Determine the degree of reaction between Si and HCl at temperatures ranging from 290°C to 360°C
Thread Content
In the polysilicon industry, if the purity of silicon powder is very high, and the temperature is between 290 and 300°C with an excess of HCl, can the reaction Si + HCl → SiHCl3 + H2 (with a molar fraction of SiHCl3 in the gas phase greater than 90%) completely convert all the silicon? I’d like to ask, thank you!
What does complete reaction mean? ? What is your reaction device?
It is about whether all the silicon powder will react; the reaction device is a fluidized bed.
Since it is a fluidized-bed silicon powder, an excess amount must always be used; theoretically, the silicon powder can react completely. However, no matter how pure the silicon powder is, it still contains a large amount of metals. If these metals are not removed from the bottom, they will clump together, preventing the reaction from proceeding properly.
It means that at temperatures ranging from 290°C to 360°C and under a pressure of 0.5 MpaG, this reaction is an irreversible one, right? Where can I find this information? Thanks!
It is an irreversible reaction. In fact, within the fluidized bed, HCl reacts quite thoroughly in the area about 3 meters below the bed. There is no such process as hydrogen reducing trichlorosilane to silicon powder, but the reaction H2+SIHCl3----SIH2Cl2 +HCl can occur, leading up to the formation of silane.
May I ask where I can find comprehensive literature on this reaction? Are there any data on reaction rates as well? Thank you!