Method of immobilizing nuclear waste in glass

Claim 1

A method of immobilizing nuclear waste characterized by: (A) preparing a composition which comprises (1) from 30% to 85% by weight, calculated as SiO 2 , of a silicon compound having the general formula SiR m (OR') n X p or Si(OSiR 3 ) 4 where each R is independently selected from alkyl to C 10 and alkenyl to C10, each R' is independently selected from R and aryl, each X is independently selected from chlorine and bromine, m is 0 to 3, n is 0 to 4, pis 0 to 1, and m + n + p equals 4; (2) from 5% to 30% by weight, calculated as Na 2 0, of a sodium compound having the general formula NaOR" or NaZR' 3 , where each R" is independently selected from R and hydrogen, and Z is carbon or boron; (3) up to about 30% by weight, calculated as Al 2 O 3 , of an aluminum compound having the general formula AlR' q (OR") r X s or Mg(Al(OR) 4 ) 2 , q is 0 to 3, r is 0 to 3, s is 0 to 1, and q + r + s equals 3; (4) from 5% to 30% by weight, calculated as the corresponding oxide, of a compound selected from boron compounds having the general formula BR' q (OR") r X s , where q + r + s equals 3, alkaline earth metal compounds having the general formula MR t (OR") u X v where M is calcium or magnesium, t is 0 to 2, u is 0 to 2, v is 0 to 1, and t + u + v equals 2, lithium compounds having the general formula LiOR, and mixtures thereof, said composition being at least partially hydrolyzed; (B) mixing into said composition up to about to an equal amount by weight of said nuclear waste at up to 500°C until the mixture is dry and organics have been removed; and (C) melting said mixture at from 800°C to 1300°C.

Claim 2

A method of immobilizing nuclear waste characterized by: (A) preparing a composition which comprises (1) from 30% to 85% by weight, calculated as SiO 2 , of a silicon compound having the general formula SiR m (OR') n X p or Si(OSiR 3 ) 4 where each R is independently selected from alkyl to C 10 and alkenyl to C10, each R' is independently selected from R and aryl, each X is independently selected from chlorine and bromine, m is 0 to 3, n is 0 to 4, pis 0 to 1, and m + n + p equals 4; (2) from 5% to 30% by weight, calculated as Na 2 0, of a sodium compound having the general formula NaOR" or NaZR' 3 , where each R" is independently selected from R and hydrogen, and Z is carbon or boron; (3) up to about 30% by weight, calculated as Al 2 O 3 , of an aluminum compound having the general formula AlR' q (OR") r X s or Mg(Al(OR) 4 ) 2 , q is 0 to 3, r is 0 to 3, s is 0 to 1, and q + r + s equals 3; (4) from 5% to 30% by weight, calculated as the corresponding oxide, of a compound selected from boron compounds having the general formula BR' q (OR") r X s , where q + r + s equals 3, alkaline earth metal compounds having the general formula MR t (OR") u X v where M is calcium or magnesium, t is 0 to 2, u is 0 to 2, v is 0 to 1, and t + u + v equals 2, lithium compounds having the general formula LiOR, and mixtures thereof, said composition being at least partially hydrolyzed; (B) mixing into said composition up to about to an equal amount by weight of said nuclear waste at up to 500°C until the mixture is dry and organics have been removed; and (C) melting said mixture at from 800°C to 1300°C.

Claim 6

A method according to any of claims 1 to 4, characterized in that the silicon compound has the general formula SiR m (OR') X where R' is alkyl to C 4 and n = 4, the sodium compound has the general formula NaOR" where R" is alkyl to C 4 , the aluminum compound has the general formula AlR' q (OR") r X s where R" is alkyl to C 4 and r is 3, the boron compound has the general formula BR' (OR") r X s where R" is alkyl to C 4 and r is 3, and the alkaline earth metal compound has the general formula MR t (OR") u X v where R" is alkyl to C 4 and u is 2.

Claim 8

A method according to any of claims 1 to 6, characterized in that the silicon compound is hydrolyzed in alcohol at a molar ratio of silicon compound to alcohol of from 0.2 to 2, with water at a molar ratio of silicon compound to water of from 0.1 to 5.

Claim 9

A method according to any of the preceding claims, characterized in that the silicon compound is at least partially hydrolyzed prior to its addition to the composition.