| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for refining silicon, which can efficiently remove impurities such as boron and others from a metal-grade silicon material, can continuously process, and can produce a high-purity silicon by a compact apparatus structure. <P>SOLUTION: A metal-grade silicon or a silica powder 1 is charged in a plasma region 8 of an ozone-containing oxygen gas atmosphere at about 2,400°C to oxidize boron contained in the powder and to remove boron as a vaporized substance, and the resultant powder is recovered as a powder 1a. The powder 1a after removal of boron is charged in a plasma region 28 of a reductive atmosphere to remove oxygen by reduction and to recover a silicon powder 1b. The silicon powder is heated to make a melt 1c, and the melt 1c is made to flow in a magnetic field of an electromagnet 35 to trap and remove metal impurity elements. The silicon melt 1c from which metal impurity elements have been removed is recovered as a silicon powder 1d by centrifugal spraying. <P>COPYRIGHT: (C)2013,JPO&INPIT |
