Thorium pertraction through hollow fiber renewal liquid membrane (HFRLM) using Cyanex 272 as carrier

Optimization of thorium solvent extraction process from feed solution with Cyanex 272 by response surface methodology (RSM)

Due to the limited reserves of uranium, the abundance of thorium compared to it and other advantages, the development of the thorium fuel cycle is of interest in different countries. The optimization of thorium extraction from a feed solution produced by Saghand ore with bis(2,4,4-trimethylpentyl) phosphinic acid (Cyanex 272) on a laboratory scale was evaluated by response surface method. The operating variables include Cyanex 272 concentration of 0.001 to 0.2 mol/L, pH of 0 to 2, equilibrium time of 5 to 60 min and aqueous to organic phase ratio of 0.5 to 2.5 were conducted. The value of R2 = 0.9695 and an error of less than 4% indicate the validity of the model. Therefore, the model is in good agreement with the experimental results. It can be said that there are significant interactions between operational parameters, which vindicate different feedbacks of the system in different operational conditions. The results showed that the 4 mol/L sulfuric acid was a suitable agent for recovering thorium ions from the loaded organic phase. In optimum conditions, the thorium purity percentage and thorium stripping efficiency were obtained 98.99 and 94.12%, respectively.

Performance evaluation of hollow fiber renewal liquid membrane for extraction of uranium(VI) from acidic sulfate solution

The performance of the hollow fiber renewal liquid membrane (HFRLM) in the continuous and recycling modes for the extraction of uranium(VI) from the acidic sulfate solution has been investigated. Alamine 336 diluted in kerosene was used as a carrier in liquid membrane (LM) phase. In the batch experiments, the effects of sulfuric acid, extractant and uranium(VI) concentration were studied and the optimum concentration of the donor and LM phases were determined 0.15 mol L−1and 0.0125 mol L−1, respectively. Various parameters affecting the HFRLM performance including the lumen and shell side flow rate, organic/aqueous volume ratio, acceptor phase type and concentration of carrier and acceptor phase were studied. The mass transfer flux increases with increasing the lumen side flow rates and the shell side flow rate did not have any significant effect. The uranium transfer flux increases with increasing O/A ratio, acceptor and Alamine 336 concentration, and reaches a maximum value at 1/20, 0.5 mol L−1and 0.0125 mol L−1, respectively. Further increase in these parameters result in uranium transfer decrement. The results show that liquid membrane phase is a rate-controlling step. Among the investigated acceptor phases, 0.5 mol L−1NH4Cl result in 60.35% uranium(VI) recovery in the recycling mode.