A method for efficiently extracting nickel from sulfur concentrate containing complex low-grade nickel

Abstract

The invention discloses a method for efficiently extracting nickel from sulfur concentrate containing complex low-grade nickel, belonging to the field of metallurgical technology. The sulfur concentrate containing complex low-grade nickel is mixed with a fluoride salt and roasted in an air atmosphere to obtain a roasted material. The roasted material is subjected to acid leaching to obtain a nickel-containing leaching solution. The nickel-containing leaching solution is subjected to hydrolysis to precipitate nickel to obtain a nickel-enriched slag. The nickel-enriched slag is successively subjected to acidolysis, extraction and back-extraction to obtain a nickel-rich solution. The nickel-rich solution is converted by carbonate to form nickel carbonate precipitate. This method can not only realize the efficient extraction of nickel resources from low-grade and difficult-to-leach nickel minerals in sulfur concentrate, but also obtain a nickel carbonate product with a purity greater than 99.99% and a nickel grade greater than 46%, realizing the resource utilization of sulfur concentrate containing complex low-grade nickel.

Description

Technical Field

[0001] The present invention relates to a method for extracting nickel from sulfur concentrate, and particularly to a method for efficiently extracting nickel from sulfur concentrate containing complex low-grade nickel, belonging to the field of metallurgical technology. Background Art

[0002] The main uses of nickel include military, aerospace, machinery, stainless steel and other fields. It is a key component in the manufacture of stainless steel, which can enhance the corrosion resistance and mechanical properties of stainless steel. Nickel is widely used in the production of alloys, including nickel-based alloys, copper-nickel alloys and nickel-chromium alloys, etc., and these alloys have important applications in the aerospace, nuclear industry, chemical and power industries.

[0003] The current main use of sulfur concentrate is to produce sulfuric acid. A large number of valuable elements contained in it, such as copper, cobalt, nickel, gold, silver, etc., are not fully extracted and utilized, resulting in waste of resources. The nickel occurrence in sulfur concentrate is complex and the grade is low. There is currently no public report on the process for recovering nickel from sulfur concentrate. Therefore, the technology for extracting nickel from sulfur concentrate needs to be developed urgently.

[0004] The nickel content in sulfur concentrate is about 0.008%, and its extraction is relatively difficult. The currently commonly used processes cannot simply and economically extract it; for example, although the pyrometallurgical process has perfect technology and large processing capacity, due to large losses during the high-temperature smelting process and high intensity of harmful tail gas release, tail gas treatment is required to meet the emission requirements, thus corresponding treatment devices need to be built, making the investment, operation and management costs higher. At the same time, the flotation process cannot achieve the recovery of nickel in sulfur concentrate, and there are also problems such as subsequent need for de-drug treatment and further purification treatment. After one roughing and one cleaning two-stage flotation, a concentrate product with a nickel grade of 0.22% can be obtained, and the nickel recovery rate is less than 30%. It can be seen that if the flotation method is used, nickel is not well enriched and the separation effect is poor, and the magnetic separation method basically has no effect on the recovery of nickel in the ore. Summary of the Invention

[0005] Aiming at the defects existing in the prior art, the purpose of the present invention is to provide a method for efficiently extracting nickel from sulfur concentrate containing complex low-grade nickel. This method adopts an optimized process flow combining "roasting - acid leaching - hydrolysis precipitation - acidolysis - extraction - carbonate conversion", which can not only achieve the efficient extraction of nickel resources in low-grade and difficult-to-leach nickel minerals in sulfur concentrate, but also obtain nickel carbonate products with a purity greater than 99.99% and a nickel grade greater than 46%, realizing the resource utilization of sulfur concentrate containing complex low-grade nickel.

