Process for the synthesis of antimony polyphosphate of high purity by the reaction of antimony(III) oxide with phosphoric acid milled to a fine suspension

摘要

The reaction is carried out without the presence of ammonium nitrate or any ammonium salt and gives a product suitable for use in the manufacture of phosphated glasses. The synthesis is effected in the following stages : (a) Milling of a mixture of Sb2O3 and 85% H3PO4 to produce a fine suspension ; (b) Progressive heating of the suspension obtained according to a thermal mode which comprises two isothermal levels between 200 deg C. and 510 deg C. ; and (c) Cooling to ambient temperature and monitoring of the properties of the product by X-ray diffraction.