Laterite-nickel ore high-pressure acid leaching residue stirring water washing-high-pressure alkaline leaching desulfurization process

Abstract

The invention provides a stirring washing-high-pressure alkaline leaching desulfurization process for laterite-nickel ore high-pressure acid leaching residues, and belongs to the technical field of environmental protection and resource reutilization. According to the method, through multi-step combined operation of water washing pretreatment, ultrasonic cleaning and high-pressure alkaline leaching, the sulfur content in the laterite-nickel ore high-pressure acid leaching residues is remarkably reduced, 2.09-2.95 wt% is reduced to 0.5 wt% or below, and the problem that high-sulfur residues cannot be effectively treated through a traditional technology is solved. And the content of SiO2, Al2O3, Cr2O3 and other impurities is further reduced through ultrasonic cleaning, the purity of the slag is improved, and a foundation is laid for subsequent efficient recovery of metal resources. According to the method, pollution of the acid leaching residues to the environment is effectively reduced, the environmental protection requirement is met, favorable conditions are created for efficient recycling of iron and other valuable metals (such as nickel, cobalt and copper), and the comprehensive utilization rate and economic benefits of resources are remarkably improved.

Description

Technical Field

[0001] The invention belongs to the technical field of environmental protection and resource recycling, and mainly relates to a high-pressure acid leaching residue stirring and water washing-high-pressure alkali leaching desulfurization process for laterite nickel ore. Background Art

[0002] With the rapid development of the global new energy industry, the market demand for nickel metal, as a vital raw material in new energy batteries, has shown a rapid growth trend. However, the global high-grade nickel ore resources are becoming increasingly depleted, prompting the industry to gradually turn its attention to the development and utilization of low-grade laterite nickel ore. Extracting nickel resources from low-grade laterite nickel ore has become one of the core development directions of the global nickel industry in the future.

[0003] At present, the mainstream technology for processing laterite nickel ore is the wet high-pressure acid leaching process. In this process, a large amount of laterite nickel ore high-pressure acid leaching slag is produced due to the low grade of the ore and the characteristics of the smelting process. The acid leaching slag is the main hazardous solid waste in the nickel industry, with a complex composition and an iron grade of up to 35% to 40%. In addition, the slag also contains a certain amount of valuable metals such as nickel, cobalt, copper, etc. However, the acid leaching slag is usually stored in the tailings reservoir for a long time in the form of solid waste, which not only causes a large amount of iron resources to be wasted, but also poses a serious ecological threat to the surrounding environment, especially the soil, due to the continuous penetration of metal ions.

[0004] Therefore, how to efficiently develop and utilize iron-containing solid waste has become a major issue in the current mining and metallurgical field.

[0005] The efficient utilization of high pressure acid leaching residue of laterite nickel ore is imminent. However, the key problem limiting its resource utilization is that the sulfur content in the residue is too high (usually more than 2%), which makes it difficult for traditional mineral processing and roasting processes to directly treat the waste residue. Summary of the invention

[0006] The technical task of the present invention is to address the deficiencies of the above prior art, and propose a desulfurization process of mechanical stirring water washing-high pressure alkali leaching of laterite nickel ore high pressure acid leaching residue. Through the combined process of mechanical stirring water washing and high pressure alkali leaching, the sulfur content in the acid leaching residue can be effectively reduced, the recovery rate of iron resources can be improved, and the efficient recovery and comprehensive utilization of iron resources can be achieved. The process realizes the effective removal of sulfate and sulfide in the high pressure acid leaching residue of laterite nickel ore through the multi-step combined operation of water washing pretreatment, ultrasonic cleaning and high pressure alkali leaching, while retaining iron and other valuable metal resources.

[0007] The technical solution adopted by the present invention is:

[0008] A high-pressure acid leaching residue stirring and water washing-high-pressure alkali leaching desulfurization process for laterite nickel ore comprises the following steps:

[0009] (1) mixing deionized water and laterite nickel ore high pressure acid leaching residue to form a slurry;

[0010] (2) mechanically stirring the slurry, washing it with water, filtering it and drying it to obtain acid leaching residue after washing;

[0011] (3) mixing the washed acid leaching residue with deionized water and then performing ultrasonic cleaning, filtering after cleaning, and drying for later use;

[0012] (4) mixing the dried acid leaching residue with an alkaline solution at a liquid-to-solid ratio of 4:1-5:1, and subjecting the mixture to a high-temperature alkaline leaching reaction in a high-pressure reactor. After the reaction, the material is filtered and washed with hot water until it is neutral;

[0013] (5) The filtered solid material is dried to obtain the desulfurized acid leaching residue.