[0006] To achieve the above technical purpose, the present invention provides a method for efficiently extracting nickel from sulfur concentrate containing complex low-grade nickel, and this method includes the following steps:

[0007] 1) The sulfur concentrate containing complex low-grade nickel is mixed with a fluoride salt and roasted in an air atmosphere to obtain a roasted material;

[0008] 2) The roasted material is subjected to acid leaching to obtain a nickel-containing leachate;

[0009] 3) The nickel-containing leachate is subjected to hydrolysis and nickel precipitation to obtain a nickel-enriched slag;

[0010] 4) The nickel-enriched slag is successively subjected to acidolysis, extraction, and back-extraction to obtain a nickel-rich solution;

[0011] 5) The nickel-rich solution is converted by carbonate to form nickel carbonate precipitate.

[0012] In view of the distribution and mineral composition characteristics of nickel elements in the sulfur concentrate containing complex low-grade nickel, the key of the present invention lies in using a fluoride salt as a roasting aid to first carry out high-temperature decomposition of the complex low-grade nickel in the sulfur concentrate in an air atmosphere. During the high-temperature process, the fluoride salt can dissociate into fluoride ions, and the radius of the fluoride ions is relatively small, which can diffuse into the crystal lattice of nickel-containing silicate minerals, thereby destroying the crystal lattice structure of the nickel-containing silicate minerals, being conducive to improving the leaching effect of nickel in the nickel-containing silicate minerals. At the same time, roasting sulfide ores in an air atmosphere can be fully oxidized and decomposed, which is conducive to the exposure of nickel minerals wrapped by sulfide ores and the decomposition of nickel sulfide ores, further improving the leaching effect of nickel minerals. In addition, due to the very low grade of nickel elements in the sulfur concentrate, the nickel concentration in the nickel-containing leachate is very low, while through hydrolysis and nickel precipitation, acidolysis, extraction, and back-extraction, the enrichment of nickel elements can be realized to obtain a high-concentration nickel-rich solution, which is conducive to subsequent carbonate conversion to obtain nickel carbonate products.

[0013] As a preferred embodiment, nickel in the sulfur concentrate containing complex low-grade nickel mainly exists in the forms of nickel-containing silicate minerals, nickel sulfide minerals, and nickel sulfate minerals, and its total nickel grade is 0.006 - 0.010%. Nickel in the sulfur concentrate containing complex low-grade nickel is mainly hosted in nickel-containing silicate minerals and nickel sulfides, and a small amount exists in nickel sulfate minerals, and its total nickel grade is about 0.008%, making direct extraction relatively difficult.

[0014] As a preferred embodiment, the mass ratio of the sulfur concentrate containing complex low-grade nickel to the fluoride salt is 100:5 - 15. If the mass ratio of the fluoride salt is too low, the network structure of the nickel-containing silicate minerals will not be completely destroyed, and nickel leaching will be incomplete. As the mass ratio of the fluoride salt increases, it is beneficial to the leaching of nickel in complex low-grade nickel minerals. However, if the mass ratio of the fluoride salt is too high, the improvement of the leaching effect of nickel resources is not obvious. Therefore, the mass ratio of the sulfur concentrate containing complex low-grade nickel to the fluoride salt is further 100:8 - 12.

[0015] As a preferred embodiment, the fluoride salt contains sodium fluoride. Sodium fluoride can dissociate into sodium ions and fluoride ions at high temperatures. The fluoride ions have a relatively small ionic radius and can diffuse into the lattice of nickel-containing silicate minerals, thereby destroying the crystal lattice structure of the nickel-containing silicate minerals, while the sodium ions can replace the nickel ions. Of course, other fluoride salts can also achieve a similar effect, but other fluoride salts may introduce unfavorable impurity cations, which has an adverse effect on the subsequent purification of nickel elements. Therefore, the preferred fluoride salt in the present invention is sodium fluoride. If a fluoride-ion-free additive is used, the lattice of the nickel-containing silicate minerals cannot be destroyed, resulting in a very low leaching rate of nickel elements in the nickel-containing silicate minerals.

