ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 23, Number 3
JKCSEZ 23(3)
June 20, 1979 

The purpose of this investigation was to study the sulfuric acid digestion of monazite sand, and to prepare rare-earths-thorium containing material from the resulting solution which would be suitable for further preparation of thorium and rare earth elements by ion-exchange. Digestion of crude monazite sand was treated in 95% sulfuric acid for 2.0 hours at 150∼250℃. The acid to sand weight ratio were 1 : 1.9∼2.8. Optimum condition was 95% sulfuric acid for 2.0 hours at 200±5℃. Within this conditions monazite sand was decomposed up to 99%.