Purification of thorium by precipitation

A precipitation method was applied to produce high-purity thorium product from industrial grade Th(NO3)4·4H2O. The conditions of pH in the thorium solution, the contents of hydrogen peroxide, calcination temperature were investigated as well as calcination time. The hydrogen peroxide of 30% (v:v) was added into the thorium solution and was continually stirred. The concentration of hydrogen peroxide was exceeded over 0.1–0.5 mol/L after suitable reaction between Th(NO3)4·4H2O and hydrogen peroxide. The pH of the solution was maintained at 2 through adding ammonium hydroxide. The precipitation obtained in the form of Th2O7·4H2O. The high-purity thorium product was prepared after calcination for 2 h at 700 °C. The purity of the purified thorium product was above 99.8%.