Impurities Distribution between SiO Gas and Reactant Materials in a Silicon Furnace

The control of the impurities inside the silicon furnace is a topic not widely investigated. Impurities in silicon can originate from quartz and carbon materials. In this work we correlate the impurity content in mixture of SiO2/SiC and SiO2/Si to the impurities carried out by SiO gas. The experiments represent the operative condition of the middle and bottom part of the furnace. Raw materials both in form of lumps and pellets are heated in graphite crucibles at 170 degree C and at 190 degree C. SiO gas is produced and collected as microsilica. Both microsilica and charge materials are analyzed chemically by ICP-MS. The experimental work is supported by thermodynamic simulations.The results give an understanding of the typology of the elements carried out of the furnace by SiO gas. In particular the abundance and typology of these impurities are correlated to the composition, the size and the physical state of the raw materials.