Evaporation of Phosphorus in Molten Silicon by an Electron Beam Irradiation Method
Evaporation of Phosphorus in Molten Silicon by an Electron Beam Irradiation Method
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DOI：
10.2320/matertrans.45.844
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发表时间：
2004-03
影响因子：
1.2
通讯作者：
Kazuhiro Hanazawa;Noriyoshi Yuge;Y. Kato
中科院分区：
文献类型：
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作者：
Kazuhiro Hanazawa;Noriyoshi Yuge;Y. Kato
以冶金级硅(MG-Si)为原料，采用连续冶金工艺，研究了电子束辐照过程中硅熔体中磷的蒸发行为。批量实验表明，磷的蒸发速率与电子束功率和磷含量成正比。除磷速率由熔融硅表面的自由蒸发控制。电子束辐照使在自由液体表面获得更高的温度成为可能，从而导致更有效的脱磷。连续流动实验表明，随着硅粉加入量的增加，出口处的磷浓度增加，这是由于硅液在炉膛内停留时间相对较短所致。因此，熔融硅在炉缸中的流动不是完全的混合反应器流型反应，而是接近于推流型反应。在150公斤规模的中试生产装置上，成功地将含磷约25质量ppm的MG-Si提纯到P<；0.1质量ppm。
The evaporation behavior of phosphorus in molten silicon during electron beam irradiation was investigated with the aim of producing solar grade silicon (SOG-Si) from metallurgical grade silicon (MG-Si) by a sequential metallurgical process. Batch experiments showed that the evaporation rate of phosphorus increased in proportion to the power of the electron beam and phosphorus content. The phosphorus removal rate was controlled by free evaporation from the molten silicon surface. Electron beam irradiation makes it possible to secure a higher temperature at the free liquid surface, which results in more efficient dephosphorization. A continuous flow experiment indicated that the phosphorus concentration at the outlet increased when the silicon feed rate was raised, which was attributed to the fact that the hearth residence time of the molten silicon was proportionally shorter. Thus, the flow of molten silicon in the hearth did not behave as a complete mixed reactor flow type reaction, but was close to a plug flow type reaction. With a 150 kg scale pilot manufacturing plant, MG-Si containing about 25 mass ppm of phosphorus was successfully purified to P < 0.1 mass ppm.