Distribution of impurity elements in slag–silicon equilibria for oxidative refining of metallurgical silicon for solar cell applications

Abstract

Distribution of impurity elements in slag-silicon equilibria for oxidative refining of metallurgical silicon for solar cell applications. Solar energy materials and solar cells, 94(12),

Study on the Kinetics of Aluminum Removal from Liquid Silicon to Slag with Mechanical Stirring

“…It is seen that the final Al content in the silicon phase increases with the increase of the initial Al 2 O 3 content in slag. Although the aluminum in the silicon would react with CaO to some extent, the main reaction for the transfer of aluminum to slag is due to Reaction [1],…”

“…As reported in the literature, [1][2][3] the impurity removal process is very slow without stirring, requiring 2-3 hours to reach slag-metal equilibrium. As shown by the present results, proper mechanical stirring would enhance greatly the removing rate of the impurities.…”

“…It would be valuable to compare the experimental results with the model calculation. According to Turkdogan, [14] the standard Gibbs energy change for Reaction [1] is described as…”

“…A number of studies have been carried out focusing on the boron and phosphorus transfer. Johnston and Barati [1] investigated the distribution of impurity elements between slag and MG-silicon doped with B and P at 1773 K (1500°C) under argon atmosphere. The reaction time needed for the system to reach equilibrium was determined to be 2 hours.…”

“…It needed at least 3 hours for the system to reach equilibrium. These studies [1][2][3] indicate that the slag-metal reaction is a very slow process without stirring.…”