A method for comprehensive extraction of valuable metals from laterite nickel ore

Abstract

The application discloses a method for comprehensively extracting valuable metals from laterite nickel ore, and comprises the following steps: adding sulfuric acid into underflow obtained by ball milling and thickening of the laterite nickel ore to obtain slurry by pre-leaching; adding the slurry into the mixed ore to obtain first leaching liquid and first leaching residue by pressure leaching; obtaining second leaching residue and second leaching liquid by solid-liquid separation after neutralization reaction of the first leaching residue; obtaining scandium hydroxide by acid pickling, extraction, washing, reverse extraction and precipitation of the second leaching residue; and obtaining nickel-cobalt-manganese hydroxide by alkaliization and impurity removal and complex precipitation of the second leaching liquid. The method has the advantages of low investment cost, low acid consumption and high valuable metal recovery rate.

Description

Technical Field

[0001] This invention relates to the field of hydrometallurgy, specifically to a method for the comprehensive extraction of valuable metals from laterite nickel ore. Background Technology

[0002] Nickel resources mainly consist of sulfide nickel ore and oxide nickel ore, with sulfide nickel ore accounting for 40% and oxide nickel ore accounting for 60%. With societal development, high-grade, easily processed sulfide nickel ore is increasingly consumed and depleted, leading to a shift in demand for nickel resources towards the more abundant oxide-type laterite nickel ore. The laterite nickel ore deposits are distributed from top to bottom as a limonite layer, a transition layer, and a residual layer, primarily containing valuable metals such as nickel, cobalt, manganese, and scandium. The limonite layer is mainly high-iron type laterite nickel ore with a nickel content of 0.9-1.5%, an iron content of 35-45%, and a magnesium content of less than 5%. The transition layer is mainly transitional laterite nickel ore with a nickel content of 1.3-1.7%, an iron content of 20-30%, and a magnesium content of 5-10%. The residual layer is mainly magnesian laterite nickel ore with a nickel content of 1.7%-2.5%, an iron content of 5-20%, and a magnesium content of 8-30%. Magnesian laterite nickel ore is often smelted using pyrometallurgical processes for stainless steel production. Transitional laterite nickel ore is often used as a blending raw material in stainless steel production, while limonite layers are mainly prepared into nickel intermediates using hydrometallurgical processes or a combination of pyrometallurgical and hydrometallurgical processes.

[0003] The main hydrometallurgical processes for laterite nickel ore include pressurized ammonia leaching, pressurized acid leaching, atmospheric leaching, and heap leaching. Among these, the Caron process is a representative example of pressurized ammonia leaching, where the laterite nickel ore is pretreated (dried, ground, etc.) before reduction, followed by ammonia leaching. This process suffers from high energy consumption, low nickel-cobalt recovery rates, and can only process laterite nickel ore with an iron content greater than 35%. The pressurized acid leaching process mainly involves ore sample preparation, pressurized acid leaching, CCD washing (continuous countercurrent washing), neutralization and impurity removal, and nickel-cobalt precipitation. This process has high investment costs, harsh operating conditions, equipment corrosion susceptibility, high maintenance costs for the autoclave, long commissioning time, and is unsuitable for minerals with high magnesium content. Atmospheric leaching involves combining seawater ball milling with reduction leaching under atmospheric pressure for acid leaching. This process consumes a large amount of acid and introduces significant amounts of impurities such as iron, aluminum, and chromium. Heap leaching also suffers from high acid consumption, long cycle times, low metal solution content, and high levels of iron and aluminum impurities. Summary of the Invention

[0004] To address the shortcomings of the existing technologies, this invention provides a method for the comprehensive extraction of valuable metals from laterite nickel ore that features low investment costs, low acid consumption, and high leaching rate of valuable metals.

[0005] This invention is achieved through the following technical solutions.

[0006] A method for the comprehensive extraction of valuable metals from laterite nickel ore, characterized in that the method comprises:

[0007] (1) The underflow obtained by ball milling and thickening laterite nickel ore is pre-leached with sulfuric acid to obtain a slurry;

[0008] (2) The slurry obtained in step (1) is added to the ore mixture and then pressure leached to obtain the first leaching solution and the first leaching residue. The first leaching residue is neutralized and then separated by solid-liquid separation to obtain the second leaching residue and the second leaching solution. The mass ratio of the added ore mixture to the mass of the laterite nickel ore (dry ore) in step (1) is 0.4 to 1.5:1, the leaching temperature is 185 to 210˚C, the leaching time is 1.5 to 2h, and the pressure is 1.6 to 2.5MPa.

[0009] (3) The second leaching residue obtained in step (2) is subjected to acid washing, extraction, washing, back-extraction and precipitation to obtain scandium hydroxide; the second leaching solution obtained in step (2) is subjected to alkalization to remove impurities and complexation precipitation to obtain nickel cobalt manganese hydroxide.

[0010] Further, in step (1) ball milling: the time is 0.5 h to 2 h, and the particle size is 200 mesh to 300 mesh;

[0011] Thickening: Underflow concentration (by mass percentage) 20%–45%, suspended solids content in overflow 0–1000 ppm; the mass ratio of added sulfuric acid (concentrated sulfuric acid) to laterite nickel ore is 1:2–1.5:1; pre-leaching temperature is 70–100˚C, time is 2–6 h.

[0012] Furthermore, the ore blending in step (2) is a limonite layer, a transitional laterite nickel ore layer, or a magnesian laterite nickel ore layer.

