Improved process for concentration of ulexite and boric acid production

Abstract

South America reserves of boron minerals are concentrated in the Central Andes. Ulexite is one of the most important borates found in these deposits. The mineral is associated with impurities such as sand, clays, chlorides and sul-fates. Boric acid is produced by leaching the ulexite with sulfuric acid and it is recovered through a process of liquid-solid separation and then, by a cooling crystalliza-tion process. The residual slurry is rejected and it is necessary to reduce its adverse environmental effects. This paper reports an improved process for ulexite concentration and boric acid production. It has been developed to minimize the pollution problems found in the present industrial process used in Argentina.