A method for simultaneously floating and separating and recovering elemental sulfur and zinc sulfide from high-sulfur residue

Abstract

The present application belongs to the technical field of comprehensive recycling of non-ferrous smelting slag, and particularly relates to a method for simultaneously floating and separating and recycling elemental sulfur and zinc sulfide from high-sulfur slag, which specifically comprises the following steps: (1) adding copper sulfate to high-sulfur slag slurry for microwave treatment, then adding hydrogen peroxide for heating treatment, and standby; (2) obtaining sulfur concentrate by floating the high-sulfur slag slurry obtained in step (1), and separating elemental sulfur and zinc sulfide by extracting the sulfur concentrate; the method promotes copper doping on zinc sulfide particles by microwave, improves the floating capacity of zinc sulfide, simultaneously floats and recycles elemental sulfur and zinc sulfide by adding xanthate collector during floating, and finally separates elemental sulfur and zinc sulfide by extraction; the method realizes efficient and high-grade recovery of sulfur and zinc sulfide at the same time, and provides comprehensive utilization of resources.

Description

Technical Field

[0001] This invention belongs to the field of comprehensive recycling technology of non-ferrous metal smelting waste residue, and in particular relates to a method for simultaneously flotating and separating and recovering elemental sulfur and zinc sulfide from high-sulfur slag. Background Technology

[0002] Zinc is an indispensable non-ferrous metal raw material in modern industry, mainly used in metallurgy, automobile manufacturing, construction, electronics, batteries, and pharmaceuticals. There are two main zinc smelting methods: pyrometallurgical zinc refining and hydrometallurgical zinc refining. Pyrometallurgical zinc refining is being gradually phased out, replaced by hydrometallurgical zinc refining, which accounts for over 80% of total capacity. Among hydrometallurgical zinc refining methods, oxygen-pressure acid leaching is the most effective and widely used.

[0003] The oxygen-pressure acid leaching process for zinc smelting generates a large amount of elemental sulfur, which is also an important chemical raw material. Therefore, flotation is used to recover elemental sulfur from the oxygen-pressure leaching residue. However, due to the characteristics of the oxygen-pressure acid leaching process, the residue still contains a considerable amount of unreacted zinc sulfide, and this zinc sulfide can interact with elemental sulfur, affecting the flotation efficiency. The sulfur concentrate after flotation is purified by thermal filtration, but thermal filtration efficiency is also affected by the interaction between elemental sulfur and zinc sulfide. In this process, the sulfur grade in the sulfur concentrate after flotation is low, the subsequent thermal filtration consumes a lot of energy, and the residue still contains a considerable amount of zinc sulfide. This not only wastes resources, but the accumulation of large amounts of residue also damages the environment. Therefore, comprehensive recovery of high-sulfur residue and development of technologies for recovering sulfur and valuable metals from high-sulfur residue are of great significance to maximize resource utilization and reduce the environmental pressure caused by leaching residue stockpiling.

[0004] Therefore, providing a method for simultaneously flotating and separating and recovering elemental sulfur and zinc sulfide from high-sulfur slag is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a method for simultaneously flotating and separating and recovering elemental sulfur and zinc sulfide from high-sulfur slag. This method utilizes microwave-assisted copper doping onto zinc sulfide particles to improve the flotation capability of zinc sulfide. During flotation, xanthate collectors are added to simultaneously recover elemental sulfur and zinc sulfide. Finally, elemental sulfur and zinc sulfide are separated by extraction. This invention achieves efficient and high-grade simultaneous recovery of sulfur and zinc sulfide, providing comprehensive resource utilization benefits.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for simultaneously flotating and separating and recovering elemental sulfur and zinc sulfide from high-sulfur slag specifically includes the following steps:

[0008] (1) After adding copper sulfate to the high-sulfur slag slurry and microwaving it, add hydrogen peroxide and heat it for later use.

[0009] (2) The high-sulfur slag slurry obtained in step (1) is subjected to flotation to obtain sulfur concentrate, and the sulfur concentrate is extracted and separated to obtain elemental sulfur and zinc sulfide.

