Method for normal-pressure oxygen leaching of zinc sulfide concentrate and recovery of sulfur in slag

Abstract

The invention relates to the technical field of wet smelting, in particular to a method for normal-pressure oxygen leaching of zinc sulfide concentrate and recovery of sulfur in slag. The method comprises the following steps: grinding the zinc sulfide concentrate to a target particle size; sulfuric acid and a leaching agent are added into the zinc sulfide concentrate to obtain a first reaction system, low-acid first-section normal-pressure oxygen leaching treatment is conducted on the first reaction system, and first-section normal-pressure oxygen leaching liquid and first-section normal-pressure oxygen leaching residues are obtained; the redox potential of the first reaction system is 280-380 mV; waste electrolyte is added into the first-section normal-pressure oxygen leaching residues to obtain a second reaction system, high-acid second-section normal-pressure oxygen leaching treatment is conducted on the second reaction system, and second-section normal-pressure oxygen leaching liquid and second-section normal-pressure oxygen leaching residues are obtained; the redox potential of the second reaction system is 350-450 mV; adding water into the second-section normal-pressure oxygen leaching residues to obtain slurry; performing sulfur transformation treatment on the slurry to obtain transformed slag; and recovering sulfur in the slag. The method can improve the direct recovery rate of sulfur recovery with 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, there is a need to provide a method for atmospheric pressure oxygen leaching of zinc sulfide concentrate and sulfur recovery from the residue, which on the one hand solves the problems of incomplete sulfur transformation in the existing atmospheric pressure oxygen-enriched leaching process and incomplete sulfur recovery due to the low sulfur content in the sulfur-depleted residue, and on the other hand solves the problem of the increase in industrial costs and energy consumption caused by the need to introduce a large amount of oxygen in the existing atmospheric pressure oxygen-enriched leaching process. Summary of the Invention

[0006] The object of the present invention is to provide a method for atmospheric pressure oxygen leaching of zinc sulfide concentrate and sulfur recovery from the residue. The specific technical solutions are as follows: A method for atmospheric pressure oxygen leaching of zinc sulfide concentrate and sulfur recovery from the residue, comprising: 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 percentages: zinc 43% - 48%, iron 9% - 15%, sulfur 32% - 35%, and the balance is impurities; Step S2: Adding sulfuric acid and a leaching agent to the zinc sulfide concentrate, mixing evenly to obtain a first reaction system, and performing low-acid one-stage atmospheric pressure oxygen leaching treatment on the first reaction system to obtain a one-stage atmospheric pressure oxygen leaching solution 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 at 280 - 380 mV by introducing oxygen; 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 h; in the evenly 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; Step S3: Adding waste electrolyte to the one-stage atmospheric pressure oxygen leaching residue, mixing evenly to obtain a second reaction system, and performing high-acid two-stage atmospheric pressure oxygen leaching treatment on the second reaction system to obtain a two-stage atmospheric pressure oxygen leaching solution and a two-stage atmospheric pressure oxygen leaching residue; the two-stage atmospheric pressure oxygen leaching solution is the leaching agent in the first reaction system; the high-acid two-stage atmospheric pressure oxygen leaching treatment includes controlling the redox potential of the second reaction system at 350 - 450 mV by introducing oxygen; the reaction temperature used in the high-acid two-stage atmospheric pressure oxygen leaching treatment is 88 - 105 °C, and the reaction time is ⑧ - 18 h; the components of the waste electrolyte include sulfuric acid and zinc sulfate; in the evenly mixed second reaction system, the molar ratio of sulfuric acid to zinc is 1.5 - 2:1; Step S4: Adding water to the two-stage atmospheric pressure oxygen leaching residue and stirring evenly to obtain a slurry; wherein, the addition amount of water is in a mass ratio of 2 - 4:1 to the two-stage atmospheric pressure oxygen leaching residue; the mass percentage of iron in the slurry is less than 5%; Step S5: Subject the slurry to sulfur transformation treatment to obtain transformed slag. If the mass percentage of total sulfur in the transformed slag is greater than or equal to 75%, directly perform hot melting filtration to recover sulfur in the slag. Before the hot melting filtration, control the water content of the transformed slag to be below 20%. If the mass percentage of total sulfur in the transformed slag is less than 75%, first perform a flotation process and then perform hot melting filtration to recover sulfur in the slag.

