Background and overview of several preparation methods of lithium carbonate
Lithium carbonate is a basic compound of lithium and has a variety of industrial uses. It is widely used in ceramics, glass, atomic energy, aerospace, military industry and refrigeration, welding, lithium alloys, lithium batteries, controlled nuclear fusion reactors, and medicine. and other fields. In addition, lithium carbonate, as a basic basic zinc carbonate material for lithium, can be converted into a variety of other lithium compounds. Battery-grade lithium carbonate is mainly used to produce lithium-ion battery cathode materials such as lithium cobalt oxide, lithium iron phosphate, lithium nickel oxide, lithium manganate or lithium nickel cobalt manganate.
Several preparation methods of lithium carbonate
Report on several preparation methods of lithium carbonate 1.
A process for preparing high-purity lithium carbonate by recycling battery-grade lithium carbonate lithium precipitation mother liquor, including the following process steps:
1) Pretreatment of lithium carbonate lithium precipitation mother liquor: Pass the lithium carbonate lithium precipitation mother liquor through a filter with a pore size of 0.7 cm-1.2 cm, then add a precipitating agent to the filtered lithium carbonate lithium precipitation mother liquor, and stir with a mixer 10min-15min until calcium salt precipitation or magnesium salt precipitation appears at the bottom of the lithium carbonate precipitation mother liquor, and the precipitate is separated to obtain mother liquor I.
2) Acidification of mother liquor I: Add an appropriate amount of acidic solution to the mother liquor I obtained in step 1) to precipitate lithium carbonate into the mother liquor. Adjust the pH value of the lithium carbonate precipitate mother liquor to 2-4, and then add it into the mother liquor I. Add 1/20 of the mass of mother liquor I of ground lime powder, and perform a bezoarization reaction at a high temperature of 80°C to 90°C to obtain mother liquor II containing lithium hydroxide.
3) Concentration of mother liquor II: Put the mother liquor II obtained in step 2) into an evaporation chamber at 140°C-160°C for a certain period of time until the water content in the mother liquor II becomes 4/5 of the mother liquor II, then add to the mother liquor Pour 70% lithium hydroxide solution into II, then place the mother liquor II at 140°C-160°C for a certain period of time, and change the water content in the mother liquor II to 4/5 of the mother liquor II to obtain the concentrated mother liquor III.
4) Acidification of mother liquor III: Pour 60%-70% sodium sulfate solution of 1/20 of the mass of mother liquor III into the mother liquor III obtained in step 3), stir for 12min-17min, and add the sodium sulfate solution after The mother liquor III is placed in a low temperature chamber for cold precipitation, and the sulfate radicals are frozen and precipitated to obtain a mixed solution of sodium hydroxide and lithium hydroxide, and a large amount of carbon dioxide is passed into the solution until the pH value of the mixed solution is adjusted to 2- 4. Obtain a mixed solution containing sodium carbonate and lithium carbonate.
5) Extraction of lithium hydroxide: Mix the mixed solution of sodium carbonate and lithium carbonate obtained in step 4) with the extraction agent 1:2, stir for 5min-6min, then let stand for 30min-40min, and then add the upper layer The sodium carbonate and the lithium carbonate in the lower layer are separated to obtain a lithium carbonate solution.
6) Obtaining lithium carbonate: Concentrate and recrystallize the lithium carbonate solution obtained in step 5) to obtain lithium carbonate solid.
Report on several preparation methods of lithium carbonate 2.
A method for purifying industrial grade lithium carbonate to prepare battery grade lithium carbonate. The specific steps are:
(1) Dissolution: Prepare 130g/L formic acid solution, slowly add industrial grade lithium carbonate to dissolve, stop adding when the reaction reaches neutral and no bubbles are generated, use a precision filtration device to filter to obtain lithium formate solution;
(2) Impurity removal: First use CH-93 cation exchange resin to treat the lithium formate liquid to remove soluble impurities, and then use a precision filtration device to filter to remove insoluble particles to obtain the purified lithium formate liquid;
(3) Re-precipitation: Heat the purified lithium formate solution to 60°C, slowly add ammonium carbonate solid, the amount added is 1.3 times the amount required for theoretical lithium precipitation, and continue the reaction for 1 hour after adding sodium perborate tetrahydrate. , after filtration, lithium carbonate and the reaction liquid are obtained, and the lithium carbonate is washed twice with water;
(4) Calcination: After washing with water, the lithium carbonate is calcined at 300°C for 2 hours to finally obtain a battery-grade lithium carbonate product.
In this example, the concentration of formic acid solution is 130g/L, the lithium content in the solution after dissolution is 19.6g/L, the lithium content in the final reaction solution is 1.5g/L, and the amount of lithium metal in a single treatment is 18.1g/L, the single lithium recovery rate is 92.34%.
Report 3 on several preparation methods of lithium carbonate.
The method of purifying battery grade lithium carbonate from industrial grade lithium carbonate is as follows:
Weigh 20g of industrial grade Li2CO3, pour it into a 600ml beaker, add 200ml of deionized water, and stir continuously to mix into a uniform Li2CO3 slurry. Measure 20 ml of formic acid, pour it into a separatory funnel, and adjust it so that formic acid is added dropwise to the Li2CO3 slurry that is continuously stirred at a uniform speed to obtain a soluble clear solution. Weigh 20g of urea, dissolve it in 50ml of deionized water, pour it into the above clear solution, put the mixed liquid into the water bath, adjust the temperature to 80°C, weigh 5g of lithium hydroxide and dissolve it in 80ml of deionized water, add and adjust with a dropper The pH of the mixed liquid is around 10, and it is stirred continuously for 5 hours. Take it out and filter it to obtain a white precipitate. Wash it repeatedly with deionized water and filter it 4 times. The solid obtained is baked in a 100°C oven for 35 hours to obtain a white powdery carbonic acid. Lithium Products.
References
[1] [Chinese invention] CN201711171953.4 A process for preparing high-purity lithium carbonate by recycling battery-grade lithium carbonate lithium precipitation mother liquor
[2] [Chinese invention] CN201911311966.6 A method for purifying industrial-grade lithium carbonate to prepare battery-grade lithium carbonate
[3] [Chinese invention] CN200910163250.6 Method for preparing battery grade lithium carbonate from industrial grade lithium carbonate
