Valenzuela et. al. (1995) [100] has proposed a hydrometallurgical procedure for the separation of molybdenum from Chilean molybdenite concentrate. The molybdenite concentrate was first leached with nitric acid originated from the reaction of NaNO3 and H2SO4, which provided a solid phase, composed of MoO3 and residual solution. Molybdenum was separated with alkylphosphonic acid PC-88A by solvent extraction method, from the leach liquor containing copper, rhenium and iron among other impurities. The extraction efficiency of molybdenum was about 96% at pH 0.8 with zero co-extraction of other metals. The loaded organic was stripped with ammonia aqueous solution. One extraction stage and two stripping stages were required for the enrichment of Mo …show more content…
al. (1998) [103] preferred DIDA over wildly known amine extractant TOA, due to its possibility of using as extractant without adding a modifier. The parameters of solvent extraction such as aqueous phase acidity, type of diluents, molybdenum concentration, and DIDA concentration were investigated to obtain the suitable condition for effective extraction of molybdenum. The extraction mechanism was an anion-exchange reaction, which formed a polymeric complex, expressed as (R2NH)n MomOp(HSO4)y, where the values of n, m, p and y are depend on the polymerization degrees of molybdenum and amine in organic and aqueous phase. The polymeric complex changes according to the concentration of DIDA and metal, aqueous acidity, diluents, time, and type of extraction process. The extraction of molybdenum was sensitive to diluents and it decreased in the order of toluene> kerosene>EDD-1. Caiozzi M et al. (1969) [104] have used tributyl phosphate (TBP) for the extraction of peroxymolybdate complex from sulphate medium. The effect of solvent extraction parameters was examined and the extraction behaviour of other ions was studied. The developed analytical procedure for molybdenum determination was used for ore …show more content…
The extraction efficiency was most successful with dichloroethane as diluents than any others. Stripping study was carried out with hydrochloric acid. The method was applied for the separation of Mo from minerals composed of different kinds of metals. In this experiment molybdenum was determined by drywashing it and was followed by spectrophotometrically analysis as a complex with Tiron at 390 nm. Turel and Patil (1996) [112] have established a rapid and selective method for the extraction of molybdenum with malachite green into nitrobenzene. The influence of solvent extraction variables on molybdenum extraction such as effect of pH, time of equilibration, solvents, effect of various anions and cations have been studied. On the basis of substoichiometric extraction method the constituent ratio of the metal-organic complexes was found as 1:1. The slope ratio method was also in agreement with the