On the Plasma-Chemical Processing of Finely Dispersed Silicon Monoxide Particles in Argon-Hydrogen Plasma Flows

Processing dispersed fractions of silicon oxides SiOx into polycrystalline silicon in a single argon-hydrogen flow of atmospheric plasma is promising. Some experimental experience has been accumulated on the use of quartz SiO2 for these purposes. Meanwhile, there are almost no data on processing particles of other oxides (e.g., silicon monoxide SiO) in this way. In this study, a set of relevant studies is carried out on an experimental setup with an electric arc plasma torch with a power consumption of up to 3 kW. The characteristic dispersity of the fractions was <= 100 mu m. As a result, using X-ray diffractometry, energy dispersive analysis, and microscopy, it is shown that the main contribution to the production of Si is made by het-erophase processes of disproportionation of gaseous SiO. Silicon is found mainly in the form of finely dispersed inclusions on the surface of unevaporated particles. The Si content (with a purity of 99.8 to 99.9%) in the products was not less than 24%. At the same time, a significant amount of it was registered in an amorphous form. Such amorphization is explained by the high cooling rates (10-100 kK/s) of unprocessed SiO particles at an exit from the high-temperature zone of the setup.