The separation of cerium from other rare earths in the hydrochloric acid solution was studied.
For two methods chosen for industrial applications, the procedures were simple and cerium of high purity was easily obtained.
（I） Fractional precipitation as phosphates :
Cerium oxidized by potassium permanganate was fractionally separated as insoluble ceric phosphate by pre-added sodium phosphate. The optimum concentration of the free hydrochloric acid was 3 %, and the yield of this case was 97 %.
（II） Fractional precipitation by hypo-chlorite.
Cerium was oxidized by sodium hypo-chlorite and fractionally precipitated. By adjusting the pH of the solution at 5.6, cerium was completely separated. The crude cerium precipitate was purified to high purity by nitric acid leaching.