Patent ID: 8528740

Claim:
A method for separating and recovering silicon particles from silicon saw kerf resulting from slicing silicon wafers from a silicon ingot, the saw kerf comprising an organic lubricating fluid and a mixture of solid particulate comprising abrasive grains, silicon particles, metal particles and oxide particles, the method comprising: contacting the saw kerf with a chelating agent soluble in the organic lubricating fluid to form a complex with one or more metals present in the saw kerf; mixing the chelated saw kerf solution with an aqueous acid solution and allowing the mixture to separate into an aqueous phase and an organic phase, the aqueous phase comprising silicon particles and the organic phase comprising the complex formed between chelating agent and the metals; collecting the aqueous phase comprising the silicon particles; and, recovering at least a portion of the silicon particles from the aqueous phase, wherein the recovered silicon particles have a carbon content of less than about 50 ppma and have a content of metal contaminants of less than about 150 ppma.