Ion exchange resins for gold cyanide extraction containing a piperazine functionality, 2 study of the gold extraction reaction

Ion exchange technology is offered as an alternative to activated carbon fo r gold cyanide recovery A new type of ion-exchange resin (PS-PIP) recovery a piperazine group, linked to a styrene-divinylbenzene. macroporous network , is described. The extraction of Au(CN)(2)(-) and other metal cyanides wit h the PS-PIP resin involves three modes of metal extraction: the protonated secondary amine groups of the resin (at acidic pH conditions), the free am ine groups of the resin (at neutral and basic pH values) and the small port ion of the quaternary ammonium groups participate in the gold extraction me chanism. The gold cyanide extraction reaction on the polymeric piperazine w as studied by a combination of metal extraction data, from batch experiment s and IR and XPS spectroscopic analysis of the metal loaded polymres. Exrac tion isotherms of gold cyanide show that gold bindign is possible from 40-6 0 mg Au/g of resin in alkaline solutions, up to 150 mg Au/g of resin in aci dic solutions. Efficient stripping of gold from the resin was achieved usin g ethanol/water solutions of sodium hydroxide, or 0.5 mol/l thiurea in sulf uric acid solutions.