Nauka i Obrazovanie (Jan 2017)

The Efficiency of Quartz Particles Evaporation in the Argon Plasma Flow of the RF Inductively Coupled Plasma Torch

  • Yu. M. Grishin,
  • L. Miao

DOI
https://doi.org/10.7463/0517.0001196
Journal volume & issue
Vol. 0, no. 5
pp. 119 – 139

Abstract

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Owing to high-power density and high-purity plasma, a RF inductively coupled plasma torch (ICPT) is widely used both in research laboratory and in industry. The potential RF ICPT application areas are powders spheroidisation, waste treatment, thermal spraying, etc.In the last decade the investigation was focused on the treatment processes of quartz into polycrystalline silicon. An analysis of these results has shown that the increasing productivity and producing high-purity silicon can be achieved only when using the electrodeless radio-frequency induction plasma torches and in case the optimum conditions for evaporation of SiO2solid particles are realized.Optimization of the RF ICPT design and power parameters calls for a wide range of computational studies. In spite of the fact that to date a large number of efforts to calculate the evaporation efficiency of powder materials have been made, a number of issues, as applied to the problem of obtaining silicon, require further research.In this paper, we present the results of a two-dimensional numerical simulation of the heating and evaporation of quartz particles in the RF ICPT channel with axial flow of gases. The main aim is to determine how the axial position of the central tube (through which the particles are injected into the discharge zone), the dispersion of the quartz powder, the amplitude of the discharge current (and, respectively, flow regimes) impact on the evaporation efficiency of quartz particles.The paper presented the numerical modeling results of heating and evaporation processes of quartz particles supplied by transporting gas to the RF ICPT channel with axial gas flow (argon). Defined the impact of the axial position of the central tube, the plasma flow regime, the discharge current, the flow rate of transporting gas, and other parameters on the evaporation efficiency of quartz particles.It is shown that the evaporation efficiency of particles reaches its maximum when their injection into the plasma flow occurs in section at the distance of 5-25 mm before the inductor at a discharge current amplitude close to JCR 75-100 A. Under aforementioned conditions the gas cooling RF ICPT with plasma power up to 10 kW provides evaporation of quartz particles with sizes up to 100-120 microns.

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