Method for enriching nickel and cobalt by roasting laterite-nickel ore with citric acid aid

Abstract

The invention discloses a method for enriching nickel and cobalt by roasting laterite-nickel ore with a citric acid auxiliary agent. The method comprises the following steps: mixing laterite-nickel ore with citric acid and an auxiliary agent, roasting at 50-300 DEG C to enable nickel and cobalt to form a leachable occurrence form, and meanwhile, promoting iron to be converted into low-solubility oxide or other stable phases, so that the dissolution of iron is reduced; the roasted clinker is ground and then leached with water or ammonia water for 30-300 min at the temperature of 10-80 DEG C, and the solid-to-liquid ratio is 1: (10-20); and then filtering separation is carried out, and leaching liquid rich in Ni and Co is obtained through pH adjustment and extraction. Compared with the prior art, the method has the advantages that the selectivity of the target metal is improved by regulating and controlling the mineral phase, improving the nickel-cobalt leaching rate and inhibiting co-leaching of iron, specifically, the nickel-cobalt leaching rate is improved by 3%-8%, and the Ni / Fe selectivity is improved by 1%. According to the method, energy consumption and acid consumption are effectively reduced, the nickel-cobalt enrichment degree is improved, and the method has the advantages of good industrial applicability and environmental protection.

Description

Technical Field

[0001] The present invention relates to the technical fields of physical separation and chemical engineering, and particularly relates to a method for enriching nickel and cobalt by roasting laterite nickel ore with a citric acid additive. Background Art

[0002] Nickel, as an important strategic metal, is widely used in multiple fields such as stainless steel manufacturing, battery materials, electroplating, and catalysts, and has become an indispensable metal in the construction of a modern system. Nickel mainly comes from nickel sulfide ore and laterite nickel ore. With the depletion of nickel sulfide ore resources, the development target has now shifted to laterite nickel ore. Laterite nickel ore is not only a nickel-cobalt associated resource but also a high-quality iron ore resource. Therefore, the efficient utilization and development of laterite nickel ore are of great significance for China's strategic security in the fields of nickel, cobalt, and iron metals.

[0003] Common treatment processes for laterite nickel ore include pyrometallurgy, hydrometallurgy, and pyrometallurgy-hydrometallurgy combined processes. The pyrometallurgy treatment process uses high-temperature smelting to form alloys or sulfides of nickel and iron, and finally obtains nickel iron or nickel matte, which is mainly used in the production of stainless steel and nickel-based alloys. However, problems such as high energy consumption, high pollution, and limited nickel recovery rate restrict its wide application in low-grade laterite nickel ore and the trend of green smelting. The hydrometallurgy treatment process is divided into ammonia leaching and acid leaching. Ammonia leaching is the earliest hydrometallurgy process, which has good selectivity, low acid consumption, and ammonia can be recycled, but there are problems such as slow reaction rate, strong ammonia volatility, complex waste liquid treatment, and poor adaptability to laterite nickel ore. Acid leaching is further divided into high-pressure acid leaching and atmospheric pressure acid leaching. High-pressure acid leaching has high nickel and cobalt recovery rates, but has high equipment investment, high energy consumption, high acid consumption, complex process, and high sewage treatment difficulty. The atmospheric pressure acid leaching process has relatively low equipment investment and simple operation, but has relatively low leaching rate, easy dissolution of iron impurities, long reaction time, and poor treatment effect on refractory ores, and there are still challenges in overall economic efficiency and environmental protection.

[0004] CN104775024A discloses a combined process of atmospheric pressure acid leaching + high-pressure acid leaching. Concentrated sulfuric acid is used for atmospheric pressure leaching to dissolve nickel, cobalt, and part of iron at 95°C to 120°C, and then the recovery rate is increased by pressure leaching at 195°C to 240°C. Finally, solid-liquid separation is carried out to recover nickel and cobalt, and by-products such as iron concentrate powder, high-grade silica, and construction sand are produced. Although this patent has certain advantages in nickel and cobalt recovery in terms of process, there are still problems such as high acid consumption, large energy consumption, cumbersome process, high equipment cost, and unstable utilization value of by-products.