[0016] As a preferred embodiment, the conditions for roasting are as follows: the roasting temperature is 500 - 700 °C, the roasting time is 2 - 4 h, and the turning frequency is 1 - 3 h / time. If the roasting temperature is too low, it will lead to incomplete oxidation of sulfide ore and insufficient destruction of the nickel mineral lattice, thus affecting the subsequent leaching of nickel elements; if the roasting temperature is too high, iron element impurities will form dense ferrites with nickel elements, which is not conducive to leaching and has a higher cost. If the roasting time is too short, it will lead to incomplete oxidation of sulfide ore; if the roasting time is too long, it will increase power consumption and the improvement of leaching effect is not obvious; through the turning process, it is beneficial to introduce oxygen and promote the oxidation of sulfide ore and the breaking of the lattice. The further preferred roasting temperature is 650 - 700 °C. The further preferred roasting time is 2 - 3 h. The further preferred turning frequency is 1 h / time.

[0017] As a preferred embodiment, the conditions for acid leaching are as follows: sulfuric acid is used as the leaching agent, the solid-liquid ratio is 1 g: 4 mL - 1 g: 6 mL, the dosage of the leaching agent is 100 - 300 g / L, the stirring speed is 200 - 400 r / min, the leaching temperature is 30 - 80 °C, and the leaching time is 0.5 - 3.0 h. On the basis of roasting the sulfur concentrate containing complex low-grade nickel, by adopting the preferred acid leaching conditions, the leaching rate of nickel can be guaranteed to reach 80 - 90%. During the acid leaching process, the dosage of the leaching agent and the leaching temperature are the main factors affecting the leaching effect. When the leaching temperature increases from room temperature to 50 °C, the nickel leaching rate remains almost unchanged. However, when it continues to increase to 80 °C, the nickel leaching rate increases by about 10%. The further preferred leaching temperature is 60 - 80 °C, the more preferred leaching temperature is 70 - 80 °C, and 80 °C is the optimal leaching temperature. When the dosage of the leaching agent increases from 100 g / L to 200 g / L, the leaching rate of nickel increases. When the dosage of the leaching agent is further increased to 300 g / L, the leaching rate of nickel decreases slightly. Therefore, the further preferred dosage of the leaching agent is 150 - 200 g / L. In contrast, when the dosage of the leaching agent is 200 g / L, the leaching effect is the best. The solid-liquid ratio and the leaching time of the leaching solution also have a certain impact on the leaching effect. For example, when the solid-liquid ratio increases from 1 g: 4 mL to 1 g: 5 mL, the leaching rate of nickel increases. When the solid-liquid ratio is further increased to 1 g: 5 mL, the leaching rate of nickel does not increase significantly. When the solid-liquid ratio is 1 g: 5 mL, the leaching effect is the best. When the leaching time increases from 0.5 h to 1 h, the leaching rate of nickel increases slightly. After the leaching time is further increased to 1.5 h, the leaching rate of nickel does not increase significantly. The further preferred leaching time is 1 h - 1.5 h.

[0018] As a preferred embodiment, the conditions for hydrolytic nickel precipitation are as follows: adjust the pH to 8.3 - 8.6, and under the condition of a temperature of 60 - 70 °C, the reaction time is 1 - 3 h.

[0019] As a preferred embodiment, the conditions for extraction are as follows: P507 is used as the extractant, the volume concentration of P507 in the extraction organic phase is 5 - 30%, the extraction phase ratio is O / A = 1:1 - 2.5, and the extraction time is 2 - 10 min. The influence of O / A on nickel extraction is relatively obvious. As the extraction aqueous phase increases, the extraction effect becomes worse. Therefore, the further preferred extraction phase ratio is O / A = 1:1 - 1.5. When O / A = 1:1, the nickel extraction rate is high and the impurities are less. In addition, as the extraction time increases, the extraction effect first increases and then decreases. Therefore, the extraction effect is the best at 4 - 6 min. Therefore, the optimal extraction time is 5 min. The extraction organic phase also contains a diluent, such as sulfonated kerosene.

[0020] As a preferred solution, the conditions for stripping are as follows: hydrochloric acid solution is used as the stripping agent, the stripping phase ratio is A / O = 3 - 5:1, and the stripping time is 1 - 3 min. Dilute hydrochloric acid with pH = 1 - 3 is used in the stripping process.