[0010] High-sulfur slag contains a large amount of elemental sulfur, and due to the characteristics of the oxygen-pressure acid leaching method for zinc smelting, elemental sulfur and zinc sulfide are mutually bound together. This invention uses microwave treatment to weaken the mutual binding state between elemental sulfur and zinc sulfide, allowing more zinc sulfide particles to be exposed and promoting copper ion doping. At the same time, adding hydrogen peroxide and heating and stirring allows copper ions to be directly doped onto the zinc sulfide particles. After adding xanthate collectors, dixanthate and metal xanthate can be adsorbed on the surface of copper-doped zinc sulfide to form dixanthate and metal xanthate. Traditional copper ion activation treatment can only form metal xanthate, while dixanthate has stronger hydrophobicity than metal xanthate. Therefore, the zinc sulfide treated with copper doping in this invention has better flotation properties.

[0011] Meanwhile, in the high-sulfur slag of this invention, calcium, lead and other substances exist as sulfates, so copper sulfate is chosen as the copper salt, which will not introduce other impurities.

[0012] The present invention achieves a flotation recovery rate of 80-98% for elemental sulfur and zinc sulfide, and a sulfur concentrate grade of 70-90%. After extraction treatment of the sulfur concentrate, the elemental sulfur recovery rate is greater than 95%, the purity is greater than 99%, and the zinc grade in the remaining zinc concentrate is 60-90%.

[0013] Preferably, the preparation method of the high-sulfur slag slurry in step (1) is as follows: after grinding the high-sulfur slag, deionized water is added to adjust the slurry and wash it. After washing, liquid-solid separation is performed to obtain washing residue. Water is added to the washing residue to obtain high-sulfur slag slurry.

[0014] This invention can remove soluble substances from high-sulfur slag through washing treatment, thereby improving the effect of subsequent pretreatment. It also improves the collection effect of the collector on zinc sulfide and elemental sulfur during flotation.

[0015] Preferably, the high-sulfur slag is the underflow slag from the second stage of zinc smelting using the oxygen pressure leaching method;

[0016] The particle size of the ore sample being ground is less than 50 micrometers;

[0017] The solid-liquid ratio of the deionized water and the high-sulfur slag is 4:1, the washing time is 10-30 minutes, and the stirring speed during washing is 300-600 rpm.

[0018] Preferably, the concentration of the high-sulfur slag slurry in step (1) is 15-35%;

[0019] The mass ratio of copper sulfate to washing slag in the high-sulfur slag slurry is 1000-3000 g / t;

[0020] The concentration of hydrogen peroxide added to the high-sulfur slag slurry is 0.1-0.5 mol / L.

[0021] Preferably, the power of the microwave processing in step (1) is 1500-2500W and the processing time is 60-120s;

[0022] The heating treatment is performed at a temperature of 80-90℃ for 3-5 hours, with a stirring speed of 300-600 rpm.

[0023] Preferably, the flotation step in step (2) is as follows: a collector and a frother are added to the high-sulfur slag slurry obtained in step (1), and aeration flotation is carried out. The slurry obtained by flotation is filtered and dried to finally obtain sulfur concentrate.

[0024] Traditional methods for separating elemental sulfur and zinc sulfide involve roughing followed by fine flotation, which separates the sulfur and zinc sulfide through multiple flotation processes. This method is inconvenient to operate and the resulting sulfur product is of low grade, requiring secondary processing. In contrast, the present invention obtains a sulfur concentrate containing high-grade elemental sulfur and a large amount of zinc sulfide through the above steps. This concentrate can be extracted to obtain sulfur with a purity greater than 99% without secondary processing. The extracted zinc sulfide concentrate can be directly used in the oxygen pressure acid leaching process for zinc smelting, realizing the recovery and utilization of zinc resources. At the same time, the extract solution in the extraction process can be recycled, greatly saving costs.