[0005] In the pyrometallurgical-wet metal combined process, the conventional method usually adopts pyrometallurgical sulphation roasting combined with wet leaching to recover and enrich valuable metals. For example, CN102220483B discloses a method for treating laterite nickel ore by two-stage roasting. This method is prone to produce acid mist and SO2 gas during the roasting process, which may complicate the reaction system and affect subsequent leaching. In addition, sulfuric acid consumption is large, and high-temperature roasting may cause side reactions and equipment corrosion, affecting the selective leaching of nickel. At the same time, the conversion and destination of iron and cobalt are unclear, which may lead to the loss of valuable metals. The document "Nonferrous Mining" studied the citric acid mixed roasting-water leaching method, which achieved efficient leaching of nickel and cobalt under low temperature conditions, but the co-leaching rate of impurities such as iron was high (about 40% to 95%), resulting in a decrease in the purity of the leaching solution and an increase in the subsequent separation cost. In addition, this method still has problems such as large acid consumption, long process time, and high energy consumption, which limits its industrial application. Therefore, how to develop a low-temperature, low-acid consumption, high-efficiency and environmentally friendly roasting-leaching process that can effectively reduce the dissolution of impurities such as iron while maintaining high leaching rates of nickel and cobalt has become a key challenge that needs to be urgently addressed in this field. Summary of the invention

[0006] In view of the problems of limited nickel and cobalt leaching rate and serious co-leaching of impurity elements such as iron in the existing laterite nickel ore treatment process, the present invention proposes a method for enriching nickel and cobalt by roasting laterite nickel ore with citric acid additives. The dissolution of impurities such as iron is suppressed by the regulation of additives (forming insoluble phases such as iron oxide compounds, silicates and iron-magnesium composite phases). This method is enriched under mild conditions, which not only effectively improves the leaching rate of nickel and cobalt valuable metals, but also optimizes the mineral phase transformation, improves the leaching selectivity, and reduces the dissolution of impurities such as iron.

[0007] In order to solve the problems of the prior art, the technical solution adopted by the present invention is:

[0008] A method for enriching nickel and cobalt by roasting laterite nickel ore with a citric acid additive comprises the following steps:

[0009] Step 1): uniformly mixing laterite nickel ore, citric acid and an additive to obtain a mixture, and roasting the mixture to obtain a roasted clinker;

[0010] Step 2): grinding the roasted clinker obtained in step 2) into powder, leaching under stirring or ultrasonic conditions to obtain a leached material, and filtering and separating the leached material to obtain a filtrate and a leached residue;

[0011] Step 3): The filtrate and leaching residue are tested and analyzed to calculate the leaching rates of nickel, cobalt, etc.; the iron, aluminum, and manganese impurities are removed step by step by adjusting the pH and the extractant to achieve the enrichment of nickel and cobalt; wherein the obtained nickel leaching rate is 62-95%, the cobalt leaching rate is 49-90%, the iron leaching rate is 31%-52%, and the magnesium leaching rate is 41%-56%.

[0012] Further, in step 1), the particle size of the laterite nickel ore ≤ 0.2 mm; the mass ratio of citric acid to the auxiliary agent is 1 - 10:0.1 - 1, and the mass ratio of the laterite nickel ore to the total mass of citric acid + auxiliary agent is 1:1.1 - 11.

[0013] Furthermore, the auxiliary agent is one or a mixture of ammonium bisulfate, sulfuric acid, or calcium carbonate.

[0014] Further, in step 2), the leaching process parameters are: the temperature is 10°C - 80°C, the solid-liquid ratio is 1:10 - 20, the leaching time is 30 - 300 min, and the reagent used for leaching is one of water or ammonia water.

[0015] Furthermore, the concentration of the ammonia water is 0.1 - 2.5 mol / L.

[0016] Further, in step 1), the roasting temperature is 50°C - 300°C, and the roasting time is 6 - 16 h.

[0017] Further, in step 2), the ultrasonic power is 120 - 240 W / L or the stirring speed is 100 - 600 r / min.

[0018] Further, in step 3), the pH value is 1 - 4.

[0019] Further, in step 3), selective extraction is carried out using P204 or P507 extractant to effectively separate impurities and improve the enrichment efficiency of nickel and cobalt.

