Selective winning of lead from sulphide ores - by leaching with hot aq. hydro:fluorosilicic acid soln. contg. hydrogen peroxide and air so only lead is dissolved

摘要

The ore is subjected to at least one treatment in which it is oxidised in an aq. soln. of H2SiF6, so the Pb is dissolved. The oxidn. pref. employs a redox pair, esp. O2/H2O2 at 0.7-1.4 volts w.r.t. a normal hydrogen electrode. The milled sulphide is pref. mixed with a soln. of H2SiF6 contg. H2O2, while a gas contg. O2 is bubbled through the soln. The Pb is pref. reclaimed from the soln. by electrolysis, while the O2 liberated at the anode is collected and used in the leaching soln., which pref. is at max. 2.0 pH. The ore is esp. galena or its concentrates. A high yield of Pb is obtd. without dissolving other metals in the ores.