Hydrofluoric distillation: a new approach to the determination of silicon, phosphorus and arsenic in siliceous materials

Abstract

Hydrofluoric distillation has been applied to the determination of silicon, phosphorus and arsenic in siliceous materials based on the formation of their heteropolymolybdates. Silicon and arsenic are separated by distillation from phosphorus and the remainder of the sample. Arsenic is determined spectrophotometrically, in the presence of silicon, by controlling the hydrofluoric acid concentration. Afterwards, the sum of silicon plus arsenic is determined gravimetrically with quinoline. Phosphorus is determined in the residue by either of the two methods.