Removal of Phosphorus, Aluminum and Calcium by Evaporation in Molten Silicon

Kinetics and Mechanism of Phosphorus Removal from Silicon in Vacuum Induction Refining

“…They reported rate constants 1.6 10 5 m=s and 2.0 10 5 m=s at 1450 ı C and 1550 ı C, respectively. Their results are relatively close to the reported rate constants by Yuge et al [7] through experiments in 0.014-0.036 Pa. Yuge and co-workers obtained rate constants 1.0 10 5 m=s, 2 10 5 m=s and [11] are all approximately 2.0 10 6 m=s. This value is around 10 times smaller than the mentioned other works [4,7]; however, it is closer to the results of the present study.…”

“…Yuge et al [6] used vacuum induction melting in 6.7 Pa at 1500 ı C and they removed phosphorus down to below 0.2 ppmw from 5 ppmw within 10 hours. In another study [7], they carried out the vacuum induction melting of MG-Si at 1500 ı C, 1550 ı C and 1642 ı C in 0.014-0.016 Pa and removed P below 0.1 ppmw at 1642 ı C within 7 hours. It has also been indicated in pilot scale that phosphorus removal from MG-Si to low levels acceptable for photovoltaic applications is possible through vacuum treatment by electron beam gun [8].…”

“…The vacuum refining of MG-Si using electron beam gun and induction melting has been studied through the previous works [4][5][6][7][8][9][10][11][12]. Although silicon content in MG-Si is around 99 wt%, the composition of the impurities varies with regard to the compositions of the raw materials used for silicon production.…”

Numerical Simulation of Phosphorus Removal from Silicon by Induction Vacuum Refining

“…Experiments to remove phosphorus under vacuum conditions were investigated by Zheng et al, [4] Miyake et al, [5] Yuge et al, [6] Suzuki et al, [7] Pires et al, [8] and Ikeda and Maeda, [9] and the thermodynamics of phosphorus in molten silicon was also presented by Miki et al [10] and Zaitsev et al [11] In the present study, a numerical model for phosphorus removal in vacuum induction refining of silicon is developed and compared to experimental data.…”

Development of Solar Grade Silicon (SoG-Si) Feedstock by Recycling SoG-Si Wastes

“…However, the size of silicon particles in the slurry was much smaller, and it is difficult to separate those fine silicon particles from the SiC particles in the equivalent size. The possible methods to recycle silicon from SoG-Si slurry wastes and to purify the SoG-Si and its wastes will be discussed include methods to remove non-metallic particles from the melt (such as sedimentation, bubble flotation [31][32] , centrifugal separation [33] , filtration [20][21][22][23][24] , electromagnetic separation, and directional solidification) and methods to remove metallic and other dissolved impurities (such as acid leaching, gas blowing (Cl 2 , O 2 [34] , SiCl 4 , etc), plasma refining [35] , evaporation [36] , electron-beam furnace [35] , fractional melting process [37] , and solidification control.…”