No abstract

Work has been carried out screening hydrometallurgical resins for application in the valorization of industrially produced jarosite. Of the seven resins tested, anion exchange resins performed poorly for valuable metal recovery. Purolite S950+ and S957, along with a strong acid resin, show good extraction properties but are selective for Fe 3+ over the other (divalent) metals. Purolite S930+ (iminodiacetic acid-functionalized resin) demonstrates selectivity for Cu 2+ over Fe 3+ but poor selectivity for Ni 2+ , Zn 2+ and Co 2+. Dowex M4195 (bispicolylamine-functionalized resin) demonstrates promise for extracting metals of value away from a mixed metal pregnant liquor solution (PLS). A three-stage column based recovery process is proposed for jarosite leachate treatment.

No abstract

In this report, the interaction of monoamide/diamide and monoamide/diglycolamide mixtures with UO 2+ 2 are investigated in pH = 1 methanolic nitric acid media. These monoamides include N,N-dimethylacetamide (DMAA), N,N-diethylacetamide (DEAA), N,N-dibutylacetamide (DBAA) and N,N-dibutylbutanamide (DBBA). N,N,N′N′tetraethylmalonamide (TEMA) and N,N,N′,N′-tetraethyldiglycolamide (TEDGA), which were chosen as model diamides and diglycolamides, respectively. Complex stability constants for each ligand were modelled using the Stability Quotients Using Absorbance Data program using UV-visible data. Complex stoichiometry of ligand mixtures was determined using Job plots and UV-Vis spectrometry. Monoamides were confirmed to produce only disolvate complexes with UO 2+ 2 in solution. The log 10 (K) values for monoamides were found to be independent of amine-side chain length, but were slightly dependent on the carbonyl-side chain length. TEDGA was found to produce multiple uranyl complexes in solution. Job plot data indicated that the uranyl cation strongly prefers to bond either only with the monoamide or diamide in ternary monoamide-diamide-UO 2 systems. Monoamide-diglycolamide-UO 2 systems were more complicated, with Job plot data indicating the potential for multiple ternary species being present is dependent on the monoamide structure.

No abstract