Method for preparing high-purity magnesium sulfate and enriching nickel (II) ions from nickel-containing serpentine
Through the acid-lysis and complexing agent chelation method of serpentine, combined with specific conversion agents and precipitants, the problem of removing nickel ions in the preparation of high-purity magnesium sulfate is solved, and the preparation of high-purity magnesium sulfate and efficient recycling of nickel resources is achieved, which is environmentally friendly and efficient.
Patent Information
- Application Number
- CN202510794754.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-14
- Publication Date
- 2025-07-25
AI Technical Summary
In the process of preparing high-purity magnesium sulfate, the removal of nickel ions is difficult, which affects the purity of the product and subsequent treatment steps. The commonly used methods have problems such as complex operation, high cost, and environmental pollution.
Serpentine is completely acid-dissolved, and the complexing agent is used to chelate with nickel ions. Combined with a specific converter to achieve separation of magnesium salt and nickel ions. The magnesium ions are converted into solids through precipitant, and the ammonium salt is recovered by crystallization of solution. Finally, high-grade nickel refined powder is obtained by concentration, drying and calcination.
It has achieved efficient separation of nickel and cobalt ions, prepared high-purity magnesium sulfate, low nickel ion content, simple process, environmentally friendly and no waste emissions, and high utilization rate of magnesium and nickel resources.
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Figure CN120366597A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of metallurgical processes, and particularly to a method for preparing high-purity magnesium sulfate from nickel-containing serpentine and enriching nickel(II) ions. Background Art
[0002] In China, the reserves of serpentine ore resources are abundant, with the proven reserves exceeding 500 million tons and being widely distributed. It is mainly distributed in Jiangxi, Sichuan, Henan, Anhui and other places, followed by Shandong, Jiangsu, Shaanxi, Inner Mongolia and other places. Its chemical formula is Mg6[Si4O 10 (OH)8, where w(MgO)=43.6%, w(SiO2)=43.3%, w(H2O)=13.1%, and sometimes a small amount of FeO, Fe2O3, NiO and other components are mixed in. There are many comprehensive development and utilization processes for serpentine ore, and the chemical process is one of the best ways to realize its value. When magnesium sulfate is extracted from serpentine by acid leaching, trace nickel in the acidolysis solution precipitates together with magnesium sulfate (Mg: 30 - 60 g / L, Ni: 20 - 600 mg / L), reducing the purity of magnesium sulfate and changing the chromaticity from pure white to light green, thus affecting the appearance and quality of the product. In the processes of hydrometallurgy and chemical production, the removal of nickel ions from magnesium sulfate solution has always been an important technological process. The presence of nickel element will not only affect the purity of the final product, but may also interfere with subsequent treatment steps. Therefore, developing effective processes for removing nickel and cobalt is crucial for improving product quality and production efficiency.
[0003] The existing processes for removing nickel and cobalt ions from magnesium sulfate solution mainly include chemical precipitation method, extraction method, ion exchange method and adsorption method, etc.
[0004] The chemical precipitation method is a common and effective method for removing metal ions. For nickel and cobalt in magnesium sulfate solution, by adjusting the pH value of the solution or the amount of sodium sulfide used, insoluble hydroxides or sulfide precipitates can be formed. However, in a solution with high magnesium and low nickel, it is difficult to precisely control the insoluble matter of nickel and magnesium, thus increasing the difficulty of treating the precipitate.
[0005] Ion exchange method: The ion exchange method utilizes the selective adsorption ability of ion exchange resin to adsorb nickel ions in the wastewater onto the resin, and then these metal ions are separated from the resin by an appropriate eluent. This method has the advantages of simple operation, good treatment effect, easy automation, etc. However, while the resin adsorbs nickel ions, it also adsorbs a certain proportion of magnesium ions, resulting in the loss of magnesium ions. At the same time, a large amount of eluent is consumed, causing certain pollution to the environment; moreover, the adsorption and elution processes are slow and time-consuming, increasing the production cost.
