Preparation background and overview of battery-grade lithium carbonate
As a new energy source, lithium-ion batteries are the most important product among battery products and are widely used in mobile communications, watches, cameras, calculators, computer memory backup power supplies, pacemakers, security alarms, Electric vehicle power supply and other fields. Battery-grade lithium carbonate is the main material for the production of energy storage batteries, and its application prospects are very broad.
Preparation of battery grade lithium carbonate
Preparation Report of Battery Grade Lithium Carbonate 1.
The clean production method of battery grade lithium carbonate includes the following steps:
(1) Preparation of β-spodumene lithium concentrate: Select 1000kg of enriched natural spodumene concentrate and place it in a rotary furnace. Control the temperature in the rotary furnace to 1100°C and roast it for 5 hours to prepare β-spodumene. -Spodumene lithium concentrate;
(2) Preparation of lithium sulfate solution: When the temperature of the rotary furnace is controlled to be 95°C, the β-spodumene lithium concentrate is crushed and sieved to make ore powder, and an excess of 25% sulfuric acid solution is added to the ore powder and mixed before being rotated. Enter the rotary furnace and sinter at 270°C for 5 hours; crush and sinter the ore powder and soak it in purified water to obtain a crude solution. Use calcium carbonate to neutralize excess sulfuric acid to adjust the pH of the crude solution to 6.5 and then filter to obtain 1000L lithium sulfate solution;
(3) Ion removal: Add 100L of 1% hydrogen peroxide solution to the above lithium sulfate solution to oxidize ferrous ions into ferric ions, then add 30% sodium hydroxide solution until the pH of the solution is 12. Mg and Fe in the solution form magnesium hydroxide and iron hydroxide precipitates; after filtering the precipitates, heat the solution to 40°C and adjust the pH to 7.0 with dilute sulfuric acid. Aluminum hydroxide precipitates form in the solution. After filtering the precipitates, use excess sodium carbonate to remove calcium ions. and other residual metal ions; after filtering and precipitating, the solution is decolorized; the filtrate is evaporated and concentrated until the Li2O content is 65 g/L, and the mixed solution containing EDTA and oxalic acid of the present invention is added to the concentrated solution (the mass ratio of the substances is 1:1) After settling for 30 minutes, filter.
(4) Preparation of lithium carbonate: Slowly add the Na2CO3 saturated solution to the filtered Li2SO4 solution obtained in the above step at a temperature of 90°C. During the feeding process, the pH value of the solution was continuously measured; with the addition of Na2CO3 saturated ammonium bicarbonate solution, the pH value of the solution gradually dropped from 12. When the mixed solution The pH is 9.0, stop adding. If the pH of the solution does not change within 30 minutes of incubation and stirring, filter it and obtain lithium carbonate precipitate;
(5) Preparation of battery grade lithium carbonate: Wash the lithium carbonate precipitate obtained in the above steps three times with 2 times the volume of purified water at room temperature, and dry the washed sample at 70°C to obtain the battery grade of the present invention. The finished product of lithium carbonate, the yield of lithium carbonate (calculated as lithium element) is 85%.
Preparation Report of Battery Grade Lithium Carbonate 2.
A method for continuously producing battery-grade lithium carbonate, including the following steps:
(1) Elution: Crush lepidolite ore to obtain lepidolite powder, add hydrochloric acid to the lepidolite powder for elution and then filter to obtain the filtrate;
(2) One-time feeding: Add 60% of the total potassium carbonate solution and 50% of the total filtrate into the reactor in a parallel feeding manner. Control the feeding time t1 to 90 min, and the feeding temperature c1 to 120-150 ℃;
(3) Secondary feeding: Add 40% of the remaining potassium carbonate solution and 50% of the total filtrate into the reactor again in parallel feeding mode, control the feeding time t2 to 100min, and the feeding temperature c2 is 110-150℃;
(4) Obtaining battery-grade lithium carbonate: After the secondary feeding is completed, the liquid-solid-liquid separation in the reactor is performed to obtain wet lithium carbonate, and then the wet lithium carbonate is washed and dried to obtain battery-grade lithium carbonate. .
The drying is done by electric heating.
The present invention directly produces battery-grade lithium carbonate and rhodium tetrafluoroborate through two parallel feedings, strictly controls the feeding time and feeding temperature, and does not require the introduction of carbon dioxide for hydrogenation. Therefore, the cost is low, the work flow is simple, and it is easy to mass-produce Production realizes the continuous production of battery-grade lithium carbonate. The raw materials used in the invention are potassium carbonate solution and lepidolite ore, so the battery-grade lithium carbonate produced has good quality, short service life and good stability.
References
[1] CN201610023541.5 Method for continuous production of battery-grade lithium carbonate
[2] [Invented in China] CN201711118967.X A method for continuously producing battery-grade lithium carbonate
