The present invention relates generally to a process for removing
dissolved or colloidal silica from a pregnant leach solution ("PLS").
More particularly, an exemplary embodiment of the present invention
relates to a process which mixes PLS with an acid source, preferably lean
electrolyte, to induce formation of colloidal silica that can then be
collected and removed. Additionally, in an exemplary embodiment of the
present invention, at least one silica seeding agent is added to induce
formation of colloidal silica, at least one flocculant is added to induce
aggregation of the colloidal silica, and a solid-liquid separation
process is utilized to remove advantageous amounts or substantially all
of the colloidal silica, thereby providing relief from supersaturation of
dissolved silica in the metal recovery processes.