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, and belongs to the technical field of metallurgy. The method comprises the following steps: mixing sulfur concentrate containing complex low-grade nickel with villiaumite, roasting in an air atmosphere to obtain a roasted material, carrying out acid leaching on the roasted material to obtain a nickel-containing leaching solution, carrying out hydrolysis nickel precipitation on the nickel-containing leaching solution to obtain nickel-enriched slag, sequentially carrying out acidolysis, extraction and reverse extraction on the nickel-enriched slag to obtain a nickel pregnant solution, the nickel pregnant solution is converted into nickel carbonate precipitate through carbonate; by means of the method, efficient extraction of nickel resources in low-grade and difficult-to-leach nickel minerals in the sulfur concentrate can be achieved, nickel carbonate products with the purity larger than 99.99% and the nickel grade larger than 46% can be obtained, and resource utilization of the sulfur concentrate containing complex low-grade nickel is achieved.

Description

Technical Field

[0001] The invention relates to a method for extracting nickel from sulfur concentrate, in particular to a method for efficiently extracting nickel from sulfur concentrate containing complex low-grade nickel, and belongs to the technical field of metallurgy. Background Art

[0002] The main uses of nickel include military industry, 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 alloy production, including nickel-based alloys, copper-nickel alloys and nickel-chromium alloys, etc. These alloys have important applications in aerospace, nuclear industry, chemical industry and power industry.

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

[0004] The sulfur concentrate contains about 0.008% nickel, which is difficult to extract. The currently used processes cannot be used to extract it simply and economically. For example, although the pyrometallurgical process is technically sound and has a large processing capacity, due to the large loss during the high-temperature smelting process and the high intensity of harmful tail gas release, tail gas treatment is required to meet the emission requirements, which requires the construction of corresponding treatment equipment, resulting in high investment, operation and management costs. At the same time, the flotation process cannot achieve the recovery of nickel in the sulfur concentrate, and there is still the need for subsequent drug removal and further purification. After two stages of 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, the separation effect is poor, and the magnetic separation method is basically ineffective for the recovery of nickel in the ore. Summary of the invention

[0005] In view of the defects of 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. The method adopts an optimized process flow combining "roasting-acid leaching-hydrolysis precipitation-acid hydrolysis-extraction-carbonate conversion", which can not only achieve 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%, thereby realizing the resource utilization of sulfur concentrate containing complex low-grade nickel.

[0006] In order to achieve the above technical purpose, the present invention provides a method for efficiently extracting nickel from a sulfur concentrate containing complex low-grade nickel, the method comprising the following steps:

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

[0008] 2) acid leaching the calcined material to obtain a nickel-containing leaching solution;

[0009] 3) The nickel-containing leaching solution is hydrolyzed to precipitate nickel to obtain nickel-enriched slag;

[0010] 4) The nickel-enriched slag is sequentially subjected to acid hydrolysis, extraction and stripping to obtain nickel noble liquid;

[0011] 5) The nickel noble solution is converted into nickel carbonate precipitate through carbonate conversion.

[0012] The present invention is aimed at the distribution of nickel elements and mineral composition characteristics in sulfur concentrate containing complex low-grade nickel. The key is to use fluorine salt as a roasting aid to first perform high-temperature decomposition of the complex low-grade nickel in the sulfur concentrate under an air atmosphere. During the high-temperature process, the fluorine salt can dissociate fluorine ions, and the radius of the fluorine ions is small, which can diffuse into the lattice of the nickel-containing silicate mineral, thereby destroying the crystal grid structure of the nickel-containing silicate mineral, which is beneficial to improving the leaching effect of nickel in the nickel-containing silicate mineral. At the same time, roasting the sulfide ore under an air atmosphere can fully oxidize and decompose, which is beneficial to the exposure of nickel minerals wrapped in the sulfide ore and the decomposition of the nickel sulfide ore, further improving the leaching effect of the nickel mineral. In addition, since the grade of nickel elements in the sulfur concentrate is very low, the nickel concentration in the nickel-containing leaching solution is very low, and the nickel element can be enriched through hydrolysis and nickel precipitation, acid hydrolysis, extraction and stripping to obtain a high-concentration nickel noble solution, which is beneficial to the subsequent carbonate conversion to obtain a nickel carbonate product.

[0013] As a preferred solution, 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 its total nickel grade is 0.006-0.010%. The nickel in the complex low-grade nickel-containing sulfur concentrate mainly exists in nickel-containing silicate minerals and nickel sulfide, and a small amount exists in nickel sulfate minerals. Its total nickel grade is about 0.008%, and direct extraction is relatively difficult.