[0014] Furthermore, in step (1), the iron content of the high pressure acid leaching slag of laterite nickel ore is 48.3-55.4wt%. The main impurities and their mass percentages in the slag are SiO2 5.20-5.60wt%, Al2O3 4.95-5.20wt% and Cr2O3 3.30-3.70wt%, wherein the harmful element sulfur content reaches 2.05-2.95wt%, mainly in the form of sulfate.

[0015] Furthermore, the particle size of the high-pressure acid leaching residue of laterite nickel ore in step (1) is fine, and the particle size of most particles is below 0.074 mm; among them, the particle occupancy rate of fine-grained particles (0.074-0.010 mm) is 20-30%, and the particle occupancy rate of micro-particles (<0.010 mm) is 70-80%.

[0016] Furthermore, the stirring rate of the mechanical stirring water washing in step (2) is 200-400 r / min, and the stirring time is 20-50 minutes; after the reaction, the slurry is filtered, and the obtained filter residue is dried in an oven at a temperature of 80-120°C; this step preliminarily removes water-soluble impurities.

[0017] Furthermore, in step (1) and step (3), the acid leaching residue is mixed with deionized water at a liquid-to-solid ratio of 4:1-5:1.

[0018] Furthermore, the ultrasonic frequency described in step (3) is 40-120kHz, and the cleaning time is 30-60 minutes; after cleaning, the slurry is filtered by suction, and the filter residue is dried in an oven for later use; this step further removes fine particle impurities that are difficult to remove by mechanical stirring and water washing.

[0019] Furthermore, in the step (4), 4-10 g of calcium oxide is first added to the dried acid leaching residue as an alkali source, and then an alkali solution is added after mixing, wherein the alkali solution is a sodium hydroxide solution with a mass concentration of 0.018-0.2 g / mL.

[0020] Furthermore, in step (4), the pressure range of the high-pressure reactor is 4-8 MPa, the magnetic speed is 400-600 rpm, the treatment temperature is 200-240° C., the reaction time is 60-80 minutes, and the hot water temperature is 80-90° C.

[0021] Furthermore, the sulfur content of the desulfurized acid leaching residue obtained in step (5) is reduced from 2.09-2.95wt% to below 0.5wt%.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention significantly reduces the sulfur content in the high-pressure acid leaching residue of laterite nickel ore from 2.09-2.95wt% to below 0.5wt% through a combined process of mechanical stirring water washing and high-pressure alkaline leaching, solving the problem that the traditional process cannot effectively treat high-sulfur residue. Ultrasonic cleaning further reduces the content of impurities such as SiO2, Al2O3 and Cr2O3, improves the purity of the residue, and lays a foundation for the efficient recovery of subsequent metal resources.

[0024] In addition, the process of the present invention is simple and suitable for large-scale industrial production, especially for processing high-sulfur laterite nickel ore acid leaching residue. The process not only effectively reduces the environmental pollution of acid leaching residue, meets environmental protection requirements, but also creates favorable conditions for the efficient recovery of iron and other valuable metals (such as nickel, cobalt, copper, etc.), significantly improving the comprehensive utilization rate of resources and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the process flow of an embodiment of the present invention. DETAILED DESCRIPTION

[0026] In order to further illustrate the technical means and effects of the present invention to achieve the expected effects, the present invention will be described in detail below in conjunction with the accompanying drawings and preferred embodiments of the specification. Obviously, the embodiments described are only some implementation cases of the present invention. The test methods described in the following embodiments are conventional methods unless otherwise specified; the reagents and materials, unless otherwise specified, can be obtained from commercial channels, and the steps described are not limitations on the reaction sequence. After understanding the inventive essence of the present invention, the steps can be adjusted. Therefore, it should be noted that the scope of protection of the present invention is not limited to the following specific embodiments, and the embodiments obtained in the art without significant creative improvements on the basis of the present invention belong to the protection scope of the present invention.

