Effect of Ammonium Salts on the Solvent Extraction of Some Transition Metals with Liquid Cation Exchangers

Abstract

The extractions of some transition metal ions from an ammoniacal solution with di-(2-ethyl hexyl) phosphoric acid and Versatic Acid 911 diluted in benzene were investigated in order to clarify the effect of ammonia on the solvent extraction. As regards the result, the extraction of these metals with D2EHPA was not affected by ammonia, while the extraction with Versatic Acid 911 was considerably affected. These results were discussed by the average ligand number of metal ammine complexes. Theoretical consideration on the solvent extraction in the presence of ammonia was performed to predict the extent of interference on the solvent extraction by the formation of metal ammine complexes in the aqueous phase. The results of this consideration were in good accordance with the experimental results of copper and zinc extraction, and were in near coincidence with the experimental results of nickel and cobalt extraction. However, there was no coincidence between the results of the theoretical consideration and the experimental results of cadmium extraction.