Patent Number: 047708174
Section: claims

1. A method of encapsulating radioactive wastes in .alpha.-alumina comprising (A) forming a solution or colloid of said radioactive wastes in a liquid that has a surface tension low enough to wet gravel-sized pieces of a porous .delta.-alumina having at least 40% porosity;  (B) permitting said solution or colloid to enter the pores of gravel-sized pieces of .delta.-alumina;  (C) evaporating said liquid;  (D) heating said gravel-sized pieces of .delta.-alumina to their alpha-alumina transformation temperature to seal said pores, thereby entrapping said radioactive wastes therein; and  (E) after said heating, washing the surface of said gravel-sized pieces to remove radioactive wastes not trapped in said pores. 2. A method according to claim 1 wherein said transformation temperature is about 1200.degree. to about 1250.degree. C. 3. A method according to claim 1 wherein a solution is formed. 4. A method according to claim 1 wherein said liquid is water. 5. A method according to claim 1 wherein said liquid is an alcohol having up to 4 carbon atoms. 6. A method according to claim 1 wherein said solution is heated below its boiling point to increase the speed and extent of its penetration into said pores.