Electrically-assisted flame aerosol synthesis of fumed silica at high production rates

The control of particle size by external electric fields is investigated during flame synthesis of particles at high production rates (up to 87 g h−1). Here needle and plate electrodes are used during synthesis of fumed silica from hexamethyldisiloxane (HMDS) in a coflow double diffusion flame at atmospheric pressure. The average primary particle diameter is reduced by a factor of two, when the applied electric field strength between two needle electrodes was increased from 0 to 1.5 kV cm−1. It was demonstrated that electrode placement is crucial for this process. Furthermore, the powder composition (soot content less than 1 wt%) was controlled by the electric field.