Lithium carbonate is one of the inorganic lithium salts which is an important chemical in various industries. It is commercially available in its anhydrous form (Li2CO3) and its role ranges from an antimanic drug to a precursor for cathode or electrolyte for batteries.
Lithium carbonate are produced from two different conventional processes, which are brine extraction and spodumene mining.
1. Brine Extraction
Majority of the lithium manufactured today is extracted from brine reservoirs located in Argentina, Bolivia and Chile, and it is called salars. Lithium brine extraction is a lengthy process that takes several months or a few years to complete, as drilling and pumping of salar brine deposits are required. The pumped brine is then transferred to evaporation ponds, allowing the water content to be significantly reduced for further processing.
Once the optimal lithium content is reached, it is sent to a recovery plant to undergo an ion exchange purification and/or filtration to remove impurities from the brine. Then, several chemical treatments are employed to isolate the products from the byproducts through precipitation. An example of precipitation reaction is when lithium sulfate content in brine solution is mixed with sodium carbonate, hence producing lithium carbonate precipitates.
Na2CO3 (aq) + Li2SO4 (aq) → Na2SO4 (aq) + Li2CO3 (s)
The concentrated brine undergoes another filtration step to separate out the precipitated lithium carbonate. Different reagents are used depending on the desired product Then, product is dried to a desired specification, ready for sale.
Alternatively, lithium can be extracted from minerals such as spodumene through mining. Once mined, the mineral is heated up to 1100°C and then down to 65°C before being crushed and heated up again with sulfuric acid.
The last step involves the addition of soda ash or sodium carbonate which results to crystallization of lithium carbonate. Subsequently, the desired product is filtered and dried.
Although these minerals contain higher lithium percentage compared to brine reservoirs, this process is more costly due to its high energy consumption and expensive raw materials to process it.
Lithium carbonate, like lithium hydroxide is a precursor to lithium compounds used as cathode and electrolyte in battery production, such as in lithium ion, nickel-cadmium and nickel hydrogen batteries. These batteries are then used for various purposes like in digital cameras, smartphones, pacemakers, etc.
Additionally, lithium carbonate is utilized in the processing of ceramics, cement, glass and aluminum. In the pharmaceutical industry, lithium carbonate is a prescription medicine used to treat bipolar disorder by restoring the balance of neurotransmitters in the brain. It is also utilized in the production of lithium ion batteries.