Winning vanadium pent:oxide and vanadate(s) - via leaching process causing no environmental pollution by toxic waste water (CS 31.5.79.)

摘要

A raw material contg. vanadium is mixed with alkali metal salts(1) and roasted to form a prod.(2), which is leached by a mixt.(3) of waste water(3a), mother liq.(3b) and new water(ec). Liqs.(3a, 3b) possess a concn. of salts(1) permitting the addn. of more salts(1) during leaching without reaching satn. Part (3d) of the soln.(3) used in leaching is cooled, esp. to -2 to 20 degrees C., to crystallise salts(1), and the supernatant liq. is added to the remaining liq.(3) to form the mother liq.(3b) re-used in leaching. The concn. of salts(1) in the leaching liq.(3) is kept near to satn. without impairing the efficiency of the leaching process. A closed cycle leaching soln. is employed in which all the toxic solns. created by the process are continuously and permanently recirculated.