Method for preparing lithium carbonate and recovering aluminum and phosphorus from amblygonite

Abstract

The invention relates to the technical field of extraction of lithium from ore, and discloses a method for preparing lithium carbonate and recovering aluminum and phosphorus from amblygonite, which comprises the following steps: levigating amblygonite ore to obtain amblygonite ore powder; roasting the amblygonite ore powder and sulfuric acid, and absorbing the generated flue gas by using a sodium hydroxide solution; the roasted material is leached with water, and a lithium-containing solution and aluminum-phosphorus-containing leaching residues are obtained; the lithium-containing filtrate is subjected to impurity removal, sodium hydroxide is added into the lithium-containing filtrate, the pH is adjusted, impurities are removed, and a daponite purified solution is obtained; concentrating and evaporating the amblygonite purified liquid, and slowly adding the lithium-rich solution into the sodium carbonate solution to carry out lithium precipitation reaction, so as to prepare battery-grade lithium carbonate; mixing the leaching residues with a sodium hydroxide solution, and carrying out suction filtration to obtain an aluminum-phosphorus filtrate; and mixing the aluminum-phosphorus filtrate with calcium chloride, and stirring to obtain an aluminum-containing filtrate and calcium phosphate filter residues. Subsequent operations such as leaching of lithium carbonate from the amblygonite leachate are not interfered, the loss of lithium oxide in the leachate is small, and comprehensive utilization of the amblygonite is realized.

Description

Technical Field

[0001] The invention relates to the field of lithium extraction from ores, and in particular to a method for preparing lithium carbonate from pyroxenite and recovering aluminum and phosphorus. Background Art

[0002] Lithium is a light metal element that exists in the form of minerals in nature, including spodumene, potassium spodumene, and sandstone spodumene. Lithium resources are widely distributed around the world, and major producing countries include Australia, Chile, Argentina, China, and Bolivia. Australia is one of the world's largest producers of lithium resources, and its Western Australia state has the world's largest lithium mine, such as the Greenbushes mine. Chile is mainly based on salt lake resources, among which Salar de Atacama is one of the world's largest lithium salt lakes, rich in lithium resources. Argentina and Bolivia also have rich lithium salt lake resources.

[0003] With the rapid development of electric vehicles and renewable energy, the global demand for lithium resources is growing rapidly. As the core component of electric vehicles and energy storage systems, lithium-ion batteries have become a key pillar of modern science and technology. This trend has spawned a global boom in the development and mining of lithium resources. However, we should also pay attention to the challenges faced by lithium resource mining, including environmental pollution, water resource management, and social responsibility.

[0004] Therefore, it is particularly important to explore the rational development and utilization of lithium resources to meet the global demand for clean energy under the premise of ensuring environmental sustainability and social responsibility. At the same time, we should also pay attention to the environmental and social issues involved in the development of lithium resources, increase supervision, ensure that resource development is coordinated with environmental protection and social responsibility, and achieve sustainable social development.

[0005] Apatite is a lithium ore and a type of phosphate mineral. Its chemical formula is LiAl(PO4)(OH)(F), and its chemical composition includes elements such as lithium, aluminum, phosphorus, fluorine and oxygen. Its theoretical mass fraction of Li2O is 10.1%, and the typical value of Li2O is 8.0%~9.0%. It is one of the minerals with a high lithium content. Apatite usually appears in white to light gray color, and sometimes in light pink. Apatite often appears with other lithium ores, such as spodumene and potassium spodumene. Although apatite accounts for a small proportion of lithium resources, with the increase in demand for lithium, people's attention to its mining and utilization is also increasing. As part of lithium resources, apatite plays a certain role in meeting the demand for clean energy in electric vehicles, energy storage systems and other fields.

[0006] In document ZL202111255770U, a method for extracting lithium from phosphate lithium aluminum stone raw material by high-temperature roasting of sulfate is disclosed, including crushing, roasting, grinding, leaching, purification and other process sections. By controlling the ingredient composition, process chain optimization and roasting process nodes, the production cost of lithium extraction can be reduced and the recovery rate of phosphate lithium aluminum stone can be improved. In this application, a variety of metal salts are used, other ions are introduced, and it is not easy to break during roasting, and more water is used, which wastes resources.

