Abstract: A hydrometallurgical process is provided for separative treatment of zinc-bearing metallurgical flue dust containing significant amounts of lead, chlorine, and iron. The process is especially suited for extraction of zinc sulfate from blast furnace white dust resulting in the smelting of secondary copper. According to the process, the flue dust is leached in sulfuric acid solution for substantially complete dissolution of soluble constituents, notably zinc, leaving insoluble residue consisting principally of lead oxide. At completion of leaching, pH is selectively adjusted corresponding to the desired extent of subsequent chloride removal. Second, the loaded leach solution is treated for chloride removal wherein chloride ion concentration is substantially and selectively reduced by precipitation of cuprous chloride, cuprous ions being provided by pH regulated reduction of cupric ions.

Abstract: A process is provided for purification of nickel sulfate via ammoniacal leaching and pH regulated solvent-extraction, while providing for regeneration of the extractant and the leach solution. The process is especially suited for hydrometallurgical extraction of high purity nickel sulfate from residue resulting in the regeneration of spent electrolyte in the electrorefining of secondary copper. According to the process, the starting material is leached in an ammonia solution of selected pH to solubilize the nickel as polyammine sulfate, followed by extracting the solubilized nickel by pH regulated solvent-extraction. The extractant is then stripped and regenerated with sulfuric acid by first scrubbing in a first pH range to remove ions that are more electropositive than nickel, then stripping with sulfuric acid in a second pH range to remove nickel ions, and then regenerating the extractant by stripping in a third pH range to remove ions that are less electropositive than nickel.

Abstract: A hydrometallurgical process is provided for the separative treatment of electrometallurgical anode slime containing precious metals and substantial amounts of tin dioxide and lead sulfate. The process is especially suited for treatment of anode slimes from the electrorefining of secondary copper to recover about 85% of the metal value contained therein, especially tin and precious metals. First, lead is separated by leaching the slime with diethylene triamine followed by carbonation to precipitate lead carbonate with subsequent regeneration of the leach solution. Second, tin is separated by leaching the undissolved residue from the amine leach with a solution of hydrochloric acid and chlorine to dissolve substantially all substances except tin dioxide.