[0025] Preferably, the collector is any one of ethyl xanthate, isopropyl xanthate, and butyl xanthate, and the mass ratio of the collector to the high-sulfur slag is 500-1000 g / t;

[0026] The foaming agent is pine oil or methyl isobutyl methanol; the mass ratio of the foaming agent to the high-sulfur slag is 20-50 g / t.

[0027] The xanthate collector selected in this invention can be adsorbed on the surface of copper-doped zinc sulfide to form dixanthate and metal xanthate, which increases the contact opportunity between zinc sulfide particles and bubbles and is beneficial to the combination of zinc sulfide particles and bubbles. Since elemental sulfur particles naturally have high hydrophobicity, they can simultaneously capture elemental sulfur and zinc sulfide.

[0028] Preferably, the stirring time after the collector is added to the high-sulfur slag slurry is 3-8 minutes, and the stirring speed is 100-300 rpm;

[0029] The stirring time after the foaming agent is added to the high-sulfur slag slurry is 3-8 minutes, and the stirring speed is 100-300 r / min.

[0030] The aeration rate is 200-800 L / h, the flotation time is 10-30 min, and the flotation foaming time is once every 2 seconds.

[0031] Preferably, the extraction in step (2) uses any one of carbon disulfide, carbon tetrachloride and tetrachloroethylene.

[0032] Preferably, the extraction temperature in step (2) is 30-80℃ and the extraction time is 10-90 min.

[0033] As can be seen from the above technical solution, compared with the prior art, the beneficial effects of the present invention are as follows:

[0034] (1) The method of the present invention recovers elemental sulfur and zinc sulfide simultaneously during flotation, which can avoid the problem that elemental sulfur and zinc sulfide are mutually wrapped during conventional flotation, resulting in poor flotation effect of elemental sulfur. Furthermore, it can recover zinc resources at the same time as recovering sulfur resources, thereby improving the comprehensive utilization efficiency of resources.

[0035] (2) In the method of the present invention, xanthate collectors can be adsorbed on the surface of copper-doped zinc sulfide to form dixanthate. Compared with the metal xanthate formed by undoped zinc sulfide, dixanthate has a better flotation effect. The method is simple to operate, the amount of copper sulfate used is low and the source is wide, the copper doping effect is good, and the collector used is a conventional xanthate reagent, which is inexpensive.

[0036] (3) The subsequent extraction and separation method of elemental sulfur and zinc sulfide in the method of the present invention is simple to operate, has a good separation effect, and the purity of the separated elemental sulfur can reach more than 99%.

[0037] (4) The overall process operation requirements of the present invention are low and the adaptability is strong. Detailed Implementation

[0038] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example 1

[0039] This invention provides a method for simultaneously flotating and separating and recovering elemental sulfur and zinc sulfide from high-sulfur slag, specifically including the following steps:

[0040] (1) The high-sulfur slag of the second stage bottom flow of zinc smelting by oxygen pressure leaching was ground. The particle size of the ore sample was less than 50 micrometers. After grinding, deionized water was added for washing. The ratio of deionized water to slag was 4:1. The washing time was 20 min. The stirring speed during washing was 600 rpm. After washing, liquid and solid separation was completed to obtain the washed slag.

[0041] The washing residue was added to water to prepare a 20% slurry. Then, 1000g / t of copper sulfate was added and stirred evenly. After stirring, the mixture was microwaved at a power of 1800W for 90s. After microwave treatment, hydrogen peroxide with a concentration of 0.1mol / L was added and the mixture was heated and stirred at 80℃ for 3 hours with a stirring speed of 300rpm. The mixture was then set aside for later use.

[0042] (2) Isopropyl xanthate and pine oil were added sequentially to the high-sulfur slag slurry obtained in step (1), with dosages of 700 g / t and 20 g / t, respectively. The mixture was stirred for 2 min at a stirring speed of 200 rpm. After stirring, aeration flotation was carried out with an aeration rate of 800 L / h, a flotation temperature of 30℃, and a flotation time of 20 min. The sulfur concentrate slurry and tailings slurry obtained by flotation were filtered and dried. The final recovery rate of elemental sulfur was 85.45%, the recovery rate of zinc sulfide was 85.63%, and the grade of elemental sulfur in the sulfur concentrate was 78.28%.