[0007] Therefore, a new technical solution is needed to solve the above technical problems. Summary of the invention

[0008] In order to solve the above problems, the present invention discloses a method for preparing lithium carbonate and recovering aluminum and phosphorus from pyroxenite. While realizing the recovery of aluminum and phosphorus, it will not interfere with subsequent operations such as leaching lithium carbonate from pyroxenite leachate, and the loss of lithium oxide in the leachate is small, thereby truly realizing the comprehensive utilization of pyroxenite.

[0009] The technical solution of the present invention is: a method for preparing lithium carbonate and recovering aluminum and phosphorus from pyroxenite, comprising the following steps: Step 1: Grind the pyroxene ore with a crusher to obtain pyroxene ore powder; Step 2: mixing pyroxenite ore powder, sodium sulfate and concentrated sulfuric acid in a ratio of 5:1-3:1-3 and then roasting to obtain a roasting material, and absorbing the flue gas generated during the roasting process with a sodium hydroxide solution; Step 3: Leaching the roasted material with water to obtain a lithium-containing solution and aluminum-phosphorus-containing leaching residue; Step 4: removing impurities from the lithium-containing filtrate by adding sodium hydroxide to the lithium-containing filtrate in step 3, adjusting the pH of the solution, and removing impurities from the solution to obtain a purified phosphate lithium aluminum stone solution; Step 5: Concentrate and evaporate the purified phosphate lithium aluminum oxide solution, slowly add the lithium-rich solution into the sodium carbonate solution to perform lithium precipitation reaction, and prepare battery-grade lithium carbonate; Step 6: mixing the leached residue with a sodium hydroxide solution, reacting at room temperature, and filtering to obtain an aluminum-phosphorus filtrate; Step 7: Mix the aluminum-phosphorus filtrate and calcium chloride and stir them thoroughly to obtain an aluminum-containing filtrate and a calcium phosphate residue.

[0010] Preferably, the pyroxenite ore in step 1 is ground to 100-300 mesh.

[0011] Preferably, in step 2, the calcination temperature is 600-800° C., and the concentration of the sodium hydroxide solution used is 0.1-2 mol / L.

[0012] Preferably, the solid-liquid ratio in step 3 is 1:1-3, the temperature is 50-80°C, and the lithium leaching rate of this method is calculated to be up to 98.4%.

[0013] Preferably, the impurities in step 4 are Al, Mg, Fe, PO4 3- , then remove the impurity Ca by adding Na2CO3 and adjust the pH of the solution to 9-12.

[0014] Preferably, the phosphate-lithium aluminum oxide purified solution in step 5 is concentrated and evaporated to a lithium-rich solution with a Li2O concentration of 30-50 g / L, and the ambient temperature of the lithium precipitation reaction is 70-95°C.

[0015] Preferably, the concentration of sodium hydroxide in step 6 is 5%-15%.

[0016] By adopting the above technical solution, The benefits of the present invention are as follows: 1. The method of roasting phosphate lithium aluminum stone with sulfuric acid and sulfate can realize the conversion of lithium in phosphate lithium aluminum stone into soluble lithium salt, reduce the amount of sulfuric acid used, and the lithium extraction rate can reach more than 98.4%. 2. The leaching solid-liquid ratio of the present invention is 1-3:1, the leaching temperature is 60-90°C, and the leaching time is 0.5-1 h, which avoids the influence of too high or too low temperature and inappropriate solid-liquid ratio on the leaching effect of lithium, and increases water consumption and energy consumption.

[0017] 3. The method for recovering aluminum and phosphorus from lithium slag adopted by the present invention separates aluminum and phosphorus, has a simple operation process, can realize resource utilization of waste slag, reduce waste of resources, protect the environment, and improve economic benefits.

[0018] 4. The present invention realizes the recovery of aluminum and phosphorus without interfering with subsequent operations such as leaching of lithium carbonate from the phosphate lithium aluminum ore leachate, and the loss of lithium oxide in the leachate is small, thus truly realizing the comprehensive utilization of phosphate lithium aluminum ore, reducing the production cost of lithium carbonate and reducing the energy consumption in the concentration process. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of a flow chart of the present invention. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention. Example