[0021] The concentration of nickel element in the nickel-rich solution obtained in the present invention is 2.3 - 2.4 g / L.

[0022] The nickel-rich solution of the present invention is subjected to carbonate conversion by adding Na2CO3 in an amount of 4 - 5 g / L, and nickel carbonate products with a purity greater than 99.99% and a nickel grade greater than 46% are obtained by precipitation.

[0023] Beneficial technical effects brought by the technical solution of the present invention compared with the prior art:

[0024] 1. Through a special roasting process for sulfur concentrate containing complex low-grade nickel, the present invention can improve the acid leaching extraction efficiency of nickel. The highest nickel leaching rate can reach 84.97%, and the nickel concentration in the leaching solution can reach 0.173 g / L. Compared with direct leaching, the leaching rate is greatly improved.

[0025] 2. By adopting hydrolysis precipitation, extraction and carbonation conversion processes for the acid leaching solution, the present invention can obtain a nickel-rich solution with a nickel concentration of 2.3 - 2.4 g / L. Through carbonation conversion, nickel carbonate with a purity greater than 99.99% and a nickel grade greater than 46% can be obtained, thus greatly improving the production efficiency and economic benefits of nickel products. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a flow chart for efficiently extracting nickel from sulfur concentrate containing complex low-grade nickel proposed by the present invention.

[0027] Figure 2 is the XRD pattern of the sulfur concentrate containing complex low-grade nickel of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0028] The following specific examples are intended to further illustrate the content of the present invention rather than limit the protection scope of the claims.

[0029] The sulfur concentrate raw materials used in the following examples:

[0030] A certain domestic mining enterprise produces 23,000 tons of sulfur concentrate annually, containing about 0.008% nickel. The contents of each component and the nickel phase in the sample are shown in Table 1 and Table 2 respectively:

[0031]

[0032]

[0033] The XRD pattern is as Figure 2 shown, fromFigure 2 It can be seen that the characteristic peaks of nickel minerals are hardly visible, indicating that its grade is extremely low.

[0034] Condition optimization experiments:

[0035] Experimental group 1:

[0036] Through a series of roasting tests, explore the effects of factors such as roasting temperature (500 - 700 °C), roasting time (2 - 4 h), number of roasting stages, type of roasting aids, dosage of roasting aids, and turning pile frequency on the roasting pretreatment of sulfur concentrate.

[0037] The specific operation process is as follows: Weigh 50 g of ore sample (-43 μm) and 10% of roasting aids into a porcelain boat, and place it in a muffle furnace. The roasting atmosphere is air. According to the muffle furnace rising 10 °C per 1 min, set the corresponding temperature and time. After roasting, cool it to room temperature and weigh it.

[0038] Effect of roasting temperature (500 - 700 °C) on the loss on ignition: Other test conditions are controlled as: grinding fineness -43 μm, 50 g of ore sample, 1 stage of roasting, roasting time 3 h, no roasting aids, turning pile frequency 1 h / time. The higher the temperature, the higher the loss on ignition. When the temperature is increased to 650 °C, further increasing the temperature does not result in a significant increase in the loss on ignition. Finally, 650 °C is determined as the optimal experimental condition.

[0039]

[0040] Effect of roasting time (2 - 4 h) on the loss on ignition: Other test conditions are controlled as: grinding fineness -43 μm, 50 g of ore sample, roasting temperature 650 °C, roasting atmosphere is air, 1 stage of roasting, no roasting aids, turning pile frequency 1 h / time. The longer the time, the higher the loss on ignition. Further increasing the time does not result in a significant increase in the loss on ignition. Finally, 3 h is determined as the optimal experimental condition.

[0041]

[0042] Effect of number of roasting stages (1 - 2) on the loss on ignition: Other test conditions are controlled as: grinding fineness -43 μm, 50 g of ore sample, roasting temperature 650 °C, roasting atmosphere is air, roasting time 3 h, no roasting aids, turning pile frequency 1 h / time. With the same total duration, the improvement of two-stage roasting compared to one-stage roasting is not obvious. Finally, 1 stage of roasting is determined as the optimal experimental condition.

