I-silicon slag iwumkhiqizo ophuma ku-silicon yensimbi encibilikayo kanye ne-ferrosilicon.Iwuhlobo lodoti oluntanta esithandweni ngesikhathi sokuncibilikisa i-silicon.Okuqukethwe kukusuka ku-45% kuya ku-70%, kanti okunye kungu-C,S,P,Al,Fe,Ca. Ishibhile kakhulu kunensimbi ye-silicon ehlanzekile. Esikhundleni sokusebenzisa i-ferrosilicon ekwenzeni insimbi, inganciphisa izindleko.