[0020] Beneficial effects:

[0021] In the present invention, valuable metals in laterite nickel ore are extracted by adopting a co-roasting - leaching treatment method with citric acid and an auxiliary agent. Under low-temperature roasting conditions, the laterite nickel ore reacts with citric acid and a small amount of auxiliary agents (ammonium bisulfate, sulfuric acid, calcium carbonate), converting insoluble salts in the ore into soluble salts, and converting iron into oxides or other stable phases with low solubility, reducing the dissolution of iron. Through the leaching process, the soluble salts are dissolved out, and the leaching solution is obtained by filtration and separation. The ionic concentrations of metals such as nickel and cobalt in the leaching solution are detected and analyzed, obtaining a nickel-rich and cobalt-rich solution with a nickel leaching rate of 62 - 95%, a cobalt leaching rate of 49 - 90%, an iron leaching rate of 31% - 52%, and a magnesium leaching rate of 41% - 56%. Impurities such as iron are removed through the extraction process to achieve the enrichment of nickel and cobalt.

[0022] Compared with traditional methods, while maintaining a similar or higher nickel and cobalt leaching rate, this process significantly reduces the co-leaching amount of iron, increasing the nickel and cobalt leaching rate from about 87% to about 95% and slightly rising the Ni / Fe selectivity. In addition, the present invention can also obtain an optimized nickel and cobalt enrichment effect at a low roasting temperature and a shorter process time, reducing energy consumption and acid consumption, being more environmentally friendly and efficient, and providing an innovative solution for the efficient, green, and sustainable extraction of laterite nickel ore. Through the optimization method, it is found that the Ni / Fe selectivity of the method of the present invention is 2.06 (about 1% higher than the existing method), and the leaching effect of nickel and cobalt is improved by 3% - 8%; after extraction, the purity of the leaching solution after removing impurities is significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a flow chart of a method for enriching nickel and cobalt by roasting laterite nickel ore with a citric acid additive according to the present invention;

[0024] Figure 2 It is the leaching rate of metal elements in Examples 1 - 7;

[0025] Figure 3 It is the XRD pattern of the leaching residue in Example 7. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] Mix the powdered laterite nickel ore with citric acid and an additive, and mix evenly to obtain a mixed material, converting the insoluble salts in the laterite nickel ore into soluble salts, and at the same time promoting the conversion of iron into oxides or other stable phases with low solubility to reduce the dissolution of iron. Among them, citric acid and the additive form an acidifying agent, and the additive is selected from: ammonium bisulfate, sulfuric acid, calcium carbonate; the mass ratio of citric acid to the additive is 1 - 10:0.1 - 1, and the mass ratio of the laterite nickel ore to the total mass of citric acid + additive is 1:1.1 - 11.

[0027] The laterite nickel ore used in the embodiments of the present invention is: silicate - magnesia type laterite nickel ore and limonite type laterite nickel ore, with a particle size of ≤0.2 mm, and the component content is controlled at: SiO2: 30% - 50%, Fe2O3: 25% - 45%, MgO: 15% - 30%, NiO: 1% - 5%, Al2O3: 1% - 5%, MnO: 0.2% - 1%, CaO: 0.2% - 1%, Cr2O3: 0.5% - 3%, ZnO: 0.1% - 0.5%, SO3: 0.05% - 0.5%, K2O: 0.05% - 0.5%.

[0028] Roast the obtained mixed material in a ceramic fiber muffle furnace at a roasting temperature of 50°C - 300°C and a roasting time of 6 - 16 h to make a roasted clinker.

[0029] The obtained calcined clinker is first ground into powder and then subjected to a leaching process to obtain leached materials. The leaching process parameters are as follows: the power of ultrasonic wave is 120 - 240 W / L or the rotation speed is 100 - 600 r / min, the temperature is 10°C - 80°C, the solid-liquid ratio is 1:10 - 20, and the leaching time is 30 - 300 min. The leaching agent is one of water and ammonia water, and the concentration of ammonia water is 0.1 - 2.5 mol / L.

[0030] The obtained leached materials are filtered and separated to obtain leaching filtrate and leaching filter residue. The leaching filter residue is detected and analyzed, which is rich in SiO2, iron oxides and a small amount of silicates. The mass percentage content of SiO2 is 57 - 68%, and it can be used as single crystal silicon material.

[0031] The leaching filtrate is diluted 50 - 400 times, and inductively coupled plasma detection is carried out to calculate the leaching rate of each valuable metal.

[0032] After detecting that the leaching solution mainly contains ions such as Ni, Co, Fe and Mg, the pH is adjusted to 1 - 4, and then combined with extraction to remove impurity ions such as Fe step by step, and finally a solution rich in Ni and Co is obtained.

