Studies on extraction of thorium by the N-oxides of 5-(4-pyridyl)nonane and trioctylamine from different mineral acid solutions and its separation from rare earth elements and yttrium

The N-oxides of 5-(4-pyridyl)nonane and trioctylamine have been evaluated for use in the extraction of thorium from different mineral acid solutions. The influence of the concentration of the solvents and salting-out agents has been investigated. The possible mechanism of extraction is discussed in the light of the results of extraction isotherms, loading-ratio data and log-log plots of reagent concentration vs. distribution ratio. Separation factors for a number of metal ions are reported and a method for the separation of thorium from rare earth elements and yttrium is also suggested. (author)