Patent ID: 9034294
Filing Date: 2015-05-19
Classification: C01B,C01D,C01P,C22B,C25B,C25C

Abstract:
1. A method of preparing lithium carbonate from a lithium chloride-rich stream, the method comprising the steps of: supplying a brine solution containing lithium and silica to a silica removal step to produce a silica-lean lithium chloride containing solution, said silica removal step operable to remove at least a portion of silica present in the brine solution; processing the silica-lean lithium chloride containing solution through a lithium chloride capture step to obtain a lithium chloride containing feed solution, said lithium chloride capture step being operable to selectively capture said lithium chloride from the silica-lean lithium chloride containing stream; contacting said lithium chloride containing feed solution with a solvent extraction mixture, said solvent extraction mixture being operable to remove at least a portion of the divalent ions present in the lithium chloride containing feed solution; producing a purified lithium chloride-rich stream having a reduced concentration of divalent ions relative to the lithium chloride containing feed solution; contacting said purified lithium chloride-rich stream with carbon dioxide and a sodium hydroxide solution in a reaction vessel to produce a solution comprising lithium carbonate, wherein said sodium hydroxide solution is prepared by electrolyzing sodium chloride in an electrochemical cell, said electrochemical cell comprising an anode, a cathode, and a semi-permeable membrane separating an anode chamber and a cathode chamber; supplying the solution comprising lithium carbonate to a separator to produce a lithium carbonate product and a sodium chloride stream; and recycling at least a portion of the sodium chloride stream to the electrochemical cell for the production of sodium hydroxide.