Methods for purifying metallurgical silicon

摘要

A method for purifying silicon bearing materials for photovoltaic applications includes providing metallurgical silicon into a crucible apparatus. The metallurgical silicon is subjected to at least a thermal process to cause the metallurgical silicon to change in state from a first state to a second state, the second stage being a molten state not exceeding 1500 Degrees Celsius. At least a first portion of impurities is caused to be removed from the metallurgical silicon in the molten state. The molten metallurgical silicon is cooled from a lower region to an upper region to cause the lower region to solidify while a second portion of impurities segregate and accumulate in a liquid state region. The liquid state region is solidified to form a resulting silicon structure having a purified region and an impurity region. The purified region is characterized by a purity of greater than 99.9999%.