On the plasma-chemical processing of finely dispersed silicon monoxide particles in argon-hydrogen plasma flows

Processing dispersed fractions of silicon oxides $\mathrm{SiO}_x$ 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 $\rm SiO_2$ for these purposes. Meanwhile, there are almost no data on processing particles of other oxides (e.g., silicon monoxide $\rm SiO$) 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 $\le100~\mu$m. As a result, using X-ray diffractometry, energy dispersive analysis, and microscopy, it is shown that the main contribution to the production of $\rm Si$ is made by het-erophase processes of disproportionation of gaseous $\rm SiO$. 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 $\rm SiO$ particles at an exit from the high-temperature zone of the setup.