The furnace is designed for smelting pig iron.First appeared in the XV century. in Europe. In Russia, the first blast furnace was built in 1620 near Tula. Then fuel for such furnaces was charcoal. Only a century later (1709), the British inventor Abraham Derby managed to carry out blast furnace smelting, replacing charcoal with charcoal coal.
Many centuries of experience changed the device of the domainfurnace, its appearance and the very scheme of production of cast iron. But the basics remained the same. Today the blast furnace is a construction of about 30 meters (height varies ± 5 m). The height of the entire structure can exceed 80 m.
How is the blast furnace arranged?
Through the upper part (top) are loaded batch(agglomerate, pellets, iron ore, manganese ore, fuel and fluxes). Below is the mine, the largest part of the blast furnace, which is an expanding cone. Due to this expansion, it is easier to lower solid materials that increase the volume when heated. The bottom (broad, cylindrical) is adjacent to the bottom of the shaft. In it, the charge is melted. Behind the rasp, below, are the shoulders, made in the form of a truncated cone with a reduced base beneath. Such a cross section is most suitable for a material volume that decreases as a result of melting.
In the cylindrical furnace, the lower part of the profile, there is burning of coke and a liquid product of melting is collected.
The horn is divided into parts: the upper zone (tuyere) and the lower one (the metal receiver, in which the products of the smelting are collected). The bottom is called the lower part of the furnace.
In the tuyere zone,which feed into the blast furnace blast (hot air). It is this site that is responsible for the burning of coke, the temperatures here grow to its maximum values of 2000 degrees. At the top of the top the temperature is lower (up to 350 degrees).
In the lower part of the furnace there is a cast-iron tap hole, which allows for the smelting products - slag and cast iron itself.
Previously, slag tap was used, but practiceIn recent decades it has been shown that it is more practical to pass slag and cast iron through a tap hole cast iron, with further separation in the main trench adjacent to the furnace.
To the oven adjoins the so-called foundry,where there are devices that open the iron tap and close it after the release of slag and cast iron. Here there are gutters with ditches, directing the product of melting into buckets.
The product released from the oven is sent to the mainTrench where the cast iron is separated from the slag (density difference). From the gutter go two ditches. One is sent to the slag, the other is cast iron. Cast iron is poured over continuously moving forms (conveyor type), after cooling down the molds are overturned and further the cast iron is directed to the wagons. Slag is poured into pools, cooled by water and granulated.
Each furnace height has its own specific temperature, which is why the process of transition to the metal from the ore flows.
In the lower part of the furnace,burning coke is the amount of oxygen. Coke burns, converting to carbon dioxide, which reacts with coke, converting already into carbon monoxide. Then there is a reaction between carbon monoxide and iron oxides. There is a restoration to the metal. Iron is saturated with carbon and cast iron is produced. In addition to three to four percent of carbon, in the alloy in minor proportions there are manganese and silicon, sulfur and phosphorus.
Actually, a blast furnace, the principle of operation of whichwas described here, may well be considered a non-waste production. Byproducts appearing in the process of production, quite find use outside the walls of factories for the production of cast iron. The slag is added to cement suitable for buildings (so widely used now is the cinder block), and blast furnace gas serves as a good fuel that heats the air fed to the blast furnace.
