The refining process is actually a REDUCTION process.
The iron ore ( oxidised iron ) is reduced in the Blast Furnace to IRON.
Three substances are mixed and added to the Blast Furnace.
They are Iron Ore (Iron(III) Oxide ; Fe2O3)
Coke (Carbon ; C)
Limestone ( Calcium carbonate ; CaCO3)
A Blast of Hot Air is sent in from the bottom (O2)
The heat makes the limestone decompose to calcium oxide(CaO) and carbon dioxide(CO2)
The Carbon then reacts with the carbon dioxide and also the air to form carbon monoxide.
CO2 + C = 2CO & "C + O2 = 2CO (4CO)
It is the Carbon Monoxide (CO) that reacts with iron ore to form iron. as carbon monoxide is a powerful reducing agent.
2Fe2O3 + 4CO = 4Fe + 4CO2 (Not Balanced)
As a secondary reaction the calcium oxide reacts with the impurities in the iron oxide (viz. sand ; SiO2) to form 'slag' (calcium silicate) .
CaO + SiO2 = CaSiO3 (slag).
Calcium silicate is used top make road surfaces, and 'breeze' blocks for building.
The iron that is collected is still impure, and whilst liquid hot, is placed in a BOS plant with an oxygen lance, to oxidise any remaining impurities, viz. sulphur, (to sulphur dioxide) and phosphorus(to Phosphorus oxide). The carbon impurity ( to carbon dioxide) is controlled at this stage in order to make steel , which contains about 0.1% to 2% carbon , depending on the nature of the steel.
Blast furnace waste gas is mainly nitrogen because nitrogen makes up about 78% of the atmosphere and is used as the primary gas for the blast furnace process. During the process, the injected air reacts with the fuel and iron ore to form nitrogen-rich waste gas.
Impurities in iron from a blast furnace can affect its strength, ductility, and other mechanical properties. For example, high levels of carbon can make the iron harder but more brittle, while sulfur and phosphorus can decrease its ductility. These impurities need to be carefully controlled during the refining process to produce iron with desired properties.
The viscosity of slag in a blast furnace typically ranges from 1 to 10 Pa.s (Pascal-seconds) at typical operating temperatures. Viscosity can vary based on factors such as temperature, composition of the slag, and other process conditions within the blast furnace.
The iron that comes out of a blast furnace is typically in a molten state, known as pig iron. It is usually cast into molds to form pig iron blocks or further processed into steel through refining processes to remove impurities and adjust its carbon content.
how does the blast furnace maintain the heat ?what is the function of CaCO3 ?how the slag protect the molten iron ?why does iron flow down to the bottom /how does the slag and molten iron get seperated ?what is use of waste gas /what is main impurity of iron in blast furnace ?
Blast furnace = Hochofen
A blast furnace is used to extract iron from its ore.
Blast furnace waste gas is mainly nitrogen because nitrogen makes up about 78% of the atmosphere and is used as the primary gas for the blast furnace process. During the process, the injected air reacts with the fuel and iron ore to form nitrogen-rich waste gas.
The viscosity of slag in a blast furnace typically ranges from 1 to 10 Pa.s (Pascal-seconds) at typical operating temperatures. Viscosity can vary based on factors such as temperature, composition of the slag, and other process conditions within the blast furnace.
Impurities in iron from a blast furnace can affect its strength, ductility, and other mechanical properties. For example, high levels of carbon can make the iron harder but more brittle, while sulfur and phosphorus can decrease its ductility. These impurities need to be carefully controlled during the refining process to produce iron with desired properties.
Its because air is forced into the furnace to increase temperature. Steve.
Govăjdia Blast Furnace was created in 1810.
It is 96% iron (the rest is mostly sulphur etc.).
The iron that comes out of a blast furnace is typically in a molten state, known as pig iron. It is usually cast into molds to form pig iron blocks or further processed into steel through refining processes to remove impurities and adjust its carbon content.
A blast furnace is a forge in which ore is smelted to meal, being intensified by a blast of hot air.
through the top of the blast furnace
'i' blast furnace of tata steel, jamshedpur,india