[0014] As a preferred solution, 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 mineral will be incompletely destroyed and the nickel leaching will be incomplete. As the mass ratio of the fluoride salt increases, it is beneficial for the leaching of nickel in the complex low-grade nickel mineral. However, if the mass ratio of the fluoride salt is too high, the leaching effect of the nickel resource is not significantly improved. 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 solution, the fluoride salt comprises sodium fluoride. Sodium fluoride can dissociate into sodium ions and fluoride ions at high temperatures. The fluoride ions have a smaller ionic radius and can diffuse into the crystal lattice of the nickel-containing silicate mineral, thereby destroying the crystal grid structure of the nickel-containing silicate mineral, while the sodium ions can replace the nickel ions. Of course, other fluoride salts can also achieve similar effects, but other fluoride salts may introduce unfavorable impurity cations, which have an adverse effect on the subsequent purification of the nickel element. Therefore, the preferred fluoride salt of the present invention is sodium fluoride. If a fluoride-free auxiliary agent is used, the crystal lattice of the nickel-containing silicate mineral cannot be destroyed, resulting in a very low leaching rate of the nickel element in the nickel-containing silicate mineral.

[0016] As a preferred solution, the roasting conditions are: roasting temperature of 500-700°C, roasting time of 2-4h, and turning frequency of 1-3h / time. If the roasting temperature is too low, the sulfide ore will be incompletely oxidized, and the nickel mineral lattice will not be fully destroyed, thereby affecting the subsequent leaching of nickel elements; if the roasting temperature is too high, iron impurities will form dense ferrites with nickel elements, which is not conducive to leaching and has higher costs. If the roasting time is too short, the sulfide ore will be incompletely oxidized; if the roasting time is too long, the power consumption will increase, and the leaching effect will not be significantly improved; through the turning process, it is beneficial to introduce oxygen, promote the oxidation of the sulfide ore and break the lattice. A further preferred roasting temperature is 650-700°C. A further preferred roasting time is 2-3h. A further preferred turning frequency is 1h / time.

[0017] As a preferred solution, the acid leaching conditions are: sulfuric acid is used as a leaching agent, the solid-liquid ratio is 1g:4mL~1g:6mL, the amount of leaching agent is 100~300g / L, the stirring speed is 200~400r / min, the leaching temperature is 30~80℃, and the leaching time is 0.5~3.0h. On the basis of roasting the sulfur concentrate containing complex low-grade nickel, the preferred acid leaching conditions are adopted to ensure that the nickel leaching rate reaches 80~90%. The amount of leaching agent and the leaching temperature during the acid leaching process are the main factors affecting the leaching effect. As the leaching temperature increases from room temperature to 50℃, the nickel leaching rate remains almost unchanged, but when it continues to increase to 80℃, the nickel leaching rate is improved to about 10%. The further preferred leaching temperature is 60~80℃, and the more preferred leaching temperature is 70~80℃, and 80℃ is the optimal leaching temperature. When the dosage of the leaching agent is increased from 100 g / L to 200 g / L, the leaching rate of the nickel element is increased. When the dosage of the leaching agent is further increased to 300 g / L, the leaching rate of the nickel element is slightly reduced. Therefore, the further preferred dosage of the leaching agent is 150~200 g / L. In contrast, the leaching effect of the leaching agent dosage of 200 g / L is the best. The leaching liquid-solid ratio and the leaching time also have a certain effect on the leaching effect. For example, as the solid-liquid ratio increases from 1g:4mL to 1g:5mL, the leaching rate of nickel is increased. When the solid-liquid ratio is further increased to 1g:5mL, the leaching rate of the nickel element is not further significantly increased. The leaching effect is best when the solid-liquid ratio is 1g:5mL. When the leaching time is increased from 0.5h to 1h, the leaching rate of nickel is slightly increased. After the leaching time is further increased to 1.5h, the leaching rate of nickel is not significantly increased. The leaching time is further preferably 1h~1.5h.

[0018] As a preferred solution, the conditions for hydrolysis and precipitation of nickel are: adjusting the pH to 8.3-8.6, at a temperature of 60-70° C., and a reaction time of 1-3 h.

[0019] As a preferred solution, the extraction conditions are: using P507 as an extractant, the volume concentration of P507 in the extracted organic phase is 5-30%, the extraction ratio is O / A=1:1-2.5, and the extraction time is 2-10min. The effect of O / A on nickel extraction is more obvious. As the amount of extracted aqueous phase increases, the extraction effect becomes worse. Therefore, the further preferred extraction ratio is O / A=1:1-1.5, and when O / A=1:1, the nickel extraction rate is high and there are fewer impurities. In addition, as the extraction time increases, the extraction effect first increases and then weakens, so the extraction effect is best at 4-6min, so the optimal extraction time is 5min. The extracted organic phase also contains a diluent, such as sulfonated kerosene.

[0020] As a preferred solution, 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. The stripping process uses dilute hydrochloric acid with a pH of 1~3.

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

[0022] The nickel noble solution of the present invention adopts 4-5g / L of Na2CO3 to carry out carbonate conversion, and precipitates to obtain a nickel carbonate product with a purity greater than 99.99% and a nickel grade greater than 46%.

[0023] Compared with the prior art, the technical solution of the present invention has the following beneficial technical effects:

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

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

[0026] Figure 1 The present invention provides a flow chart for efficiently extracting nickel from a complex low-grade nickel-sulfur concentrate.

[0027] Figure 2 The figure is the XRD diagram of the complex low-grade nickel-sulfur concentrate of the present invention. DETAILED DESCRIPTION

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

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

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

[0031]

[0032]

[0033] XRD pattern Figure 2 As shown, from Figure 2 It can be seen that the characteristic peaks of nickel minerals are almost invisible, indicating that its grade is extremely low.

