The "Improved" Siemans Process for Producing Polysilicon for Solar Cells.

[eppur_se_muova]

1. I can't help but wonder if that figure is correct. Much SiCl4 is converted by hydrogenation ...

or reaction with Si back to HSiCl3, the most useful intermediate. Recycling within the Siemens process should keep the amount of SiCl4 down, with most of it ultimately being converted to silicon. I was under the impression this is basically the same way silicon for ICs is produced, so you'd sort of think they had this problem in hand after all this time, wouldn't you ?

SiCl4 is also used to produce optical fibers, so I wonder if there really is such a great need for means of "getting rid of" SiCl4.

https://www.sciencedirect.com/topics/engineering/siemens-process

Unfortunately, it appears that the whole process is run in batches (horrors!) so this may complicate logistics pretty badly.