Recovery of Lithium from Low-grade Ores.
U S Pat 4 285 914 1981 Aug; :
Lithium is recovered from low-grade ores, such as clays, by the addition of cao or caco3 and chlorination with h2o-hcl vapor to convert the lithium to soluble licl. The process is carried out at 550 deg-800 deg c, and the optimum amounts of cao or caco3 should be 80-200 pct of stoichiometric amount of cao for reaction with free silica. Thus, clay containing 0.6 pct li and 25 pct sio2 as mixed with 33 pct of cao. The mixture was chlorinated at 700 deg c for 30 min with h2o-hcl vapor containing 20 pct hcl. The vapor flowrate was 50 cm3/min-g ore. After chlorination, the sample was leached with h2o at 80 deg c for 5 min, and the lithium recovery was 70 pct.
U.S. Pat. 4,285,914, Aug. 25, 1981; Chem. Abstr. 94:87,867A