[0027] like Figure 1 As shown, the present invention provides a laterite nickel ore high-pressure acid leaching residue mechanical stirring water washing-high-pressure alkali leaching desulfurization process, comprising the following steps:

[0028] (1) High-pressure acid leaching residue of laterite nickel ore is used as raw material, and the iron content in the acid leaching residue is 48.3-55.4wt%. The main impurities and mass percentages in the slag are SiO2 5.20-5.60wt%, Al2O3 4.95-5.20wt% and Cr2O3 3.30-3.70wt%, and the content of harmful element sulfur is 2.05-2.95wt%. The particle size of the acid leaching residue is fine, and the embedded particle size of most particles is less than 0.074mm, among which the fine-grained (0.074-0.010mm) particles account for 20-30%, and the micro-particle (<0.010mm) particles account for 70-80%.

[0029] (2) Deionized water and high-pressure acid leaching residue of laterite nickel ore are mixed at a liquid-solid ratio of 4:1-5:1 to form a slurry. The slurry is poured into a leaching agitator, sealed and stirred for 20-50 minutes at a stirring rate of 200-400r / min to promote the removal of soluble impurities. After the reaction is completed, the slurry is separated into solid and liquid by a suction filter, and the filter residue is placed in an oven at 80-120°C for drying to obtain a preliminarily treated leaching residue.

[0030] (3) Mix the dried leached residue with deionized water in a mass ratio of 4:1-5:1 to form a slurry; place the slurry in a beaker of an ultrasonic cleaning machine for ultrasonic cleaning at an ultrasonic frequency of 40-120kHz for 30-60 minutes. The cleaning process is stirred by a stirring rod to further remove residual impurities. After cleaning, the slurry is filtered through a suction filter, and the filter residue is placed in an oven for drying to obtain the treated leached residue. This step further reduces the content of sulfur and other insoluble impurities in the acid leaching residue.

[0031] (4) A high-pressure alkali leaching test was carried out in a laboratory micro-high-pressure reactor with a reactor volume of 100 mL, a temperature control accuracy of ±5°C, and a magnetic sub-speed set to 400-600 rpm. First, the acid leaching residue sample was weighed and 4-10 g of calcium oxide was added as an alkali source. Then, 0.018-0.2 g / mL of sodium hydroxide solution was added at a liquid-to-solid ratio of 4:1-5:1, and the reactor cover was covered and tightened. The reaction temperature was set to 200-240°C and the insulation time was 60-80 minutes. After the reaction was completed, the reactor was taken out and cooled with hot water, and the resulting slurry was separated from the solid by a suction filter. The filter cake was washed with hot water at 80-90°C until neutral, and then dried to obtain the final treated acid leaching residue with a greatly reduced sulfur content.

[0032] The present invention effectively removes sulfur and other impurities from the acid leaching residue of laterite nickel ore through multiple processes of mechanical stirring water washing, ultrasonic cleaning and high-pressure alkaline leaching, and significantly improves the purity of the acid leaching residue. Compared with the traditional roasting desulfurization process, the present invention avoids high-temperature treatment, has a simple process flow, low energy consumption, and reduces pollution to the environment, which is in line with the development trend of green metallurgy. High-pressure alkaline leaching achieves the removal of harmful elements in the acid leaching residue under relatively mild conditions, greatly reduces the sulfur content, and retains the valuable metals in the slag. Through this pretreatment process, not only the effective utilization of resources is achieved, but also the potential impact of waste slag on the environment is significantly reduced, which has good industrial application prospects and economic benefits.

[0033] The specific parameters of each step are detailed in each embodiment.

[0034] Example 1

[0035] A high-pressure acid leaching residue mechanical stirring water washing-high-pressure alkali leaching desulfurization process for laterite nickel ore comprises the following steps:

[0036] (1) The TFe content in the high-pressure acid leaching residue of laterite nickel ore used in this embodiment is 49.5wt%, the main iron mineral is hematite, the distribution rate is 98.7%, the main impurities include SiO2, Al2O3 and Cr2O3, the contents are 5.30wt%, 5.00wt% and 3.50wt%, respectively, and the S content is 2.15wt%. The particle size of the acid leaching residue is fine, the fine particle grade (0.074-0.010mm) accounts for 20.44%, and the micro-particle grade (<0.010mm) accounts for 79.56%.

