RECOVERY OF CYANIDE FROM WASTE WATERS BY AN ION EXCHANGE PROCESS

摘要

ROGERS, BERESKIN & PARRInventor: Carla C. FreyW. Ronald HatchMargaret K. WitteTitle: RECOVERY OF CYANIDE FROM WASTEWATERS BY AN ION EXCHANGE PROCESSABSTRACT OF THE DISCLOSUREA process is described for the substantially completerecovery of cyanide reagent and metal forming water solublemetal-cyanide complexes contained in mill effluents andwaste waters. The process is comprised of a loading cyclewherein the metal-cyanide complexes are adsorbed onto abasic ion exchange resin and the free cyanide containingcolumn effluent is returned to the mill. The metal ions,which are usually mostly copper, nickel and zinc, and thecomplexing cyanide are eluted in the subsequent regenerantcycle by an acid solution having controlled pH and controlledredox potential, the latter being measured against thesaturated calomel electrode. The preferred oxidant tocontrol the redox potential of the regenerant solution ishydrogen peroxide. The generated hydrogen cyanide is spargedwith air, or removed by subatmospheric pressure from theregenerant solution, and dissolved in an alkaline scrubbersolution for reuse. The metal ions are recovered from ableed solution.