A process for recovering cyanide from feed material containing cyanide and copper
involves the steps of: (a) contacting the feed material with a strong base anion
exchange resin whereby copper and cyanide from the feed material are adsorbed onto
the resin; (b) contacting the resulting resin with an eluant solution containing
free cyanide ion to elute copper and cyanide from the resin; (c) separating the
eluted resin from the eluting solution or eluate from step (b); (d) acidifying
the eluate from step (b) to precipitate copper; (e) separating the acidified solution
from the precipitate in step (d) and alkalizing directly or after concentration
the separated solution containing HCN; (f) contacting the eluted resin from step
(b) with an acid to condition the resin and remove additional cyanide while leaving
most of the copper in the resin phase; (g) converting the HCN solution formed in
step (f) to cyanide ion, directly or after concentration of the HCN solution, by
the addition of alkali; and (h) returning the conditioned resin from step (f) to
step (a) above.
