Artificial Compounds of the Crandallite Type; A new Material for Separation and Immobilization of Fission Products

Abstract

ABSTRACTMinerals of the crandallite group (Ca, Sr. Ba, Pb, REE) H Al3((po4) 2/(OH)6) exhibit manifold possibilities for element substitutions. They occur as hydrothermal precipitates together with tin tungsten mineralization [1], as placer minerals [2], neo-formed minerals in lateritic profiles [3, 4] and lake sediments [5].An easy and cheap method of synthesizing an artificial crandallite-type material was developed. By adding 4.2 g of crandallite to an aqueous solution containing 300 g/l sodium nitrate, 0.6 g/l europium nitrate and 0.6 g/l thorium nitrate, europium and thorium were effectively separated from the solution. This was also demonstrated for Ce. La, Nd, Gd, Zr, Ba and Sr.Artificial crandallite-type material laden with strontium was subjected to a Soxlet test. A dissolution of strontium of 0.06 to 0.08 wt.% with reference to the total strontium content resulted. As shown by Herold [6] the substitution of Ca by larger bivalent or higher charged ions results in an increase in the thermodynamic and thermal stability of artificial crandallites.