[0013] Furthermore, when both the lateritic nickel ore and the blended ore being pre-leached are limonite layers, the pressure is 1.6~2.5 MPa and the leaching time is 1.5~2 h; when either the lateritic nickel ore or the blended ore being pre-leached is a transitional lateritic nickel ore or magnesian lateritic nickel ore, the leaching time is 1.5~2 h, the total pressure is 1.6 MPa~2.5 MPa, and the oxygen partial pressure is 0~35% of the total pressure.

[0014] Further, the limonite layer comprises (by mass percentage): nickel content 0.9-1.5%, iron content 35-45%, and magnesium content less than 5%; the transitional lateritic nickel ore comprises (by mass percentage): nickel content 1.3-1.7%, iron content 20-30%, and magnesium content 5-10%; the magnesian lateritic nickel ore comprises (by mass percentage): nickel content 1.7-2.5%, iron content 5-20%, and magnesium content 8-30%.

[0015] Further, in step (2), the first leaching residue is neutralized using a calcium carbonate slurry with a concentration of 15-30%. The process conditions for the neutralization reaction are: pH 1-2, temperature 60-100˚C, and time 0.5-2h.

[0016] Further, in step (3), the second leaching residue obtained in step (2) is pickled with sulfuric acid at a solid-liquid ratio (mass ratio) of 1:1 to 1:5 to obtain a pickling solution. The pickling process conditions are: pickling pH of 0 to 1, pickling time of 0.5 to 4 hours, pickling temperature of 60 to 100°C, and pickling times of 1 to 5.

[0017] Further, in step (3) extraction: the extractant and diluent are added to the pickling solution for extraction to obtain a loaded organic phase and raffinate, and the raffinate is incorporated into the second leachate; wherein, the extractant is one or a mixture of several of P204 (di(2-ethylhexyl) phosphate), P507 (2-ethylhexyl phosphate mono-2-ethylhexyl ester), and TBP (tributyl phosphate), the diluent is sulfonated kerosene, the extractant is 1% to 30% of the diluent (by volume percentage), the ratio of aqueous phase (pickling solution): oil phase (extractant) is 10:1 to 30:1, the extraction time is 3 to 30 min, and the standing time after extraction is 5 to 30 min.

[0018] Further, in step (3) washing: a detergent is added to the supported organic phase obtained after extraction and phase separation. The detergent used is sulfuric acid or hydrochloric acid, and the concentration of the detergent is expressed as [H+]. + The concentration is 1~8 mol / L. The ratio of the aqueous phase (hydrochloric acid or sulfuric acid) to the oil phase (extractant) in the washing process is 1:1~1:30. The washing temperature is 10~90℃, the washing time is 5~30 min, and the number of washing cycles is 1~10. Back-extraction: A back-extraction agent, specifically liquid alkali, is added to the loaded organic phase obtained after washing and phase separation. The concentration of the liquid alkali is expressed as [OH-]. - The concentration of the extractant is 1-10 mol / L. The ratio of the back-extraction aqueous phase (back-extraction agent) to the oil phase (loaded organic phase after washing and phase separation) is 1:1-1:30. The back-extraction time is 3-30 min, and the settling time after back-extraction is 5-30 min. Precipitation: Add a precipitant to the aqueous phase obtained after back-extraction and phase separation. The precipitant used is sulfuric acid or hydrochloric acid. Control the pH at 8-11 and the reaction time is 0.5-4 h.

[0019] Further, the process conditions for alkalization and impurity removal in step (3) are as follows: the alkalization and impurity removal agent used is calcium carbonate or sodium hydroxide, the impurity removal temperature is 40-80 ˚C, the impurity removal pH is 2.8-5.5, and the impurity removal time is 2-4h; the process conditions for complexation and precipitation reaction are as follows: a complexing agent and a precipitant are added to the impurity-removed liquid obtained by alkalization and impurity removal, the complexing agent used is ammonia water, the amount of ammonia water added is 10% (by volume percentage) of the second leaching liquid, the precipitant used is magnesium oxide, the reaction temperature is controlled at 40-80 ˚C, the pH is 7.0-9.0, and the reaction time is 2h-8h.

[0020] Furthermore, the precipitate generated by the complexation precipitation in step (3) enters the ammonia recovery system for ammonia water recovery, and the evaporation temperature is controlled at 80-150 ˚C. The recovered ammonia water is recycled.

[0021] The present invention provides a method for the comprehensive extraction of valuable metals from laterite nickel ore, characterized by low investment cost, good operating conditions, low acid consumption, low maintenance cost, high nickel, cobalt, and manganese leaching rates, and a wide range of applicable raw materials. The recovery rate of scandium among the valuable metals is >90%; the leaching rate of nickel is ≥95%, with an overall recovery rate of ≥92%; the leaching rate of cobalt is ≥95%, with a recovery rate of ≥92%; and the leaching rate of manganese is ≥95%, with a recovery rate of ≥92%. Attached Figure Description

[0022] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0023] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0024] like Figure 1 As shown, a method for the comprehensive extraction of valuable metals from laterite nickel ore includes:

[0025] (1) A slurry with a concentration (by mass percentage) of 20% to 45% (more preferably 20% to 35%, more preferably 35% to 40%) is obtained by ball milling and thickening of laterite nickel ore (latite nickel ore is one or more of limonite layer, transitional layer laterite nickel ore, and magnesian laterite nickel ore). Sulfuric acid is added to the slurry for pre-leaching. The ball milling time is 0.5 h to 2 h, preferably 0.5 h to 1 h, more preferably 1 h to 2 h, and the particle size requirement is 200 mesh to 300 mesh. The suspended solids content in the overflow obtained by thickening is 0 to 1000 ppm. The mass ratio of added sulfuric acid (concentrated sulfuric acid) to the mass of laterite nickel ore is 1:2 to 1.5:1, preferably 1:3 to 1.5:1, and most preferably 1.2:1. The pre-leaching temperature is 70 ˚C to 100˚C, more preferably 85 ˚C to 100˚C, and the time is 2 to 6 h.

