Amax Incorporated

Weldon P Zundel

Cvetko B Nikolic

Robert S Rickard

John M Laferty

Gary G Van Riper

Waste water containing over 2 ppm Mo and at least one heavy metal impurity selected from the group consisting of Fe, Mn, Cu, Zn, Pb, and Cd, and also containing cyanide ion (CN) is treated by passing waste water having an adjusted pH value ranging from about 3 to 4 through an ion-exchange resin column selective to the removal of Mo and provide an ion-exchange effluent containing at least one of said heavy metal impurities and said cyanide ion. The pH value of the effluent is then adjusted to a range of about 7 to 11 sufficient to precipitate the heavy metal impurity having the highest pH requirement for precipitation, following which the precipitate is flocculated and the effluent containing the flocculated precipitate then subjected to electrolysis using insoluble electrodes to form electrolytic oxygen and hydrogen and effect electroflotation of the flocculated precipitate and form a froth thereof which is separated from the effluent by skimming.

Waste water treatment

A method is provided for separating nickel and cobalt from a cobalt-nickel precipitate, the cobalt being in the cobaltic state. The method comprises dissolving the precipitate in an ammonium sulfate solution containing NH.sub.3, acidifying the solution to a pH of about 1.5 to 3.0 and then cooling the solution to produce a nickel-ammonium sulfate precipitate highly enriched in nickel. The precipitate is separated from the solution and the solution passed through an ion exchange column selective to the removal of nickel, the solution remaining containing said cobalt substantially free of nickel, the cobalt solution being then sent to cobalt recovery.

Nickel-cobalt separation

A method is provided for enriching nickel in a nickel-cobalt solution to a nickel-to-cobalt ratio of over 2000:1, wherein an aliquot portion of the solution is removed, the nickel precipitated from said aliquot portion in the nickelous state, the nickelous precipitate thereafter oxidized to the nickelic state and the oxidized nickel precipitate then mixed with the remaining nickel-cobalt solution to oxidize the cobalt therein to the cobaltic state which precipitates from the solution, thereby highly enriching the solution in nickel.

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Golden, CO, United States of America

Weldon P Zundel