[0043]

[0044] Effect of types of roasting aids on leaching rate: Other test conditions were controlled as follows: grinding fineness -43μm, ore sample 50g, roasting temperature 650°C, roasting atmosphere air, roasting time 3h, number of roasting stages 1 stage, dosage of roasting aids 10%, turning pile frequency 1h / time. Direct leaching conditions were: temperature 80°C, stirring speed 300r / min, particle size -43μm, sulfuric acid concentration 200g / L, solid-liquid ratio 1:5, and leaching time 1.5h. Finally, it was determined that sodium fluoride was the optimal roasting aid for the experiment.

[0045]

[0046] Effect of dosage of roasting aids on leaching rate: Other test conditions were controlled as follows: grinding fineness -43μm, ore sample 50g, roasting temperature 650°C, roasting atmosphere air, roasting time 3h, number of roasting stages 1 stage, roasting aid sodium fluoride, turning pile frequency 1h / time. Direct leaching conditions were: temperature 80°C, stirring speed 300r / min, particle size -43μm, sulfuric acid concentration 200g / L, solid-liquid ratio 1:5, and leaching time 1.5h. Finally, it was determined that the dosage of roasting aids being 10% was the optimal condition for the experiment.

[0047]

[0048] The roasting test research found that the optimal roasting conditions were: roasting at 650°C for 3h, with sodium fluoride as the roasting aid, the addition amount of the roasting aid being 10%, turning pile frequency 1h / time, and number of roasting stages 1 stage.

[0049] Experimental group 2:

[0050] Through a series of direct leaching experiments on the roasted samples, the effects of conditions such as solid-liquid ratio (1:4~1:6), dosage of leaching agent (0~300g / L), stirring speed (200~400r / min), leaching temperature (60~80°C), and leaching time (0.5~3h) on the leaching of nickel in sulfur concentrate were investigated.

[0051] Effect of stirring speed (200~400r / min) on nickel leaching rate:

[0052] Other test conditions were controlled as follows: grinding fineness -43μm, sulfuric acid concentration 200g / L, leaching temperature 80°C, solid-liquid ratio 1:5, and leaching time 1.5h. The effect of stirring speed on nickel leaching rate was not obvious, and the change in nickel leaching was small with the increase of stirring speed. The optimal stirring speed condition was determined to be 300r / min.

[0053]

[0054] Effect of temperature (30~80°C) on nickel leaching rate:

[0055] Other test conditions were controlled as follows: grinding fineness -43μm, stirring speed 300 r / min, sulfuric acid concentration 200 g / L, solid-liquid ratio 1:5, leaching time 1.5 h. Temperature has a certain influence on nickel leaching. When the temperature increases from room temperature to 50 °C, the nickel leaching rate remains almost unchanged. However, when the temperature continues to increase to 80 °C, the nickel leaching rate increases slightly, about 10%. Therefore, 80 °C was determined as the optimal leaching temperature.

[0056]

[0057] Effect of the concentration of the leaching agent (sulfuric acid) (0 - 300 g / L) on the nickel leaching rate:

[0058] Other test conditions were controlled as follows: grinding fineness -43μm, stirring speed 300 r / min, temperature 80 °C, solid-liquid ratio 1:4, leaching time 1 h. When the dosage of the leaching agent increased from 100 g / L to 200 g / L, the leaching rate of nickel increased. When the dosage of the leaching agent increased to 300 g / L, the leaching rate of nickel decreased slightly. In comparison, the leaching effect was the best when the dosage of the leaching agent was 200 g / L. Therefore, 200 g / L was determined as the optimal dosage of the leaching agent.

[0059]

[0060] Effect of the solid-liquid ratio (1:4 - 1:6) on the nickel leaching rate:

[0061] Other test conditions were controlled as follows: grinding fineness -43μm, stirring speed 300 r / min, temperature 80 °C, sulfuric acid concentration 200 g / L, leaching time 1.5 h. When the solid-liquid ratio increased from 1:4 to 1:5, the leaching rate of nickel increased. When the solid-liquid ratio increased to 1:6, the leaching rate of nickel did not increase significantly. In comparison, the leaching effect was the best when the solid-liquid ratio was 1:5. Therefore, 1:5 was determined as the optimal solid-liquid ratio.

