Silicon tetrachloride
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That expert knew how the large amount of silicon tetrachloride produced during polysilicon production was separated out! Is it behind the reactor?
Take a look below; there have been discussions on it at http://bbs.hcbbs.com/viewthread.php?tid=74006
No. In fact, SiCl4 produced by the reduction furnace, together with the unreacted SiHCl3, is recovered by CDI to form a mixture of chlorosilanes. It is sent to the distillation section where it is separated through distillation, and then to the hydrogenation section for hydrogenation, thereby achieving the recycling of SiCl4. The separation of SiCl4 relies on the fact that different substances have different boiling points at the same pressure and temperature; thus, those with higher boiling points emerge from the bottom of the distillation tower, while those with lower boiling points come out from the top of the tower.
Silicon tetrachloride produced in the reduction furnace is sent for off-gas recovery together with the unreacted materials; the separated liquids such as silicon tetrachloride and trichlorosilane are subjected to distillation for purification and separation before being sent back to the reduction process.