TBP-Impregnated Siplite LX-16 Polymeric Resin for Thorium Extraction from Nitrate Medium, Part A: Preparation and Extraction Performance

Abstract

Impregnation of tri butyl phosphate (TBP) solvent into polymeric resin, commercially known as Siplite LX-16, using the two commonly used dry and wet methods were applied. The suitable conditions for wet impregnation were 70% solvent concentration in kerosene with solvent/resin (S/R) ratio of 6.0 and left 24 hours for impregnation at room temperature before separation and washing with hot water then drying overnight at a temperature of 50 o C, where at these conditions the resin impregnated with 1.99 g TBP/g resin. In case of dry impregnation requires solvent concentration was 55% in acetone at S/R ratio of 5.0 and shaking for 4.0 h then left in the air till complete volatilization of acetone and finally drying overnight at a temperature of 50 o C, where at these conditions one resin impregnated with 2.057 g TBP. Results of testing performance of the prepared TBP impregnated Siplite LX-16 resin against thorium extraction from nitrate medium reveal that extraction efficiency of 70.7% was achieved after 30 min. which can be enough to attain equilibrium. Thorium extraction from the nitrate medium requires high free acidity rather than nitrate from salts (salting out agent addition), however, for economical consideration and reagent saving, it can practically conduct the extraction at free normality of 3.0 N at which 62% extraction efficiency could be achieved at the condition of initial thorium concentration of 2.0 g/l, aqueous/resin "A/R" ratio of 25 and the phases contacted for 30 min. The calculated theoretical saturation capacity for the prepared TBP impregnated Siplite LX-16 resin was 292.7 mg Th / g impregnated resin which is considered high capacity, so it was recommended to use solutions containing high levels of thorium concentrations reached to several grams per liter to decrease the treated volumes at shorter time as well as verify almost complete saturation.