[0062]

[0063] Effect of the leaching time (0.5 - 3.0 h) on the nickel leaching rate:

[0064] Other test conditions were controlled as follows: grinding fineness -43μm, stirring speed 300 r / min, temperature 80 °C, sulfuric acid concentration 200 g / L, solid-liquid ratio 1:5. When the leaching time increased from 0.5 h to 1.5 h, the leaching rate of nickel increased slightly. After the leaching time increased to 1.5 h, the leaching rate of nickel did not increase significantly. Therefore, the leaching time was determined to be 1.5 h.

[0065]

[0066] The optimal conditions for direct leaching were determined as follows: temperature 80°C, stirring speed 300 r / min, particle size -43 μm, sulfuric acid concentration 200 g / L, solid-liquid ratio 1:5, and leaching time 1.5 h.

[0067] Experimental group 3

[0068] A series of extraction experiments were carried out on the nickel-enriched solution obtained by dissolving nickel in the precipitate to explore the effects of core variables such as O / A ratio, extractant type, pH value, reaction time, extraction temperature, sulfuric acid concentration, etc. on nickel extraction.

[0069] The specific experimental operation method is as follows: Measure 50 mL of leaching solution, a certain amount of extractant and kerosene (5 mL of extractant + 45 mL of kerosene), stir and react on a magnetic stirrer at a stirring speed of 600 r / min for 2 - 10 min. After the reaction is complete, transfer it to a separating funnel, let it stand for 10 - 15 min, separate the liquid, and obtain the raffinate and the loaded organic phase; Add a certain concentration and volume of stripping agent to the loaded organic phase (oil phase) obtained by liquid separation, react for 10 - 15 min, after the reaction is complete, transfer it to a separating funnel, let it stand for 10 - 15 min, separate the liquid, and obtain the nickel-rich solution and the organic phase.

[0070] Effect of extractant on nickel extraction:

[0071] Effect of O / A on nickel extraction: When O / A is 1:1 - 1:2.5, the fixed conditions are: extractant P507, 50 mL of leaching solution, pH value 4, oil phase (5 mL of extractant + 45 mL of kerosene), reaction time 5 min. The test results show that the effect of O / A on nickel extraction is relatively obvious. As the extraction aqueous phase increases, the extraction effect becomes worse. When O / A = 1:1, the nickel extraction rate is high and the impurities are less. Therefore, the optimal condition is 1:1.

[0072]

[0073] Effect of extraction time on nickel extraction: The extraction time is controlled between 3 - 7 min, and other fixed conditions are: extractant P507, O / A = 1:1, 50 mL of leaching solution, oil phase (5 mL of extractant + 45 mL of kerosene), pH value 4. The test results show that as the extraction time increases, the extraction effect first increases and then decreases. The extraction effect is the best at 5 min. Therefore, the optimal time is 5 min.

[0074]

[0075] The optimal experimental conditions for extraction are as follows: use 25% of extractant P507, 75% of sulfonated kerosene as diluent, pH value 3.5 - 4, phase ratio 1:1, and reaction time 5 min.

[0076] The following examples were carried out under the best conditions obtained from the above optimization experiments:

[0077] Example 1

[0078] This embodiment provides a method for efficiently extracting nickel from a sulfur concentrate containing complex low-grade nickel, comprising the following steps:

[0079] Oxidation roasting: roasting is carried out under the conditions of roasting temperature of 650°C, roasting atmosphere of air, roasting time of 3h, sodium fluoride of 10% (relative to the amount of sulfur concentrate containing complex low-grade nickel), and turning frequency of 1h / time. The sulfur concentrate containing complex low-grade nickel is 0.0039% nickel in silicate, 0.0039% nickel in nickel sulfide, 0.0006% nickel in nickel sulfate, and the total nickel content is 0.0084%.

