Method for producing sodium perborate

Claim 1

A PROCESS FOR THE PRODUCTION OF A READILY WATERSOLUBLE PERBORATE STABILIZED BY AN ALKALINE EARTH METAL SILICATE WHICH COMPRISES PLACING A SODIUM METABORATE SOLUTION IN CONTACT WITH A HYDROGEN PEROXIDE SOLUTION CONTAINING AN ALKALINE EARTH METAL HALIDE, STIRRING THE REACTION MIXTURE CONTINUOUSLY BUT NOT VIGOROUSLY AND PRECIPITATING THE SODIUM PERBORATE AT A TEMPERATURE BETWEEN 0 AND 15%C. FROM A SOLUTION IN WHICH THE RELATIVE SUPERSATURATION, EXPRESSED BY THE RELATION BETWEEN THE WEIGHT OF PERBORATE VIRTUALLY PRESENT IN THE SOLUTION AND THE WEIGHT OF PERBORATE NORMALLY SOLUBLE IN WATER AT 20%C., IS COMPRISED BETWEEN 4 AND 12, SAID ALKALINE EARTH METAL SILICATE BEING PRODUCED IN SITU IN SAID REACTION MIXTURE BY THE IN SITU REACTION BETWEEN SAID ALKALINE EARTH METAL HALIDE AND SODIUM SILICATE, SAID SODIUM SILICATE BEING INTRODUCED INTO THE REACTION MIXTURE ONLY WHEN AT LEAST A PART OF THE SODIUM PERBORATE HAS PRECIPITATED, AND THE REACTION BETWEEN THE METABORATE AND THE HYDROGEN PEROXIDE BEING CARRIED OUT IN THE PRESENCE OF A WETTING AGENT SELECTED FROM THE GROUP CONSISTING OF AN ALKALI METAL SALT OF AN ALKYL SULPHATE, AN ALKYL SULPHONATE, AN ARYL SULPHONATE, AN ALKYLARYL SULPHONATE, A POLYOXYPROPYLENE GLYCOL, A POLYVINYL ALCOHOL, A POLYOXYALKENE ETHANOL, AND AN ALKYL CELLULOSE.