Separation of Uranium from Rare Earths using Tertiary Amine from Sulfate Solutions

A sulfate leach liquor of 0.78 g/l uranium and 0.57 g/L rare earths produced from Abu-Zeniema wastes was subjected to different extraction experiments using tri-octyl amine as a solvent.  Complete extraction of uranium from rare earths sulfate solutions was performed using a sulfate leach liqueur of pH 1.25, 10% TOA in kerosene, 1/20 organic to aqueous phase ratio and stirring for three minutes at room temperature.  The saturation capacity of 14.0 g U/L was performed after three contacts between sulfate leach liquor and TOA organic solvent. The optimum uranium stripping conditions from the saturated TOA solvent were performed using sodium carbonate as a stripping agent with 0.75M molarity, 3 minutes contact time and 1/4 aqueous to organic ratio. Three stages of contacts counter currently were required for uranium stripping from the loaded organic using the optimum stripping conditions. A strip solution of 47.6 g U/L was obtained by two contacts between a fresh saturated solvent and the same carbonate strip solution. A fine grained uranium peroxide cake with 65.1% U was attained from the stripping solution by hydrogen peroxide precipitation at pH 2

Recovery of rare earth elements from El-Sela effluent solutions

The study area of Gabal El Sela at Halaib environ is located at about 20 km west of Abu Ramad City, Egypt. An uraniferous ore material associated with REE was subjected to sulphuric acid leaching for the extraction of uranium mainly and REEs as a by-product. 93.9% of U and 60% of REEs content were leached using −0.5 mm ground ore with 100 g/l sulfuric acid, acid/ore ratio of 2.0 and agitate for 6 h at 40 °C. After uranium extraction, effluent solutions containing 135 ppm rare earths were treated with 30% ammonium hydroxide to pH of 9.3 to enhance the rare earth elements concentration. The precipitated cake was filtered then dried at 110 °C. The dried cake containing 16.2% rare earth elements was dissolved by hydrochloric acid at pH 1.0. The rare earths precipitated cakes of 36.9, 45.7 and 48.7% REEs were recovered successfully from the chloride leach liquor of 900 ppm rare earths by using 5% v/v from 50% HF, 6% wt/v oxalic acid and 4.8% wt/v oxalic acid to chloride solution with heating for one hour which respectively. 73.5% REEs precipitated cake was achieved by double precipitation, firstly by hydrofluoric acid followed by oxalic acid precipitation

Cadmium and iron removal from phosphoric acid using commercial resins for purification purpose

International audienceThree commercial resins bearing sulfonic, amino phosphonic, or phosphonic/sulfonic reactive groups have been tested for the removal of iron and cadmium from phosphoric acid solutions. The sorption properties are compared for different experimental conditions such as sorbent dosage (0.5–2.5 g L−1), phosphoric acid concentration (from bi-component solutions, 0.25–2 M), and metal concentrations (i.e., in the range 0.27–2.7 mmol Cd L−1 and 0.54 mmol Fe L−1) with a special attention paid to the impact of the type of reactive groups held on the resins. The sulfonic-based resin (MTC1600H) is more selective for Cd (against Fe), especially at high phosphoric acid concentration and low sorbent dosage, while MTS9500 (aminophosphonic resin) is more selective for Fe removal (regardless of acid concentration and sorbent dosage). Equilibrium is reached within 2–4 h. The resins can be ranked in terms of cumulative sorption capacities according the series: MTC1600H > MTS9570 > MTS 9500. Sulfuric acid (0.5–1 M) can be efficiently used for the desorption of both iron and cadmium for MTC1600H, while for MTS9570 (phosphonic/sulfonic resin) sulfuric acid correctly desorbs Cd (above 96% at 1 M concentration), contrary to Fe (less than 30%). The aminophosphonic resin shows much poorer efficiency in terms of desorption. The sulfonic resin (i.e., MTC1600H) shows much higher sorption capacity, better selectivity, comparable uptake kinetics (about 2 h equilibrium time), and better metal desorption ability (higher than 98% with 1 M acid concentration, regardless of the type of acid). This conclusion is confirmed by the comparison of removal properties in the treatment of different types of industrial phosphoric acid solutions (crude, and pre-treated H3PO4 solutions). The three resins are inefficient for the treatment of crude phosphoric acid, and activated charcoal pre-treatment (MTC1600H reduced cadmium content by 77%). However, MTC1600H allows removing over 93% of Fe and Cd for H3PO4 pre-treated by TBP solvent extraction, while the others show much lower efficiencies (< 53%)