Consortium Fur Elektrochemische Industrie Gmbh

Heliotronic Forshungs Und Entwicklungsgesellschaft Fur Solarzellen

Michael Wohlschlager

Josef Dietl

Claus Holm

Jorg Kotilge

Pure silicon is obtained in a semicontinuous process by reducing quartz sand with aluminum in a slag medium based on alkaline earth metal silicates. The slag serves thereby simultaneously as a solvent for the aluminum oxide that forms and as an extraction medium for impurities that occur. The silicon formed separates out of the silicate slag and can be separated off. The aluminum oxide produced by the reduction can be separated from the slag and used for recovery of reusable aluminum.

Semicontinuous process for the production of pure silicon

A process is provided for purifying metallurgical-grade silicon for the manufacture of solar cells, wherein the acid treatment of the silicon, known per se, is combined with vacuum evaporation. This may be optionally combined with slag extraction and directional solidification.

Process for purifying metallurgical-grade silicon

A process for protecting carbon bodies against attack by molten silicon by applying a separating protective layer is provided which is characterized in that a separating layer is applied to the surface of the carbon body to be protected in such a manner as to wet it. The separating layer consists of alkaline earth metal fluorides in admixture with 0 to 90 mole % of alkaline earth metal silicates having a melting point lower than that of silicon.

Growing community of inventors

Unterpfaffenhofen, Germany

Michael Wohlschlager