[0026] (2) The slurry obtained in step (1) is added to the ore mixture and pressure leached to obtain the first leaching solution (discharge or reuse) and the first leaching residue. The first leaching residue is neutralized with a calcium carbonate slurry with a concentration of 15-30% and then separated by solid-liquid separation to obtain the second leaching residue and the second leaching solution. The ore mixture consists of a limonite layer, a transitional lateritic nickel ore layer, or a magnesian lateritic nickel ore layer. The limonite layer includes (by mass percentage): nickel content 0.9-1.5%, iron content 35-45%, magnesium content 0.9-1.5%, iron content 35-45%, magnesium content 0.9-1.5%, iron content 35-45%, magnesium content 35-45%, iron ... The amount is less than 5%; the transitional lateritic nickel ore includes (by mass percentage): nickel content 1.3-1.7%, iron content 20-30%, magnesium content 5-10%; the magnesian lateritic nickel ore includes (by mass percentage): nickel content 1.7-2.5%, iron content 5-20%, magnesium content 8-30%; the mass ratio of the added ore to the lateritic nickel ore (dry ore) in step (1) is 0.4-1.5:1, preferably 0.8-1.4:1, and the leaching temperature is 185°C. The leaching temperature is 190°C to 210°C, preferably 190°C to 210°C, the leaching time is 1.5 to 2 hours, and the pressure is 1.6 to 2.5 MPa, preferably 1.8 to 2.2 MPa. When both the lateritic nickel ore and the blended ore being pre-leached are limonite layers, the pressure is 1.6 to 2.5 MPa, and the leaching time is 1.5 to 2 hours. When either the lateritic nickel ore or the blended ore being pre-leached is a transitional lateritic nickel ore or magnesian lateritic nickel ore, the leaching time is 1.5 to 2 hours, the total pressure is 1.6 MPa to 2.5 MPa, and the oxygen partial pressure is 0 to 35% of the total pressure. The neutralization reaction conditions are: pH 1 to 2, neutralization reaction temperature 60°C to 100°C, and neutralization reaction time 0.5 to 2 hours.

[0027] (3) The second leaching residue obtained in step (2) is subjected to acid washing, extraction, washing, back-extraction and precipitation to obtain scandium hydroxide; the second leaching liquid obtained in step (2) is subjected to alkalization to remove impurities and complexation precipitation to obtain nickel cobalt manganese hydroxide; the precipitate generated by complexation precipitation is fed into the ammonia recovery system for ammonia water recovery, and the evaporation temperature is controlled at 80 ˚C~150 ˚C. The recovered ammonia water is recycled.

[0028] Pickling: The second leaching residue obtained in step (2) is pickled with 98% sulfuric acid at a solid-liquid ratio (mass ratio) of 1:1 to 1:5 (preferably 1:3 to 1:5) to obtain a pickling solution. The pickling process conditions are: pickling pH of 0 to 1, pickling time of 0.5 to 4 hours, pickling temperature of 60 ˚C to 100˚C, and pickling times of 1 to 5 times.

[0029] Extraction: The extractant and diluent are added to the pickling solution for extraction, and the phases are separated to obtain a loaded organic phase and a raffinate. The raffinate is then added to the second leachate to recover cobalt, nickel, and manganese. The extractant is one or a mixture of several of P204 (di(2-ethylhexyl) phosphate), P507 (2-ethylhexyl phosphate mono-2-ethylhexyl), and TBP (tributyl phosphate). The diluent is sulfonated kerosene. The extractant accounts for 1% to 30% (by volume percentage) of the diluent, preferably 5% to 20%. The ratio of aqueous phase (pickling solution) to oil phase (extractant) is 10:1 to 30:1, preferably 15:1 to 25:1. The extraction time is 3 to 30 minutes, and the settling time after extraction is 5 to 30 minutes.

[0030] Washing: A washing agent, such as sulfuric acid or hydrochloric acid, is added to the supported organic phase obtained after extraction and phase separation. The concentration of the washing agent is expressed as [H+]. + The concentration is 1~8 mol / L, the ratio of aqueous phase (hydrochloric acid or sulfuric acid) to oil phase (extractant) in the washing process is 1:1~1:30, preferably 1:15~1:20, the washing temperature is 10˚C~90℃, the washing time is 5~30 min, and the number of washing cycles is 1~10.

[0031] Back-extraction: A back-extraction agent, specifically liquid alkali, is added to the supported organic phase obtained after washing and phase separation. The concentration of the liquid alkali is expressed as [OH-]. - The concentration of the extractant is 1-10 mol / L, preferably 5-8 mol / L. The ratio of the back-extracting aqueous phase (back-extractant) to the oil phase (loaded organic phase after washing and separation) is 1:1-1:30, preferably 1:15-1:20. The back-extraction time is 3-30 min, and the settling time after back-extraction is 5-30 min. Precipitation: Add a precipitant to the aqueous phase obtained after back-extraction and separation. The precipitant used is sulfuric acid or hydrochloric acid. Control the pH at 8-11, and the reaction time is 0.5-4 h.

