CN-121992220-A - Method for extracting lithium from lepidolite and concentrating equipment

CN121992220ACN 121992220 ACN121992220 ACN 121992220ACN-121992220-A

Abstract

The invention provides a method for extracting lithium from lepidolite and concentrating equipment, and relates to the field of battery material production. The method for extracting lithium from lepidolite and the concentration equipment comprise the following steps of S1, adding sulfuric acid into lepidolite, heating to 200-300 ℃ for roasting, destroying mineral crystal lattices through an acid leaching process, stirring, leaching and filtering to obtain silicon dioxide and mixed sulfate solution, and S2, cooling, crystallizing and filtering the mixed sulfate solution to obtain alum and solution containing Li + . According to the method for extracting lithium from lepidolite, provided by the invention, a small amount of lithium and aluminum contained in gypsum residues generated in the process of extracting lithium from lepidolite are recycled, the gypsum residues are subjected to advanced treatment, the high-value and green closed-loop of aluminum and lithium are realized by utilizing the amphoteric hydroxide characteristic and reagent circulation, the industrial solid waste disposal pressure is reduced, the environmental pollution risk is reduced, the maximum utilization of resources is realized, and the waste emission is reduced.

Inventors

YAO LI
WEI DONGDONG
XU HAIYUE
PAN RUI
LIAO XIN
PAN LONGHUI
LIAO QIANG
XIAO ZHEN

Assignees

宜丰九岭锂业有限公司

Dates

Publication Date: 20260508
Application Date: 20260115

Claims (10)

1. A method for extracting lithium from lepidolite, comprising the steps of: S1, adding sulfuric acid into lepidolite, heating to 200-300 ℃ for roasting, destroying mineral crystal lattices through an acid leaching process, and stirring, leaching and filtering to obtain silicon dioxide and mixed sulfate solution; S2, cooling, crystallizing and filtering the mixed sulfate solution to obtain alum and Li + -containing solution; S3, adding Ca (OH) 2 into the solution containing Li + , filtering after reaction to obtain gypsum residue and a new solution containing Li + , evaporating and concentrating the new solution containing Li + , adding carbonate, and precipitating after reaction to obtain lithium carbonate; S4, mixing alum with Ca (OH) 2 for reaction, filtering to obtain gypsum residues and K + 、Rb + 、Cs + -containing solution, evaporating and concentrating the solution, separating out potassium sulfate, and capturing Rb + 、Cs + by using molecularly imprinted resin to prepare rubidium salt and cesium salt; S5, mixing gypsum residues with water, then adding NaOH solution, stirring and reacting for 20-40 minutes at 120-150 ℃, and filtering to obtain gypsum and digestive juice containing NaAlO 2 、Li + and excessive NaOH; S6, adding Al (OH) 3 fine powder into the digestive juice to enable the KS value to reach 2.0, then slowly cooling the filtrate from 70 ℃ to 40 ℃, carrying out stirring reaction, filtering to obtain aluminum hydroxide and a solution containing Li + and NaOH, and concentrating the solution; S7, adding sodium phosphate dodecahydrate into the solution containing Li + , stirring at 50-70 ℃ to react, filtering, washing with water, and drying to obtain pure lithium phosphate and filtrate.
2. The method of claim 1, further comprising adding Ca (OH) 2 to the filtrate of S7, reacting, filtering to obtain NaOH-containing solution, and recycling to S5.
3. The method of extracting lithium from lepidolite according to claim 1, wherein the carbonate in S3 is sodium carbonate or potassium carbonate.
4. A concentrating apparatus for extracting lithium from lepidolite according to any one of claims 1 to 3, comprising a concentrating cartridge having a heating structure disposed therein; The exhaust barrel is communicated with the top end of the concentration barrel; The scraper structure is arranged in the exhaust barrel, and the output end of the scraper structure extends to the interior of the concentration barrel; the liquid storage cylinder is communicated with the liquid outlet end at the bottom of the concentration cylinder; The filtering structure is rotatably arranged in the liquid storage barrel; and the rotating device is used for driving the filtering structure to rotate.
5. The concentrating apparatus of claim 4 wherein the scraper structure comprises a drive means, a rotating tube and a plurality of scrapers, the top end of the rotating tube penetrates through and is rotatably mounted at the top end of the exhaust tube, the bottom end of the rotating tube extends to the interior of the concentrating tube, the plurality of scrapers are symmetrically mounted on the rotating tube, and gaps are left between the scrapers and the inner wall of the concentrating tube.
6. The concentrating apparatus of claim 5 wherein the filter structure comprises a mounting ring rotatably mounted inside the reservoir and a filter screen mounted inside the mounting ring; the rotating device comprises a mounting frame and a second motor, wherein the mounting frame is mounted on the liquid storage barrel, the second motor is mounted on the mounting frame, and the second motor penetrates through the liquid storage barrel and then is connected with the mounting ring.
7. The concentrating apparatus of claim 6 further comprising a flushing structure for flushing the non-filtration side of the screen.
8. The concentrating apparatus of claim 7 wherein the flushing structure comprises an L-shaped frame having one end mounted to the bottom of the mounting ring and the other end suspended below the filter screen, a mounting tube rotatably mounted to the L-shaped frame and aligned with the center of the filter screen, a spray tube horizontally connected to the top end of the mounting tube, and a fitting tube mounted to the other end of the mounting tube; The scraper structure further comprises a rotary connector, a liquid inlet pipe and two driving blocks, wherein the liquid inlet pipe is connected with the rotary pipe through the rotary connector, the bottom end of the rotary pipe extends to the inside of the liquid storage cylinder, the two driving blocks are installed at intervals at the bottom end of the rotary pipe, the bottom end of the rotary pipe is in a concave arc shape, and the bottom end of the assembly pipe is in a convex arc shape; When the rotating device drives the filtering structure to turn over, the assembly pipe is positioned between the two driving blocks and is communicated with the rotating pipe.
9. The concentrating apparatus of claim 8 wherein the drive means comprises a bracket, a first motor mounted on the top end of the exhaust stack by the bracket, a main gear mounted on the output end of the first motor, and a secondary gear mounted on the rotating tube, the main gear meshing with the secondary gear.
10. The concentrating apparatus of claim 6 wherein the mounting ring has shafts mounted on both sides thereof, and the reservoir has runners on both sides thereof, the shafts correspondingly sliding into the runners.

