Now let's talk about raw materials for ironmaking process.
In order to process iron, of course we need some iron source.
There are several iron ore mines in the world, so we get the iron ore to produce iron.
The iron ore is basically iron oxide but this is not a pure chemical it contains certain
levels of impurities and through the iron making process the oxygen from iron ore must
be taken out.
This is done by carbon.
Carbon is contained in coke.
Coke is also available in several coke mines, coal mines.
Using this iron ore and coke we produce iron.
There are several different types of iron ore available.
Depending on its chemical composition, its mineralogical name is different.
The most relevant iron ore is hematite.
This is basically Fe2O3.
The other types of iron ore is magnetite.
This is Fe3O4.
These 2 are very relevant iron ores.
Some other types of iron ore is available.
This is called limonite or illmenite.
All these are oxide types iron ore.
On the other hand, there are different types of carbonate types of iron ore available.
This is called siderite.
All these basically contains iron, and we could take iron from this iron ore to iron
making process.
Unfortunately, this is not a pure chemical it contains certain impurities and the impurities
we call as gangue.
It is typically composed of silica and alumina, and some other types of impurity like phosphorus.
Now look at coke.
Coke is basically delivered as carbon into the system.
If it could use the pure chemical carbon then it would be much better, however, the pure
carbon is quite expensive and what we can get from the mines is not coke, but this is
coal.
Coal is natural available carbon source.
Once coal is obtained, this is brought into ironmaking plant.
Then we change it to coke.
The coke is finally used in ironmaking process.
And similar to iron ore, the coal and coke also contain certain amount of impurities.
This is called ash.
This is also, silica, alumina and certain level of sulfur.
Now let's look at basic reactions happening in ironmaking process.
If we roughly describe our metal reactions then iron oxide in iron ore reacts with carbon
in coke then iron oxide reduced, by this direction we could get iron and carbon and oxygen forms
carbon monoxide gas and this disappears.
This is quite simply described, however, in order to allow this kind of reaction happening,
we need some heat.
During iron making process there are also important reactions.
Carbon in other form, in fuel gas and oxygen in hot air are blasted into reaction vessel,
the blast furnace and it forms carbon dioxide gas and generate a lot of heat.
This is applied to these raw materials and iron becomes molten state.
Once this carbon dioxide gas is generated then this reacts with carbon and coke and
if forms carbon monoxide gas back.
This carbon monoxide again reacts with iron ore and it is used to reduce iron ore.
The third reason is called Boudouard's reaction, and this is one of the important reactions
in iron making process.
Right hand side shows the full description of ironmaking plant.
In the middle, we have reaction vessel called blast furnace.
This blast furnace has raw material supply facility and hot air supplying facility and
tapping facility for producing hot metal and slag.
Inside this blast furnace, what is happening?
We have iron ore supplied and coke.
They stay layer by layer and hot air is blasted into this blast furnace.
The air first reacts with fuel to form carbon dioxide gas.
This carbon dioxide gas reacts with coke to form carbon monoxide gas- this is Boudouard
reaction.
This carbon monoxide gas reacts with ore in order to produce ore into iron.
The iron is also carburized by coke so it becomes molten state then liquid iron falls
down.
By this way we could get molten iron from blast furnace.
This is basic ironmaking process.
Kim, Nack JoonProfessor
Suh, Dong WooAssociate Professor
Kang, Youn-BaeProfessor
Kim, Sung-JoonProfessor