[0006] Solvent extraction method: The solvent extraction method utilizes the contact between an organic solvent and an aqueous phase containing metal ions, and realizes the selective extraction of metal ions based on the difference in the distribution coefficients of different substances between the two phases. For nickel in magnesium sulfate solution, a suitable extractant and organic solvent can be selected to transfer it from the aqueous phase to the organic phase through the extraction process. The advantages of the solvent extraction method are high selectivity for metal ions, strong treatment capacity, and easy realization of continuous operation. However, this method also has some limitations, such as the selection and recovery of extractants, the consumption and pollution of organic solvents, etc.; moreover, for high-magnesium and low-nickel solutions, the cost of extracting nickel with organic extractants is too high. Summary of the Invention
[0007] The technical problem to be solved by the present invention is to provide a method for preparing high-purity magnesium sulfate and enriching nickel (II) ions from nickel-containing serpentine in view of the deficiencies of the above-mentioned prior art. The serpentine is completely acid-hydrolyzed to completely release nickel and magnesium in the ore; after the nickel ions in the high-magnesium and low-nickel salt solution obtained by acid hydrolysis are chelated with a complexing agent, a specific conversion agent is used to separate the magnesium salt solid from the nickel ions; then a precipitating agent is used to completely convert the magnesium ions in the solution into a solid, and the ammonium salt in the solution is recovered by solution crystallization; finally, the residual nickel-rich solution is concentrated / dried / calcined to obtain high-grade nickel concentrate powder.
[0008] The present invention provides a method for preparing high-purity magnesium sulfate and enriching nickel (II) ions from nickel-containing serpentine, comprising the following steps:
[0009] S1. Take the original nickel-containing serpentine ore and crush it. After crushing, calcine it for 0.5 - 2 h at 500 - 800 °C to obtain a powder.
[0010] S2. While stirring, add the powder obtained in S1 to distilled water to make a slurry, then add H2SO4 for acid hydrolysis. After washing the solid residue, an acid hydrolysis solution is obtained. After centrifugation, a magnesium-rich salt solution and acid hydrolysis silica are obtained.
[0011] S3. Add a magnesium compound to the magnesium-rich salt solution obtained in S2, adjust the pH value to 5 - 7, separate after aging, and wash the precipitate to obtain a nickel magnesium sulfate solution.
[0012] S4. Take the nickel magnesium sulfate solution obtained in S3 and evaporate it to dryness. Dry it at a temperature of 50 °C for 8 h, then dry it at a temperature of 80 °C for 6 h, and finally dry it at a temperature of 150 °C for 12 h. Then perform secondary calcination at 300 °C for 6 h to obtain anhydrous magnesium sulfate containing nickel sulfate. The anhydrous magnesium sulfate containing nickel sulfate is redissolved in distilled water and mixed with the nickel magnesium sulfate solution to obtain a mixed solution.
[0013] S5. Take the mixed solution obtained in S4, add an ethanol solution containing salicylic acid to it, and stir well to obtain a magnesium concentrate solution.
[0014] S6. While stirring, an alcohol-ketone organic solvent is added to the magnesium concentrate solution obtained in S5. After solid-liquid separation, a precipitate and residual liquid 1 are obtained. After the precipitate is washed and dried, magnesium sulfate hexahydrate is obtained.
[0015] S7. A carbonate solution is added to the residual liquid 1 obtained in S6. After solid-liquid separation, a magnesium ion-containing precipitate and residual liquid 2 are obtained. After drying, basic magnesium carbonate is obtained.
[0016] S8. Ethanol is added to the residual liquid obtained in S7. After solid-liquid separation, a precipitate and residual liquid 2 are obtained. The precipitate is washed and dried to obtain ammonium sulfate; the residual liquid is distilled to recover ethanol and distillation residue. This step is repeated and the obtained distillation residues are combined.
[0017] S9. The combined distillation residues are evaporated to dryness and calcined three times at a temperature of 850 °C for 2 h to obtain nickel concentrate powder.
[0018] According to the method for preparing high-purity magnesium sulfate and enriching nickel(II) ions from nickel-containing serpentine provided by the present invention, the instrument for crushing in S1 is a Raymond mill, and the mesh number after crushing is 200 - 400 meshes.
[0019] According to the method for preparing high-purity magnesium sulfate and enriching nickel(II) ions from nickel-containing serpentine provided by the present invention, the concentration of H2SO4 in S2 is 0.5 - 4 mol / L, the leaching temperature for acidolysis is 60 - 90 °C, the leaching time for acidolysis is 0.5 - 3 h, the solution for washing the solid residue is distilled water, the rotation speed for centrifugation is 1000 - 5000 r / min, and the centrifugation time is 3 - 20 min.
[0020] According to the method for preparing high-purity magnesium sulfate and enriching nickel(II) ions from nickel-containing serpentine provided by the present invention, the magnesium compound in S3 is magnesium oxide, magnesium carbonate, magnesium hydroxide or basic magnesium carbonate, the aging time is 0.5 - 4 h, and the solution for washing the precipitate is distilled water.
