For the recovery of lanthanides and actinides such as europium and uranium from spent nuclear oxide fuel, the sulfide process which consists of three steps such as, 1) voloxidation, 2) selective sulfurization and 3) selective dissolution, has been proposed. The new process has some advantages for the recovery of nuclear materials from spent fuel with more effective and convenient methods comparing with conventional wet processes. Lanthanide oxides were selectively sulfurized by the use of CS2 at temperature lower than 673 K, while actinide oxides such as UO2 remain as oxide. After the sulfurization, lanthanides were found to dissolve into nitric acid. The sulfurization and dissolution behavior of plutonium was studied by the use of chemical analogue, CeO2 and plutonium tracer. From the results, the separation of lanthanides and actinides could be achieved by the sulfide method, i.e. selective sulfurization and dissolution. The applicability of the sulfide process to the spent nuclear fuel reprocessing was also discussed.
The lithium ion secondary batteries (LIBs) are widely used as electrochemical power sources in modern-life appliances and the usage of LIBs has rapidly increased. Recycling of LIBs has increasingly become important because their safe disposal may become a serious problem due to the presence of flammable and toxic elements or compounds although spent LIBs are not generally classified as dangerous waste and at the same time, some economic benefits could be achieved in recovery of major components from LIBs. Since spent LIBs represent a valuable waste material for recovery of metals or compounds, recycling of spent batteries may result in economic benefits. The extraction and separation of Co and Li by solvent extraction using D2EHPA and EHPNA (PC-88A) as extractant alone and in combination with TOA and TBP from chloride and sulfate solutions were investigated to obtain the fundamental data for the hydrometallurgical treatment of the spent lithium ion secondary batteries. From this study, the extractant combination, EHPNA/TOA, is favorable to the separation of Co and Li from chloride and sulfate solutions compared with other extractants tested in this study. It was also found that the separation efficiency of Co and Li with EHPNA/TOA from chloride solution was better than that from sulfate solution.