Volume reduction of aqueous waste by evaporative crystallization of burkeite and sodium salts
AssigneeCogema Engineering Corporation
InventorDonald James Geniesse
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Abstract
A method of treating aqueous salt solutions to provide a solution suitable for vitrification to a stable glass matrix for long term storage is described. In particular, salt solutions composed of aqueous nuclear waste materials are suitable for treatment by the described method. Specifically, salt solutions which have a sulfate to sodium mole ratio that does not permit easy vitrification into stable glasses may be treated by the present invention. The present method decreases the volume of vitrified glass.
Claims27
A process for the removal of burkeite from a salt solution comprising aluminum ions, carbonate ions, fluoride ions, sodium ions, calcium ions, and sulfate ions comprising:
- adding alkali to a salt solution comprising salts comprising aluminum ions, carbonate ions, fluoride ions, sodium ions, calcium ions, and sulfate ions to form a solution containing alkali soluble compounds;
- optionally filtering the solution to remove any undissolved solids and to produce a solution essentially free of solids;
- evaporating excess water from the solution to produce a saturated solution, wherein during the evaporating step the temperature of the solution is between about 50° C. and about 150° C. and the pressure of the solution is between about 0.2 atmospheres to about 2 atmospheres—has been inserted;
- precipitating burkeite from the saturated solution;
- and
- separating the precipitated burkeite from the saturated solution.
A process for the removal of burkeite and sodium-containing complex salts from a salt solution comprising aluminum ions, sodium ions, carbonate ions, calcium ions, fluoride ions and sulfate ions comprising:
- adding either hydroxide or water to a salt solution comprising salts comprising aluminum ions, sodium ions, carbonate ions, calcium ions, fluoride ions and sulfate ions to solubilize aluminum containing compounds thereby to form a solution containing soluble aluminum compounds from the salt solution;
- optionally filtering off any undissolved solid material from the solution containing soluble aluminum compounds to produce a solution essentially free of solids;
- evaporating excess water from the solution essentially free of solids to produce a saturated solution, wherein during the evaporating step the temperature of the solution is between about 50° C. and about 150° C. and the pressure of the solution is between about 0.2 atmospheres to about 2 atmospheres—has been inserted;
- precipitating burrkeite and sodium-containing complex salts from the saturated solution;
- and
- separating the precipitated burkeite and sodium-containing complex salts from the saturated solution.
Dependencies are inferred from the claim text.