Why is the air entering the blast furnace heated?
Another product of the ironmaking process, in addition to molten iron and slag, is hot dirty gases. This gas has a considerable energy value so it is burned as a fuel in the “hot blast stoves” which are used to preheat the air entering the blast furnace to become “hot blast”.
What is used to prepare the outer shell of blast furnace?
Blast furnace, a vertical shaft furnace that produces liquid metals by the reaction of a flow of air introduced under pressure into the bottom of the furnace with a mixture of metallic ore, coke, and flux fed into the top.
What enters a blast furnace?
In a blast furnace, fuel (coke), ores, and flux (limestone) are continuously supplied through the top of the furnace, while a hot blast of air (sometimes with oxygen enrichment) is blown into the lower section of the furnace through a series of pipes called tuyeres, so that the chemical reactions take place throughout …
How do you remove impurities from a blast furnace?
Impurities in the iron from the Blast Furnace include carbon, sulphur, phosphorus and silicon. These have to be removed. Sulphur has to be removed first in a separate process. Magnesium powder is blown through the molten iron and the sulphur reacts with it to form magnesium sulphide.
Why is caco3 added to blast furnace?
Limestone is calcium carbonate (CaCO3) and it is added to the blast furnace to remove the impurities in the iron ore, as mentioned above. Silicon dioxide will react with the calcium oxide to form calcium silicate, known as slag.
Which burns hotter coal or coke?
Coal is a shiny, black fossil fuel that contains impurities, emits smoke when burned, and produces less heat than coke. Coke is a dull, black byproduct of coal that burns hotter and cleaner.
Why do we use coke for making steel but not coal?
Coke is used as a fuel and a reducing agent in melting iron ore. It is produced by baking coal until it becomes carbon by burning off impurities without burning up the coal itself. When coke is consumed it generates intense heat but little smoke, making it ideal for smelting iron and steel.
Which coal has no caking power?
Non Coking Coal does not have any caking properties and it is mainly used as thermal coal for power generation. It has a higher ash content and also used in industries like cement, fertilizer, glass, ceramic, paper, chemical and brick manufacturing.
What is caking and non caking coal?
A non-caking coal is that coal which on heating in absence of air doesn’t from a coherent mass of residue. A Caking coal, when heated in a similar way, leaves a solid coherent residue. The non-coking coals are those coals which may form a solid-residue but may not be suitable for manufacture of coke.
What is free burning coal?
i. A bituminous coal having so little fusibility that enough air for rapid combustion can flow between the lumps and high enough in volatiles and fixed carbon to burn readily.