EXPERIMENTAL STUDY OF THE EFFECT OF REACTIVE GAS INJECTION GEOMETRY IN ATMOSPHERIC PRESSURE INDUCTIVE PLASMA TORCH ON THE CHEMICAL EFFICIENCY

摘要

The effect of the reactant gas injection mode into inductively coupled plasma has been investigated, through the volatilization reaction of a graphite target submitted to argon-oxygen plasma. A graphite disk is positioned at different distances under the plasma torch. The addition of oxygen to the plasma results in a carving of the graphite surface, which depend on the injection mode: into the outer, the intermediate or the inner argon flow. The mass losses permit to evaluate the global efficiency. The profile of the graphite surface at the end of the operation reflects the distribution of the reactive species. The graphite is heated by induction in order to stabilise its temperature between 1500 and 1800 K and to obtain stable reaction conditions. The most efficient, from the point of view of the reactive gas, consists in addition to the inner flow. The most homogeneous volatilization is obtained when the reactant is added to the outer flow.