Technical report. Three extractions of a diethyl ether solution of uranyl nitrate with small portions of water are effective in removing rare earths, as is shown by radio-gadolinium and radio-europium tracer experiments. A study of representative ethers, alcohols, ketones, and esters showed that diethyl ether and a mixture of 85% ethyl methyl ketone with 15% xylene are the best solvents for the extraction.

Technical report abstract. A rapid procedure for the preparation of very pure carrier-free Zr and Nb tracer involves the chloroform extraction of the cupferrides of Zr and Nb activities from process solutions. Zr and Nb form very stable chloroform soluble cupferrides in acid solutions (CK-993) and are separated from other fission elements almost quantitatively to yield pure mixture of Zr and Nb activity. A minimum of operations is required and the method is easily adaptable to remote control.