composed of the following components in mass percentage: 43% to 48% zinc, 9% to 15% iron, 32% to 35% sulfur, and the remainder being impurities; Step S2, adding sulfuric acid and a leaching agent to the zinc sulfide concentrate, mixing to obtain a first reaction system, and subjecting the first reaction system to a low-acid, one-stage atmospheric pressure oxygen leaching treatment to obtain a one-stage atmospheric pressure oxygen leaching liquid and a one-stage atmospheric pressure oxygen leaching residue; the low-acid, one-stage atmospheric pressure oxygen leaching treatment includes controlling the redox potential of the first reaction system to be 280-380 mV by passing oxygen; in the mixed first reaction system, the mass concentration of sulfuric acid is 70-80 g / L, the mass concentration of iron is less than or equal to 15 g / L, and the mass concentration of zinc is greater than or equal to 105 g / L; the reaction temperature used in the low-acid, one-stage atmospheric pressure oxygen leaching treatment is 88-105° C., and the reaction time is 6-15 hours; Step S3: adding a spent electrolyte to the first-stage atmospheric pressure oxygen leaching residue, mixing them to obtain a second reaction system, and subjecting the second reaction system to a high-acid second-stage atmospheric pressure oxygen leaching treatment to obtain a second-stage atmospheric pressure oxygen leaching liquid and a second-stage atmospheric pressure oxygen leaching residue; the second-stage atmospheric pressure oxygen leaching liquid is used as the leaching agent in the first reaction system; the high-acid second-stage atmospheric pressure oxygen leaching treatment includes controlling the redox potential of the second reaction system to be 350-450 mV by passing oxygen; the spent electrolyte comprises sulfuric acid and zinc sulfate; and the molar ratio of sulfuric acid to zinc in the mixed second reaction system is 1.5-2:1; Step S4, adding water to the second-stage atmospheric pressure oxygen leaching residue and stirring to obtain a slurry; wherein the mass ratio of the added water to the second-stage atmospheric pressure oxygen leaching residue is 2-4:1; the mass percentage of iron in the slurry is less than 5%; the reaction temperature used in the high-acid second-stage atmospheric pressure oxygen leaching treatment is 88-105° C., and the reaction time is 8-18 hours; Step S5: subjecting the slurry to sulfur conversion treatment to obtain conversion slag; if the total sulfur content in the conversion slag is greater than or equal to 75%, directly performing hot melt filtration to recover the sulfur in the slag; before the hot melt filtration, controlling the moisture content of the conversion slag to be less than 20%; if the total sulfur content in the conversion slag is less than 75%, first performing a flotation process, and then performing hot melt filtration to recover the sulfur in the slag; In step S5, the sulfur conversion treatment includes feeding the slurry into a conversion kettle, adding a surfactant, and blowing in gas; the pH value of the slurry is 0.5-5; the conversion temperature is controlled to be 130-160°C, the conversion time is 10-60 minutes, and the pressure in the conversion kettle is 0.3-0.8 MPa; the amount of the surfactant added is 1‰-5‰ of the solid mass in the slurry; the converted slurry is cooled to 80-90°C, and liquid-solid separation is performed to obtain conversion slag.

2. The method for atmospheric pressure oxygen leaching of zinc sulfide concentrate and sulfur recovery from slag according to claim 1, characterized in that: The surfactant includes at least one of sodium lignin sulfonate and calcium lignin sulfonate.

3. The method for atmospheric pressure oxygen leaching of zinc sulfide concentrate and sulfur recovery from slag according to claim 1, characterized in that: The gas includes at least one of air and nitrogen.

4. The method for atmospheric pressure oxygen leaching of zinc sulfide concentrate and sulfur recovery from slag according to claim 1, characterized in that: The oxygen content of the gas in the transition kettle is controlled to be 0-21% by volume.

5. The method for atmospheric pressure oxygen leaching of zinc sulfide concentrate and sulfur recovery from slag according to any one of claims 1 to 4, characterized in that: The flotation process includes adding the transformation slag and water in a mass ratio of 1-2:10-15 into a flotation tank, and sequentially performing roughing, scavenging, and cleaning to obtain flotation concentrate and flotation tailings; performing hot melt filtration on the flotation concentrate to recover sulfur in the slag; and controlling the water content of the flotation concentrate to be below 20% before the hot melt filtration. In the flotation process, the stirring rate is controlled to be 1000-2000 r / min and the aeration volume is controlled to be 150-400 L / h.

6. The method for atmospheric pressure oxygen leaching of zinc sulfide concentrate and sulfur recovery from slag according to claim 5, characterized in that: The roughing time is 10-15 minutes; the material residence time during the sweeping selection is 15-25 minutes; and the material residence time during the finishing selection is 5-10 minutes.

7. The method for atmospheric pressure oxygen leaching of zinc sulfide concentrate and sulfur recovery from slag according to claim 5, characterized in that: The hot melt filtration adopts a hot melt temperature of 140-155° C. and a hot melt time of 10-30 minutes.

8. The method for atmospheric pressure oxygen leaching of zinc sulfide concentrate and sulfur recovery from slag according to claim 5, characterized in that: In the step S1, the target particle size is D90≤45 μm.

9. The method for atmospheric pressure oxygen leaching of zinc sulfide concentrate and sulfur recovery from slag according to claim 5, characterized in that: The first stage atmospheric pressure oxygen leaching solution is subjected to conventional iron removal, purification and zinc electrowinning treatment to obtain zinc.

Images