[0037] (2) Deionized water and high-pressure acid leaching residue of laterite nickel ore were mixed at a liquid-solid ratio of 4.5:1 to prepare slurry. The slurry was poured into a leaching agitator, sealed and stirred for 40 minutes, and the stirring speed was set to 320 rpm. After stirring, the slurry was separated into solid and liquid by a suction filter, and the filter residue was placed in an oven at 80°C for drying.

[0038] (3) The dried leaching residue is mixed with deionized water at a liquid-to-solid ratio of 4.5:1 to form a slurry. The slurry is placed in an ultrasonic cleaning machine for ultrasonic cleaning, with an ultrasonic time of 35 minutes and an ultrasonic frequency of 40 kHz. After cleaning, the slurry is filtered through a suction filter, and the filter residue is placed in an oven at 80°C for drying to obtain the treated leaching residue.

[0039] (4) A high-pressure alkali leaching test was carried out in a laboratory micro-high-pressure reactor with a volume of 100 mL, a temperature control accuracy of ±5°C, and a magnetic sub-speed set to 500 rpm. Weigh the acid leaching residue sample, add 4.5 g of calcium oxide as an alkali source, and then add 0.018 g / mL of sodium hydroxide solution at a liquid-solid ratio of 4.5:1. Set the reaction temperature to 220°C and the insulation time to 1 hour. After the reaction is completed, take out the reactor and cool it with hot water. The resulting slurry is separated into solid and liquid by a suction filter. The filter cake is washed with hot water at 80°C until neutral and then dried.

[0040] (5) Under the optimized process conditions, the S content dropped from 2.15wt% to 0.29wt% and the desulfurization rate was 86.51%.

[0041] Example 2

[0042] The method is the same as in Example 1, except that:

[0043] (1) The TFe content in the high-pressure acid leaching residue of laterite nickel ore used in this embodiment is 52.0wt%, the main iron mineral is hematite, and the distribution rate is 97.2%. The main impurities include SiO2, Al2O3 and Cr2O3, and the contents are 5.50wt%, 4.95wt% and 3.60wt%, respectively, and the S content is 2.05wt%. The particle size distribution of the acid leaching residue is that the fine particle level (0.074-0.010mm) accounts for 24.00%, and the micro-particle level (<0.010mm) accounts for 76.00%.

[0044] (2) Deionized water and high-pressure acid leaching residue of laterite nickel ore were mixed at a liquid-solid ratio of 4:1 to form a slurry. The slurry was poured into a leaching agitator, sealed and stirred for 45 minutes, and the stirring speed was set to 300 rpm. After the reaction was completed, the slurry was separated into solid and liquid by a suction filter, and the filter residue was placed in an oven at 85°C for drying.

[0045] (3) The dried leached residue is mixed with deionized water at a liquid-to-solid ratio of 4:1 to form a slurry. The slurry is placed in an ultrasonic cleaning machine for ultrasonic cleaning, with an ultrasonic time of 30 minutes and an ultrasonic frequency of 40 kHz. After cleaning, the slurry is filtered through a suction filter, and the filter residue is placed in an oven at 80°C for drying.

[0046] (4) A high-pressure alkaline leaching test was carried out in a laboratory micro-autoclave. The acid leaching residue sample was weighed, 4 g of calcium oxide was added as an alkali source, and 0.018 g / mL of NaOH solution was added at a liquid-to-solid ratio of 4:1. The reaction temperature was 240 °C and the insulation time was 80 minutes. After the reaction was completed, the autoclave was cooled to room temperature, the slurry was filtered through a suction filter, and the filter cake was washed with 80 °C hot water until neutral and then dried.

[0047] (5) Under the optimized process conditions, the S content dropped from 2.05wt% to 0.30wt% and the desulfurization rate was 85.37%.

