How to reduce carbon and oxygen content in polysilicon production
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Recently, the carbon and oxygen content in the polysilicon produced by our factory has been exceeding the specified limits. Several discussion meetings were held, but no practical solutions were found. I’d like to discuss this with all of you
Is the carbon content also above the limit? Our factory has never had it
It’s normal for the carbon content to be above the limit; it exceeds that level when it’s not properly controlled!
Reply to 4# wei8jun: The carbon content may be introduced by hydrogenated graphite electrodes; the specifics are not yet clear. I hope to learn more from everyone*
Reply to 5# caohong*a_09: The carbon content may also exceed the limit during the hydrogenation process
I’m not sure what the carbon content level is under your company’s control, nor whether the hydrogen gas obtained through dry recovery in your company is used directly in the reduction furnace or in other processes. You could conduct tests to measure the carbon content in the hydrogen gas fed into the reduction furnace as well as that in the raw materials: CH4, CO2, CO........................
I think there might be issues with the graphite base used for restoration as well; additionally, it’s unclear whether carbon dioxide levels are monitored during the driving process of replacement – both of these factors could affect the carbon content
We found that the exhaust gas contained a high amount of CH4; nobody knows where this comes from. It is inferred that it may come from the raw materials; industrial silicon powder is used as such raw material, and carbon is inevitably present, so dichloromethane may have mixed in from the raw materials.