Description

Method for extracting lithium from lepidolite and concentrating equipment Technical Field The invention relates to the field of battery material production, in particular to a method for extracting lithium from lepidolite and concentrating equipment. Background As the lightest metal, lithium has a range of properties that make it suitable for a variety of uses including batteries, ceramics, glass, lubricants, aluminum smelting and polymers. In recent years, the share of lithium-based batteries in the global market has increased significantly. The global over 80% lithium production comes from salt lake brines (lithium content 0.06% -0.15%) because the cost of extracting lithium from brines is much lower than from solid minerals. However, due to the rapid increase in demand for lithium ion batteries by hybrid and electric vehicles, lithium resource shortage may occur in the future. Therefore, solid lithium minerals should be utilized more efficiently and economically as secondary resources to meet the increasing lithium and lithium salt demands. The early lepidolite processing relies on a high-temperature roasting-leaching process, and has three main core problems that the energy consumption and pollution are high, namely, limestone/sulfate roasting (800-1000 ℃) is adopted, each ton of lithium consumes more than 800kg of standard coal, and waste gases such as SO 2, fluoride and the like are discharged, SO that the environmental protection cost accounts for more than 30 percent of the total investment; the element recovery rate is low, the lithium extraction rate is only 60-70%, rubidium and cesium are hardly recovered, and aluminum and silicon are stacked in a waste residue form; the process compatibility is poor, the traditional alkali method is used for roasting to generate indissolvable aluminosilicate to prevent subsequent accompanying element separation, and the acid method is used for leaching to solve the double problems of equipment corrosion and interference of calcium and magnesium impurities. Accordingly, there is a need to provide a method for extracting lithium from lepidolite that solves the above-described technical problems. Disclosure of Invention The invention provides a method for extracting lithium from lepidolite, which solves the problems that the lithium extraction rate is low in lithium extraction of lepidolite through a high-temperature roasting-leaching process, and recovery of incidental elements such as rubidium and cesium still has room for improvement. In order to solve the technical problems, the method for extracting lithium from lepidolite and the concentration equipment provided by the invention comprise the following steps: S1, adding sulfuric acid into lepidolite, heating to 200-300 ℃ for roasting, destroying mineral crystal lattices through an acid leaching process, and stirring, leaching and filtering to obtain silicon dioxide and mixed sulfate solution; S2, cooling, crystallizing and filtering the mixed sulfate solution to obtain alum and Li + -containing solution; S3, adding Ca (OH) 2 into the solution containing Li +, filtering after reaction to obtain gypsum residue and a new solution containing Li +, evaporating and concentrating the new solution containing Li +, adding carbonate, and precipitating after reaction to obtain lithium carbonate; S4, mixing alum with Ca (OH) 2 for reaction, filtering to obtain gypsum residues and K +、Rb+、Cs+ -containing solution, evaporating and concentrating the solution, separating out potassium sulfate, and capturing Rb +、Cs+ by using molecularly imprinted resin to prepare rubidium salt and cesium salt; S5, mixing gypsum residues with water, then adding NaOH solution, stirring and reacting for 20-40 minutes at 120-150 ℃, and filtering to obtain gypsum and digestive juice containing NaAlO 2、Li+ and excessive NaOH; S6, adding Al (OH) 3 fine powder into the digestive juice to enable the KS value to reach 2.0, then slowly cooling the filtrate from 70 ℃ to 40 ℃, carrying out stirring reaction, filtering to obtain aluminum hydroxide and a solution containing Li + and NaOH, and concentrating the solution; S7, adding sodium phosphate dodecahydrate into the solution containing Li +, stirring at 50-70 ℃ to react, filtering, washing with water, and drying to obtain pure lithium phosphate and filtrate. Preferably, ca (OH) 2 is added to the filtrate in S7, filtered after reaction to obtain NaOH-containing solution, and recycled back to S5. Preferably, the carbonate in S3 is sodium carbonate or potassium carbonate. The invention also provides concentrating equipment for the method for extracting lithium from lepidolite, which comprises a concentrating barrel, wherein a heating structure is arranged in the concentrating barrel; The exhaust barrel is communicated with the top end of the concentration barrel; The scraper structure is arranged in the exhaust barrel, and the output end of the scraper structure extends to the interior of the concentration