Silicon and silicon carbide powders recycling technology from wire-saw cutting waste in slicing process of silicon ingots

A study on recycling silicon and silicon carbide powders from wire-saw slurry containing silicon carbide, silicon kerfs, polyethylene glycol (PEG), and iron fragments in the wire-saw slicing silicon ingots process was conducted. Recycling technology was suggested. PEG from the slurry was removed using filter press, and iron particles from the slurry were removed using high gradient magnetic separator. To separate silicon carbide and silicon particles hydrocyclone assembly was used. Recovered silicon carbide powder (95 wt% SiC, 4 wt% Si and 1 wt% Fe) can be used again in the process of cutting silicon ingots. Obtained recovered powder with high Si content after additional purification further can be used as a feedstock together with the amorphous silicon for crystal growth by directional solidification in an induction furnace.