Method and apparatus for refining metallurgical grade silicon to produce solar grade silicon
US8329133B2 · kind B2 · utility
2Cited by
16References
15Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Oct 28, 2009 |
| Grant date | Dec 11, 2012 |
| Priority date | — |
| Expiry date | Oct 28, 2029 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF27B17/0016
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A method and apparatus for refining metallurgical silicon to produce solar grade silicon for use in photovoltaic cells. A crucible in a vacuum furnace receives a mixture of metallurgical silicon and a reducing agent such as calcium disilicide. The mix is melted in non-oxidizing conditions within the furnace under an argon partial pressure. After melting, the argon partial pressure is decreased to produce boiling and the process ends with directional solidification. The process reduces impurities, such as phosphorus, to a level compatible with solar-grade silicon and reduces other impurities significantly.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.