[0021] According to the method for preparing high-purity magnesium sulfate and enriching nickel(II) ions from nickel-containing serpentine provided by the present invention, in S5, the mass-volume ratio of salicylic acid to ethanol solution in the ethanol solution containing salicylic acid is 0.300 - 1.000 g:10 mL, the volume ratio of the mixed solution to the ethanol solution containing salicylic acid is 200 mL:10 mL, and the stirring time is 0.5 h.
[0022] According to the method for preparing high-purity magnesium sulfate and enriching nickel (II) ions from nickel-containing serpentine provided by the present invention, the alcohol-ketone organic solvent in S6 is methanol, ethanol or acetone, the volume ratio of the magnesium concentrate solution to the alcohol-ketone organic solvent is 1:0.5-5, and the solution used for the washing is a mixed solution of ethanol and water with a volume ratio of 1:1.
[0023] According to the method for preparing high-purity magnesium sulfate and enriching nickel (II) ions from nickel-containing serpentine provided by the present invention, the carbonate in S7 is ammonium carbonate, the concentration of the carbonate solution is 1.0 mol / L, and the dosage of the carbonate solution is 47.8-49.2 mL.
[0024] According to the method for preparing high-purity magnesium sulfate and enriching nickel (II) ions from nickel-containing serpentine provided by the present invention, the solution used for the washing in S8 is ethanol, and the temperature for distillation and recovery is 70-80 °C.
[0025] According to the method for preparing high-purity magnesium sulfate and enriching nickel (II) ions from nickel-containing serpentine provided by the present invention, the evaporation-to-dryness temperature in S9 is 120 °C.
[0026] The present invention has the following advantages compared with the prior art:
[0027] The present invention provides a method for preparing high-purity magnesium sulfate and enriching nickel (II) ions from nickel-containing serpentine. By using the method of complexing complex with nickel and cobalt ions, the efficient separation of nickel and cobalt ions from magnesium salts is realized. This method has the advantages of simple process, convenient operation, high yield, green environmental protection, and no three-waste discharge. The magnesium sulfate prepared by the present invention has a high purity, up to 99.9%, the nickel ion content is less than 0.1 μg / g, the nickel ion enrichment solution can be converted into high-grade nickel concentrate powder, and the utilization rate of magnesium and nickel resources is high. Description of the Drawings
[0028] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to these drawings without creative efforts.
[0029] Figure 1 It is the process flow chart for preparing high-purity magnesium sulfate and enriching nickel (II) ions in Example 2;
[0030] Figure 2 It is the phase identification diagram of acid-leached ore in Example 2;
[0031] Figure 3 It is the phase analysis of magnesium sulfate hexahydrate in Example 2. Detailed Embodiments
[0032] In the following examples, the high-magnesium and low-nickel salt solution is from the acidolysis solution of serpentine. The nickel-containing serpentine comes from Hanzhong, Shaanxi. Its phase analysis and XRF test results are as follows Figure 1 and shown in Table 1;
[0033] Table 1 Analysis of the elemental composition of nickel-containing serpentine rock in Hanzhong, Shaanxi
[0034]
[0035] The results of the whole-rock analysis of serpentine are shown in Table 2 below:
[0036] Table 2 Phase analysis of nickel-containing serpentine rock in Hanzhong, Shaanxi
[0037]
[0038]
[0039] Example 1
[0040] This example provides a method for preparing high-purity magnesium sulfate and enriching nickel(II) ions from nickel-containing serpentine. The specific steps are as follows:
[0041] S1. Weigh 300.920 g of anhydrous magnesium sulfate and 2.872 g of nickel sulfate heptahydrate respectively, dissolve them in distilled water, and prepare a 1000 mL high-magnesium and low-nickel salt solution. The concentrations of magnesium ions and nickel ions are 60 g / L and 600 mg / L respectively;
[0042] S2. Take 200 mL of the high-magnesium and low-nickel salt solution obtained in S1 and evaporate it to dryness. Dry it in stages, that is, dry it at 50 °C for 8 h, then dry it at 80 °C for 6 h, then dry it at 150 °C for 12 h, and finally calcine it at 300 °C for 6 h to obtain 60.693 g of anhydrous magnesium sulfate;
[0043] S3. Take 200 mL of the high-magnesium and low-nickel salt solution obtained in S1, add 10 mL of an ethanol solution containing 0.340 g of salicylic acid, and stir for 0.5 h to obtain a mixed solution for standby;
[0044] S4. Under mechanical stirring, slowly add 200 mL of ethanol to the mixed solution obtained in S3. A large amount of white solid rapidly precipitates during the addition. After the addition, perform solid-liquid separation. The obtained white solid is washed with a mixed solvent of ethanol and water (V:V = 1:1), and dried naturally for 12 h to obtain magnesium sulfate hexahydrate, weighing 98.081 g, and store it sealed;
[0045] The separated liquid is distilled at a temperature of 70-80 °C to obtain ethanol and distillation residue, and the ethanol can be recycled for reuse;
[0046] S5. Add 72.8 mL of ammonium carbonate solution with a concentration of 1.0 mol / L to the distillation residue obtained in S4 to precipitate the remaining magnesium ions. After solid-liquid separation, a preliminary precipitate product and a residual liquid are obtained. The preliminary precipitate product is dried to obtain 5.763 g of magnesium carbonate.
