Abstract: It is possible to produce battery grade metallic lithium from naturally occurring or industrial brine by a process comprising the following steps: (i) precipitating magnesium with calcium hydroxide; (ii) removal of boron via extraction of solvents; (iii) precipitation of lithium with sodium carbonate; (iv) transformation of lithium carbonate to bicarbonate of lithium with carbonic acid; (v) decomposition of bicarbonate of lithium into high purity lithium carbonate as a result of heating of the solution. Re-precipitation of lithium carbonate by the formation of bicarbonate of lithium allows for the removal of the majority of contaminants which co-purify with lithium carbonate and yield battery grade highly purified lithium carbonate.