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Cadmium Recovery <br /> Cadmium arrives at the Facility as cadmium cyanide complexes <br /> concentrated on ion exchange resins and bulk shipments of <br /> wastewater containing concentrated cadmium. The resin is <br /> regenerated with caustic soda and water then treated to oxidize <br /> the cyanide. The regenerant solution and the bulk shipments of <br /> wastewater are transferred to a small plating cell and the <br /> cadmium is electrolytically recovered. Wastewater not <br /> containing cadmium is neutralized, filtered and discharged. <br /> Chrome Recovery <br /> Bulk shipments of chrome in the hexavalent form are reacted <br /> with sodium bisulfite for reduction to the trivalent form. <br /> Trivalent chrome is also concentrated on ion exchange resins. <br /> The resin regenerant solution (produced by flushing with <br /> caustic soda and water) and the reduced bulk shipment solutions <br /> are treated by precipitation. The chrome hydroxide is <br /> dewatered and resold. Any waste waters from these treatment <br /> processes that do not contain chrome are neutralized and <br /> filtered before discharge to the sewer. <br /> Zinc Recovery <br /> Zinc cyanide complexes in bulk shipments of waste water and <br /> . concentrated on ion exchange resins are treated to oxidize the : <br /> cyanide after the resin is regenerated. The zinc is then <br /> precipitated as zinc hydroxide, fixated and resold or disposed. <br /> Wastewater generated during these treatment processes that does <br /> not contain zinc is neutralized and filtered before discharge. <br /> Nickel Recovery <br /> Nickel enters the Facility as nickel in acidic wastewater and <br /> concentrated on ion exchange resin. The bulk shipments of <br /> electroless nickel are run through an activated carbon column <br /> to remove the organic chelating agents present. The ion <br /> exchange resins are regenerated using sulfuric acid, sodium <br /> chloride and water. The regenerant solutions and bulk <br /> shipments of both types are treated by precipitating the nickel <br /> as nickel hydroxid'e, dewatered, and resold on the secondary <br /> metals market. Wastewaters from these treatments, not <br /> containing nickel, are neutralized, filtered and dishcharged. <br /> Lead Recovery <br /> Bulk shipments of wastewater containing lead and a lead <br /> hydroxide sludge generated during in-plant treatment are the <br /> two forms of lead arriving at the Facility. The lead is <br /> precipitated from the wastewater as lead hydroxide. Both <br /> sludges are dewatered and sold if possible. Fixation and <br /> disposal is the other alternative. Wastewater generated during <br /> these processes, not containing lead, is neutralized and <br /> filtered before discharge. <br /> A-9 <br />