Effect of dichlorodihydrosilicon in the reduction furnace feed on the reduction reaction
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A small amount of dichlorodihydrosilicon was produced during the deposition reaction in the reduction furnace; even after recovery processing, trichlorosilane still contained a small amount of dichlorodihydrosilicon (5%-10%). Please advise: what impact does the presence of dichlorodihydrosilicon in the feed to the reduction furnace have on the reduction reaction? This post was last edited by LHY8771 on 2009-3-5 10:14.]
:Q: Who are you from, Banzhu? Why ask such a professional question? TCS feedstock for polysilicon production by the Siemens method? ? ? In the TCS feedstock used for the production of polysilicon via the Siemens process, can some STC and DCS be doped in it? If so, what would be the approximate percentage content? I have already posted a similar thread. Of course, all of these can be added, and if the percentage added is appropriate, it will be beneficial for the reaction as well as help save costs! Now I just don’t know what percentage is appropriate!
It seems no one has answered; are they afraid of leaking information? Under normal circumstances, if the feed does not contain dichlorodihydrosilicon, the amount in the output is at most 1%-2%; a level of 5%-10% indicates that the molar ratio in the feed has not been optimized properly.
Actually, this is beneficial for the reaction, and it has little to do with the concentration. I’m referring to American technology; it seems that understanding of this aspect isn’t very widespread in China yet.
(5%-10%) dichlorodihydrosilicon? Still call it a small amount? It’s a bit dangerous to use dichlorodihydrosilicon in the reaction! It definitely affects product quality; the polycrystalline rods become loose.
In my opinion, a 5%-10% increase in the amount entering the system increases the risk, but it remains within controllable limits. Looseness also won’t have a significant impact. Of course, in such cases it is necessary to adjust the reduction parameters; usually, an excess of dichlorodihydrosilane results in a low conversion rate inside the reduction furnace, as dichlorodihydrosilane is typically present in high amounts in recycled materials, while it is hardly found in the raw materials. ] This post was last edited by zjiris on 2009-3-7 at 22:33
The content level needs to be kept below a certain value; if it’s too high, well, it can be deadly! But it’s just a small amount; it doesn’t matter. It is indeed beneficial for the reaction. Last edited by yezi7414 on 2009-3-8 20:31]
On the rooftop! Not too much! It’s very dangerous! It might be related to the physicochemical properties of lol dichlorodihydrosilicon! Be extremely careful! Don’t act recklessly! !
The result of incomplete rough distillation. You should go to the distillation department to resolve this! It’s because they didn’t control Tawain.
Based on production experience, there is more dichlorodihydrosilicon and more amorphous silicon in the furnace
A level of 5% doesn’t seem that uncommon, but it’s also not particularly dangerous. But it definitely has some impact on the reduction reaction
The reduction process is complete; the concentration of dichlorodihydrosilane cannot be very high, and it is advantageous for the feed to contain a small amount of dichlorodihydrosilane
The reduced exhaust gas contains a small amount of dichlorodihydrosilane; if the adsorption and desorption steps in dry recovery are carried out properly, the content of dichlorodihydrosilane in the material obtained through dry recovery will be very low. After further purification of this material, there will be no dichlorodihydrosilane left at all. Don’t you have methods for purifying the dry recovery material?
It’s that problem again; let me add something more. DCS reacts with hydrogen more rapidly than TCS, and the temperature required for this reaction is also slightly lower. It might be advisable to introduce DCS when the temperature inside the furnace is low, and then gradually reduce the amount of DCS used or stop its supply once the temperature rises. This experiment was conducted abroad a long time ago, with good results, and can serve as a reference in China. Overall, DCS is beneficial for the reaction.
Agreed; the presence of a small amount of dichlorodihydrosilicon can, to some extent, suppress the occurrence of side reactions and improve the utilization rate of trichlorosilane
Dichlorodihydrosilane is a low-boiling compound; during distillation, it is removed quite thoroughly, and the material reflux ratio is set reasonably, so there should not be such an abundance of dichlorodihydrosilane. A concentration of 5-10% will have some effect on reduction.
Below 10%, there should be no problem; at higher levels, it poses safety risks. It also affects the quality of polysilicon.
9# happyfatboys does not agree with your view. In fact, such a high concentration of dichlorodihydrosilicon is obtained under conditions of reduced ratios, which are not optimal. Distillation can be used to remove this amount of dichlorodihydrosilicon from the system, but then the downstream processing steps related to dichlorodihydrosilicon must be taken into consideration. In reality, optimizing the reduction ratios is still the best approach, as it helps to avoid the need for additional downstream processes and enhances safety during production.
The temperature and flow rate of the distillation tower are not well controlled :)