METHOD OF PURIFYING METALLURGICAL SILICON BY DIRECTIONAL SOLIDIFICATION

摘要

The method is used to purify metallurgical silicon (3) by directional solidification to obtain solar or photovoltaic-grade silicon (6). A crystallization step uses at least one silicon seed (2), preferably of solar grade (6) or even microelectronic grade, having, for example, a purity that is substantially equal to or greater than a predetermined purity of the solar-grade silicon (6). The silicon seed (2) which covers the bottom of the crucible can come from a previous crystallization or be made up of a silicon wafer. The use of a textured single crystal or multi-crystal seed (2) enables the crystallographic orientation of the solar-grade silicon (6). A solid metallurgical silicon intermediate layer can be arranged on the silicon seed (2) and a metallurgical silicon load (3) is arranged on the intermediate layer.