SOLVENT-EXTRACTION OF MOLYBDENUM-(VI) BY DIISODODECYLAMINE FROM SULFURIC-ACID-SOLUTION

Solvent extraction of molybdenum (VI) from sulphuric acid solutions (0 .25-0.3 M) by diisododecylamine (DIDA) was investigated. One of the ad vantages of DIDA over TOA (tri-n-octyl amine) is the possibility of us ing the extractant without a modifier in the DIDA-diluent system. The influences of aqueous phase acidity, type of diluent, molybdenum conce ntration, and DIDA concentration on the extraction of molybdenum (VI) has been examined. As discussed below, the extraction proceeds in an a nion-exchange reaction involving the formation of polymeric molybdenum -DIDA complexes, whose compositions change with time and depend on the process regime. The extraction efficiency for molybdenum (VI) by DIDA decreases in the order: toluene, kerosene, EDD-1 (extraction de-aroma tic diluent, an aliphatic type of kerosene) in accordance with the dil uent nature. This observation is consistent with the content of aromat ic substances in the diluents mentioned. (C) 1998 Elsevier Science B.V .