US 6,048,507 A · Process for the purification of lithium carbonate

Abstract

Disclosed are methods for preparing high purity lithium carbonate which can be used for pharmaceutical applications, electronic grade crystals of lithium or to prepare battery-grade lithium metal. Lithium carbonate as commercially produced from mineral extraction, lithium-containing brines or sea water, in aqueous solution is used as a feedstock and reacted with carbon dioxide under pressure to form dissolved lithium bicarbonate. Impurities in the lithium carbonate feedstock are either solubilized or precipitated out. Dissolved impurities are physically separated from the lithium bicarbonate using an ion selective means, such as an ion exchange material, or by liquid--liquid extraction. Purified lithium carbonate is then precipitated.

Claims33

Dependent claims

A method of producing high purity lithium carbonate, comprising the steps of:

reacting impure Li.sub.2 CO.sub.3 in a first aqueous solution with CO.sub.2 to form a second aqueous solution containing dissolved LiHCO.sub.3, dissolved compounds and insoluble compounds, wherein said dissolved compounds and said insoluble compounds include inpurities from said impure Li.sub.2 CO.sub.3 ;
separating unreacted CO.sub.2 and said insoluble compounds from said second aqueous solution;
separating said dissolved impurities from said second aqueous solution by contacting with an ion selective medium to remove said dissolved impurities including divalent and trivalent ions;
and
precipitating Li.sub.2 CO.sub.3 from said second aqueous solution.

2 more elements

Dependencies are inferred from the claim text.

Process for the purification of lithium carbonate

Life of this patent

Process for the purification of lithium carbonate

Life of this patent

Abstract

Claims33