Recovery of zinc and copper from scrap - by lixiviation with aq ammonium bicarbonate and pptn as basic carbonates

摘要

Scrap material, e.g. ferriferous waste with brass, etc., lean minerals, slags are finely crushed and leached with aq. NH4CO3 in the presence of O2 at 0-45 degrees C. and pH 8.3-9.5. Soln. contains e.g. 100 g./l. NH4HCO3, and leaching is effected until the soln. is satd. w.r.t. Cu and/or Zn. CO2 is used at 2 bars, pref. in two stages, at 1.5 bar to recover the Zn and some Cu, and 1.5 bar residual Cu. Liquor can then be recycled. Process and appts. are simple, and no expensive reactant recovery is involved.