[0043] The sulfur concentrate was ground, and carbon tetrachloride was added as an extractant after grinding. The extraction temperature was 50℃ and the extraction time was 80 min. After extraction, sulfur and zinc sulfide concentrates were obtained. The sulfur purity was 99% and the zinc sulfide grade in the zinc sulfide concentrate was 71.63%. Example 2

[0044] This invention provides a method for simultaneously flotating and separating and recovering elemental sulfur and zinc sulfide from high-sulfur slag, specifically including the following steps:

[0045] (1) The high-sulfur slag of the second stage bottom flow of zinc smelting by oxygen pressure leaching was ground. The particle size of the ore sample was less than 50 micrometers. After grinding, deionized water was added for washing. The solid-liquid ratio of deionized water to slag was 4:1. The washing time was 15 min. The stirring speed during washing was 500 rpm. After washing, liquid and solid were separated to obtain the washed slag.

[0046] The washing residue was added to water to prepare a slurry with a concentration of 25%, and then 1500 g / t of copper sulfate was added. After stirring evenly, it was microwaved. During the microwave treatment, the microwave power was 1500 W and the microwave time was 60 s. After the microwave treatment, hydrogen peroxide with a concentration of 0.3 mol / L was added, and the mixture was heated and stirred. The heating temperature was 85℃ and the heating time was 4 h. The stirring speed was 400 rpm. The mixture was then set aside for later use.

[0047] (2) Isopropyl xanthate and pine oil were added sequentially to the high-sulfur slag slurry obtained in step (1), with dosages of 800 g / t and 30 g / t, respectively. Both were stirred for 2 min at a stirring speed of 200 rpm. After stirring, aeration flotation was carried out with an aeration rate of 400 L / h, a flotation temperature of 30℃, and a flotation time of 25 min. The sulfur concentrate slurry and tailings slurry obtained by flotation were filtered and dried. Finally, the recovery rate of elemental sulfur was 75.47%, the recovery rate of zinc sulfide was 77.58%, and the grade of elemental sulfur in the sulfur concentrate was 72.43%.

[0048] The sulfur concentrate was ground, and carbon tetrachloride was added as an extractant after grinding. The extraction temperature was 70℃ and the extraction time was 50 min. After extraction, sulfur and zinc sulfide concentrates were obtained. The sulfur purity was 99% and the zinc sulfide grade in the zinc sulfide concentrate was 62.56%. Example 3

[0049] This invention provides a method for simultaneously flotating and separating and recovering elemental sulfur and zinc sulfide from high-sulfur slag, specifically including the following steps:

[0050] (1) The high-sulfur slag of the second stage bottom flow of zinc smelting by oxygen pressure leaching was ground. The particle size of the ore sample was less than 50 micrometers. After grinding, deionized water was added for washing. The solid-liquid ratio of deionized water to slag was 4:1. The washing time was 35 min. The stirring speed during washing was 600 rpm. After washing, liquid and solid were separated to obtain the washed slag.

[0051] The washing residue was added to water to prepare a 20% slurry. Then, 2000 g / t of copper sulfate was added and stirred evenly. After stirring, the mixture was microwaved at a power of 2000 W for 110 s. After microwave treatment, hydrogen peroxide with a concentration of 0.5 mol / L was added and the mixture was heated and stirred at a temperature of 90℃ for 5 hours with a stirring speed of 300 rpm. The mixture was then set aside for later use.

[0052] (2) Isopropyl xanthate and pine oil were added sequentially to the high-sulfur slag slurry obtained in step (1), with dosages of 900 g / t and 20 g / t, respectively. Both were stirred for 2 min at a stirring speed of 200 rpm. After stirring, aeration flotation was carried out with an aeration rate of 200 L / h, a flotation temperature of 30℃, and a flotation time of 15 min. The sulfur concentrate slurry and tailings slurry obtained by flotation were filtered and dried. Finally, the recovery rate of elemental sulfur was 96.78%, the recovery rate of zinc sulfide was 98.56%, and the grade of elemental sulfur in the sulfur concentrate was 88.65%.

