Development of tandem-modulated induction thermal plasmas and their application to high-rate production of nanomaterials

Abstract

We present a novel methodology for synthesizing functional nanopowders by integrating tandem pulse-modulated induction thermal plasmas (Tandem-PMITP) with time-controlled feedstock feeding (TCFF). The Tandem-PMITP system employs two radio-frequency (RF) coils within a single plasma torch to generate an axially extended plasma column. The upper coil maintains plasma stability, while the modulated lower coil generates dynamic thermal fields. This configuration facilitates efficient feedstock evaporation and promotes robust nanoparticle nucleation, enabling high production rates of 800–1000 g/h at 20 kW for a range of oxide materials. A comprehensive numerical thermofluid model has been developed to characterize the plasma fields, feedstock behavior, and aerosol dynamics. The model indicates that modulation-induced entrainment significantly enhances vapor cooling and nucleation. The proposed Tandem-PMITP+TCFF system exhibits considerable promise for scalable and efficient nanoparticle production.