[0007] Optionally, in step S5, the sulfur transformation treatment includes feeding the slurry into a transformation kettle, adding a surfactant, and blowing in a gas. The pH value of the slurry is 0.5 - 5. Control the transformation temperature to be 130 - 160°C, the transformation time to be 10 - 60 min, and the pressure in the transformation kettle to be 0.3 - 0.8 MPa. The addition amount of the surfactant is 1‰ - 5‰ of the solid mass in the slurry. Cool the transformed slurry to 80 - 90°C and perform liquid-solid separation to obtain the transformed slag.

[0008] Optionally, the surfactant includes at least one of sodium lignosulfonate, calcium lignosulfonate, and lignite.

[0009] Optionally, the gas includes at least one of air and nitrogen.

[0010] Optionally, control the volume percentage of oxygen content in the gas in the transformation kettle to be 0 - 21%.

[0011] Optionally, the flotation process includes adding the transformed slag and water to a flotation cell in a mass ratio of 1 - 2:10 - 15 and performing rough selection, scavenging, and cleaning in sequence to obtain flotation concentrate and flotation tailings. Perform hot melting filtration on the flotation concentrate to recover sulfur in the slag. Before the hot melting filtration, control the water content of the flotation concentrate to be below 20%. Control the stirring rate to be 1000 - 2000 r / min and the aeration rate to be 150 - 400 L / h during the flotation process.

[0012] Optionally, the rough selection time is 10 - 15 min; the residence time of the material during scavenging is 15 - 25 min; the residence time of the material during cleaning is 5 - 10 min.

[0013] Optionally, the hot melting temperature used for the hot melting filtration is 140 - 155°C, and the hot melting time is 10 - 30 min.

[0014] Optionally, in step S1, the target particle size is D90 ≤ 45 μm.

[0015] Optionally, subject the first-stage atmospheric oxygen leaching solution to conventional iron removal, purification, and zinc electrowinning treatments to obtain zinc.

[0016] Applying the technical solution of the present invention has at least the following beneficial effects: (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.

[0017] (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.

[0018] (3) The zinc sulfide concentrate of the present invention is crushed and ground to a target particle size of D90≤45μm, which is convenient for the leaching of zinc and iron elements and improves the subsequent recovery of sulfur. If a smaller target particle size is used, the increase in sulfur recovery rate is not obvious, but the cost of crushing and grinding will increase significantly. If a larger target particle size is used, the leaching of zinc and iron elements is insufficient, and the sulfur recovery rate will also decrease.

[0019] In addition to the purposes, features, and advantages described above, the present invention has other purposes, features, and advantages. The present invention will be further described in detail below with reference to the drawings. Brief Description of the Drawings

[0020] The drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1 It 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 Embodiments

