Reduction of SiO 2 by Molten Al

The bulk reaction of Al and SiO 2 was reexamined in light of results of thin‐film work. When the bulk reaction was conducted under vacuum in such a way that the oxide film on the Al was almost completely absent, the reaction started immediately and proceeded at a rate more rapid than that observed by previous workers, who conducted the experiment in air at atmospheric pressure. Results obtained at 700° to 820°C indicate that the activation energy for the reaction is 42±5 kcal/mol when oxide films are absent from the surface of the molten Al.