The separation and purification technology of lithium carbonate is an important part of the application of this substance and involves a variety of methods.

First, precipitation is a common purification technique. Its principle is to utilize lithium carbonate to react with other impurities to generate precipitates with small solubility under different temperatures, pressures, concentrations, etc., so as to achieve separation. Commonly used precipitants include limestone, calcium hydroxide, calcium carbonate and so on. By controlling the precipitation conditions and repeatedly washing the precipitate, high purity lithium carbonate can be obtained.

Secondly, solvent extraction method is also an effective separation technique. This method utilizes the difference in solubility of lithium carbonate in different solvents to selectively transfer it from one solvent to another. Commonly used extractants include tributyl phosphate, dimethylheptyl methylphosphonate, and so on. High purity lithium carbonate can be obtained by selecting a suitable extractant and counter-extraction conditions.

In addition, the ion exchange method is one of the commonly used separation techniques. This method utilizes the different adsorption capacities of ion exchangers for different ions to achieve the separation of lithium carbonate from other impurities. Commonly used ion exchangers include sulfonated coal and ion exchange resin. By selecting a suitable ion exchanger and elution conditions, high purity lithium carbonate can be obtained.

In addition to the above methods, a variety of separation techniques such as electrodialysis, membrane separation and crystallization can be used for the purification of lithium carbonate. In practical application, according to the source of lithium carbonate, purity requirements, production scale and other factors, select the appropriate combination of separation techniques to achieve the best purification results.

It is worth noting that the separation and purification process of lithium carbonate also requires attention to some key factors. For example, avoiding the introduction of new impurities, controlling temperature and pressure, and selecting appropriate operating parameters. All these factors will affect the purity and quality of the final product.

With the continuous progress of science and technology, new lithium carbonate separation and purification technologies may also appear in the future. Therefore, research and development work in related fields still needs to be deepened to promote the sustainable development of the lithium carbonate industry.