[0032] The process conditions for alkalization and impurity removal are as follows: the alkalization and impurity removal agent used is calcium carbonate or sodium hydroxide, the impurity removal temperature is 40 ˚C~80 ˚C, the impurity removal pH is 2.8~5.5, preferably 3.2~5.0, and the impurity removal time is 2~4h; the process conditions for complexation and precipitation reaction are as follows: a complexing agent and a precipitant are added to the impurity-removed liquid obtained by alkalization and impurity removal. The complexing agent used is ammonia water, and the amount of ammonia water added is 10% (by volume percentage) of the second leaching liquid. The precipitant used is magnesium oxide, the reaction temperature is controlled at 40 ˚C~80 ˚C, the pH is 7.0~9.0, and the reaction time is 2h~8h. Example

[0033] (1) The underflow obtained by ball milling and thickening of laterite nickel ore (a limonite layer) is pre-leached with sulfuric acid to obtain a slurry; wherein, ball milling: time is 0.5 h, particle size is 200 mesh; thickening: underflow concentration is 45%, and the suspended solids content in the overflow is 900 ppm; the mass ratio of sulfuric acid added to laterite nickel ore is 1:2; the pre-leaching temperature is 90 ˚C, and the time is 6 h.

[0034] (2) The slurry obtained in step (1) is added to the ore mixture and pressure leaching is performed to obtain the first leaching solution and the first leaching residue. The first leaching residue is neutralized and then separated by solid-liquid separation to obtain the second leaching residue and the second leaching solution. The ore mixture is a limonite layer (including nickel content of 1.5%, iron content of 45%, and magnesium content of 4%). The mass ratio of the added ore mixture to the mass of the laterite nickel ore in step (1) is 1.4:1. The leaching pressure is 2.5 MPa, the temperature is 210 ˚C, and the leaching time is 1.5 hours. Neutralization reaction: 15% calcium carbonate slurry is used for neutralization reaction. The pH of the neutralization reaction is 1, the neutralization reaction temperature is 80 ˚C, and the neutralization reaction time is 2 hours.

[0035] (3) The second leaching residue obtained in step (2) is subjected to acid washing, extraction, washing, back-extraction and precipitation to obtain scandium hydroxide;

[0036] Pickling: The second leaching residue is pickled with sulfuric acid at a mass ratio of 1:1 to obtain pickling solution. The pickling pH is 1, the pickling time is 0.5 h, the pickling temperature is 80˚C, and the pickling is repeated twice.

[0037] Extraction: The extractant and diluent are added to the pickling solution for extraction, and the resulting raffinate is added to the second leachate; wherein, the extractant is P204, the diluent is sulfonated kerosene, the extractant is 1% of the diluent, the ratio of water phase to oil phase is 10:1, the extraction time is 3 min, and the settling time after extraction is 30 min.

[0038] Washing: A washing agent, specifically sulfuric acid, is added to the supported organic phase obtained after extraction and phase separation. The concentration of the washing agent is expressed as [H+]. + The concentration meter is 8 mol / L, the ratio of water phase to oil phase in the washing process is 1:1, the washing temperature is 10℃, the washing time is 30 min, and the number of washing cycles is 5.

[0039] The back-extraction process conditions are as follows: A back-extraction agent is added to the supported organic phase obtained after washing and phase separation. The back-extraction agent used is liquid alkali, and the concentration of the liquid alkali is expressed as [OH-]. - The concentration was 2 mol / L, the ratio of aqueous phase to oil phase in the back-extraction was 1:1, the back-extraction time was 3 min, and the settling time after back-extraction was 30 min.

[0040] Precipitation: Add a precipitant, sulfuric acid, to the aqueous phase obtained by back-extraction and phase separation, control the pH at 11, and the reaction time at 0.5 h.

[0041] The second leachate obtained in step (2) is subjected to alkalization for impurity removal and complexation precipitation to obtain nickel cobalt manganese hydroxide. The precipitate produced by complexation precipitation is then fed into an ammonia recovery system for ammonia recovery. The evaporation temperature is controlled at 150 ˚C, and the recovered ammonia is recycled. The alkalization for impurity removal uses calcium carbonate as the alkalizing agent, with a removal temperature of 40 ˚C, a removal pH of 3.2, and a removal time of 2 hours. The complexation precipitation involves adding a complexing agent and a precipitant to the precipitate. The complexing agent used is ammonia, and the amount of ammonia added is 10% of the second leachate. The precipitant used is magnesium oxide, with a reaction temperature of 40 ˚C, a pH of 7.0, and a reaction time of 8 hours.

[0042] The recovery rate of scandium among valuable metals is 91%; the leaching rate of nickel is 95%, and the overall recovery rate is 92%; the leaching rate of cobalt is 95%, and the recovery rate is 92%; the leaching rate of manganese is 95%, and the recovery rate is 92%. Example

[0043] (1) The underflow obtained by ball milling and thickening of laterite nickel ore (transitional layer laterite nickel ore) is pre-leached with sulfuric acid to obtain slurry;

[0044] Among them, ball milling time was 2 hours and particle size was 300 mesh; thickening process conditions: underflow concentration was 35% and the suspended solids content in overflow was 10 ppm; the mass ratio of sulfuric acid added to laterite nickel ore was 1.5:1; the pre-leaching temperature was 100˚C and the time was 6 hours.

