A novel process for silica decomposition consisting of transferring a thermal are directly to a silica anode was investigated. The effects of current (150-250 A), plasma gas flow rate (10-20 L/min of Ar), and plasma gas composition (0-2.8% H-2) on the rate of decomposition were examined. The decomposition rate ranged from 0.09 to 1.8 g/min and was determined to be heat-transfer-limited, with decomposition occurring below the are root where the anode surface attained its boiling point. The decomposition rate was independent of plasma gas flow rate, suggesting that convective heat transfer was reduced significantly by the counterflow of decomposition products (SiO(g) and O-2) from the surface. Increasing the current increased the decomposition rate because heat input to the anode because of electron flow and are radiation increased. Adding H-2 to the plasma gas increased the decomposition rate because of an increase in radiative heat transfer to the anode, a reduction in the theoretical energy requirement for decomposition, and a consumption of O-2 which lowered the silica boiling point. The fumed silica produced had properties typical of commercial fumed silica products.