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0022] Example 1: A method for atmospheric pressure oxygen leaching of zinc sulfide concentrate and sulfur recovery from slag, comprising: Step S1: Crush and grind the zinc sulfide concentrate to a target particle size; the target particle size is D90≤45μm; the zinc sulfide concentrate is composed of the following components by mass percentage: zinc 46.68%, iron 10.21%, sulfur 34.52%, and the balance is impurities; Step S2: Add sulfuric acid (with a mass percentage of 98% and a dosage of 50 g) and a leaching agent to 500 g of the zinc sulfide concentrate, mix well to obtain a first reaction system, and perform low-acid single-stage atmospheric oxygen leaching treatment on the first reaction system to obtain a single-stage atmospheric oxygen leaching solution (the volume of the single-stage atmospheric oxygen leaching solution is 2.5 L, where the mass concentration of zinc is 147.5 g / L, the mass concentration of iron is 10.78 g / L, and the mass concentration of sulfuric acid is 15 g / L) and a single-stage atmospheric oxygen leaching residue (the mass of the single-stage atmospheric oxygen leaching residue is 385 g, where 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 single-stage atmospheric oxygen leaching treatment includes controlling the redox potential of the first reaction system to 360 mV by introducing oxygen; the reaction temperature for the low-acid single-stage atmospheric oxygen leaching treatment is 95 °C, and the reaction time is 12 h; in the mixed first reaction system, the mass concentration of sulfuric acid is 75 g / L, the mass concentration of iron is 11.7 g / L, and the mass concentration of zinc is 109 g / L; Step S3: Perform conventional iron removal, purification, and zinc electrowinning treatment on the single-stage atmospheric oxygen leaching solution to obtain zinc; add waste electrolyte (the components of the waste electrolyte include sulfuric acid and zinc sulfate; the volume of the waste electrolyte is 2.5 L, where the mass concentration of zinc sulfate is 135.7 g / L and the mass concentration of sulfuric acid is 160 g / L) to the single-stage atmospheric oxygen leaching residue, mix well to obtain a second reaction system, and perform high-acid two-stage atmospheric oxygen leaching treatment on the second reaction system to obtain a two-stage atmospheric oxygen leaching solution (the volume of the two-stage atmospheric oxygen leaching solution is 2.5 L, where 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 a two-stage atmospheric oxygen leaching residue (the mass of the two-stage atmospheric oxygen leaching residue is 195 g, where 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 two-stage atmospheric oxygen leaching solution is the leaching agent in the first reaction system; the high-acid two-stage atmospheric oxygen leaching treatment includes controlling the redox potential of the second reaction system to 420 mV by introducing oxygen; the reaction temperature for the high-acid two-stage atmospheric oxygen leaching treatment is 95 °C, and the reaction time is 12 h; in the mixed second reaction system, the molar ratio of sulfuric acid to zinc is 1.92:1; Step S4: Add water to the two-stage atmospheric oxygen leaching residue and stir to mix well to obtain a slurry; where the mass ratio of the added water to the mass of the two-stage atmospheric oxygen leaching residue is 3:1; the mass percentage of iron in the slurry is less than 5%, specifically 3.09%; 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%.

[0023] 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.

[0024] 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.

[0025] 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%.

[0026] Example 2: See also Figure 1 A method for atmospheric pressure oxygen leaching of zinc sulfide concentrate and recovery of sulfur from slag, comprising: 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; Step S2: Add sulfuric acid (with a mass percentage of 98% and a dosage of 30 g) and a leaching agent to 500 g of the zinc sulfide concentrate. After mixing evenly, a first reaction system is obtained. Perform low-acid one-stage atmospheric pressure oxygen leaching treatment on the first reaction system 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, where the mass concentration of zinc is 145.55 g / L, the mass concentration of iron is 8.21 g / L, and the mass concentration of sulfuric acid is 13.8 g / L) and a one-stage atmospheric pressure oxygen leaching residue (the mass of the one-stage atmospheric pressure oxygen leaching residue is 396 g, where 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 one-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 adopted for the low-acid one-stage atmospheric pressure oxygen leaching treatment is 89 °C, and the reaction time is 12 h; in the evenly mixed first reaction system, the mass concentration of sulfuric acid is 77 g / L, the mass concentration of iron is 1.7 g / L, and the mass concentration of zinc is 109 g / L; Step S3: Perform conventional iron removal, purification, and zinc electrowinning treatment on the one-stage atmospheric pressure oxygen leaching solution to obtain zinc; add waste electrolyte (same as in Example 1) to the one-stage atmospheric pressure oxygen leaching residue. After mixing evenly, a second reaction system is obtained. Perform high-acid two-stage atmospheric pressure oxygen leaching treatment 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, where 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 of the two-stage atmospheric pressure oxygen leaching residue is 215 g, where 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 two-stage atmospheric pressure oxygen leaching solution is the leaching agent in the first reaction system; the high-acid two-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 adopted for the high-acid two-stage atmospheric pressure oxygen leaching treatment is 95 °C, and the reaction time is 12 h; in the evenly mixed second reaction system, the molar ratio of sulfuric acid to zinc is 1.85:1; Step S4: Add water to the two-stage atmospheric pressure oxygen leaching residue and stir evenly to obtain a slurry; where the mass ratio of the added water to the mass of the two-stage atmospheric pressure oxygen leaching residue is 3:1; the mass percentage of iron in the slurry is 3.55%; Step S5: Perform sulfur transformation treatment on the slurry to obtain a transformed residue; if the total sulfur mass percentage in the transformed residue is less than 75%, first perform a flotation process, and then perform hot melting filtration to recover sulfur in the residue.