[0045] (2) The slurry obtained in step (1) is added to the ore mixture and then pressure leaching is performed to obtain the first leaching solution and the first leaching residue. The first leaching residue is neutralized and then separated by solid-liquid separation to obtain the second leaching residue and the second leaching solution.

[0046] The ore blending consisted of transitional lateritic nickel ore (containing 1.5% nickel, 25% iron, and 8% magnesium), with the mass ratio of the blending ore to the lateritic nickel ore from step (1) being 1.2:1. Oxygen pressure leaching was employed at a temperature of 200˚C, a leaching time of 2 hours, a total pressure of 2.0 MPa, and an oxygen partial pressure of 35% of the total pressure.

[0047] The neutralization reaction process conditions are as follows: a 30% calcium carbonate slurry is used for the neutralization reaction, the pH of the neutralization reaction is 2, the neutralization reaction temperature is 100˚C, and the neutralization reaction time is 1h.

[0048] (3) The second leaching residue obtained in step (2) is subjected to acid washing, extraction, washing, back-extraction and precipitation to obtain scandium hydroxide;

[0049] The pickling process conditions are as follows: the second leaching residue is pickled with sulfuric acid at a mass ratio of 1:5 to obtain a pickling solution, the pickling pH is 0.5, the pickling time is 2 hours, the pickling temperature is 60 ˚C, and the pickling is performed 4 times.

[0050] Extraction process conditions: The extractant and diluent are added to the pickling solution for extraction, and the resulting raffinate is added to the second leachate; wherein, the extractant is P507, the diluent is sulfonated kerosene, the extractant is 30% of the diluent, the water phase: oil phase ratio is 30:1, the extraction time is 15 min, and the settling time after extraction is 5 min.

[0051] Washing process conditions: The detergent used is hydrochloric acid, and the concentration of the detergent is [H+]. + The concentration meter is 1 mol / L, the ratio of water phase to oil phase in the washing process is 1:30, the washing temperature is 90℃, the washing time is 20 min, and the washing is done once.

[0052] The back-extraction process conditions are as follows: the back-extraction agent used is liquid alkali, with a concentration of [OH-]. - The concentration of the sample was 10 mol / L, the ratio of aqueous phase to oil phase in the back-extraction was 1:30, the back-extraction time was 30 min, and the settling time after back-extraction was 5 min.

[0053] Precipitation process conditions: Hydrochloric acid was used as the precipitant, the pH was controlled at 8, and the reaction time was 4 hours.

[0054] The second leachate obtained in step (2) is subjected to alkalization to remove impurities and complexation precipitation to obtain nickel cobalt manganese hydroxide. The precipitate produced by complexation precipitation is then fed into an ammonia recovery system for ammonia recovery. The evaporation temperature is controlled at 100 ˚C. The recovered ammonia is recycled.

[0055] The process conditions for alkalization and impurity removal are as follows: sodium hydroxide is used as the alkalization and impurity removal agent, the impurity removal temperature is 80 ˚C, the impurity removal pH is 5.5, and the impurity removal time is 4 hours; the process conditions for complexation and precipitation are as follows: ammonia is used as the complexing agent, the amount of ammonia added is 10% of the second leachate, magnesium oxide is used as the precipitant, the reaction temperature is controlled at 80 ˚C, the pH is 9.0, and the reaction time is 2 hours.

[0056] The recovery rate of scandium among valuable metals was 92%; the leaching rate of nickel was 96%, with an overall recovery rate of 93%; the leaching rate of cobalt was 97%, with a recovery rate of 94%; and the leaching rate of manganese was 96%, with a recovery rate of 93%. Example

[0057] (1) The underflow obtained by ball milling and thickening laterite nickel ore (magnesian laterite nickel ore) is pre-leached with sulfuric acid to obtain a slurry;

[0058] The ball milling process conditions were as follows: time was 1 hour, and particle size was 250 mesh; the thickening process conditions were: underflow concentration of 25% and suspended solids content in overflow of 100 ppm; the mass ratio of sulfuric acid added to laterite nickel ore was 1.3:1; the pre-leaching temperature was 85 ˚C and the time was 3 hours.

[0059] (2) The slurry obtained in step (1) is added to the ore mixture and then pressure leaching is performed to obtain the first leaching solution and the first leaching residue. The first leaching residue is neutralized and then separated by solid-liquid separation to obtain the second leaching residue and the second leaching solution.

[0060] The ore blending consisted of magnesian laterite nickel ore (containing 1.7% nickel, 20% iron, and 15% magnesium), with the mass ratio of the blending ore to the laterite nickel ore from step (1) being 0.8:1. Oxygen pressure leaching was employed at a temperature of 190˚C, a leaching time of 1.8 h, a total pressure of 1.8 MPa, and an oxygen partial pressure of 30% of the total pressure.

[0061] The neutralization reaction process conditions are as follows: a 20% calcium carbonate slurry is used for the neutralization reaction, the pH of the neutralization reaction is 1.5, the neutralization reaction temperature is 80 ˚C, and the neutralization reaction time is 0.5 h.

[0062] (3) The second leaching residue obtained in step (2) is subjected to acid washing, extraction, washing, back-extraction and precipitation to obtain scandium hydroxide;

[0063] The pickling process conditions are as follows: the second leaching residue is pickled with 98% sulfuric acid at a mass ratio of 1:3 to obtain a pickling solution. The pickling pH is 0.2, the pickling time is 2.5 h, the pickling temperature is 85 ˚C, and the pickling is performed 3 times.