[0033] The present invention uses the following formula to calculate the leaching rate:

[0034]

[0035] Among them, the mass of the target metal in the solution is calculated by the product of the volume of the leaching solution and the concentration of the target metal in the solution, that is:

[0036] Mass of target metal in solution = Csolution × Vsolution (2)

[0037] The total mass of the target metal in the raw material is obtained by multiplying the content of the metal in the raw ore or calcined material by the feeding mass, that is:

[0038] Total mass of this metal in raw material = Craw material × Mfeeding (3)

[0039] The calculation method of Ni / Fe selectivity is as follows:

[0040]

[0041] The following provides 7 embodiments of the present invention. If not specifically specified, the technical means not described in detail in the embodiments are conventional means well known to those skilled in the art.

[0042] Example 1

[0043] First, use a crusher to grind the original laterite nickel ore into fine powder to ensure the uniformity of composition and detect the components. Mix the laterite nickel ore powder with citric acid and ammonium bisulfate. When mixing, the mass ratio of citric acid to ammonium bisulfate is 5:1, and the mass ratio of laterite nickel ore powder to the total mass of (citric acid + ammonium bisulfate) is 1:6. After fully mixing it with a ball mill, use a hydraulic press to make it into a uniform block. The obtained block-shaped mixture is roasted in a ceramic fiber muffle furnace at a roasting temperature of 150 °C, a heating rate of 3 °C / min, a roasting holding time of 12 h, and natural cooling. Take out the roasted clinker after firing from the crucible and grind it into powder with a particle size ≤ 0.2 mm for later use.

[0044] Weigh a certain amount of roasted clinker, leach it with water, and control the reaction conditions: the solid-liquid ratio is 1:10, the ultrasonic power is 240 W / L, the leaching temperature is 30 °C, and the leaching time is 120 min.

[0045] After the leaching is completed, filter it. For the obtained leaching solution after filtration, take 0.5 mL of the leaching filtrate and put it into a volumetric flask and dilute it 200 times. After detecting the concentration and components of valuable metal ions: Ni: 0.8135 ppm; Co: 0.0623 ppm; Fe: 6.502 ppm; Mg: 3.102 ppm. After calculating the leaching rate, it is obtained that the leaching rate of Ni is 91%; the leaching rate of Co is 84%; the leaching rate of Fe is 46%; the leaching rate of Mg is 47%, and the Ni / Fe selectivity is 1.97. Adjust the pH of the leaching solution to 2.1, and then use P204 for extraction to obtain a solution enriched with nickel and cobalt. The specific extraction steps are conventional technical means in this field, and only the separation effect needs to be achieved.

[0046] Example 2

[0047] Grind the laterite nickel ore into powder. The mass ratio of laterite nickel ore powder to the total mass of citric acid + dilute sulfuric acid is mixed at 1:6.4, where citric acid: sulfuric acid is 6:0.4. After mixing evenly, put the material into a corundum crucible, and then put it into a muffle furnace for roasting. The heating rate is 3 °C / min, the roasting temperature is 120 °C and keep it warm for 12 h, and then cool it naturally with the furnace. Take out the fired mixture from the crucible and grind it into powder particles with a particle size ≤ 0.2 mm for later use.

[0048] Weigh 20 g of roasted clinker, then add water according to a solid-liquid ratio of 1:10, and seal the beaker mouth to avoid contact with air. The leaching test condition parameters are as follows: the leaching temperature is 35 °C, the ultrasonic power is 200 W / L, the leaching temperature is 40 °C, the leaching time is 100 min. After leaching is completed, filter. For the filtrate obtained after filtration, take 0.25 mL of the leaching filtrate and put it into a volumetric flask and dilute it 400 times. After detection, the concentrations and components of valuable metal ions are as follows: Ni: 1.022 ppm; Co: 0.0824 ppm; Fe: 11.752 ppm; Mg: 5.822 ppm.

[0049] After calculating the leaching rate: the leaching rate of Ni is 73%; the leaching rate of Co is 66%; the leaching rate of Fe is 52%; the leaching rate of Mg is 56%, and the Ni / Fe selectivity is 1.4. Adjust the pH to 2.5, and then use P204 for extraction to obtain a solution enriched in nickel and cobalt. The specific extraction steps are conventional technical means in this field, and only the separation effect needs to be achieved.