[0047] S6. Slowly add 200 mL of ethanol to the residual liquid obtained in S5. During the addition process, a large amount of white solid rapidly precipitates. After the addition, solid-liquid separation is carried out. The obtained white solid is washed with a small amount of ethanol and naturally dried, weighing 56.236 g. The liquid obtained by solid-liquid separation is distilled at 75 °C to recover ethanol and a distillation residue. The ethanol can be recycled.
[0048] S7. Combine the distillation residues obtained multiple times in S6, evaporate to dryness and calcine to obtain high-grade nickel concentrate powder. The tail gas from the calcination is collected and further converted into by-product ammonium (sub) sulfate.
[0049] Table 3 Determination of nickel content in magnesium sulfate hexahydrate obtained in different steps of Example 1
[0050] Example Serial Number / Step Ni (μg / g) 1 / S2 1871 1 / S4 0.02
[0051] Take 1.002 g of anhydrous magnesium sulfate obtained in step S2 of Example 1 and 1.000 g of magnesium sulfate hexahydrate obtained in step S4, dissolve them separately in 100 mL of distilled water, and prepare a nickel standard solution. Then, use a graphite furnace atomic absorption spectrometer to measure the nickel content according to the standard curve.
[0052] Example 2
[0053] This example provides a method for preparing high-purity magnesium sulfate and enriching nickel (II) ions from nickel-containing serpentine, and the specific steps are as follows:
[0054] S1. Take the nickel-containing serpentine raw ore, crush it using a Raymond mill, and the crushed mesh size is 200 mesh. Take 400 g of the crushed raw ore powder and calcine it at 500 °C for 0.5 h to obtain 352 g of powder.
[0055] S2. While stirring, add all the powder obtained in S1 into distilled water to make a slurry. The liquid (V / L) to solid (m / kg) ratio (L:S is 3 - 10), then add inorganic acid H2SO4 for acid leaching for 0.5 h. The acid leaching temperature is 75 °C, and the concentration of the inorganic acid is 3 mol / L. After washing the solid residue with a small amount of distilled water, an acid leaching solution is obtained. After centrifuging at a speed of 3500 r / min for 10 min, a magnesium-rich salt solution and acid-leached silica are obtained.
[0056] S3. Add magnesium oxide to the magnesium-rich salt solution obtained in S2, and later add an appropriate amount of hydrogen peroxide or introduce air to adjust the pH value to 5 - 7. After aging for 1 h, separate to obtain an orange-red precipitate. Wash the precipitate with distilled water to obtain a low-nickel magnesium sulfate solution;
[0057] S4. Take 200 mL of the low-nickel magnesium sulfate solution obtained in S3 and evaporate it to dryness. Dry it in stages, that is, dry at 50 °C for 8 h, then dry at 80 °C for 6 h, then dry at 150 °C for 12 h, and finally calcine at 300 °C for 6 h to obtain 43.862 g of anhydrous magnesium sulfate (containing trace amounts of nickel sulfate). This anhydrous magnesium sulfate is redissolved in 200 mL of distilled water and combined with the low-nickel magnesium sulfate solution to obtain a mixed solution;
[0058] S5. Take 200 mL of the mixed solution obtained in S4, add 10 mL of an ethanol solution containing 0.301 g of salicylic acid to it, and stir well for 0.5 h to obtain a high-magnesium concentrate solution;
[0059] S6. While stirring, add 200 mL of ethanol to the high-magnesium concentrate solution obtained in S5. During the addition process, a large amount of white solid rapidly precipitates. After adding, perform solid-liquid separation to obtain a white solid precipitate and distillation residue. The obtained white solid precipitate is washed with a mixed solvent of ethanol and water (V:V = 1:1), and after natural drying, 70.646 g of magnesium sulfate hexahydrate with a purity greater than 99.9% is obtained, and its phase analysis is as Figure 3 shown;
[0060] S7. Add 49.2 mL of a 1.0 mol / L ammonium carbonate solution to the distillation residue obtained in S6. Perform solid-liquid separation to obtain a magnesium ion-containing precipitate and a residue. After drying, 4.493 g of basic magnesium carbonate is obtained.
