Environmentally acceptable waste disposal by conversion of hydrothermally labile compounds

The present invention relates to a process for the disposal of waste or the conversion of hydrothermally labile chemical groups and compounds to species which are environmentally acceptable, or are amendable to further degradation by conventional disposal systems to produce environmentally acceptable products, which process comprises: (a) conveying an aqueous solution or slurry of ordnance waste material into a reaction zone capable of withstanding the temperatures and pressures of hydrothermal decomposition; (b) reacting the waste material in the reaction zone with an aqueous composition comprising one or more alkali or alkaline earth metal silicates, borates, phosphates, biphosphates, or trisubstituted-phosphates, at between 200 DEG C. and 500 DEG C. and at a pressure between 10 and 400 atmospheres for between about 0.01 and 10 minutes; (c) producing compounds which are environmentally acceptable or are amenable to further degradation by conventional disposal systems; and (d) optionally degrading further the compounds of step (e) by reaction in a conventional disposal system. The waste includes ordnance waste, process waste, agricultural waste and the like.