PROCESS FOR THE SEPARATION OF METALLIC IMPURITIES CONTAINED IN AQUEOUS NICKEL SALT SOLUTIONS

摘要

1314924 Nickel; solvent extraction of metallic contaminants LE NICKEL 5 July 1971 [8 July 1970] 31502/71 Heading C1A Metallic contaminants, e.g. cobalt, iron, copper, zinc and manganese are removed from an aqueous nickel solution by solvent extraction with a solution of a sulphonium thiocyanate in a water immiscible organic solvent. The thiocyanate may have the formula in which R 1 , R 2 and R 3 may be alkyl, alkaryl, aralkyl, or aryl radicals. R 1 may be a methyl radical and R 2 and R 3 alkyl radicals containing from 8-18 carbon atoms. The organic solvent is preferably diisobutyl ketene but may also be another ketene, an aliphatic ester or benzene, toluene, hexane or dodecane or mixtures thereof with octanol or isodecanol. The nickel salts (e.g. chlorates, nitrates or sulphates) may then be recovered from the aqueous phase. Compounds of the other metals may be removed from the organic phase, e.g. by (a) treatment with ammonium sulphate and ammonia, (b) oxidation of the metal ion to a state where it no longer forms a complex with the sulphonium thiocyanate and precipitation of the metal ion in the form of an insoluble salt or hydroxide, (c) first treating it with sulphurous acid, sodium sulphite or zinc, cobalt or copper sulphates at a pH of about 1À5 to remove iron, secondly treating it with zinc or copper sulphates to remove cobalt, thirdly treatment with zinc sulphate to remove copper and lastly treating it with ammonia or ammonium sulphate to remove zinc.