[0061] S8. Slowly add 200 mL of ethanol to the residue obtained in S7. During the addition process, a large amount of white solid rapidly precipitates. After adding, perform solid-liquid separation to obtain a white solid and a residue. The obtained white solid is washed with a small amount of ethanol and naturally dried to obtain 40.526 g of ammonium sulfate; the liquid obtained by solid-liquid separation is distilled and recovered at a temperature of 70 - 80 °C to obtain ethanol and a distillation residue. The ethanol can be recycled and reused. Repeat the above steps to combine the obtained distillation residues;
[0062] S9. Evaporate the distillation residue obtained in S8 to dryness and calcine it to obtain 2.065 g of nickel concentrate powder, in which NiO accounts for 57.01%, MnO accounts for 15.64%, and CoO accounts for 4.72%. The tail gas from the calcination is collected and further converted into a by-product (sub) ammonium sulfate.
[0063] The contents of nickel, manganese, and cobalt in the high-purity magnesium sulfate hexahydrate prepared in Example 2 are shown in Table 2 below:
[0064] Determination of Nickel, Manganese and Cobalt Contents in Magnesium Sulfate Hexahydrate Obtained in Example 2
[0065] Example Serial Number Ni (μg / g) Mn (μg / g) Co (μg / g) 2 0.01 0.02 0.01
[0066] Take 1.000 g of magnesium sulfate hexahydrate obtained in Step 6 of Example 2 and dissolve it in 100 mL of distilled water to measure the above data;
[0067] According to the above data, the recovery rate of magnesium element is 98.1%, the recovery rate of nickel element is 96.51%, and the recovery rates of manganese and cobalt are 94.22% and 97.27% respectively.
[0068] Example 3
[0069] This example provides a method for preparing high-purity magnesium sulfate and enriching nickel(II) ions from nickel-containing serpentine, and the specific steps are as follows:
[0070] S1. Take the nickel-containing serpentine raw ore, crush it with a Raymond mill, and the fineness after crushing is 400 mesh. Take 400 g of the crushed raw ore powder and calcine it at 800 °C for 2 h to obtain 348 g of powder;
[0071] S2. While stirring, add all the powder obtained in S1 into distilled water to make a slurry, with the liquid (V / L) to solid (m / kg) ratio (L:S) of 3 - 10, and then add inorganic acid H2SO4 for acid leaching for 3 h. The leaching temperature for acidolysis is 90 °C, and the concentration of the inorganic acid is 4 mol / L. Wash the solid residue with a small amount of distilled water to obtain the acidolysis solution, and centrifuge it at a speed of 5000 r / min for 3 min to obtain a magnesium-rich salt solution and acidolysis silica white;
[0072] S3. Add magnesium carbonate to the magnesium-rich salt solution obtained in S2, and later add an appropriate amount of hydrogen peroxide or blow air to adjust the pH value to 5 - 7. After aging for 4 h, separate to obtain an orange-red precipitate. Wash the precipitate with distilled water to obtain a low-nickel magnesium sulfate solution;
[0073] S4. Take 200 mL of the low-nickel magnesium sulfate solution obtained in S3 and evaporate it to dryness. Dry it in stages at 50 °C for 8 h, then at 80 °C for 6 h, then at 150 °C for 12 h, and finally calcine it at 300 °C for 6 h to obtain 43.126 g of anhydrous magnesium sulfate (containing trace nickel sulfate). Dissolve the anhydrous magnesium sulfate in 200 mL of distilled water and combine it with the low-nickel magnesium sulfate solution to obtain a mixed solution;
[0074] S5. Take 200 mL of the mixed solution obtained in S4, add 10 mL of an ethanol solution containing 1.000 g of salicylic acid to it, and stir well for 0.5 h to obtain a high-magnesium concentrate solution;
[0075] S6. While stirring, add 200 mL of methanol to the high-magnesium concentrate solution obtained in S5. During the addition process, a large amount of white solid rapidly precipitates. After the addition, perform solid-liquid separation to obtain a white solid precipitate and distillation residue. The obtained white solid precipitate is washed with a mixed solvent of ethanol and water (V:V = 1:1), and after natural drying, 69.867 g of magnesium sulfate hexahydrate with a purity greater than 99.9% is obtained;
[0076] S7. Add the distillation residue obtained in S6 to 48.6 mL of ammonium carbonate solution with a concentration of 1.0 mol / L. Perform solid-liquid separation to obtain a magnesium ion-containing precipitate and residue. After drying, 4.127 g of basic magnesium carbonate is obtained.
