Process for removing ferric iron from a solution containing dissolved ferric iron

摘要

1308761 Removing FeSP3+/SP from solution ELECTROLYTIC ZINC CO OF AUSTRALASIA Ltd 5 Jan 1971 [15 May 1970] 436/71 Heading C1A Ferric iron is precipitated from an aqueous solution containing 5 g./l. FeSP3+/SP together with other ions (Zn, Cu, Co and/or Ni; SO 4 SP2-/SP and/or Cl-) by treatment with a neutralizing agent while maintaining the pH of the pulp so obtained at 1À7 to 3À5 and the temperature of the pulp at from 50‹ C. up to the boiling point at atmospheric pressure, preferably 65-95‹ C.; the solution and the neutralizing agent being continuously introduced into a precipitation vessel and being agitated therein and the rates of input of the reactants being controlled so as to maintain the specified conditions and to maintain the concentration of dissolved ferric iron in the solution component of the pulp at # 1 g./l., and separating the precipitated iron compound or compounds from the pulp. The starting solution may be a metal sulphate solution containing ZnSO 4 which has been produced by acid leaching of zinc plant residues, or by leaching of calcined zinc concentrates containing zinc ferrite, or by leaching suitable ores, concentrates or residues containing both Zn and Fe. Examples of neutralizing agent are zinc oxide calcine, zinc oxide fume, zinc silicate, zinc carbonate, basic zinc sulphate, limestone or magnesium oxide. The pulp may be flocculated by a polyacrylamide additive prior to filtration.