[0021] 100 g of phosphate lithium aluminum stone powder, 40 g of sodium sulfate and 40 g of concentrated sulfuric acid were mixed evenly, and the temperature was raised to 800 ° C and calcined for 1 hour to obtain 155 g of calcined product. The calcined product was leached with deionized water, and the solid-liquid ratio of the calcined product and deionized water was 1:2. The leaching was carried out at 70 ° C for 30 min, and 310 mL of lithium-containing solution was obtained by filtration. The concentration of the solution was 19.08 g / L. The lithium-containing solution was evaporated and concentrated to 35 g / L. Sodium hydroxide was added at 80 ° C to adjust the pH of the solution to 12 to precipitate Al and Mg in turn. The lithium-containing purified solution was filtered to obtain a lithium-containing purified solution. The lithium-containing purified solution was slowly added to 160 mL of sodium carbonate solution (250 g / L) at 90 ° C for lithium precipitation to obtain lithium carbonate solid.

[0022] 100 g of phosphate lithium aluminum leaching residue was added to 400 mL of 15% sodium hydroxide solution, stirred at room temperature for 30 min, and filtered to obtain aluminum-phosphorus filtrate. Calcium chloride was added to the filtrate to obtain 395 mL of aluminum-containing filtrate and 38.36 g of calcium phosphate residue. The comprehensive extraction rates of aluminum and phosphorus in the phosphate lithium aluminum leaching residue were 92.3% and 95.8%, respectively. Example

[0023] 100 g of phosphate lithium aluminum stone powder, 40 g of sodium sulfate and 40 g of concentrated sulfuric acid were mixed evenly, and the temperature was raised to 800 ° C and calcined for 1 hour to obtain 155 g of calcined product. The calcined product was leached with deionized water, and the solid-liquid ratio of the calcined product and deionized water was 1:2. The leaching was carried out at 70 ° C for 30 min, and 310 mL of lithium-containing solution was obtained by filtration. The concentration of the solution was 19.08 g / L. The lithium-containing solution was evaporated and concentrated to 35 g / L. Sodium hydroxide was added at 80 ° C to adjust the pH of the solution to 12 to precipitate Al and Mg in turn. The lithium-containing purified solution was filtered to obtain a lithium-containing purified solution. The lithium-containing purified solution was slowly added to 160 mL of sodium carbonate solution (250 g / L) at 90 ° C for lithium precipitation to obtain lithium carbonate solid.

[0024] 100 g of the leached residue of ferroalloy was added to 635 mL of a sodium hydroxide solution with a mass fraction of 10%, stirred at room temperature for 30 min, and filtered to obtain an aluminum-phosphorus filtrate. Calcium chloride was added to the filtrate to obtain 631 mL of aluminum-containing filtrate and 36.6 g of calcium phosphate residue. The comprehensive extraction rates of aluminum and phosphorus in the leached residue of ferroalloy were 93.1% and 94.5%, respectively. Example

[0025] 100 g of phosphate lithium aluminum stone powder, 40 g of sodium sulfate and 40 g of concentrated sulfuric acid were mixed evenly, and the temperature was raised to 800 ° C and calcined for 1 hour to obtain 155 g of calcined product. The calcined product was leached with deionized water, and the solid-liquid ratio of the calcined product and deionized water was 1:2. The leaching was carried out at 70 ° C for 30 min, and 310 mL of lithium-containing solution was obtained by filtration. The concentration of the solution was 19.08 g / L. The lithium-containing solution was evaporated and concentrated to 35 g / L. Sodium hydroxide was added at 80 ° C to adjust the pH of the solution to 12 to precipitate Al and Mg in turn. The lithium-containing purified solution was filtered to obtain a lithium-containing purified solution. The lithium-containing purified solution was slowly added to 160 mL of sodium carbonate solution (250 g / L) at 90 ° C for lithium precipitation to obtain lithium carbonate solid.

[0026] 100 g of phosphate lithium aluminum leaching residue was added to 1341 mL of 5% sodium hydroxide solution, stirred at room temperature for 30 min, filtered to obtain aluminum-phosphorus filtrate, and calcium chloride was added to the filtrate to obtain 1337 mL of aluminum-containing filtrate and 35.2 g of calcium phosphate residue. The comprehensive extraction rates of aluminum and phosphorus in the phosphate lithium aluminum leaching residue were 90.4% and 93.7%, respectively.