[0048] Example 3

[0049] The method is the same as in Example 1, except that:

[0050] (1) The TFe content in the high-pressure acid leaching residue of laterite nickel ore used in this embodiment is 55.4wt%, the main iron mineral is hematite, and the distribution rate is 95.6%, the main impurities include SiO2, Al2O3 and Cr2O3, and the contents are 5.45wt%, 5.10wt% and 3.55wt% respectively, and the S content is 2.95wt%. The particle size distribution of the acid leaching residue is that the fine particle level (0.074-0.010mm) accounts for 21.50%, and the micro-particle level (<0.010mm) accounts for 78.50%.

[0051] (2) Deionized water and high-pressure acid leaching residue of laterite nickel ore were mixed at a liquid-solid ratio of 4.5:1 to prepare slurry. The slurry was poured into a leaching agitator, sealed and stirred for 40 minutes, and the stirring speed was set to 280 rpm. After stirring, the slurry was separated into solid and liquid by a suction filter, and the filter residue was placed in an oven at 110°C for drying.

[0052] (3) The dried leached residue is mixed with deionized water at a liquid-to-solid ratio of 4.5:1 to form a slurry. The slurry is placed in an ultrasonic cleaning machine for ultrasonic cleaning at a time of 40 minutes and a frequency of 50 kHz. After cleaning, the slurry is filtered through a suction filter, and the filter residue is placed in an oven at 80°C for drying.

[0053] (4) A high-pressure alkaline leaching test was carried out in a laboratory micro-autoclave. The acid leaching residue sample was weighed, 7 g of calcium oxide was added as an alkali source, and 0.018 g / mL of NaOH solution was added at a liquid-to-solid ratio of 4.5:1. The reaction temperature was set to 210 °C and the insulation time was 1 hour. After the reaction was completed, the slurry was filtered through a suction filter, and the filter cake was washed with 80 °C hot water until neutral and then dried.

[0054] (5) Under the optimized process conditions, the S content dropped from 2.95wt% to 0.39wt% and the desulfurization rate was 86.44%.

[0055] Example 4

[0056] The method is the same as in Example 1, except that:

[0057] (1) The TFe content in the high-pressure acid leaching residue of laterite nickel ore used in this embodiment is 50.5wt%, the main iron mineral is hematite, and the distribution rate is 94.4%. The main impurities include SiO2, Al2O3 and Cr2O3, and the contents are 5.20wt%, 5.15wt% and 3.40wt%, respectively, and the S content is 2.35wt%. The particle size distribution of the acid leaching residue is that the fine particle size accounts for 23.00% and the microparticle size accounts for 77.00%.

[0058] (2) Deionized water and high-pressure acid leaching residue of laterite nickel ore were mixed at a liquid-solid ratio of 4:1 to prepare slurry. The slurry was poured into a leaching agitator, sealed and stirred for 50 minutes, and the stirring speed was set to 310 rpm. After stirring, the slurry was separated into solid and liquid by a suction filter, and the filter residue was placed in an oven at 80°C for drying.

[0059] (3) The dried leached residue is mixed with deionized water at a liquid-to-solid ratio of 4:1 to form a slurry. The slurry is placed in an ultrasonic cleaning machine for ultrasonic cleaning, with an ultrasonic time of 35 minutes and an ultrasonic frequency of 40 kHz. After cleaning, the slurry is filtered through a suction filter, and the filter residue is placed in an oven at 80°C for drying.

[0060] (4) A high-pressure alkaline leaching test was carried out in a laboratory micro-autoclave. The acid leaching residue sample was weighed, 6 g of calcium oxide was added as an alkali source, and 0.018 g / mL of NaOH solution was added at a liquid-to-solid ratio of 4:1. The reaction temperature was set to 230 °C and the insulation time was 1 hour. After the reaction was completed, the slurry was filtered through a suction filter, and the filter cake was washed with 80 °C hot water until neutral and then dried.

[0061] (5) Under the optimized process conditions, the S content dropped from 2.35wt% to 0.34wt% and the desulfurization rate was 85.53%.