[0064] Extraction process conditions: The extractant and diluent are added to the pickling solution for extraction, and the resulting raffinate is added to the second leachate; wherein, the extractant is TBP, the diluent is sulfonated kerosene, the extractant is 25% of the diluent, the water phase: oil phase ratio is 15:1, the extraction time is 30 min, and the settling time after extraction is 15 min.

[0065] Washing process conditions: The detergent used is sulfuric acid, with a concentration of [H+]. + The concentration meter is 4 mol / L, the ratio of water phase to oil phase in the washing process is 1:15, the washing temperature is 50℃, the washing time is 5 min, and the number of washing cycles is 8.

[0066] The back-extraction process conditions: The back-extraction agent used is liquid alkali, liquid alkali [OH] - The concentration of the sample was 5 mol / L, the ratio of aqueous phase to oil phase in the back-extraction was 1:15, the back-extraction time was 15 min, and the settling time after back-extraction was 15 min.

[0067] Precipitation process conditions: sulfuric acid was used as the precipitant, the pH was controlled at 10, and the reaction time was 2 hours.

[0068] The second leachate obtained in step (2) is subjected to alkalization to remove impurities and complexation precipitation to obtain nickel cobalt manganese hydroxide. The precipitate produced by complexation precipitation is then fed into an ammonia recovery system for ammonia recovery. The evaporation temperature is controlled at 130 ˚C. The recovered ammonia is recycled.

[0069] The process conditions for alkalization and impurity removal are as follows: the alkalization and impurity removal agent used is calcium carbonate, the impurity removal temperature is 60 ˚C, the impurity removal pH is 4, and the impurity removal time is 3 hours; the process conditions for complexation and precipitation reaction are as follows: the complexing agent used is ammonia water, the amount added is 10% of the second leachate, the precipitant used is magnesium oxide, the reaction temperature is controlled at 60 ˚C, the pH is 8.0, and the reaction time is 5 hours.

[0070] The recovery rate of scandium among valuable metals was 93%; the leaching rate of nickel was 96%, with an overall recovery rate of 93%; the leaching rate of cobalt was 97%, with a recovery rate of 94%; and the leaching rate of manganese was 95%, with a recovery rate of 92%. Example

[0071] (1) The underflow obtained by ball milling and thickening laterite nickel ore (a layer of limonite) is pre-leached with sulfuric acid to obtain a slurry;

[0072] The ball milling process conditions are as follows: time is 1.5h, particle size is 270 mesh; the thickening process conditions are: underflow concentration (by mass percentage) is 40%, and the suspended solids content in the overflow is 50ppm; the mass ratio of sulfuric acid added to laterite nickel ore is 1.2:1; the pre-leaching temperature is 90˚C, and the time is 4h.

[0073] (2) The slurry obtained in step (1) is added to the ore mixture and then pressure leaching is performed to obtain the first leaching solution and the first leaching residue. The first leaching residue is neutralized and then separated by solid-liquid separation to obtain the second leaching residue and the second leaching solution.

[0074] The ore mixture is a limonite layer (including 0.9% nickel, 35% iron, and 4% magnesium), and the mass ratio of the ore mixture to the laterite nickel ore in step (1) is 0.7:1; the leaching pressure is 2.2 MPa, the temperature is 200˚C, and the leaching time is 2 hours.

[0075] The neutralization reaction process conditions are as follows: a 25% calcium carbonate slurry is used for the neutralization reaction, the pH of the neutralization reaction is 1.8, the neutralization reaction temperature is 90˚C, and the neutralization reaction time is 1.5h.

[0076] (3) The second leaching residue obtained in step (2) is subjected to acid washing, extraction, washing, back-extraction and precipitation to obtain scandium hydroxide;

[0077] The pickling process conditions are as follows: the second leaching residue is pickled with 98% sulfuric acid at a mass ratio of 1:4 to obtain a pickling solution. The pickling pH is 0.8, the pickling time is 3 hours, the pickling temperature is 90˚C, and the pickling is performed 5 times.

[0078] Extraction process conditions: The extractant and diluent are added to the pickling solution for extraction, and the resulting raffinate is added to the second leachate; wherein, the extractant is P204 and P507, the diluent is sulfonated kerosene, the extractant is 20% of the diluent, the water phase: oil phase ratio is 20:1, the extraction time is 20 min, and the settling time after extraction is 20 min.

[0079] Washing process conditions: The detergent used is hydrochloric acid, with a concentration of [H+]. + The concentration meter is 6 mol / L, the ratio of water phase to oil phase in the washing process is 1:20, the washing temperature is 80℃, the washing time is 10 min, and the number of washing cycles is 7.

[0080] The back-extraction process conditions are as follows: the back-extraction agent used is liquid alkali, with a concentration of [OH-]. - The concentration of the sample was 4 mol / L, the ratio of aqueous phase to oil phase in the back-extraction was 1:20, the back-extraction time was 20 min, and the settling time after back-extraction was 20 min.

[0081] Precipitation process conditions: Hydrochloric acid was used as the precipitant, the pH was controlled at 9, and the reaction time was 3 hours.

[0082] The second leachate obtained in step (2) is subjected to alkalization to remove impurities and complexation precipitation to obtain nickel cobalt manganese hydroxide. The precipitate produced by complexation precipitation is then fed into an ammonia recovery system for ammonia recovery. The evaporation temperature is controlled at 80 ˚C. The recovered ammonia is recycled.