[0053] The sulfur concentrate was ground, and carbon tetrachloride was added as an extractant after grinding. The extraction temperature was 30℃ and the extraction time was 10 min. After extraction, sulfur and zinc sulfide concentrates were obtained. The sulfur purity was 99% and the zinc sulfide grade in the zinc sulfide concentrate was 82.81%. Comparative Example 1

[0054] A method for separating and recovering elemental sulfur and zinc sulfide from high-sulfur slag is provided, specifically including the following steps:

[0055] The high-sulfur slag from the second stage of zinc smelting by oxygen pressure leaching was ground. The particle size of the ground ore sample was less than 50 micrometers. After grinding, deionized water was added for washing. The solid-liquid ratio of deionized water to slag was 4:1. The washing time was 30 minutes and the stirring speed was 600 rpm. After washing, liquid and solid separation was completed to obtain the washed slag.

[0056] The washing residue was added to water to prepare a 20% slurry, and then 2000 g / t of copper sulfate was added. Isopropyl xanthate and pine oil were added to the pretreated slurry in sequence at a dosage of 900 g / t and 20 g / t, respectively. The mixture was stirred for 2 min at a stirring speed of 200 rpm. After stirring, aeration flotation was carried out at an aeration rate of 200 L / h, a flotation temperature of 30℃, and a flotation time of 15 min. The sulfur concentrate slurry and tailings slurry obtained from the flotation were filtered and dried, and the final zinc sulfide recovery rate was 60.27%. Comparative Example 2

[0057] A method for separating and recovering elemental sulfur and zinc sulfide from high-sulfur slag is provided, specifically including the following steps:

[0058] The high-sulfur slag from the second stage of zinc smelting by oxygen pressure leaching was ground. The particle size of the ground ore sample was less than 50 micrometers. After grinding, deionized water was added for washing. The solid-liquid ratio of deionized water to slag was 4:1. The washing time was 30 minutes and the stirring speed was 600 rpm. After washing, liquid and solid separation was completed to obtain the washed slag.

[0059] Washing residue was added to water to prepare a 20% slurry. Then, 2000 g / t of copper sulfate was added, and the mixture was stirred evenly before microwave treatment. The microwave power was 1500 W and the microwave time was 60 s. Isopropyl xanthate and pine oil were added to the pretreated slurry in sequence at a dosage of 900 g / t and 20 g / t, respectively. The mixture was stirred for 2 min at a stirring speed of 200 rpm. After stirring, aeration flotation was carried out at an aeration rate of 200 L / h, a flotation temperature of 30℃, and a flotation time of 15 min. The sulfur concentrate slurry and tailings slurry obtained from the flotation were filtered and dried, and the final zinc sulfide recovery rate was 66.83%. Comparative Example 3

[0060] A method for separating and recovering elemental sulfur and zinc sulfide from high-sulfur slag is provided, specifically including the following steps:

[0061] The high-sulfur slag from the second stage of zinc smelting by oxygen pressure leaching was ground. The particle size of the ground ore sample was less than 50 micrometers. After grinding, deionized water was added for washing. The solid-liquid ratio of deionized water to slag was 4:1. The washing time was 30 minutes and the stirring speed was 600 rpm. After washing, liquid and solid separation was completed to obtain the washed slag.

[0062] The washing residue was added to water to prepare a 20% slurry. Then, 2000 g / t of copper sulfate and 0.3 mol / L hydrogen peroxide were added. The mixture was heated and stirred at 90℃ for 4 hours at a stirring speed of 300 rpm. Isopropyl xanthate and pine oil were added to the pretreated slurry in sequence at 900 g / t and 20 g / t, respectively, and stirred for 2 minutes at a stirring speed of 200 rpm. After stirring, aeration flotation was carried out at an aeration rate of 200 L / h, a flotation temperature of 30℃, and a flotation time of 15 minutes. The sulfur concentrate slurry and tailings slurry obtained from the flotation were filtered and dried, and the final zinc sulfide recovery rate was 62.64%.