[0077] S8. Slowly add 200 mL of ethanol to the residue obtained in S7. During the addition process, a large amount of white solid rapidly precipitates. After the addition, perform solid-liquid separation to obtain a white solid and residue. The obtained white solid is washed with a small amount of ethanol and naturally dried to obtain 39.983 g of ammonium sulfate; the liquid obtained by solid-liquid separation is distilled and recovered at a temperature of 80 °C to obtain ethanol and distillation residue. Ethanol can be recycled. Repeat the above steps to combine the obtained distillation residues;
[0078] S9. Evaporate the distillation residue obtained in S8 to dryness and calcine it to obtain 2.122 g of nickel concentrate powder, in which NiO accounts for 56.15%, MnO accounts for 15.06%, and CoO accounts for 4.13%. The tail gas from the calcination is collected and further converted into a by-product, ammonium (sub) sulfate.
[0079] Example 4
[0080] This example provides a method for preparing high-purity magnesium sulfate and enriching nickel (II) ions from nickel-containing serpentine, and the specific steps are as follows:
[0081] S1. Take the nickel-containing serpentine raw ore and crush it using a Raymond mill. The fineness after crushing is 300 mesh. Take 400 g of the crushed raw ore powder and calcine it at 700 °C for 1 h to obtain 343 g of powder;
[0082] S2. While stirring, add all the powder obtained in S1 to distilled water to make a slurry. The liquid (V / L) to solid (m / kg) ratio (L:S is 3 - 10), and then add inorganic acid H2SO4 for acid leaching for 3 h. The leaching temperature for acidolysis is 60 °C, and the concentration of the inorganic acid is 0.5 mol / L. Wash the solid residue with a small amount of distilled water to obtain an acid leaching solution. After centrifuging at a speed of 1000 r / min for 20 min, a magnesium-rich salt solution and acid-leached silica are obtained;
[0083] S3. Add magnesium hydroxide to the magnesium-rich salt solution obtained in S2, and later add an appropriate amount of hydrogen peroxide or blow in air to adjust the pH value to 5 - 7. After aging for 3 h, separate to obtain an orange-red precipitate. Wash the precipitate with distilled water to obtain a low-nickel magnesium sulfate solution;
[0084] S4. Take 200 mL of the low-nickel magnesium sulfate solution obtained in S3 and evaporate it to dryness. Dry it in stages: dry at a temperature of 50 °C for 8 h, then dry at a temperature of 80 °C for 6 h, then dry at a temperature of 150 °C for 12 h, and finally calcine at 300 °C for 6 h to obtain 42.056 g of anhydrous magnesium sulfate (containing trace amounts of nickel sulfate). This anhydrous magnesium sulfate is redissolved in 200 mL of distilled water and combined with the low-nickel magnesium sulfate solution to obtain a mixed solution;
[0085] S5. Take 200 mL of the mixed solution obtained in S4, add 10 mL of an ethanol solution containing 0.600 g of salicylic acid to it, and stir well for 0.5 h to obtain a high-magnesium concentrate solution;
[0086] S6. While stirring, add 200 mL of ethanol to the high-magnesium concentrate solution obtained in S5. During the addition process, a large amount of white solid rapidly precipitates. After adding, perform solid-liquid separation to obtain a white solid precipitate and distillation residue. Wash the obtained white solid precipitate with a mixed solvent of ethanol and water (V:V = 1:1), and after natural drying, obtain 68.458 g of magnesium sulfate hexahydrate with a purity greater than 99.9%;
[0087] S7. Add the distillation residue obtained in S6 to 47.8 mL of an ammonium carbonate solution with a concentration of 1.0 mol / L, perform solid-liquid separation to obtain a precipitate containing magnesium ions and a residue. After drying, obtain 4.068 g of basic magnesium carbonate.
[0088] S8. Slowly add 200 mL of ethanol to the residue obtained in S7. During the addition process, a large amount of white solid rapidly precipitates. After adding, perform solid-liquid separation to obtain a white solid and a residue. Wash the obtained white solid with a small amount of ethanol and dry it naturally to obtain 39.039 g of ammonium sulfate; perform solid-liquid separation on the liquid obtained, distill and recover ethanol and distillation residue at a temperature of 70 - 80 °C. The ethanol can be recycled for reuse, and repeat the above steps to combine the obtained distillation residues;
[0089] S9. Evaporate the distillation residue obtained in S8 to dryness and calcine it to obtain 1.986 g of nickel concentrate powder, in which NiO accounts for 57.56%, MnO accounts for 14.36%, and CoO accounts for 4.25%. Collect the tail gas from the calcination and further convert it into a by-product (ammonium) sulfite.
