Patent ID: 7695705
Filing Date: 2010-04-13
Classification: C01B

Abstract:
1. A method for making ultrafine silica particles, comprising: (a) introducing a solid silica powder into a plasma chamber having an axial flow direction; (b) heating the powder by means of a plasma as the powder flows through the plasma chamber, yielding a gaseous product stream; (c) contacting the gaseous product stream with a plurality of quench streams injected into the plasma chamber through a plurality of quench stream injection ports, wherein the quench streams are injected at flow rates and injection angles that result in the impingement of the quench streams with each other within the gaseous product stream, thereby producing ultrafine silica particles; (d) passing the ultrafine silica particles along the axial flow direction of the plasma chamber through a converging member located within the plasma chamber at an outlet end of the plasma chamber; and (e) collecting the ultrafine silica particles, wherein the ultrafine silica particles have an average primary particle size of no more than 50 nanometers.