Silicon slag ndi mankhwala opangidwa kuchokera ku smelting zitsulo silikoni ndi ferrosilicon.Ndi mtundu wa zinyalala zoyandama pa ng'anjo posungunula silicon. Zomwe zili mu 45% mpaka 70%, ndipo zina zonse ndi C,S,P,Al,Fe,Ca. Ndiwotsika mtengo kwambiri kuposa chitsulo choyera cha silicon. M'malo mogwiritsa ntchito ferrosilicon popanga zitsulo, imatha kuchepetsa mtengo.