[0050] Example 3

[0051] First, the laterite nickel ore is vibrationally crushed and then ground into powder, and its composition is detected. The mass ratio of citric acid to calcium carbonate is 3:0.5. After mixing the laterite nickel ore powder (particle size ≤ 0.2 mm) with citric acid + calcium carbonate evenly according to a mass ratio of 1:3.5, roast it in a ceramic fiber muffle furnace. The heating rate is 3 °C / min, the roasting temperature is 160 °C, and after holding for 16 h, cool it to room temperature, and grind the roasted clinker into powder for standby (particle size ≤ 0.2 mm).

[0052] Weigh a certain amount of roasted clinker, add water for leaching, and stir with a magnetic stirrer. The leaching temperature is 35 °C, the solid-liquid ratio is 1:15, the rotation speed is 300 r / min, the leaching time is 120 min, and then filter and separate. For the filtrate obtained after filtration, take 0.5 mL of the leaching filtrate and put it into a volumetric flask and dilute it 200 times. After detection, the concentrations and components of valuable metal ions are as follows: Ni: 0.9872 ppm; Co: 0.0714 ppm; Fe: 7.883 ppm; Mg: 4.831 ppm;.

[0053] After calculating the leaching rate: the leaching rate of Ni is 62%; the leaching rate of Co is 49%; the leaching rate of Fe is 31%; the leaching rate of Mg is 41%, and the Ni / Fe selectivity is 2. Adjust the pH to 2.1, and then use P507 for extraction to obtain a solution enriched in nickel and cobalt. The specific extraction steps are conventional technical means in this field, and only the separation effect needs to be achieved.

[0054] Example 4

[0055] First, the laterite nickel ore is vibrationally crushed and then ground into powder, and the composition of the ore powder is detected. The laterite nickel ore powder is mixed with citric acid and ammonium bisulfate in a mass ratio of 1:8.6, and the mass ratio of citric acid to ammonium bisulfate is 8:0.6. After thoroughly mixing them using a ball mill, it is made into blocks using a hydraulic press. The obtained mixed material blocks are roasted in a ceramic fiber muffle furnace at a temperature of 140 °C for 16 h. After cooling to room temperature with the furnace, the fired mixed material is taken out from the crucible and ground into powder (particle size ≤ 0.2 mm) for later use.

[0056] Weigh a certain amount of roasted clinker, leach it with water, and stir it with a magnetic stirrer. The reaction conditions are controlled as follows: the solid-liquid ratio is 1:15, the leaching temperature is 20 °C, the rotation speed is 400 r / min, and the leaching time is 200 min. After leaching is completed, filtration is carried out. For the filtrate obtained after filtration, 0.25 mL of the leaching filtrate is taken and placed in a volumetric flask and diluted 400 times. After detection, the concentration and composition of valuable metal ions are as follows: Ni: 0.4804 ppm; Co: 0.0374 ppm; Fe: 4.798 ppm; Mg: 1.676 ppm.

[0057] After calculating the leaching rate: the leaching rate of Ni is 68%; the leaching rate of Co is 59%; the leaching rate of Fe is 42%; the leaching rate of Mg is 48%, and the Ni / Fe selectivity is 1.62. Adjust the pH to 2.9, and then use P204 for extraction to obtain a solution enriched with nickel and cobalt. The specific extraction steps are conventional technical means in this field and only need to achieve the separation effect.

[0058] Example 5

[0059] First, the laterite nickel ore is vibrationally crushed and ground into powder, and the chemical substance composition therein is detected. Then, the obtained laterite nickel ore is mixed with citric acid and ammonium bisulfate according to (citric acid: ammonium bisulfate = 8:1) and a mass ratio of 1:9. After thoroughly mixing them using a ball mill, it is made into blocks using a hydraulic press. The obtained mixed material blocks are roasted in a ceramic fiber muffle furnace at a temperature of 120 °C for 14 h. After cooling, the fired roasted material is taken out from the crucible and ground into powder. Weigh a certain amount of roasted clinker and complete leaching under the condition of ultrasonic waves with water. The reaction controls the solid-liquid ratio of 1:15, the ultrasonic power of 300 W / L, the leaching temperature of 20 °C, and the leaching time of 200 min. After complete leaching, filtration is carried out. For the filtrate obtained after filtration, 0.25 mL of the leaching filtrate is taken and placed in a volumetric flask and diluted 400 times. After detection, the concentration and composition of valuable metal ions are as follows: Ni: 0.5181 ppm; Co: 0.0462 ppm; Fe: 4.892 ppm; Mg: 2.311 ppm.

