(1. 昆明理工大學(xué) 冶金與能源工程學(xué)院，昆明 650093；
2. 云南冶金集團(tuán)總公司 技術(shù)中心，昆明650031；
3. 昆明冶研新材料股份有限公司，昆明 650031)
摘 要: 應(yīng)用有關(guān)熱力學(xué)數(shù)據(jù)研究了與多晶硅主要生產(chǎn)工藝即西門子法相關(guān)的“Si-Cl-H”三元系的復(fù)雜化學(xué)反應(yīng)，研究SiCl4氫化轉(zhuǎn)化為SiHCl3過(guò)程中可能發(fā)生的15個(gè)反應(yīng)，給出15個(gè)反應(yīng)的 —T圖；并確定5個(gè)獨(dú)立的反應(yīng)，給出這5個(gè)獨(dú)立反應(yīng)的 —T圖；高溫時(shí)主反應(yīng)(1)的 增長(zhǎng)較慢，而反應(yīng)(2)和(5)的 快速增大，1 373 K時(shí)，主反應(yīng)(1)的 較小，為0.157 1。進(jìn)一步研究溫度、壓強(qiáng)和進(jìn)料配比 對(duì)SiCl4氫化率的影響，并繪制出SiCl4氫化率隨這些因素的變化曲線。結(jié)果表明：當(dāng)壓強(qiáng)和進(jìn)料配比一定時(shí)，SiCl4的氫化率隨溫度的升高先增加后降低；增大壓強(qiáng)或增加進(jìn)料配比 都會(huì)提高SiCl4的氫化率；SiCl4氫化轉(zhuǎn)化為SiHCl3過(guò)程的最佳操作條件為溫度為1 000 ℃，壓強(qiáng)為0.3 MPa，進(jìn)料配比 為4，在此條件下，SiCl4的氫化率為25.78%。
關(guān)鍵字: SiCl4；SiHCl3；熱力學(xué)；轉(zhuǎn)化
（1. Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology,
Kunming 650093, China;
2. Technology Center, Yunnan Metallurgy Group Co., Kunming 650031, China;
3. Kunming Yeyan New-Material Co., Ltd., Kunming 650031, China）
Abstract:Based on the thermodynamic data for the related pure substances, fifteen possible chemical reactions in the SiCl4 hydrogenation system of Siemens process that is one of the main process for the polysilicon production were studied. The curves of the fifteen chemical reactions in the system versus temperature were fitted by the assistant of computer. The values of for most reactions are greater than zero at the range of 973K to 1 773 K. That is to say that the value of equilibrium constant is small. Therefore, the small degree of the reactions was carried on. Five independent reactions in the process were decided and the relation between and temperature was fitted by the assistance of computer based on the thermodynamic data for the related pure substances. The value of for main reaction (1) increases a little at high temperature, but the value of for side-reactions (2) and (5) increase quickly. Besides, the value of for main reaction (1) is low at low temperature, for example only 0.157 1 at 1 373 K. Therefore, the transformation ratio of SiCl4 to SiHCl3 being low is a objective fact which can not be changed. Furthermore, the influencing factors, such as the temperature, pressure and feeding mole ratio, on the transformation ratio from SiCl4 to SiHCl3 were studied. The diagrams of η—transformation ratio are presented as function of temperature, pressure and feeding mole ration, respectively. The transformation ratio of SiCl4 to SiHCl3 decreases with increasing the temperature, and the pressure have a positive effect on the transformation ratio. Furthermore, the excess of H2 is necessary in SiCl4 hydrogenation system of the modified Siemens process. From the thermodynamic above, The results show that the optimum operation parameters are at 1 050 ℃, 0.3 MPa and feeding mole ratio of 4. Under this condition, the transformation ratio from SiCl4 to SiHCl3 is 25.78%.
Key words: SiCl4; SiHCl3; thermodynamics; transformation
