Plasma fullerene production from powdered carbon black

Abstract

A new modification of the gas discharge method for fullerene production is developed. Powdered amorphous carbon particles admitted into the flowing plasma of a plasmatron are used as a source of carbon atoms, in distinct from the conventional approach, where this aim is reached through the thermal vaporization of a graphite anode. The fullerene yield vs carbon black feeding rate has a smooth maximum, reaching about 2%. A physical model for vaporization of a small carbon particle in a weakly ionized plasma is built, which allows one to establish the interconnection between the time taken for vaporization of a particle, its size and the plasma temperature. Estimations based on this interconnection show that the effective vaporization of particles of micron size is reached using He or Ar gas carrier flowing with velocity of about 100 cm/s through the plasmatron channel of about 10 cm in length. The results of preliminary experiments are in agreement with those estimations. The main advantages of the proposed approach relate to continuous input of carbon feedstock materials into plasma zone, relatively low energy cost of carbon vaporization and usage of low cost carbon black produced from waste hydrocarbons.