(1) Cupola structure
The basic structure of the cupola is shown in Figure 1. The furnace body, bellows and flue are welded with steel plates. The inside of the shaft is usually made of refractory bricks to protect against the high temperature caused by coke burning. In order to store iron, most cupolas are equipped with a forehearth.
(2) The principle of cupola melting
During the smelting process, the lower part of the shaft is filled with coke, called the bottom coke. A batch of iron (powder, scrap, recycled material, ferroalloy, etc.), coke and flux (limestone, fluorite, etc.) are alternately placed on top of the bottom coke. By blasting, the bottom coke is strongly burned, and the generated high-temperature furnace gas rises along the height of the furnace body to melt the upper layer of iron.
(3) Advantages and Disadvantages of Cupola Melting and Its Application
Cupola is the most commonly used cast iron smelting equipment. It uses coke as a fuel, and the heat generated by coke combustion is directly used to melt the charge and increase the temperature of the molten iron, saving energy consumption compared to electric furnaces and other furnaces. And the equipment is relatively simple, both large and small factories can be used. However, the cupola also has certain disadvantages, mainly because the molten iron is directly in contact with the coke, so the process of iron-carbon carbonation and sulfur-increasing occurs during the smelting process.
The cupola furnace-electric furnace double-smelting method or the cupola-induction furnace double-smelting method is adopted to make full use of the cupola furnace with high melting efficiency, the electric furnace and the induction furnace have strong iron superheating ability and easy control of chemical composition. The advantages.