METHOD FOR RECOVERING SOLAR GRADE SILICON

摘要

The invention concerns a method of refining and converting particulate silicon to silicon lumps, where the method comprises mixing the particulate silicon with at least one slag forming compound in a weight ratio, particulate silicon:slag forming compound(s), from 1:10 to 3:1 in a crucible, wherein the at least one slag forming compound will form a liquid the slag at the operating temperature of the process that has a viscosity lower than 2 Ns/m2 and a wetting angle towards silicon of at least 20°, heating the mixture of particulate silicon and slag forming component(s) to a temperature above the liquidus temperature of the slag, injecting a stream of gas through at least one point of the bottom of the crucible and maintain the gas flushing for a period of time, solidifying and cooling the molten mixture, and separating formed silicon agglomerates/lumps from the slag.