Method of purifying metallurgical-grade silicon
AssigneeHeliotronic Forschungs- und Entwicklungsgesellschaft fur Solarzellen-Grundstoffe mbH
InventorsJosef Dietl, Claus Holm
Life of this patent
Estimating the term…
Abstract
A method of purifying metallurgical-grade silicon for the production of silicon solar cells is provided, in which metallurgical-grade silicon is dissolved in aluminum and brought into contact with an aluminum sulphide extraction melt. Thereafter, the silicon is crystallized out and separated off by cooling the melt to a minimum temperature of 600.degree. C. The aluminum melt remaining can then be recharged with silicon, heated, brought into contact with the extraction melt, so that additional silicon can be crystallized out.
Claims7
A method of purifying metallurgical-grade silicon by dissolution in aluminum and treatment with an extraction melt, comprising the steps of:
- dissolving the silicon to be purified in aluminum to produce a mixed melt;
- bringing said mixed melt into contact with an aluminum sulphide extraction melt;
- and
- thereafter crystallizing out and separating off the silicon by slowly cooling the mixed melt to a minimum temperature of 600.degree. C.
Dependencies are inferred from the claim text.