A cupola melts iron
Basic principle Ordinary cupola is basically a straight barrel: from bottom to top, four legs support the bottom, body and top of the furnace, forming the entire furnace.
Cupola smelting principle:
The air entering the furnace by the tuyere will react with the bottom coke to generate heat, and the generated high temperature furnace gas will flow upward. The charge (metal charge, flux and coke) will be stratified according to a certain quality and be gradually preheated after being added in batches through the charging port.
Finally, the metal charge on the top of the bottom coke melts from solid to liquid, and the liquid metal continues to heat through the red hot coke and furnace gas (called overheating), and enters the front furnace through the furnace cylinder and bridge. The bottom coke burning and metal charge melting make the charge level in the furnace gradually drop, and after one layer of charge is melted, the next layer of charge is supplemented, so the continuous cycle makes the melting continue. The limestone in the charge is decomposed into carbon dioxide and quicklime under the action of furnace gas. Lime combines with ash in coke, eroded lining and oxide in charge to form slag with low melting point. Under the joint action of furnace gas, coke and slag, the chemical composition of liquid iron changes gradually.
The final chemical composition of liquid iron depends not only on the chemical composition of the charge, but also on a series of metallurgical reactions produced during the smelting process. There are three important processes in cupola, namely bottom coke combustion, heat transfer and metallurgical reaction. Bottom coke combustion is the basis of heat transfer, mass transfer and metallurgical reaction.