[0027] In the step S5, the sulfur transformation treatment includes feeding the slurry into a transformation kettle, adding a surfactant, and blowing in a gas; the pH value of the slurry is 2; the transformation temperature is controlled at 150°C, the transformation time is 30 min, and the transformation air pressure is 0.5 MPa; the surfactant is sodium lignosulfonate, and its addition amount is 3‰ of the solid mass in the slurry; the transformed slurry is cooled to 85°C, and after liquid-solid separation, a transformed residue (the mass of the transformed residue is 214 g, in which 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 balance is impurities) and a transformed liquid (645 mL, the mass concentration of Zn is 0.084 g / L, and the mass concentration of Fe is 0.55 g / L) are obtained; the transformed liquid can replace the water in step S4 and be recycled for sulfur transformation treatment.

[0028] The gas is air, and the oxygen content of the gas in the transformation kettle is controlled at 21% to avoid the problem that iron is oxidized to iron oxide, resulting in the depletion of sulfur content in the sulfur slag and incomplete sulfur recovery.

[0029] The flotation process includes adding the transformed residue and water to a flotation cell in a mass ratio of 1.5:12, and successively performing rough selection, scavenging, and cleaning to obtain a flotation concentrate (the mass of the flotation concentrate is 171.2 g, in which 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 balance is impurities) and a flotation tailing (the mass of the flotation tailing is 42.8 g, in which the mass percentage of zinc is 1.25%, the mass percentage of iron is 32%, the mass percentage of sulfur is 12%, and the balance is impurities); the flotation concentrate is subjected to hot melting filtration to recover sulfur in the slag; before the hot melting filtration, the water content of the flotation concentrate is controlled to be below 20%; in the flotation process, the stirring rate is controlled at 1500 r / min, and the aeration rate is 200 L / h.

[0030] The rough selection time is 12 min; the residence time of the material during scavenging is 18 min; the residence time of the material during cleaning is 8 min.

[0031] The hot melting temperature adopted for the hot melting filtration is 145°C, the hot melting time is 20 min, and hot sulfur and hot filter residue are obtained; the hot sulfur is kept at 145°C for 20 min, and then pumped for granulation to obtain sulfur with a sulfur content of 99.8% and a direct sulfur recovery rate of 89%.

[0032] Comparative Example 1: Different from Example 1, in step S2, the low-acid first-stage atmospheric oxygen leaching treatment includes passing oxygen to control the redox potential of the first reaction system at 200 mV; performing low-acid first-stage atmospheric oxygen leaching treatment on the first reaction system to obtain a first-stage atmospheric oxygen leaching solution (the volume of the first-stage atmospheric oxygen leaching solution is 2.5 L (the same as in Example 1), where 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 first-stage atmospheric oxygen leaching residue (the mass of the first-stage atmospheric oxygen leaching residue is 412 g, where 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 balance is impurities); in the 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 (the same as in Example 1); In step S3, the molar ratio of sulfuric acid to zinc in the mixed second reaction system is 1.66:1; performing high-acid second-stage atmospheric oxygen leaching treatment on the second reaction system to obtain a second-stage atmospheric oxygen leaching solution (the volume of the second-stage atmospheric oxygen leaching solution is 2.5 L (the same as in Example 1), where the mass concentration of zinc is 109.2 g / L (the 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 second-stage atmospheric oxygen leaching residue (the mass of the second-stage atmospheric oxygen leaching residue is 302 g, where 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 balance is impurities); In step S5, after liquid-solid separation, a transformation residue (the mass of the transformation residue is 302 g, where the mass percentage of zinc is 8.14%, the mass percentage of iron is 11.35%, the mass percentage of sulfur is 76.7%, and the balance is impurities) and a transformation solution (906 mL, Zn 0.123 g / L, Fe 0.16 g / L) are obtained.

[0033] The sulfur content of sulfur is 99.5%, and the direct recovery rate of sulfur is 82%.

