To provide a method capable of reducing effectively impurities, especially B, in flux used for production of high purity Si for a solar cell by a metallurgical method; capable of removing easily, quickly and quantitatively B in Si by using flux for production of high purity Si for a solar cell by the metallurgical method, because the obtained flux contains an extremely small amount of B or substantially nothing thereof; and capable of obtaining extremely inexpensively high purity Si usable for a solar cell having purity of about 6N, by evaporating and removing P by local high-temperature heating or the like under high vacuum from Si from which B is removed, and further by reducing metal impurities by unidirectional solidification or the like.
In this method for removing impurities in flux, the flux containing impurities is heated and melted, and gas containing either or both of steam and oxygen is blown into the molten flux, to thereby reduce impurities in the flux.
Saori Shigematsu
Katsunari Kobayashi
Takeshi Ishikawa
Next Patent: METHOD FOR REMOVING IMPURITY IN FLUX