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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 hydroxide, 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 />