[0080] Leaching: Leaching for 1.5h at a temperature of 80°C, a stirring speed of 300r / min, a sulfuric acid concentration of 200g / L, and a solid-liquid ratio of 1g:5mL. The nickel leaching rate was 84.97%.

[0081] Nickel precipitation: adjust pH to 8.4, temperature to 65℃, reaction time to 1h. The nickel precipitation rate reaches 99.21%.

[0082] Acid dissolution: Use sulfuric acid solution with a pH of 0.5 and a temperature of 65°C to fully dissolve the nickel enriched material.

[0083] Nickel extraction: 25% of the extractant P507, 75% of sulfonated kerosene as diluent, pH value of 3.8, O / A ratio of 1:1, time of 5 minutes. The extraction rate was 99.36%.

[0084] Stripping: using hydrochloric acid solution with pH of 1.8, A / O =4:1, reaction time of 3min, stripping rate of 99.83%, and the concentration of nickel noble solution obtained was 2.4g / L.

[0085] Precipitation: Mix the nickel noble solution with 4.8g / L Na2CO3, place the mixture on a magnetic stirrer, stir it thoroughly at a stirring speed of 500r / min, and react for 5min to obtain nickel carbonate precipitation. During the precipitation process, 4-5g / L Na2CO3 is used for every 100mL of nickel noble solution, and the purity of the nickel carbonate obtained by precipitation is greater than 99.99%, and the nickel grade is greater than 46%.

[0086] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for efficiently extracting nickel from a sulfur concentrate containing complex low-grade nickel, characterized in that: The following steps are involved: 1) A sulfur concentrate containing complex low-grade nickel is mixed with a fluoride salt and roasted in an air atmosphere to obtain a roasted material; the fluoride salt comprises sodium fluoride; the roasting conditions are: a roasting temperature of 400-680° C., a roasting time of 0.5-4.0 h, and a turning frequency of 1-3 h / time; 2) acid leaching the calcined material to obtain a nickel-containing leaching solution; 3) The nickel-containing leaching solution is hydrolyzed to precipitate nickel to obtain nickel-enriched slag; 4) The nickel-enriched slag is sequentially subjected to acid hydrolysis, extraction and stripping to obtain nickel noble liquid; 5) The nickel noble solution is converted into nickel carbonate precipitate through carbonate conversion; The nickel in the complex low-grade nickel-containing sulfur concentrate mainly exists in the form of nickel-containing silicate minerals, nickel sulfide minerals and nickel sulfate minerals, and the total nickel grade thereof is 0.006-0.010%.

2. The method for efficiently extracting nickel from sulfur concentrate containing complex low-grade nickel according to claim 1, characterized in that: The mass ratio of the sulfur concentrate containing complex low-grade nickel to the fluoride salt is 100:5-15.

3. The method for efficiently extracting nickel from sulfur concentrate containing complex low-grade nickel according to claim 1, characterized in that: The acid leaching conditions are: sulfuric acid is used as the leaching agent, the solid-liquid ratio is 1g:4mL~1g:6mL, the leaching agent dosage is 100~300g / L, the stirring speed is 300~700r / min, the leaching temperature is 30~80℃, and the leaching time is 0.5~5h.

4. The method for efficiently extracting nickel from sulfur concentrate containing complex low-grade nickel according to claim 1, characterized in that: The conditions for hydrolyzing nickel are as follows: adjusting the pH to 8.3-8.6, at a temperature of 60-70° C., and reacting for 1-3 hours.

5. The method for efficiently extracting nickel from sulfur concentrate containing complex low-grade nickel according to claim 1, characterized in that: The extraction conditions are: using P507 as the extractant, the volume concentration of P507 in the extracted organic phase is 5-30%, the extraction phase ratio is O / A=1:1-2.5, pH=3.5-4, and the extraction time is 2-10 min.

6. The method for efficiently extracting nickel from sulfur concentrate containing complex low-grade nickel according to claim 1, characterized in that: The stripping conditions are: using hydrochloric acid solution as the stripping agent, the stripping phase ratio is A / O=3~5:1, and the stripping time is 1~3min.

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