Quantitative separation of trace amount of rare earth elements from nuclear grade alumina

Alumina oxide is an exceptionally important ceramic material which has many technological applications. Alumina (Al₂O₃) occurs in nature as the minerals corundum, diaspore, gibbsite and bauxite. α-Al₂O₃ is one of the promising insulating ceramic materials for International Thermonuclear Experimental Reactor (ITER) and commercial reactors, because of its high electrical resistance. More than 90% alumina produced worldwide is utilized in the production of aluminum. In this work, microwave dissolution method has been developed for quantitative dissolution of alumina followed by quantitative separation of trace amount of rare earth elements from alumina matrix. The aluminum and rare earth elements were precipitated with NaOH solution. In presence of excess amount of sodium hydroxide solution, aluminum form soluble sodium-aluminate, while rare earth hydroxides retain as precipitate. The precipitate is separated from the solution using Whatmann-542 filter paper and washed with plenty of water to remove excess sodium hydroxide. The precipitates redissolved in concentrated hydrochloric acid and bring in suitable medium for analysis. The separation method was validated using standard addition method. The separated rare earth elements were quantified by ICP-MS. The result shows that the rare earth elements quantitatively separated from the aluminum matrix