[0034] Condition optimization experiment:

[0035] Experimental Group 1:

[0036] Through a series of roasting tests, the effects of roasting temperature (500~700℃), roasting time (2~4h), number of roasting stages, type of roasting aids, dosage of roasting aids, and turning frequency on the roasting pretreatment of sulfur concentrate were explored.

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

[0038] Effect of roasting temperature (500~700℃) on loss on ignition rate: Other experimental conditions were controlled as follows: grinding fineness -43μm, ore sample 50g, roasting stage 1, roasting time 3h, no roasting aid, and turning frequency 1h / time. The higher the temperature, the higher the loss on ignition rate. When the temperature was raised to 650℃, the loss on ignition rate did not increase significantly when the temperature was further raised. Finally, 650℃ was determined to be the optimal experimental condition.

[0039]

[0040] Effect of roasting time (2~4h) on loss on ignition rate: Other experimental conditions were controlled as follows: grinding fineness -43μm, ore sample 50g, roasting temperature 650℃, roasting atmosphere air, roasting stage 1, no roasting aid, and turning frequency 1h / time. The longer the time, the higher the loss on ignition rate. Further increasing the time, the loss on ignition rate did not increase significantly. Finally, 3h was determined to be the optimal experimental condition.

[0041]

[0042] Effect of roasting stage number (1~2) on ignition loss rate: Other experimental conditions were controlled as follows: grinding fineness -43μm, ore sample 50g, roasting temperature 650℃, roasting atmosphere air, roasting time 3h, no roasting aid, and turning frequency 1h / time. The total time was the same, and the two-stage roasting was not significantly improved compared with the one-stage roasting. Finally, the roasting stage number 1 was determined to be the optimal experimental condition.

[0043]

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

[0045]

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

[0047]

[0048] The roasting test study found that the optimal roasting conditions are: roasting temperature 650℃, roasting time 3h, roasting aid sodium fluoride, roasting aid addition amount 10%, turning frequency 1h / time, and roasting stage number 1.

[0049] Experimental Group 2:

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

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

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

[0053]

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

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

[0056]

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

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

[0059]

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

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

[0062]

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

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

[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 of nickel-precipitated acid solution to explore the effects of key variables such as O / A ratio, type of extractant, pH value, reaction time, extraction temperature, and sulfuric acid concentration on nickel extraction.

[0069] The specific experimental operation method is as follows: measure 50mL of leachate, a certain amount of extractant and kerosene (5mL extractant + 45mL kerosene), stir on a magnetic stirrer for reaction, the stirring speed is 600r / min, the reaction time is 2~10min, after the reaction is complete, transfer to a separatory funnel, let stand for 10~15min, separate, 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 separation, react for 10~15min, after the reaction is complete, transfer to a separatory funnel, let stand for 10~15min, separate and obtain nickel noble liquid and organic phase.

[0070] Effect of extractant on nickel extraction:

[0071] Effect of O / A on nickel extraction: O / A is 1:1~1:2.5, and the fixed conditions are: extractant P507, 50mL leaching solution, pH value 4, oil phase (5mL extractant + 45mL kerosene), reaction time 5min. The test results show that the effect of O / A on nickel extraction is more obvious. With the increase of the extraction water phase, 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 was controlled between 3 and 7 minutes, and other fixed conditions were: extractant P507, O / A=1:1, 50 mL leaching solution, oil phase (5 mL extractant + 45 mL kerosene), pH value was 4. The test results showed that with the increase of extraction time, the extraction effect first increased and then weakened. The extraction effect was best at 5 minutes, so the optimal time was 5 minutes.

[0074]

[0075] The optimal experimental conditions for extraction were: using 25% of the extractant P507, 75% of sulfonated kerosene as the diluent, pH value of 3.5-4, a ratio of 1:1, and a reaction time of 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) The sulfur concentrate containing complex low-grade nickel is mixed with fluoride salt and roasted in an air atmosphere to obtain a roasting material; 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.

2. The method for efficiently extracting nickel from sulfur concentrate containing complex low-grade nickel according to claim 1, characterized in that: 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%.

3. A method for efficiently extracting nickel from a sulfur concentrate containing complex low-grade nickel according to claim 1 or 2, characterized in that: The mass ratio of the sulfur concentrate containing complex low-grade nickel to the fluoride salt is 100:5-15; and / or, The fluoride salt comprises sodium fluoride.

4. A method for efficiently extracting nickel from a sulfur concentrate containing complex low-grade nickel according to claim 1 or 2, characterized in that: The roasting conditions are as follows: the roasting temperature is 400-680° C., the roasting time is 0.5-4.0 h, and the turning frequency is 1-3 h / time.

5. 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.

6. The method for efficiently extracting nickel from sulfur concentrate containing complex low-grade nickel according to claim 1, characterized in that: The conditions for hydrolysis and precipitation of nickel are: adjusting the pH to 8.3-8.6, at a temperature of 60-70° C., and the reaction time is 1-3 hours.

7. 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.

8. 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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