1. Carbonization purification process

1) Physical properties of lithium carbonate

In the production process of lithium carbonate, due to the characteristics of the lithium carbonate material itself, it is very easy to adhere to the container wall. Over time, it will form very hard crystal scale, which needs to be treated regularly. In addition, the solubility of lithium carbonate material decreases with increasing temperature, and heating the solution further exacerbates material scarring.

2) Introduction to Carbonization Purification Process

The carbonization pyrolysis purification process involves mixing industrial grade lithium carbonate with a certain amount of deionized water to form a slurry, and then introducing high-purity CO2 gas during the stirring process to convert the slightly water-soluble LiCO3 into the highly soluble LiHCO3, which is then filtered to remove impurities. The carbonized liquid is filtered through a precision filter, and impurities such as fluorine, calcium, and magnesium are removed from the resin before entering the pyrolyzer. The pyrolyzer operates continuously, and the decomposition is completed by heating and constant temperature reaction, followed by centrifugal heat transfer. Then, drying, airflow crushing, iron removal, packaging and other processes are carried out to produce battery grade lithium carbonate.

3) Characteristics of continuous carbonization pyrolysis

(1) Reasonable design of process parameters and equipment structure, reducing the carbon dioxide gas carried out with the material during carbonization process, and improving the utilization rate of carbon dioxide;

(2) Lithium carbonate carbonization adopts multi-stage series operation to prolong the material residence time and increase the conversion rate; The material and carbon dioxide are operated in reverse flow, resulting in high utilization efficiency of carbon dioxide.

(3) The lithium bicarbonate solution is preheated using a thermal decomposition mother liquor to increase the feed temperature and reduce steam consumption. The preheater is designed with one on standby to avoid serious scaling that affects production. At the same time, a special design is adopted to reduce the amount of lithium bicarbonate decomposition and extend the service life;

(4) The thermal decomposition system adopts multiple parallel devices, which can achieve backup and increase production capacity simultaneously;

(5) This system uses low-pressure steam to indirectly heat the material during thermal decomposition, reducing the heat transfer temperature difference between the heating steam and the material and minimizing scaling on the heat exchange surface;

(6) Reasonably designed decomposition system, equipped with external heating heat exchanger, long scar formation cycle, and easy cleaning;

(7) The centrifugal mother liquor is filtered through a precision filter to maximize the recovery of lithium carbonate through the centrifuge and improve the direct yield of lithium carbonate;

(8) Carbon dioxide circulation device, which keeps carbon dioxide in a flowing state and increases the reaction rate;

(9) The thermal decomposition mother liquor is treated by MVR evaporation crystallization, which can directly recover most of the lithium carbonate and return it to the carbonization process, improving the lithium recovery rate and reducing the consumption of acid, alkali, etc.

(10) The system operates continuously, with a high degree of automation and low manual labor intensity

4) Summary Explanation

Our company has mature technology for continuous carbonization and thermal precipitation of lithium carbonate. At present, multiple sets of carbonization pyrolysis systems are operating continuously and stably in China, producing qualified battery grade lithium carbonate and high-purity lithium carbonate according to user requirements. At the same time, our company has a mature lithium hydroxide carbonization process for converting lithium hydroxide into lithium carbonate, and the product quality can reach battery grade lithium carbonate. Welcome to consult and inspect manufacturers in the lithium battery industry.