Arsenic and antimony removal from copper sulphide ores - by leaching ore with hot aq. alkaline soln. of sodium sulphide which dissolves arsenic and antimony

摘要

The ore is leached with an aq. alkaline soln. at pH 13-14, contg 40-80 g/l Na2S, and used at 120-200 deg.C and a satd. steam pressure (SSP) of min. 2 bars, so all the As and Sb in the ore are dissolved. The soln. is then sepd. from the ore, and is treated to recover the As and Sb in an insol. form. Leaching is pref. undertaken at 150 deg.C using an SSP of 4.6 bars and a soln. contg. 40-80 g/l Na2S and 10-20 g/l NaOH ised to adjust the PH. The leaching soln. is pref. made by dissolving crystals of Na2S, 9H2O in a normal soln. of NaOH to obtain a mother liq., and an esp. pref. leaching soln. contains 40 g/l Na2S and 80 g/l NaOH. Used to protect the environment, As and Sb must be removed from copper sulphide ores before their sale to copper foundries.