An Anomalous Reaction of Silicon Oxide and Aluminum via Ball Milling

Abstract

Previous studies have shown that the ball milling technique, which mechanically heats and releases energy, often causes a displacement reaction between various metals and metal oxides. Sometimes ball milling causes a selfpropagating heat synthesis reaction (SHS) to occur. This study was undertaken to see whether the ball milling technique could provide a method to extract pure silicon from silicon oxide. Since silicon oxide and aluminum are readily available materials, the ball milling process would be an easy and cost-efficient way to produce silicon. The parameters tested in this study included varying the amount of aluminum, total powder mass, number of balls (kinetic energy), and milling atmosphere. Parameters also tested were additions of acetone and alcohol. X-ray diffraction was used to determine what elements and compounds were present before and after ignition. This study discovered that when silicon oxide and aluminum are milled SHS does not occur despite the reaction being highly exothermic. It does not appear possible to slow down the localized reactions to the point where SHS can occur.