Metallurgy of open-bath plasma processes

Abstract -Thermodynamic simulation of the carbothermic chemical reactions likely to occur in the open bath of a d.c. transferred plasma-arc furnace using a standard slag comprising CaO, MgO, A1203, and SiO, as a basis, and with FeO, Crz03, MnO, and ZnO added at various carbon levels, has shown that the high temperatures expected in the arc attachment zone (AAZ) can cause unacceptable products to be produced at the expense of the desired ones and result in higher consumption of energy. The thermal inertia of the AAZ can be used in efforts to assess the level of control needed over the feed rate, distribution of the feed, and power input of a particular process in order to limit high temperature excursions, which cause so-called 'side reactions', e.g. the reduction of MgO to Mg vapour