Abstract: A study was made to develop an economical method of preparing pure rare earth nitrate mixture from volved leaching the calcined ore with nitric aicid. The proccss is discussed under the following headings: calcination of the ore, leaching of calcine, filtration studies, solvcnt cxtraction, and nitric acid recovery. Results obtained from the study showed that over 98% of the rare earths could be recovered. About 18% of the nitric acid fed to the leaching operation was combined with rare earths or was lost in the nitric acid recovery operation. (J.H.M.)