[0027] Comparative Example 100 g of phosphate lithium aluminum leaching residue was added to 289 mL of 20% sodium hydroxide solution, stirred at room temperature for 30 min, filtered to obtain aluminum-phosphorus filtrate, and calcium chloride was added to the filtrate to obtain 282 mL of aluminum-containing filtrate and 38.74 g of calcium phosphate residue. The comprehensive extraction rates of aluminum and phosphorus in the phosphate lithium aluminum leaching residue were 91.6% and 94.1%, respectively.

[0028] In summary, the method for preparing battery-grade lithium carbonate from lithium aluminum phosphate and recycling aluminum and phosphorus in lithium slag reduces the amount of sulfuric acid used in the lithium aluminum phosphate ore acid mixture, making separation easier; while leaching lithium oxide, it does not contain other impurity ions, so that the amount of sodium hydroxide and carbonate consumed in the impurity removal process is greatly reduced, which is convenient for industrial production; finally, the leached slag containing aluminum and phosphorus is added with sodium hydroxide solution to dissolve aluminum and phosphorus in the solution, and then calcium chloride is added to precipitate the phosphorus in the solution in the form of calcium phosphate for recovery, while aluminum exists in the solution in the form of tetrahydroxyaluminate, thereby realizing the separation and recovery of aluminum and phosphorus.

[0029] It should be understood by those skilled in the art that the embodiments of the present invention described above and shown in the accompanying drawings are only examples and do not limit the present invention, and the purpose of the present invention has been fully and effectively achieved. The functional and structural principles of the present invention have been demonstrated and explained in the embodiments, and the embodiments of the present invention may be deformed or modified in any way without departing from the principles.

Claims

1. A method for preparing lithium carbonate from pyroxenite and recovering aluminum and phosphorus, It is characterized in that The following steps are involved: Step 1: Grind the pyroxene ore with a crusher to obtain pyroxene ore powder; Step 2: mixing pyroxenite ore powder, sodium sulfate and concentrated sulfuric acid in a ratio of 5:1-3:1-3 and then roasting to obtain a roasting material, and absorbing the flue gas generated during the roasting process with a sodium hydroxide solution; Step 3: Leaching the roasted material with water to obtain a lithium-containing solution and aluminum-phosphorus-containing leaching residue; Step 4: removing impurities from the lithium-containing filtrate by adding sodium hydroxide to the lithium-containing filtrate in step 3, adjusting the pH of the solution, and removing impurities from the solution to obtain a purified phosphate lithium aluminum stone solution; Step 5: Concentrate and evaporate the purified phosphate lithium aluminum oxide solution, slowly add the lithium-rich solution into the sodium carbonate solution to perform lithium precipitation reaction, and prepare battery-grade lithium carbonate; Step 6: mixing the leached residue with a sodium hydroxide solution, reacting at room temperature, and filtering to obtain an aluminum-phosphorus filtrate; Step 7: Mix the aluminum-phosphorus filtrate and calcium chloride and stir them thoroughly to obtain an aluminum-containing filtrate and a calcium phosphate filter residue.

2. The method for preparing lithium carbonate and recovering aluminum and phosphorus from pyroxenite according to claim 1, Features: The pyroxenite ore in step 1 is ground to a size of 100-300 mesh.

3. The method for preparing lithium carbonate and recovering aluminum and phosphorus from pyroxenite according to claim 1, Features: In step 2, the calcination temperature is 600-800° C., and the concentration of the sodium hydroxide solution used is 0.1-2 mol / L.

4. The method for preparing lithium carbonate and recovering aluminum and phosphorus from pyroxenite according to claim 1, Features: The solid-liquid ratio in step 3 is 1:1-3, the temperature is 50-80°C, and the lithium leaching rate of this method is calculated to be up to 98.4%.

5. The method for preparing lithium carbonate and recovering aluminum and phosphorus from pyroxenite according to claim 1, Features: The impurities in step 4 are Al, Mg, Fe, PO 4 3- , and then by adding Na 2 CO 3 Remove Ca and adjust the solution pH to 9-12.

6. The method for preparing lithium carbonate and recovering aluminum and phosphorus from pyroxenite according to claim 1, Features: The phosphate lithium aluminum ore purified solution in step 5 is concentrated and evaporated to Li 2 The lithium-rich solution has an O concentration of 30-50 g / L and the ambient temperature for lithium precipitation reaction is 70-95 °C.

7. The method for preparing lithium carbonate and recovering aluminum and phosphorus from pyroxenite according to claim 1, Features: The concentration of sodium hydroxide in step 6 is 5%-15%.

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