Recovery of boron from waste streams

A method for the recovery of boron compounds from waste streams containing boric acid and combustible organic materials in water by incineration of the combustible organic materials and dehydration of the boric acid to boric oxide. Quenching of the boric oxide, depending upon temperature and water content, yields orthoboric and/or metaboric acids in vapor phase and polyboric acid in liquid phase which is cooled along with the products of the combustion of the organic materials and, in the presence of water, converted to a mixture of boric acids in solid and liquid phase leaving the products of combustion in vapor phase. The mixture of boric acids is then separated from the products of combustion.