Decontamination Studies of Radioactive Thorium by Natural Clays

Abstract

A sensitive spectrophotometric method for the determination of microquantities of thorium in exchange studies with natural clays was developed. The uptake capacity of natural local clays was found to be 10 – 17 meq. Th/100 gm clay. The uptake increases in the sequence fine > medium > coarse. It starts at pH values of 1.1 to 1.3, where ion-exchange mechanism prevails. At higher pH of about 3.7 decontamination occurs because of the precipitation of thorium. An explanation of the uptake mechanism was endeavoured. The effect of competing ions was also investigated.