[0090] Example 5
[0091] This embodiment provides a method for preparing high-purity magnesium sulfate and enriching nickel(II) ions from nickel-containing serpentine, and the specific steps are as follows:
[0092] S1. Take the original nickel-containing serpentine ore, crush it using a Raymond mill, and the mesh number after crushing is 300. Take 400 g of the crushed original ore powder and calcine it at 600 °C for 1.5 h to obtain 346 g of powder;
[0093] S2. While stirring, add all the powder obtained in S1 into distilled water to make a slurry, with the liquid (V / L) to solid (m / kg) ratio (L:S) being 3 - 10, then add inorganic acid H2SO4 for acidolysis leaching for 2 h. The leaching temperature for acidolysis is 75 °C, and the concentration of the inorganic acid is 2.5 mol / L. Wash the solid residue with a small amount of distilled water to obtain the acidolysis solution. After centrifuging at a speed of 4000 r / min for 8 min, a magnesium-rich salt solution and acidolysis silica white are obtained;
[0094] S3. Add basic magnesium carbonate to the magnesium-rich salt solution obtained in S2, and later add an appropriate amount of hydrogen peroxide or blow air to adjust the pH value to 5 - 7. After aging for 2 h, separate to obtain an orange-red precipitate. Wash the precipitate with distilled water to obtain a low-nickel magnesium sulfate solution;
[0095] S4. Take 200 mL of the low-nickel magnesium sulfate solution obtained in S3 and evaporate it to dryness. Dry it in stages, drying at 50 °C for 8 h, then at 80 °C for 6 h, then at 150 °C for 12 h, and finally calcine it at 300 °C for 6 h to obtain 42.327 g of anhydrous magnesium sulfate (containing trace nickel sulfate). This anhydrous magnesium sulfate is redissolved in 200 mL of distilled water and combined with the low-nickel magnesium sulfate solution to obtain a mixed solution;
[0096] S5. Take 200 mL of the mixed solution obtained in S4, add 10 mL of an ethanol solution containing 0.750 g of salicylic acid to it, and stir well for 0.5 h to obtain a high-magnesium concentrate solution;
[0097] S6. While stirring, add 200 mL of acetone to the high-magnesium concentrate solution obtained in S5. During the addition process, a large amount of white solid rapidly precipitates. After adding, perform solid-liquid separation to obtain a white solid precipitate and distillation residue. The obtained white solid precipitate is washed with a mixed solvent of ethanol and water (V:V = 1:1), and after natural drying, 68.621 g of magnesium sulfate hexahydrate with a purity greater than 99.9% is obtained;
[0098] S7. Add 47.9 mL of a 1.0 mol / L ammonium carbonate solution to the distillation residue obtained in S6, perform solid-liquid separation to obtain a magnesium ion-containing precipitate and a residue, and after drying, 4.326 g of basic magnesium carbonate is obtained.
[0099] S8. Slowly add 200 mL of ethanol to the residual liquid obtained in S7. During the addition process, a large amount of white solid rapidly precipitates. After the addition, perform solid-liquid separation to obtain a white solid and a residual liquid. Wash the obtained white solid with a small amount of ethanol and dry it naturally to obtain 39.011 g of ammonium sulfate; distill and recover the liquid obtained by solid-liquid separation at a temperature of 70-80 °C to obtain ethanol and a distillation residual liquid. The ethanol can be recycled. Repeat the above steps to combine the obtained distillation residual liquids.
[0100] S9. Evaporate the distillation residual liquid obtained in S8 to dryness and calcine it to obtain 2.230 g of nickel concentrate powder, in which NiO accounts for 59.24%, MnO accounts for 16.42%, and CoO accounts for 3.22%. Collect the tail gas generated during calcination and further convert it into a by-product, (sub) ammonium sulfate.
[0101] The above are only the preferred embodiments of the present invention and do not impose any limitations on the present invention. Any simple modifications, changes, and equivalent variations made to the above embodiments based on the technical essence of the invention still fall within the protection scope of the technical solution of the present invention.
