Development of a process for recovery of helium from monazite sand

The pilot plant studies made to develop a process for helium recovery from monazite and its purification are described. The steps in the developed process are : (1) liberation of helium from monazite processing plant during caustic digestion of the ore, (2) collection of the crude gas (30-50% helium) after removal of condensables and drying, (3) removal of hydrogen by catalytic combination with oxygen to form water vapour using de-oxo catalyst bed, (4) removal of oxygen and nitrogen by condensation (helium content is raised 98% in this step) and (5) passing the gas over activated charcoal cooled by liquid nitrogen. In the final step, 99.995% pure helium is obtained. Trials have shown that the process is feasible. (M.G.B.)