METHOD FOR REFINING SILICON WITH SLAG AND APPARATUS FOR PRODUCING HIGH PURITY SILICON

摘要

PROBLEM TO BE SOLVED: To provide a method and apparatus for refining silicon simply obtaining silicon having a boron concentration level required for solar batteries while suppressing production cost on an industrial production scale.;SOLUTION: This method for refining silicon with slag comprises bringing one-portion of molten slag supplied by dividing into a plurality of portions into contact with molten silicon, holding for a predetermined period of time, and discharging the used molten slag, and repeating this unit operation for a plurality of times for migrating boron in the molten silicon to the molten slag and removing boron. The silicon refining process with slag comprises one or two or more unit operations, and the process is divided into m refining stages where compositions of molten slag used are different from each other, so that (n+1)-th molten slag used in (n+1)-th refining stage has stronger oxidizing power to the boron in the molten silicon than that of n-th molten slag used in n-th refining stage, Provided that m is a natural number of 2 or more, and n is a natural number satisfying the relation of n≤m-1.;COPYRIGHT: (C)2007,JPO&INPIT