[0034] Comparative Example 2: Different from Example 1, in step S2, the low-acid first-stage atmospheric oxygen leaching treatment includes passing oxygen to control the redox potential of the first reaction system to 450 mV; performing low-acid first-stage atmospheric oxygen leaching treatment on the first reaction system to obtain a first-stage atmospheric oxygen leaching solution (the volume of the first-stage atmospheric oxygen leaching solution is 2.5 L (the same as in Example 1), where 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 first-stage atmospheric oxygen leaching residue (the mass of the first-stage atmospheric oxygen leaching residue is 326 g, where 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 balance is impurities); in the 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; In step S3, the molar ratio of sulfuric acid to zinc in the mixed second reaction system is 3.57:1; performing high-acid second-stage atmospheric oxygen leaching treatment on the second reaction system to obtain a second-stage atmospheric oxygen leaching solution (the volume of the second-stage atmospheric oxygen leaching solution is 2.5 L (the same as in Example 1), where 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 second-stage atmospheric oxygen leaching residue (the mass of the second-stage atmospheric oxygen leaching residue is 192 g, where 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 balance is impurities); In step S5, after liquid-solid separation, a transformation residue (the mass of the transformation residue is 191 g, where 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 balance is impurities) and a transformation liquid (576 mL, the mass concentration of Zn is 0.053 g / L, and the mass concentration of Fe is 0.14 g / L) are obtained; The sulfur content of sulfur is 99.5%, and the direct recovery rate of sulfur is 80%.

[0035] Comparative Example 3: A method for atmospheric oxygen leaching of zinc sulfide concentrate and sulfur recovery from the residue, including: Step S1, crushing and grinding 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: zinc 46.68%, iron 10.21%, and sulfur 34.52%, and the balance is impurities; Step S2: Add sulfuric acid (with a mass percentage of 98% and a dosage of 50 g) and a leaching agent to 500 g of the zinc sulfide concentrate. After mixing evenly, a first reaction system is obtained. Perform low-acid one-stage atmospheric pressure oxygen leaching treatment on the first reaction system 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, where the mass concentration of zinc is 140.08 g / L, the mass concentration of iron is 8.69 g / L, and the mass concentration of sulfuric acid is 72 g / L) and a one-stage atmospheric pressure oxygen leaching residue (the mass of the one-stage atmospheric pressure oxygen leaching residue is 376 g, where 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 one-stage atmospheric pressure oxygen leaching treatment includes controlling the redox potential of the first reaction system at 360 mV by introducing oxygen; the reaction temperature adopted for the low-acid one-stage atmospheric pressure oxygen leaching treatment is 95 °C, and the reaction time is 12 h; in the evenly mixed first reaction system, the mass concentration of sulfuric acid is 122 g / L, the mass concentration of iron is 9 g / L, and the mass concentration of zinc is 99 g / L; Step S3: Perform conventional iron removal, purification, and zinc electrowinning treatment on the one-stage atmospheric pressure oxygen leaching solution to obtain zinc; add waste electrolyte (same as in Example 1) to the one-stage atmospheric pressure oxygen leaching residue. After mixing evenly, a second reaction system is obtained. Perform high-acid two-stage atmospheric pressure oxygen leaching treatment 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, where 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 a two-stage atmospheric pressure oxygen leaching residue (the mass of the two-stage atmospheric pressure oxygen leaching residue is 223 g, where 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 two-stage atmospheric pressure oxygen leaching solution is the leaching agent in the first reaction system; the high-acid two-stage atmospheric pressure oxygen leaching treatment includes controlling the redox potential of the second reaction system at 300 mV by introducing oxygen; the reaction temperature adopted for the high-acid two-stage atmospheric pressure oxygen leaching treatment is 95 °C, and the reaction time is 12 h; the components of the electrolyte include sulfuric acid and zinc sulfate; the molar ratio of sulfuric acid to zinc in the evenly mixed second reaction system is 2:1; Step S4: Add water to the two-stage atmospheric pressure oxygen leaching residue and stir evenly to obtain a slurry; among them, the mass ratio of the added water to the mass of the two-stage atmospheric pressure oxygen leaching residue is 3:1; the mass percentage of iron in the slurry is 3.29%; Step S5: Perform sulfur transformation treatment on the slurry to obtain a transformed residue; if the total sulfur mass percentage in the transformed residue is less than 75%, first perform a flotation process (same as in Example 2), and then perform hot melting filtration (same as in Example 2) to recover sulfur in the residue.

