ON-LINE CONTINUOUS MONITORING OF A PLASMA PURIFICATION PROCESS USING ANALYSIS OF METALS IN FLUE GASES BY ICP-OES

An on-line technique initially developed to monitor metallic pollutants in the flue gases of incineration plants has been adapted to be used in a metal purification process combining an inductive cold crucible with a RF plasma torch. The reactor for purification was designed to simplify the transposition of the process. The out gases from the reactor are continuously sampled and injected into a commercial ICP-based analytical system. The interface between the process and the control unit for the ICP torch involves a stabilised pressure environment and a calibrated tube. With this system the elements in the out gases, concentrations ranging from 1 μg.m⁻³ to 0.1 g.m⁻³, can be continuously monitored. This diagnostic technique has been used to study the operating conditions for the purification process.