[0083] The process conditions for alkalization and impurity removal are as follows: sodium hydroxide is used as the alkalization and impurity removal agent, the impurity removal temperature is 70 ˚C, the impurity removal pH is 2.8, and the impurity removal time is 3 hours; the process conditions for complexation and precipitation are as follows: ammonia is used as the complexing agent, the amount added is 10% of the second leachate, magnesium oxide is used as the precipitant, the reaction temperature is controlled at 70 ˚C, the pH is 8.5, and the reaction time is 7 hours.

[0084] The recovery rate of scandium among valuable metals was 91%; the leaching rate of nickel was 96%, with an overall recovery rate of 93%; the leaching rate of cobalt was 95%, with a recovery rate of 92%; and the leaching rate of manganese was 95%, with a recovery rate of 92%. Example

[0085] (1) The underflow obtained by ball milling and thickening laterite nickel ore is pre-leached with sulfuric acid to obtain a slurry;

[0086] The ball milling process conditions were as follows: time 1.7 h, particle size 230 mesh; thickening process conditions: underflow concentration 45%, suspended solids content in overflow 500 ppm; the mass ratio of sulfuric acid added to laterite nickel ore was 1.4:1; pre-leaching temperature was 95 ˚C, time 5 h.

[0087] (2) The slurry obtained in step (1) is added to the ore mixture and then pressure leaching is performed to obtain the first leaching solution and the first leaching residue. The first leaching residue is neutralized and then separated by solid-liquid separation to obtain the second leaching residue and the second leaching solution.

[0088] The ore blending consisted of magnesian laterite nickel ore (containing 2.5% nickel, 7% iron, and 25% magnesium), with the mass ratio of the blending ore to the laterite nickel ore from step (1) being 0.5:1. Oxygen pressure leaching was employed at a temperature of 200˚C, a leaching time of 1.7 h, a total pressure of 1.8 MPa, and an oxygen partial pressure of 15% of the total pressure.

[0089] The neutralization reaction process conditions are as follows: a 18% calcium carbonate slurry is used for the neutralization reaction, the pH of the neutralization reaction is 2, the neutralization reaction temperature is 65 ˚C, and the neutralization reaction time is 1.8h.

[0090] (3) The second leaching residue obtained in step (2) is subjected to acid washing, extraction, washing, back-extraction and precipitation to obtain scandium hydroxide;

[0091] The pickling process conditions are as follows: the second leaching residue is pickled with 98% sulfuric acid at a mass ratio of 1:3 to obtain pickling solution, the pickling pH is 0.2, the pickling time is 4 hours, the pickling temperature is 70 ˚C, and the pickling is performed once.

[0092] Extraction process conditions: The extractant and diluent are added to the pickling solution for extraction, and the resulting raffinate is added to the second leachate; wherein, the extractant is TBP, the diluent is sulfonated kerosene, the extractant is 5% of the diluent, the water phase:oil phase ratio is 25:1, the extraction time is 25 min, and the settling time after extraction is 25 min.

[0093] Washing process conditions: The detergent used is sulfuric acid, with a concentration of [H+]. + The concentration meter is 3 mol / L, the ratio of water phase to oil phase in the washing process is 1:25, the washing temperature is 40℃, the washing time is 25 min, and the number of washing cycles is 3.

[0094] The back-extraction process conditions are as follows: the back-extraction agent used is liquid alkali ammonia, with a concentration of [OH] - The concentration of the sample was 7 mol / L. The ratio of the aqueous phase to the oil phase in the back-extraction was 1:5. The back-extraction time was 25 min, and the settling time after back-extraction was 25 min.

[0095] Precipitation process conditions: Hydrochloric acid was used as the precipitant, the pH was controlled at 10, and the reaction time was 3 hours.

[0096] The second leachate obtained in step (2) is subjected to alkalization to remove impurities and complexation precipitation to obtain nickel cobalt manganese hydroxide. The precipitate produced by complexation precipitation is then fed into an ammonia recovery system for ammonia recovery. The evaporation temperature is controlled at 90 ˚C. The recovered ammonia is recycled.

[0097] The process conditions for alkalization and impurity removal are as follows: the alkalization and impurity removal agent used is calcium carbonate, the impurity removal temperature is 50 ˚C, the impurity removal pH is 3.7, and the impurity removal time is 3 hours; the process conditions for complexation and precipitation reaction are as follows: the complexing agent used is ammonia water, the amount added is 10% of the second leachate, the precipitant used is magnesium oxide, the reaction temperature is controlled at 50 ˚C, the pH is 8.5, and the reaction time is 6 hours.

[0098] The recovery rate of scandium among valuable metals is 94%; the leaching rate of nickel is 98%, with an overall recovery rate of 95%; the leaching rate of cobalt is 98%, with a recovery rate of 95%; and the leaching rate of manganese is 97%, with a recovery rate of 94%.

[0099] Comparative Example

[0100] (1) The underflow obtained by ball milling and thickening laterite nickel ore (a layer of limonite) is pre-leached with sulfuric acid to obtain a slurry;

[0101] (2) The slurry obtained in step (1) is added to the serpentine ore and then subjected to pressure leaching to obtain leachate and leaching residue; the temperature is 170˚C and the leaching time is 4h.

[0102] (3) The leachate obtained in step (2) is alkalized to remove impurities and then complexed and precipitated to obtain nickel cobalt manganese hydroxide.

[0103] Among valuable metals, nickel had a leaching rate of 85% and a total recovery rate of 80%; cobalt had a leaching rate of 87% and a recovery rate of 85%; and manganese had a leaching rate of 80% and a recovery rate of 86%.

