Patent Number: 047724315
Section: abstract

The invention relates to a process for the immobilization of nuclear waste in a borosilicate glass.. In the process, the following are mixed simultaneously:. a silica-based gel precursor, PA0 a concentrated aqueous solution of a boron compound, and concentrated aqueous solutions of the other constituents of the final glass, i.e. a solution (solutions) of the waste to be treated and a solution of the vitrification adjuvant, PA0 with vigorous stirring, mixing taking place at between 20.degree. and 80.degree. C., preferably at 65.degree.-70.degree. C., in proportions corresponding to the desired composition of the glass, the said mixture having an acid pH, preferably a pH of between 2.5 and 3.5, and the said mixture is dried, calcined at between 300.degree. and 500.degree. C. and then melted.. The invention is applied to the treatment of solutions of nuclear waste, especially to solutions of fission products.