Evaluation of uranium adsorption using magnetic-polyamine chitosan from sulfate leach liquor of Sela ore material, South Eastern Desert, Egypt

Abstract

Chitosan particles with magnetic properties were prepared by co-precipitation method combined with hydrothermal treatment, then crosslinked with epichlorohydrin followed by grafting of triethylenetetramine. The obtained adsorbent material was characterized by means of FTIR and XRD and its adsorption properties towards uranyl ions were firstly investigated from synthetic solutions as a function of pH, contact time and initial uranium concentration using batch method and at room temperature. The maximum adsorption capacity was found to be158.43 mg/g at pH 4 and initial uranium concentration of 300 mg/l. Urea solution of 0.5 mol/l acidified with a few drops of sulfuric acid 0.2 mol/l can be efficiently used for uranium recovery and the adsorbent can be recycled for at least five successive cycles with limited decrease in adsorption performance. Subsequently, the application efficiency of the adsorbent material was evaluated by testing uranyl adsorption from sulfate leach liquor of Sela ore material after adaptation of leaching conditions. Uranium ore sample was subjected to acid conventional leaching through direct agitation with sulfuric acid and the relevant variables affecting leaching efficiency were optimized as 60 g/l sulfuric acid with liquid/solid weight ratio 3 at 45 °C for 90 minutes. Under these conditions, the leaching efficiency of uranium was 92%. Uranium adsorption capacity from sulfate leach liquor was found to be 132.98 mg/g at pH 4 and shaken time of 60 minutes with initial uranium concentration of 200 mg/l. This adsorption capacity represents only about 87% from the adsorption ability from synthetic solutions (152.86 mg/g) at the same conditions.