Process and apparatus for purifying silicon

• US 4,747,906 A
• Filed: 07/27/1987
• Issued: 05/31/1988
• Est. Priority Date: 08/07/1986
• Status: Expired due to Term

• Current Assignee: Showa Denko KK
• Original Assignee: Showa Aluminum Corporation (Resonac Holdings Corp.)
• Inventors: Otsuka, Ryotatsu, Shingu, Hideo, Toyoda, Kazuo, Tanimoto, Shigemi
• Primary Examiner(s): Sever, Frank
• Application Number:
  US07/077,921
• Time in Patent Office: 309 Days
• Field of Search: 156/621, 156/624, 156/DIG. 64, 156/616 R, 156/616 A, 23/295 R, 23/300, 23/301, 210/773, 210/774, 210/175, 427/93, 427/45.1, 427/82, 427/86, 423/324, 423/348, 422/248
• US Class Current: 23/301
• CPC Class Codes: C01B 33/037 Purification by zone-melting C30B13/00

Abstract

Crude silicon is purified by melting the crude silicon, maintaining the molten silicon above the solidification temperature thereof in an inert gas atmosphere, and rotating a hollow rotary cooling member as immersed in the molten silicon while introducing a cooling fluid into the cooling member to cause high-purity silicon to crystallize on the outer surface of the cooling member.

Claims

1. A process for purifying crude silicon comprising melting the crude silicon, maintaining the molten silicon above the solidification temperature thereof in an inert gas atmosphere, and providing a hollow rotary cooling member immersed in the molten silicon, rotating and introducing a cooling fluid into the cooling member to cause high-purity silicon to crystallize on the outer surface of the cooling member.

2. A process as defined in claim 1 wherein the cooling member is rotated at a peripheral speed of 500 to 6,000 mm/sec.

3. A process as defined in claim 1 wherein the cooling member is rotated at a peripheral speed of 500 to 1,500 mm/sec.

4. A process as defined in claim 1 wherein the inert gas is argon gas.