[0060] The leaching rate is calculated as follows: the leaching rate of Ni is 82%, the leaching rate of Co is 72%, the leaching rate of Fe is 48%, the leaching rate of Mg is 50%, and the Ni / Fe selectivity is 1.7. The pH is adjusted to 2.6, and then P507 is used for extraction to obtain a solution enriched in nickel and cobalt. The specific extraction steps are conventional technical means in the art, and only the separation effect needs to be achieved.

[0061] Example 6

[0062] First, the dried laterite nickel ore is vibrated and ground into powder, and its composition is detected. The laterite nickel ore, (citric acid and ammonium bisulfate) are mixed in a mass ratio of 1:3, wherein citric acid: ammonium bisulfate = 2:1, and the mixed roasted material is placed in a muffle furnace for roasting at a heating rate of 3°C / min and a roasting temperature of 150°C for 14h. After the work is completed, the furnace is cooled, and the fired mixture is taken out of the crucible and ground into powder. A certain amount of roasted clinker is weighed and 0 .1mol / L ammonia solution, solid-liquid ratio of 1:13, stirring rate of 350r / min, leaching temperature of 45℃, leaching time of 180min, filtration after completion of leaching, take 0.5mL of the filtrate obtained after filtration, put it into a volumetric flask and dilute it 200 times. The concentration and composition of valuable metal ions were tested: Ni: 0.6062ppm; Co: 0.0411ppm; Fe: 4.889ppm; Mg: 3.021ppm.

[0063] The leaching rate is calculated as follows: the leaching rate of Ni is 73%, the leaching rate of Co is 62%, the leaching rate of Fe is 36%, the leaching rate of Mg is 49%, and the Ni / Fe selectivity is 2.02. The pH is adjusted to 3.1, and then P507 is used for extraction to obtain a solution enriched in nickel and cobalt. The specific extraction steps are conventional technical means in the art, and only the separation effect needs to be achieved.

[0064] Example 7

[0065] First, the laterite nickel ore is vibrated and crushed, then ground into powder, and the composition of the ore powder is detected. The laterite nickel ore powder is mixed with citric acid and ammonium bisulfate in a mass ratio of 1:6.8, and the mass ratio of citric acid and ammonium bisulfate is 6:0.8. After being fully mixed in a ball mill, it is made into blocks with a hydraulic press. The resulting mixed material block is roasted in a ceramic fiber muffle furnace at a temperature of 130°C for 12 hours. After cooling to room temperature with the furnace, the fired mixture is taken out of the crucible and ground into powder (particle size ≤ 0.2mm) for later use.

[0066] Weigh a certain amount of calcined clinker, add water for leaching, and control the reaction conditions: the solid-liquid ratio is 1:10, the ultrasonic power is 220 W / L, the leaching temperature is 30 °C, and the leaching time is 180 min. After leaching is completed, filter. For the filtrate obtained after filtration, take 0.5 mL of the leaching filtrate and put it into a volumetric flask and dilute it 200 times. After testing, the concentrations and components of valuable metal ions are as follows: Ni: 0.7418 ppm; Co: 0.0632 ppm; Fe: 5.756 ppm; Mg: 3.258 ppm.

[0067] After calculating the leaching rates: the leaching rate of Ni is 95%; the leaching rate of Co is 90%; the leaching rate of Fe is 46%; the leaching rate of Mg is 56%, and the Ni / Fe selectivity is 2.06. Adjust the pH to 2.7, and then use P204 for extraction to obtain a solution enriched with nickel and cobalt. The specific extraction steps are conventional technical means in the art and only need to achieve the separation effect.

[0068] Existing Process 1

[0069] In the literature "Nonferrous Mining": After drying the laterite nickel ore, grind it to a certain particle size using a sample preparation machine. The ratio of the ore sample to citric acid is 1:10. After mixing them evenly, put them into an oven and roast at 100 °C. After roasting for 12 h, naturally cool to room temperature. Leach and filter the roasted product under the conditions of a solid-liquid ratio of 1:10 and ultrasonic treatment for 12 h; After calculating the leaching rates: the leaching rates of Ni and Co are about 87%; the leaching rate of Fe is 43%; the leaching rate of Mg is 58%, and the Ni / Fe selectivity is 2.05.

