A large amount synthesis of nanopowder using modulated induction thermal plasmas synchronized with intermittent feeding of raw materials

A large amount synthesis method for titanium dioxide (TiO₂) nanopowder is proposed by direct evaporation of titanium powders using Ar-O₂ pulse-modulated induction thermal plasma (PMITP). To realize a large amount synthesis of nanopowder, the PMITP method was combined with the intermittent and heavy load feeding of raw material powder, as well as the quenching gas injection. The intermittent powder feeding was synchronized with the modulation of the coil current sustaining the PMITP for complete evaporation of the injected powder. Synthesized particles by the developed method were analyzed by FE-SEM and XRD. Results indicated that the synthesized particles by the 20-kW PMITP with a heavy loading rate of 12.3 g min⁻¹ had a similar particle size distribution with the mean diameter about 40 nm to those with light loading of 4.2 g min⁻¹.