[0062] Example 5

[0063] The method is the same as in Example 1, except that:

[0064] (1) The TFe content in the high-pressure acid leaching residue of laterite nickel ore used in this embodiment is 53.0wt%, the main iron mineral is hematite, and the distribution rate is 98.1%. The main impurities include SiO2, Al2O3 and Cr2O3, and the contents are 5.35wt%, 5.00wt% and 3.30wt%, respectively, and the S content is 2.60wt%. The particle size distribution of the acid leaching residue is that the fine particle size accounts for 30.00% and the microparticle size accounts for 69.00%.

[0065] (2) Deionized water and high-pressure acid leaching residue of laterite nickel ore were mixed at a liquid-solid ratio of 4.5:1 to prepare slurry. The slurry was poured into a leaching agitator, sealed and stirred for 40 minutes, and the stirring speed was set to 300 rpm. After stirring, the slurry was separated into solid and liquid by a suction filter, and the filter residue was placed in an oven at 80°C for drying.

[0066] (3) The dried leached residue is mixed with deionized water at a liquid-to-solid ratio of 4.5:1 to form a slurry. The slurry is placed in an ultrasonic cleaning machine for ultrasonic cleaning, with an ultrasonic time of 30 minutes and an ultrasonic frequency of 45 kHz. After cleaning, the slurry is filtered through a suction filter, and the filter residue is placed in an oven at 80°C for drying.

[0067] (4) A high-pressure alkaline leaching test was carried out in a laboratory micro-autoclave. The acid leaching residue sample was weighed, 5 g of calcium oxide was added as an alkali source, and 0.018 g / mL of NaOH solution was added at a liquid-to-solid ratio of 4.5:1. The reaction temperature was set to 220 °C and the insulation time was 1 hour. After the reaction was completed, the slurry was filtered through a suction filter, and the filter cake was washed with 80 °C hot water until neutral and then dried.

[0068] (5) Under the optimized process conditions, the S content dropped from 2.60wt% to 0.36wt% and the desulfurization rate was 86.15%.

[0069] Example 6

[0070] The method is the same as in Example 1, except that:

[0071] (1) The TFe content in the high-pressure acid leaching residue of laterite nickel ore used in this embodiment is 48.3wt%, the main iron mineral is hematite, the distribution rate is 97.7%, the main impurities include SiO2, Al2O3 and Cr2O3, the contents are 5.60wt%, 5.20wt% and 3.70wt%, respectively, and the S content is 2.90wt%. The particle size distribution of the acid leaching residue is that the fine particle size accounts for 25.00% and the microparticle size accounts for 75.00%.

[0072] (2) Deionized water and high-pressure acid leaching residue of laterite nickel ore were mixed at a liquid-solid ratio of 4:1 to prepare slurry. The slurry was poured into a leaching agitator, sealed and stirred for 35 minutes, and the stirring speed was set to 280 rpm. After stirring, the slurry was separated into solid and liquid by a suction filter, and the filter residue was placed in an oven at 80°C for drying.

[0073] (3) The dried leached residue is mixed with deionized water at a liquid-to-solid ratio of 4:1 to form a slurry. The slurry is placed in an ultrasonic cleaning machine for ultrasonic cleaning at a time of 40 minutes and a frequency of 40 kHz. After cleaning, the slurry is filtered through a suction filter, and the filter residue is placed in an oven at 80°C for drying.

[0074] (4) A high-pressure alkaline leaching test was carried out in a laboratory micro-autoclave. The acid leaching residue sample was weighed, 5 g of calcium oxide was added as an alkali source, and 0.018 g / mL of NaOH solution was added at a liquid-to-solid ratio of 4:1. The reaction temperature was set at 200 °C and the holding time was 1 hour. After the reaction was completed, the slurry was filtered through a suction filter, and the filter cake was washed with 80 °C hot water until neutral and then dried.

[0075] (5) Under the optimized process conditions, the S content dropped from 2.90wt% to 0.41wt% and the desulfurization rate was 85.86%.

[0076] The above technical scheme explains the technical idea of ​​the present invention, which cannot be used to limit the protection scope of the present invention. Any changes and modifications made to the above technical scheme based on the technical essence of the present invention without departing from the content of the technical scheme of the present invention shall fall within the protection scope of the technical scheme of the present invention.