[0070] Existing Process 2

[0071] In the literature "Nonferrous Mining": After drying the laterite nickel ore, grind it to an appropriate particle size. Mix it evenly with citric acid at a ratio of 1:10, and then place the mixture in an oven and roast at 140 °C. After roasting for 24 h, naturally cool to room temperature. Leach and filter the roasted product under the conditions of a solid-liquid ratio of 1:10 and ultrasonic treatment for 360 min; After calculating the leaching rates: the leaching rate of Ni is 97.7%; the leaching rate of Co is 97.9%; the leaching rate of Fe is 96%; the leaching rate of Mg is 80%, and the Ni / Fe selectivity is 1.02.

[0072] Table 1 XRF of the Leaching Residue in Example 7

[0073]

[0074] Table 2 Comparative Analysis Table of the Present Invention and Existing Processes

[0075]

[0076] In summary, while maintaining a similar or higher nickel and cobalt leaching rate, the present invention significantly reduces the co-leaching amount of iron, increasing the nickel and cobalt leaching rate from about 87% to about 95% and slightly increasing the Ni / Fe selectivity. In addition, the present invention can also obtain an optimized nickel and cobalt enrichment effect at a low roasting temperature and in a shorter time, reducing energy consumption and acid consumption, and being more environmentally friendly and efficient.

Claims

1. A method for enriching nickel and cobalt from laterite nickel ore by roasting with citric acid additive, which is characterized in that, It includes the following steps: Step 1): Uniformly mix laterite nickel ore with citric acid and an auxiliary agent, and then calcine to obtain a calcined clinker; Step 2): Grind the calcined clinker into powder, and then leach it under stirring or ultrasonic conditions to obtain a leached material. Filter and separate the leached material to obtain a filtrate and a leached residue; Step 3): Detect and analyze the filtrate and the leached residue obtained in Step 2), and calculate the leaching rates of nickel, cobalt, etc. Remove iron, aluminum, and manganese impurities step by step by adjusting the pH and the extractant to achieve the enrichment of nickel and cobalt. Among them, the leaching rate of the obtained nickel is 62-95%, the leaching rate of cobalt is 49-90%, the leaching rate of iron is 31%-52%, and the leaching rate of magnesium is 41%-56%.

2. A method for enriching nickel and cobalt from calcined laterite nickel ore with citric acid additive, characterized in that, In Step 1), the particle size of the laterite nickel ore ≤ 0.2 mm; the mass ratio of citric acid to the auxiliary agent is 1-10: 0.1-1, and the mass ratio of the laterite nickel ore to the total mass of citric acid + auxiliary agent is 1:1.1-11.

3. A method for enriching nickel and cobalt from laterite nickel ore by roasting with citric acid additive, characterized in that, In Step 1), the auxiliary agent is one or a mixture of ammonium bisulfate, sulfuric acid, or calcium carbonate.

4. The method for enriching nickel and cobalt from calcined laterite nickel ore with citric acid additive according to claim 1, characterized in that In Step 1), the calcination temperature is 50°C-300°C, and the calcination time is 6-16 h.

5. A method for enriching nickel and cobalt from laterite nickel ore by roasting with a citric acid additive, characterized in that, In Step 2), the leaching process parameters are: the temperature is 10°C-80°C, the solid-liquid ratio is 1:10-20, the leaching time is 30-300 min, and the leaching reagent used is one of water or ammonia water.

6. The method for enriching nickel and cobalt from laterite nickel ore roasted with citric acid additive according to claim 5, characterized in that, The concentration of the ammonia water is 0.1-2.5 mol / L.

7. A method for enriching nickel and cobalt from calcined laterite nickel ore with a citric acid additive, as claimed in claim 1, wherein In Step 2), the ultrasonic power is 120-240 W / L or the stirring speed is 100-600 r / min.

8. A method for enriching nickel and cobalt from laterite nickel ore by roasting with citric acid additive, characterized in that, In Step 3), the pH value is 1-4.

9. A method for enriching nickel and cobalt from laterite nickel ore by roasting with citric acid additive, characterized in that, In Step 3), a P204 or P507 extractant is used for selective extraction to effectively separate impurities and improve the enrichment efficiency of nickel and cobalt.

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