A Source Sampling Technique for Particulale and Gaseous Fluorides

Abstract

Sampling of effluents that contain fluorides is often hampered by the reactivity of hydrogen fluoride. Although techniques have been developed for sampling ambient air, they are not applicable to stack effluents which contain higher concentrations of fluoride, water, and particulates. A sampling system for the separation and collection of gaseous and particulate fluorides was devised and tested. In this system a heated glass probe serves as a reactor for converting hydrogen fluoride to silicon tetrafluoride before the particulate is filtered. Laboratory tests have demonstrated quantitative recoveries of hydrogen fluoride after the test mixtures pass through the probe and through filter papers impregnated with sodium bicarbonate. The equipment has performed satisfactorily in field sampling.