Abstract: By means of the process and by means of the apparatus, fused silicon is produced continuously, or in phases, and zonally cast into a mold in which it is caused to solidify zonally. The temperature conditions in the solidification zone are controlled with the aid of a movable heating zone, by means of which the crystallization front is adjusted to the rising level that fills up the mold, this level being in turn controlled by the fusion rate of the silicon. Polycrystalline silicon blocks can be obtained in which, because of the flat shape of the crystallization front, the columnar single-crystal domains within the blocks extend almost vertically and which represent an excellent solar cell base material having high diffusion lengths and lifetimes of the minority charge carriers, from which solar cells of correspondingly high efficiencies can be produced.

Abstract: A process and apparatus for the manufacture of silicon rods having a colur structure comprising monocrystalline crystal zones with a crystallographic preferred orientation. Molten silicon is transferred from a silicon reservoir into a crystallization chamber which is formed by rollers arranged in a leak-proof manner in the shape of the desired rod cross-section. There the silicon first forms a stable outer shell of solidified material and, while it continues to crystallize, it is withdrawn at the bottom and released by the rollers. Owing to the short period of contact with a vessel wall a silicon rod is obtained that is particularly free of impurites.

Abstract: A process and apparatus for the manufacture of silicon blocks having a columnar structure comprising monocrystalline crystal zones having a crystallographic preferred orientation. In a casting process, each mold filled with molten silicon is transferred, before the silicon has solidified completely, to a separate crystallization station where the silicon can then crystallize completely. During this process, the exposed surface of the silicon is maintained in a molten state until the end of the solidification process has almost been reached. The process allows the various, necessary steps to be carried out simultaneously and yields high-quality solar cell base material.

Abstract: A process and apparatus for the regeneration of shaped carbon, and especially graphite, bodies used in the presence of molten silicon. The shaped bodies are heated in an inert atmosphere to a temperature in the range of from 1700.degree. to 3000.degree. C. and maintained at this temperature for a defined period of time. The process substantially prolongs the service life of the shaped bodies. The apparatus includes at least one evacuable loading chamber, and evacuable heatable heating chamber connected to the loading chamber and an evacuable coolable cooling chamber connected to the heating chamber. A support capable of moving between the loading, heating and cooling chambers is adpated for receiving the shaped bodies to be regenerated.

Abstract: A residual melt of liquid silicon is removed from a crucible containing the ame by immersing in the melt a capillary body of carbon felt, the melt being absorbed by the capillary body, and removing the capillary body and absorbed melt from the crucible.