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AssigneesP. B. Macedo, T. A. Litovitz
InventorsDanh C. Tran, Pedro B. Macedo, Joseph H. Simmons, Catherine J. Simmons, Nicholas Lagakos
Estimating the term…
This invention relates to the immobilization of toxic, e.g., radioactive materials, internally in a silicate glass or silica gel matrix for extremely long periods of time. Toxic materials, such as radioactive wastes containing radioactive anions, and in some cases cations, which may be in the form of liquids, or solids dissolved or dispersed in liquids or gases, are internally incorporated into a glass matrix, having hydrous organofunctionalsiloxy groups, e.g., hydrous aminoalkylsiloxy or carboxyorganosiloxy, bonded to silicon atoms of said glass and/or hydrous polyvalent metals bonded to silicon atoms of said glass through divalent oxygen linkages or otherwise immobilized therein, by a process which involves the ion exchange of said toxic, radioactive anions with hydroxyl groups attached to said organofunctionalsiloxy groups or with hydroxyl groups attached to the hydrous polyvalent metal. Thereafter, the resulting glass now characterized by a distribution of internally bonded or immobilized, toxic, radioactive anions can be packaged in suitable containers, and disposed of as by burial, and/or they can be sintered to collapse the pores thereof prior to disposal or for producing useful radiation sources. The porous glass or a porous silica gel having said silicon-bonded organofunctionalsiloxy groups and/or said hydrous polyvalent metal oxy groups, the pores of said glass or silica gel remaining open and uncollapsed, can be used advantageously as a backfill for an underground radioactive waste burial site and as overpack in the waste disposal container. Also included is a novel method for bonding the polyvalent metal to the porous silica glass or gel by substituting the protons of the silicon-bonded hydroxyl groups thereof with an alkali metal or ammonium cation followed by displacement of said cation with the non-radioactive polyvalent metal cation.
A process for separating and immobilizing radioactive anions and/or radioactive cations from a liquid containing same comprising contacting said liquid with a porous silica glass or gel comprising at least 82 mol percent silica having interconnected pores and (a) non-radioactive cationic organosiloxy groups bonded to silicon of the glass or gel on the internal surfaces of said pores and non-radioactive anions ionically bonded to said cationic organosiloxy groups and displaceable by said radioactive anions;
Process as claimed in claim 3 wherein said ammonium organosiloxy groups are represented by the formula:
A sintered silicon dioxide-containing matrix containing radioactive anions internally bonded to internal silicon atoms of said matrix through polyvalent metal oxy groups selected from the group consisting of ##STR17##
A method for the prevention of the dissemination of radioactive materials into the environment comprising surrounding radwaste containing radioactive cations and/or radioactive anions in a silica gel or silica glass substrate with an ion exchange backfill comprising a porous silicate glass or silica gel having interconnected pores and non-radioactive cationic and/or anionic groups bonded to silicon of the glass or gel on the internal surfaces of the pores thereof, said non-radioactive cationic and/or anionic groups being capable of being displaced by said radioactive cations and/or anions.
A process for containing a radioactive material which comprises impregnating a porous silicage glass having interconnected pores and non-radioactive organofunctionalsiloxy groups bonded to silicon of the glass and/or having non-radioactive hydrous polyvalent metal oxides bonded to silicon of the glass through divalent oxygen linkages on the internal surfaces of said pores, said a liquid solution containing radioactive anions to dispose said solution within the pores of said glass to provide a distribution of internally bonded radioactive anions within the pores of said glass, and heating the porous glass to collapse said pores containing said internally bonded radioactive anions.
A method for preparing an anion exchange medium for the removal of radioactive anions from a liquid stream comprising bonding anion exchange groups to silicon-bonded oxygen of a porous silicate glass or porous silica-gel having interconnected pores, said anion exchange groups being polyvalent hydrous metal oxide groups exhibiting anion exchange properties involving surface hydroxyl groups, the hydrous metal oxide groups being bonded to silicon via divalent oxygen linkages by converting silicon-bonded hydroxyl groups of said porous glass or silica gel to alkali metal oxy groups, displacing the alkali metal ions with polyvalent metal nitrate groups, and replacing the nitrate groups with hydroxyl groups.
An underground reservoir for storing radioactive ionic wastes which are contained in a silica gel or silica glass substrate comprising a container containing said wastes disposed within an underground cavity and a backfill surrounding said container, said backfill comprising particles of silica glass or gel having interconnected pores and nonradioactive ions ionically bonded to ionic groups or atoms bonded to silicon of said glass or gel on the internal surfaces of said pores, said non-radioactive ions being displaceable bu said radioactive ions of said waste.
A package for storing radioactive ionic wastes which are contained in a silica gel or silica-glass substrate comprising a container containing said wastes and an overpack surrounding said wastes, said overpack comprising particles of silica glass or gel having interconnected pores and non-radioactive ions ionically bonded to ionic groups or atoms bonded to silicon of said glass or gel on the internal surfaces of said pores, said non-radioactive ions being displaceable by said radioactive ions of said waste.
A process for separating and immobilizing radioactive anions and/or radioactive cations from a liquid containing same comprising contacting said liquid with a porous silica glass or gel comprising at least 82 mol percent silica having interconnected pores and (a) non-radioactive cationic organosiloxy groups bonded to silicon of the glass or gel on the internal surfaces of said pores and non-radioactive anions ionically bonded to said cationic organosiloxy groups and displaceable by said radioactive anions;
A method for the preparation of the dissemination of radioactive materials into the environment comprising surrounding radwaste containing radioactive cations and/or radio-active anions with an ion exchange backfill comprising a porous silicate glass or silica gel having interconnected pores and (a) non-radioactive cationic organosiloxy groups bonded to silicon of the glass or gel on the internal surfaces of said pores and non-radioactive anions ionically bonded to said cationic organosiloxy groups and displaceable by said radioactive anions;
Dependencies are inferred from the claim text.