How to Use 1), For 1-5 T furnace: - while a small amount molten iron in the furnace, - or with some molten iron remained, add the carbon additive one-time, - then add the other material. which can make carbon additive fully absorbed. 2), For greater than 5 T furnace: - mix proper carbon additive with charging material as suggested first, - and then along with the increase of charging material gradually, - that is, before the molten metal rising up to about 2/3 height of furnace, - all carbon additive shall be added. It guarantees sufficient melting & absorbing time before molten metal out, and improves the absorption of carbon.