[0036] In the step S5, the transformed slag (the mass of the transformed slag is 222 g, wherein the mass percentage of zinc is 9.27%, the mass percentage of iron is 13.15%, the mass percentage of sulfur is 65.7%, and the balance is impurities) and the transformed liquid (669 mL, the mass concentration of Zn is 0.17 g / L, and the mass concentration of Fe is 0.20 g / L) are obtained through liquid-solid separation.

[0037] The flotation process obtains flotation concentrate (the mass of the flotation concentrate is 177.6 g, wherein 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, wherein 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).

[0038] The sulfur content of sulfur is 99.3%, and the direct recovery rate of sulfur is 82.5%.

[0039] Comparative Example 4: A method for atmospheric pressure oxygen leaching of zinc sulfide concentrate and sulfur recovery from the slag, comprising: 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 percentages: zinc 46.68%, iron 10.21%, and sulfur 34.52%, and the balance is impurities; Step S2: Adding sulfuric acid (mass percentage 98%, dosage 50 g) and a leaching agent to 500 g of the zinc sulfide concentrate, uniformly mixing to obtain a first reaction system, and performing low-acid one-stage atmospheric pressure oxygen leaching treatment on the first reaction system 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 147.5 g / L, the mass concentration of iron is 15.35 g / L, and the mass concentration of sulfuric acid is 28 g / L) and a one-stage atmospheric pressure oxygen leaching slag (the mass of the one-stage atmospheric pressure oxygen leaching slag is 385 g, 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 one-stage atmospheric pressure oxygen leaching treatment includes controlling the redox potential of the first reaction system to 360 mV by passing oxygen; the reaction temperature adopted for the low-acid one-stage atmospheric pressure oxygen leaching treatment is 95 °C, and the reaction time is 12 h; in the uniformly mixed first reaction system, the mass concentration of sulfuric acid is 85 g / L, the mass concentration of iron is 14.6 g / L, and the mass concentration of zinc is 108 g / L; Step S3: Perform conventional iron removal, purification, and zinc electrowinning on the first-stage atmospheric oxygen leaching solution to obtain zinc; add waste electrolyte (same as in Example 1) to the first-stage atmospheric oxygen leaching residue, mix well to obtain a second reaction system, and perform high-acid two-stage atmospheric oxygen leaching on the second reaction system to obtain a second-stage atmospheric oxygen leaching solution (the volume of the second-stage atmospheric oxygen leaching solution is 2.5 L, where 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 a second-stage atmospheric oxygen leaching residue (the mass of the second-stage atmospheric oxygen leaching residue is 192 g, where 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 oxygen leaching solution is the leaching agent in the first reaction system; the high-acid two-stage atmospheric oxygen leaching treatment includes controlling the redox potential of the second reaction system to 500 mV by passing oxygen; the reaction temperature for the high-acid two-stage atmospheric oxygen leaching treatment is 95 °C, and the reaction time is 12 h; 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; Step S4: Add water to the second-stage atmospheric oxygen leaching residue and stir to mix evenly to obtain a slurry; where the mass ratio of the added water to the mass of the second-stage atmospheric oxygen leaching residue is 3:1; the mass percentage of iron in the slurry is 1.65%; Step S5: Perform sulfur transformation treatment on the slurry to obtain a transformed residue; if the total sulfur mass percentage in the transformed residue is greater than or equal to 75%, directly perform hot melting filtration (same as in Example 1) to recover sulfur in the residue; before the hot melting filtration, control the water content of the transformed residue to be below 20%.

[0040] In Step S5, the sulfur transformation treatment is the same as in Example 1. After liquid-solid separation, a transformed residue (the mass of the transformed residue is 194 g, where 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 a transformed liquid (576 mL, the mass concentration of Zn is 0.053 g / L, and the mass concentration of Fe is 0.45 g / L) are obtained; the transformed liquid can replace the water in Step S4 and be recycled for sulfur transformation treatment.