[0063] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for simultaneously flotating and separating and recovering elemental sulfur and zinc sulfide from high-sulfur slag, characterized in that, The high-sulfur slag is the underflow slag from the second stage of zinc smelting using the oxygen pressure leaching method; specifically, it includes the following steps: (1) After adding copper sulfate to the high sulfur slag slurry and microwave treatment, hydrogen peroxide is added for heating treatment and it is ready for use; the preparation method of the high sulfur slag slurry is as follows: after grinding the high sulfur slag, deionized water is added to adjust the slurry and wash it. After washing, liquid-solid separation is performed to obtain washing residue. Water is added to the washing residue to obtain high sulfur slag slurry. (2) The high-sulfur slag slurry obtained in step (1) is floated to obtain sulfur concentrate, and the sulfur concentrate is extracted and separated to obtain elemental sulfur and zinc sulfide; wherein, the flotation step is: a collector and a frother are added to the high-sulfur slag slurry obtained in step (1), and aeration flotation is carried out. The slurry obtained by flotation is filtered and dried to finally obtain sulfur concentrate.

2. The method for simultaneously flotating and separating and recovering elemental sulfur and zinc sulfide from high-sulfur slag according to claim 1, characterized in that, The particle size of the ore sample being ground is less than 50 micrometers; The solid-liquid ratio of the deionized water and the high-sulfur slag is 4:1, the washing time is 10-30 minutes, and the stirring speed during washing is 300-600 rpm.

3. The method for simultaneously flotating and separating and recovering elemental sulfur and zinc sulfide from high-sulfur slag according to claim 1, characterized in that, The concentration of the high-sulfur slag slurry mentioned in step (1) is 15-35%; The mass ratio of copper sulfate to washing slag in the high-sulfur slag slurry is 1000-3000 g / t; The concentration of hydrogen peroxide added to the high-sulfur slag slurry is 0.1-0.5 mol / L.

4. The method for simultaneously flotating and separating and recovering elemental sulfur and zinc sulfide from high-sulfur slag according to claim 1, characterized in that, The power of the microwave processing in step (1) is 1500-2500W, and the processing time is 60-120s; The heating treatment is performed at a temperature of 80-90℃ for 3-5 hours, with a stirring speed of 300-600 rpm.

5. The method for simultaneously flotating and separating and recovering elemental sulfur and zinc sulfide from high-sulfur slag according to claim 1, characterized in that, The collector is any one of ethyl xanthate, isopropyl xanthate, and butyl xanthate, and the mass ratio of the collector to the high-sulfur slag is 500-1000 g / t; The foaming agent is pine oil or methyl isobutyl methanol; the mass ratio of the foaming agent to the high-sulfur slag is 20-50 g / t.

6. The method for simultaneously flotating and separating and recovering elemental sulfur and zinc sulfide from high-sulfur slag according to claim 5, characterized in that, The stirring time after the collector is added to the high-sulfur slag slurry is 3-8 minutes, and the stirring speed is 100-300 rpm. The stirring time after the foaming agent is added to the high-sulfur slag slurry is 3-8 minutes, and the stirring speed is 100-300 r / min. The aeration rate is 200-800 L / h, the flotation time is 10-30 min, and the flotation foaming time is once every 2 seconds.

7. The method for simultaneously flotating and separating and recovering elemental sulfur and zinc sulfide from high-sulfur slag according to claim 1, characterized in that, The extraction in step (2) uses any one of carbon disulfide, carbon tetrachloride and tetrachloroethylene.

8. The method for simultaneously flotating and separating and recovering elemental sulfur and zinc sulfide from high-sulfur slag according to claim 1, characterized in that, The extraction temperature in step (2) is 30-80℃, and the extraction time is 10-90 min.