The mechanism and preparation of nano-SnO2@fly ash antistatic composite powder

Abstract

In order to solve the problems of poor antistatic property of fly ash (FA), high cost and easy agglomeration of nano tin dioxide (TO), chemical co-precipitation method was adopted to synthesize nano-SnO2@fly ash (shell@core, TOFA) antistatic composite powder. Volume resistivity was used as indicator of TOFA antistatic performance to be experimentally studied. The results showed that volume resistivity was reduced from 7.32 × 109 Ω·cm (FA) to 1.82 × 105 Ω·cm (TOFA). Under pH = 4 condition, the electrostatic attraction between TO precursor and FA didn't significantly improve agglomeration. The pH = 12 condition of two substances surface repeled each other and relyed the interaction of TO precursor functional group and FA surface hydroxyl group on forming (Al)Si-O-Sn chemical bonding at high temperature calcination, which facilitated the formation of nanoscale tetragonal crystalline phase TO to uniformly distribute on the surface of micron-sized FA. The antistatic mechanism was derived from oxygen vacancies and tin interstitium in the intrinsic defects of TO nanoparticles.