Claims
1. A method for preparing high - purity magnesium sulfate and enriching nickel (II) ions from nickel - containing serpentine, characterized in that, The following steps are involved: S1, taking nickel-containing serpentine ore and crushing it, and then calcining it for the first time at 500-800° C. for 0.5-2 h to obtain powder; S2, adding the powder obtained in S1 into distilled water for slurrying while stirring, then adding H2SO4 for acid hydrolysis, washing the solid residue to obtain an acid hydrolysis solution, and centrifuging to obtain a magnesium salt-rich solution and acid-hydrolyzed white carbon black; S3, adding a magnesium compound to the magnesium-rich salt solution obtained in S2, adjusting the pH value to 5-7, separating after aging, washing the precipitate, and obtaining a nickel-magnesium sulfate solution; S4, evaporating the nickel-magnesium sulfate solution obtained in S3, drying at 50° C. for 8 h, then drying at 80° C. for 6 h, and finally drying at 150° C. for 12 h, and then performing secondary calcination at 300° C. for 6 h to obtain anhydrous magnesium sulfate containing nickel sulfate, and the anhydrous magnesium sulfate containing nickel sulfate is redissolved in distilled water and mixed with the nickel-magnesium sulfate solution to obtain a mixed solution; S5, taking the mixed solution obtained in S4, adding the ethanol solution containing salicylic acid thereto, and stirring thoroughly to obtain a magnesium solution; S6, adding an alcohol-ketone organic solvent to the magnesium solution obtained in S5 while stirring, and obtaining a precipitate and a residual liquid 1 through solid-liquid separation, and the precipitate is washed and dried to obtain magnesium sulfate hexahydrate; S7, adding a carbonate solution to the residual liquid 1 obtained in S6, solid-liquid separation to obtain a precipitate containing magnesium ions and a residual liquid 2, and drying to obtain basic magnesium carbonate; S8, adding ethanol to the residual liquid obtained in S7, performing solid-liquid separation to obtain a precipitate and residual liquid 2, washing and drying the precipitate to obtain ammonium sulfate; distilling and recovering the residual liquid to obtain ethanol and distillation residual liquid, repeating this step and combining the obtained distillation residual liquids; S9, evaporating the combined distillation residue to dryness and calcining it three times at 850° C. for 2 h to obtain nickel concentrate.
2. The method for preparing high-purity magnesium sulfate and enriching nickel (II) ions from nickel-containing serpentine according to claim 1, characterized in that The crushing instrument in S1 is a Raymond mill, and the mesh size after crushing is 200-400 meshes.
3. The method for preparing high-purity magnesium sulfate and enriching nickel (II) ions from nickel-containing serpentine according to claim 1, wherein The concentration of H2SO4 in S2 is 0.5-4 mol / L, the leaching temperature of the acid hydrolysis is 60-90°C, the leaching time of the acid hydrolysis is 0.5-3h, the solution for washing the solid residue is distilled water, the centrifugal speed is 1000-5000r / min, and the centrifugal time is 3-20min.
4. The method for preparing high-purity magnesium sulfate and enriching nickel (II) ions from nickel-containing serpentine according to claim 1, characterized in that, The magnesium compound in S3 is magnesium oxide, magnesium carbonate, magnesium hydroxide or basic magnesium carbonate, the aging time is 0.5 to 4 hours, and the solution for washing the precipitate is distilled water.
5. The method for preparing high-purity magnesium sulfate and enriching nickel (II) ions from nickel-containing serpentine according to claim 1, wherein S5: The mass volume ratio of salicylic acid and ethanol solution in the ethanol solution containing salicylic acid is 0.300-1.000 g:10 mL, the volume ratio of the mixed solution and the ethanol solution containing salicylic acid is 200 mL:10 mL, and the stirring time is 0.5 h.
6. The method for preparing high-purity magnesium sulfate and enriching nickel (II) ions from nickel-containing serpentine according to claim 1, wherein The alcohol-ketone organic solvent in S6 is methanol, ethanol or acetone, the volume ratio of the magnesium solution to the alcohol-ketone organic solvent is 1:0.5-5, and the solution used for the washing is a mixed solution of ethanol and water in a volume ratio of 1:
1.
7. The method for preparing high-purity magnesium sulfate and enriching nickel (II) ions from nickel-containing serpentine according to claim 1, characterized in that The carbonate described in S7 is ammonium carbonate, the concentration of the carbonate solution is 1.0 mol / L, and the dosage of the carbonate solution is 47.8 - 49.2 mL.
8. The method for preparing high-purity magnesium sulfate and enriching nickel (II) ions from nickel-containing serpentine according to claim 1, characterized in that, The solution used for the washing in S8 is ethanol, and the temperature for distillation and recovery is 70 - 80 °C.
9. The method for preparing high-purity magnesium sulfate and enriching nickel (II) ions from nickel-containing serpentine according to claim 1, wherein The temperature for evaporation to dryness in S9 is 120 °C.