Solvent extraction method of separating ferric chloride from nickel

Abstract

Ferric chloride is separated from nickel chloride in a spent etchant solution 10 using a solvent extractant system 12. An extractant solution 14 is mixed with an HCl solution 16 to form an aqueous layer 18 and an organic extractant 20. The organic extractant 20 is introduced into an extraction section 22 of the system 12 and mixed with a recycled, stripped organic solvent 32 and a first raffinate 34 to form a first mixture 36 which is separated into a first organic layer 38 and a Ni-containing aqueous layer 40. A feed solution 44 consisting of the spent etchant solution 10 and concentrated HCl is combined with the first organic layer 38 to form a second mixture 46 which is separated into the first raffinate 34 and an organic solution 47 having a high concentration of iron. The solution 47 is introduced into a stripping section 48 of the system 12 and mixed with a raffinate 58 to form a third mixture 60 which is separated into a partially stripped organic layer 62 and an aqueous ferric chloride solution 64. A second HCl solution 66 is combined with the organic layer 62 to form a fourth mixture 68 which is separated into the organic solvent 32 and the raffinate 58. The aqueous ferric chloride solution 64 is processed 70 to provide either a concentrated ferric chloride etchant solution 72 in a continuous system 13, or a dried ferric chloride salt 74, in a non-continuous system.