Claims

1. A high-pressure acid leaching residue stirring and washing-high-pressure alkaline leaching desulfurization process for laterite nickel ore, characterized in that: The following steps are involved: (1) mixing deionized water and laterite nickel ore high pressure acid leaching residue to form a slurry; (2) mechanically stirring the slurry, washing it with water, filtering it and drying it to obtain acid leaching residue after washing; (3) mixing the washed acid leaching residue with deionized water and then performing ultrasonic cleaning, filtering after cleaning, and drying for later use; (4) mixing the dried acid leaching residue with an alkaline solution at a liquid-to-solid ratio of 4:1-5:1, and subjecting the mixture to a high-temperature alkaline leaching reaction in a high-pressure reactor. After the reaction, the material is filtered and washed with hot water until it is neutral; (5) The filtered solid material is dried to obtain the desulfurized acid leaching residue.

2. The process for desulfurization of laterite nickel ore high-pressure acid leaching residue by stirring and washing-high-pressure alkaline leaching according to claim 1, characterized in that: The iron content of the high-pressure acid leaching slag of laterite nickel ore in step (1) is 48.3-55.4wt%, and the main impurities and mass percentages in the slag are SiO2 5.20-5.60wt%, Al2O3 4.95-5.20wt% and Cr2O3 3.30-3.70wt%, wherein the content of harmful element sulfur reaches 2.05-2.95wt%, mainly existing in the form of sulfate.

3. The process for desulfurization of laterite nickel ore high-pressure acid leaching residue by stirring and washing-high-pressure alkaline leaching according to claim 1, characterized in that: The particle size of the high-pressure acid leaching residue of laterite nickel ore in step (1) is fine, and most of the particles have a particle size below 0.074 mm; among them, the particle occupancy rate of fine-grained particles (0.074-0.010 mm) is 20-30%, and the particle occupancy rate of micro-particles (<0.010 mm) is 70-80%.

4. The process for desulfurization of laterite nickel ore high-pressure acid leaching residue by stirring and washing-high-pressure alkaline leaching according to claim 1, characterized in that: The stirring rate of the mechanical stirring water washing in step (2) is 200-400 r / min, and the stirring time is 20-50 minutes; after the reaction, the slurry is filtered, and the obtained filter residue is dried in an oven at a temperature of 80-120°C; this step preliminarily removes water-soluble impurities.

5. The process for desulfurization of laterite nickel ore high-pressure acid leaching residue by stirring and washing-high-pressure alkaline leaching according to claim 1, characterized in that: In the steps (1) and (3), the acid leaching residue is mixed with deionized water at a liquid-to-solid ratio of 4:1-5:

1.

6. The process for desulfurization of laterite nickel ore high-pressure acid leaching residue by stirring and washing-high-pressure alkaline leaching according to claim 1, characterized in that: The ultrasonic frequency described in step (3) is 40-120kHz, and the cleaning time is 30-60 minutes; after cleaning, the slurry is filtered by suction, and the filter residue is dried in an oven for later use; this step further removes fine particle impurities that are difficult to remove by mechanical stirring and water washing.

7. The process for desulfurization of laterite nickel ore high-pressure acid leaching residue by stirring and washing-high-pressure alkaline leaching according to claim 1, characterized in that: In the step (4), 4-10 g of calcium oxide is first added to the dried acid leaching residue as an alkali source, and then an alkali solution is added after mixing. The alkali solution is a sodium hydroxide solution with a mass concentration of 0.018-0.2 g / mL.

8. The process for desulfurization of laterite nickel ore high-pressure acid leaching residue by stirring and washing-high-pressure alkaline leaching according to claim 1, characterized in that: In step (4), the pressure range of the high-pressure reactor is 4-8 MPa, the rotation speed of the magnet is 400-600 rpm, the treatment temperature is 200-240° C., the reaction time is 60-80 minutes, and the temperature of the hot water is 80-90° C.

9. The process for desulfurization of laterite nickel ore high-pressure acid leaching residue by stirring and washing-high-pressure alkaline leaching according to claim 1, characterized in that: The sulfur content of the desulfurized acid leaching residue obtained in step (5) is reduced from 2.09-2.95wt% to below 0.5wt%.

Images