Spectrophotometric determination of phosphorus(V) oxide in cements and clinkers with molybdovanadate reagent

Abstract

The current method of determining phosphorus(V) oxide in cements and clinkers has been investigated in an attempt to improve its reliability. The method in use at the Building Research Station is that for U.K. internal trade, as described in B.S. 4550 : Part 2 : 1970, in which phosphate is complexed as the molybdovanadophosphate and the intensity of the yellow colour produced is measured. Investigations have shown that silica in solution interferes with the development of the colour and a modified determination procedure has been developed in order to minimise this interference and to reduce the relative error for phosphorus(V) oxide determination in cements.