[0041] The sulfur content of sulfur is 99.7%, and the direct recovery rate of sulfur is 76%.

[0042] Comparative Example 5: A method for atmospheric oxygen leaching of zinc sulfide concentrate and sulfur recovery from the residue, including: Step S1: Crush and grind the zinc sulfide concentrate to the target particle size; the target particle size is D90 ≤ 65 μm; the zinc sulfide concentrate is composed of the following components by mass percentage: zinc 46.68%, iron 10.21%, and sulfur 34.52%, and the balance is impurities; Step S2: Add sulfuric acid (with a mass percentage of 98% and a dosage of 30 g) and a leaching agent to 500 g of the zinc sulfide concentrate. After mixing evenly, a first reaction system is obtained. Perform low-acid single-stage atmospheric oxygen leaching treatment on the first reaction system to obtain a single-stage atmospheric oxygen leaching solution (the volume of the single-stage atmospheric oxygen leaching solution is 2.5 L, in which 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 single-stage atmospheric oxygen leaching residue (the mass of the single-stage atmospheric oxygen leaching residue is 433 g, in which 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 single-stage atmospheric oxygen leaching treatment includes controlling the redox potential of the first reaction system to 320 mV by passing oxygen; the reaction temperature adopted for the low-acid single-stage atmospheric oxygen leaching treatment is 89 °C, and the reaction time is 12 h; in the evenly 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; Step S3: Perform conventional iron removal, purification, and zinc electrowinning treatment on the single-stage atmospheric oxygen leaching solution to obtain zinc; add waste electrolyte (the same as in Example 1) to the single-stage atmospheric oxygen leaching residue. After mixing evenly, a second reaction system is obtained. Perform high-acid two-stage atmospheric oxygen leaching treatment on the second reaction system to obtain a two-stage atmospheric oxygen leaching solution (the volume of the two-stage atmospheric oxygen leaching solution is 2.5 L, in which 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 oxygen leaching residue (the mass of the two-stage atmospheric oxygen leaching residue is 281 g, in which 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 balance is impurities); the two-stage atmospheric oxygen leaching solution is the leaching agent in the first reaction system; the high-acid two-stage atmospheric oxygen leaching treatment includes controlling the redox potential of the second reaction system to 400 mV by passing oxygen; the reaction temperature adopted for the high-acid two-stage atmospheric oxygen leaching treatment is 95 °C, and the reaction time is 12 h; the components of the electrolyte include sulfuric acid and zinc sulfate; in the second reaction system, the molar ratio of sulfuric acid to zinc is 1.54:1; Step S4: Add water to the two-stage atmospheric oxygen leaching residue and stir evenly to obtain a slurry; wherein, the mass ratio of the added water to the mass of the two-stage atmospheric oxygen leaching residue is 3:1; the mass percentage of iron in the slurry is 2.28%; Step S5: Perform sulfur transformation treatment on the slurry to obtain a transformed residue; if the total sulfur mass percentage in the transformed residue is less than 75%, first perform a flotation process, and then perform hot melting filtration to recover sulfur in the residue.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] Table 1 Changes in sulfur recovery core parameters and sulfur recovery data

[0048] 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: 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. 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. 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. 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; 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. 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.

[0049] 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 sulfur recovery from the residue, characterized in that, Including: Step S1: Grind the zinc sulfide concentrate to a target particle size. The zinc sulfide concentrate consists of the following components by mass percentage: zinc 43% - 48%, iron 9% - 15%, sulfur 32% - 35%, and the balance is impurities. Step S2: Add sulfuric acid and a leaching agent to the zinc sulfide concentrate, mix well to obtain a first reaction system, and perform low - acid first - stage atmospheric oxygen leaching on the first reaction system to obtain a first - stage atmospheric oxygen leachate and a first - stage atmospheric oxygen leaching residue. The low - acid first - stage atmospheric oxygen leaching includes controlling the redox potential of the first reaction system at 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. Step S3: Add waste electrolyte to the first - stage atmospheric oxygen leaching residue, mix well to obtain a second reaction system, and perform high - acid second - stage atmospheric oxygen leaching on the second reaction system to obtain a second - stage atmospheric oxygen leachate and a second - stage atmospheric oxygen leaching residue. The second - stage atmospheric oxygen leachate is the leaching agent in the first reaction system. The high - acid second - stage atmospheric oxygen leaching includes controlling the redox potential of the second reaction system at 350 - 450 mV by passing oxygen. The components of the waste electrolyte include sulfuric acid and zinc sulfate. In the mixed second reaction system, the molar ratio of sulfuric acid to zinc is 1.5 - 2:

1. Step S4: Add water to the second - stage atmospheric oxygen leaching residue and stir well to obtain a slurry. Among them, the mass ratio of the added water to the mass of the second - stage atmospheric oxygen leaching residue is 2 - 4:

1. The mass percentage of iron in the slurry is less than 5%. Step S5: Perform sulfur transformation treatment on the slurry to obtain a transformed residue. If the total sulfur mass percentage in the transformed residue is greater than or equal to 75%, directly perform hot melting filtration to recover sulfur in the residue. Before the hot melting filtration, control the water content of the transformed residue below 20%. If the total sulfur mass percentage in the transformed residue is less than 75%, first perform a flotation process and then perform hot melting filtration to recover sulfur in the residue.

2. The method for atmospheric pressure oxygen leaching of zinc sulfide concentrate and sulfur recovery from slag according to claim 1, wherein The reaction temperature for the low - acid first - stage atmospheric oxygen leaching is 88 - 105 °C, and the reaction time is 6 - 15 h. The reaction temperature for the high - acid second - stage atmospheric oxygen leaching is 88 - 105 °C, and the reaction time is 8 - 18 h. In Step S5, the sulfur transformation treatment includes feeding the slurry into a transformation kettle, adding a surfactant, and blowing in a gas. The pH value of the slurry is 0.5 - 5. Control the transformation temperature at 130 - 160 °C, the transformation time at 10 - 60 min, and the pressure in the transformation kettle at 0.3 - 0.8 MPa. The addition amount of the surfactant is 1‰ - 5‰ of the solid mass in the slurry. Cool the transformed slurry to 80 - 90 °C and perform liquid - solid separation to obtain the transformed residue.

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

4. The method for atmospheric pressure oxygen leaching of zinc sulfide concentrate and sulfur recovery from slag according to claim 2, characterized in that, The gas includes at least one of air and nitrogen.

5. The method for atmospheric pressure oxygen leaching of zinc sulfide concentrate and sulfur recovery from slag according to claim 2, characterized in that, Control the volume percentage of oxygen in the gas in the transformation kettle at 0 - 21%.

6. The method for atmospheric pressure oxygen leaching of zinc sulfide concentrate and sulfur recovery from slag according to any one of claims 1-5, characterized in that, The flotation process includes adding the transformed slag and water into a flotation cell in a mass ratio of 1-2:10-15, and successively performing rough selection, scavenging, and cleaning to obtain flotation concentrate and flotation tailings; thermally melting and filtering the flotation concentrate to recover sulfur in the slag; before the thermal melting and filtering, controlling the water content of the flotation concentrate to be below 20%. In the flotation process, the stirring rate is controlled to be 1000-2000 r / min, and the aeration rate is 150-400 L / h.

7. The method for atmospheric pressure oxygen leaching of zinc sulfide concentrate and sulfur recovery from slag according to claim 6, characterized in that, The rough selection time is 10-15 min; the residence time of the material during scavenging is 15-25 min; the residence time of the material during cleaning is 5-10 min.

8. The method for atmospheric pressure oxygen leaching of zinc sulfide concentrate and sulfur recovery from slag according to claim 6, characterized in that, The thermal melting temperature used for the thermal melting and filtering is 140-155 °C, and the thermal melting time is 10-30 min.

9. The method for atmospheric pressure oxygen leaching of zinc sulfide concentrate and sulfur recovery from slag according to claim 6, characterized in that, In the step S1, the target particle size is D90 ≤ 45 μm.

10. The method for atmospheric pressure oxygen leaching of zinc sulfide concentrate and sulfur recovery from slag according to claim 6, characterized in that, The primary atmospheric oxygen leaching solution is subjected to conventional iron removal, purification, and zinc electrowinning treatments to obtain zinc.

Images