[0104] The above description is merely a preferred embodiment of the present invention and is not limited to the invention. It should be noted that those skilled in the art can make other equivalent improvements based on the technical teachings provided by the present invention, all of which can achieve the purpose of the present invention and should be considered within the scope of protection of the present invention.

Claims

1. A method for the comprehensive extraction of valuable metals from laterite nickel ore, characterized in that, The method includes: (1) The underflow obtained by ball milling and thickening laterite nickel ore is pre-leached with sulfuric acid to obtain a slurry; (2) The slurry obtained in step (1) is added to the ore mixture and pressure leaching is performed to obtain the first leaching solution and the first leaching residue. The first leaching residue is neutralized and then separated by solid-liquid separation to obtain the second leaching residue and the second leaching solution. The mass ratio of the added ore mixture to the mass of the laterite nickel ore in step (1) is 0.4 to 1.5:1, the leaching temperature is 185 to 210˚C, the leaching time is 1.5 to 2h, and the pressure is 1.6 to 2.5MPa. (3) The second leaching residue obtained in step (2) is acid-washed with sulfuric acid at a solid-liquid ratio of 1:1 to 1:5 to obtain an acid washing solution. The acid washing pH is 0 to 1, the acid washing time is 0.5 to 4 hours, the acid washing temperature is 60 to 100°C, and the acid washing is repeated 1 to 5 times. The extractant and diluent are added to the acid washing solution for extraction to obtain a loaded organic phase and a raffinate. The raffinate is added to the second leaching solution. The extractant is one or a mixture of P204, P507, and TBP. The diluent is sulfonated kerosene. The extractant is 1% to 30% of the diluent. The water phase to oil phase ratio is 10:1 to 30:

1. The extraction time is 3 to 30 minutes. The settling time after extraction is 5 to 30 minutes. A detergent is added to the loaded organic phase obtained by extraction and phase separation. The detergent is sulfuric acid or hydrochloric acid. The concentration of the detergent is expressed as [H+] concentration. The concentration of the aqueous phase is 1~8 mol / L, the ratio of the aqueous phase to the oil phase in the washing process is 1:1~1:30, the washing temperature is 10~90℃, the washing time is 5~30 min, and the number of washing cycles is 1~10; a back-extraction agent is added to the loaded organic phase obtained after washing and phase separation. The back-extraction agent is liquid alkali, and the concentration of the liquid alkali is 1~10 mol / L based on the concentration of [OH-]. The ratio of the aqueous phase to the oil phase in the back-extraction is 1:1~1:30, the back-extraction time is 3~30 min, and the settling time after back-extraction is 5~30 min; a precipitant is added to the aqueous phase obtained after back-extraction and phase separation. The precipitant is sulfuric acid or hydrochloric acid, the pH is controlled at 8~11, and the reaction time is 0.5~4 h to obtain scandium hydroxide; an alkalizing and impurity-removing agent is added to the second leachate obtained in step (2) for alkalization and impurity removal. The alkalizing and impurity-removing agent is calcium carbonate or sodium hydroxide, and the impurity removal temperature is 40~80℃. The impurity removal process involves adjusting the pH to 2.8–5.5 and the removal time to 2–4 hours. A complexing agent and a precipitant are added to the impurity-removed solution obtained through alkalization to induce complexation precipitation. The complexing agent used is ammonia water, with an addition amount of 10% of the second leaching solution. The precipitant used is magnesium oxide. The reaction temperature is controlled at 40–80 ˚C, the pH at 7.0–9.0, and the reaction time at 2–8 hours to obtain nickel cobalt manganese hydroxide. The precipitate produced by the complexation precipitation enters an ammonia recovery system for ammonia recovery. The evaporation temperature is controlled at 80–150 ˚C, and the recovered ammonia water is recycled.

2. The method according to claim 1, characterized in that, Step (1) Ball milling: time is 0.5 h to 2 h, particle size is 200 mesh to 300 mesh; thickening: underflow concentration is 20% to 45%, and the content of suspended solids in the overflow is 0 to 1000 ppm; the mass ratio of sulfuric acid added to laterite nickel ore is 1:2 to 1.5:1; the pre-leaching temperature is 70 to 100˚C, and the time is 2 to 6 h.

3. The method according to claim 1, characterized in that, The ore blending in step (2) is limonite layer, transitional laterite nickel ore or magnesian laterite nickel ore.

4. The method according to claim 3, characterized in that, When both the lateritic nickel ore and the blended ore being pre-leached are limonite layers, the pressure is 1.6~2.5 MPa and the leaching time is 1.5~2 h. When either the lateritic nickel ore or the blended ore being pre-leached is a transitional lateritic nickel ore or magnesian lateritic nickel ore, the leaching time is 1.5~2 h, the total pressure is 1.6 MPa~2.5 MPa, and the oxygen partial pressure is 0~35% of the total pressure.

5. The method according to claim 3 or 4, characterized in that, The limonite layer comprises: nickel content 0.9-1.5%, iron content 35-45%, and magnesium content less than 5%; the transitional lateritic nickel ore layer comprises: nickel content 1.3-1.7%, iron content 20-30%, and magnesium content 5-10%; the magnesian lateritic nickel ore layer comprises: nickel content 1.7-2.5%, iron content 5-20%, and magnesium content 8-30%.

6. The method according to claim 1 or 2, characterized in that, In step (2), the first leaching residue is neutralized using a calcium carbonate slurry with a concentration of 15-30%. The neutralization reaction process conditions are: pH 1-2, neutralization reaction temperature 60-100˚C, and neutralization reaction time 0.5-2h.

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