The degradation of coke in a blast furnace is mainly due to the carbon loss reaction caused by CO
2
erosion, that is, the coke solution loss reaction
(C
coke
+ CO
2
= 2CO)
. The loose structure and the decreasing strength of coke affect the skeleton support and good permeability of a blast furnace.
What is the main reaction in the blast furnace?
The main chemical reaction producing the molten iron is:
Fe
2
O
3
+ 3CO → 2Fe + 3CO
. This reaction might be divided into multiple steps, with the first being that preheated air blown into the furnace reacts with the carbon in the form of coke to produce carbon monoxide and heat: 2 C
( s )
+ O
2 ( g )
→ 2 CO.
What is the purpose of burning coke in a blast furnace?
Blast furnace ironmaking makes use of coke as the
major source for both energy and reduction of iron oxides
. In the blast furnace process, coke has multifunctions and plays an important role as reductant, burden support, and fuel.
What is the product of blast furnace called?
The product of blast furnace is
pig iron
which is an intermediate product in the production of steel. It is also called crude iron.
Which gas is formed during burning of coke?
The carbon dioxide reacts with the coke and in turn produces
carbon monoxide
, which further reacts with oxygen in the gas as long as it is available.
What is iron ore?
Iron ore is a mineral substance which, when heated in the presence of a reductant, will yield metallic iron (Fe). It almost always consists of iron oxides, the primary forms of which are magnetite (Fe
3
O
4
) and
hematite
(Fe
2
O
3
). Iron ore is the source of primary iron for the world’s iron and steel industries.
How is iron produced in a blast furnace?
The production of iron from its ore involves
an oxidation-reduction reaction carried out
in a blast furnace. … The iron found in iron ores are found in the form of iron oxides. As a result of these impurities, iron must be first separated from the gangue and then converted to pure iron.
What is limestone used for in blast furnace?
Limestone is also used
to remove impurities from the blast furnace when making iron
. The impurities are mostly silicon dioxide (also known as sand). The calcium carbonate in the limestone reacts with the silicon dioxide to form calcium silicate (also known as slag).
What is the role of coke and flux in smelting?
Coke and flux are used in the smelting. The phenomenon in
which ore is mixed with suitable flux and coke and is heated to fusion
is known as smelting. Oxide of matter obtained from nature or by calcination or roasting is reduced by a coke through smelting. During smelting the impurities are also removed.
What is M40 in coke?
The resistance, in Micum drum, is an international standardized method, being the most used one, indices obtained in the test are: M40=
mechanical resistance M10
= abrasion For a high quality coke these indices must have values between M40= 80 ÷ 85% and M10 = 5 ÷ 7%.
Why is it called pig iron?
The common mold shape that is used for ingots was with a branching structure formed within sand. This configuration is similar to the look of a litter of piglets suckling on a sow.
Once the metal has hardened and cooled, the little ingots or “pigs” are broken into a thinner runner
, hence the name “pig iron.”
Why is wrought iron called?
Wrought iron is tough, malleable, ductile, corrosion resistant, and easily welded. … It was given the name wrought
because it was hammered, rolled or otherwise worked while hot enough to expel molten slag
. The modern functional equivalent of wrought iron is mild steel, also called low-carbon steel.
What is metal slag?
Steel slag,
a by-product of steel making
, is produced during the separation of the molten steel from impurities in steel-making furnaces. The slag occurs as a molten liquid melt and is a complex solution of silicates and oxides that solidifies upon cooling.
Which iron ore is used in blast furnace?
Iron is mainly extracted from
hematite (Fe
2
O
3
)
and magnetite ores. Natural or direct shipping iron ores contain between 50-70% iron and can be fed directly into the blast furnace. Fe
3
O
4
decomposes when heated to ferrous oxide (FeO) and ferric oxide (Fe
2
O
3
) via Fe
3
O
4
→ FeO + Fe
2
O
3
.
What is boiler flue gas?
Flue gas refers to a
chemical byproduct substance that is generated as a result of a combustion reaction
that has escaped through long pipes such as those in boilers, furnaces or steam generators. Flue gas may also be referred to as exhaust gas and may act as a reactor agent for atmospheric corrosion.
What is difference between coal and coke?
Coal is a lustrous, black fossil fuel that includes impurities, generates smoke, and generates
less heat than coke when burned
. Coke is a dingy, black coal waste that burns hotter and cleaner. … Coke is a fuel made from mineral coal that has been calcined or dry distilled.
What is zinc ore?
Zinc ore is most commonly found as zinc carbonate (ZnCO
3
), known as
calamine or smithsonite
. It generally occurs as rounded, crystalline crusts or granular, honeycombed masses that have a vitreous or pearly luster and are typically dirty brown or grey in colour.
What is iron ore reduction?
Direct reduction of iron is
the removal of oxygen from iron ore or other iron bearing materials in
the solid state, i.e. without melting, as in the blast furnace. The reducing agents are carbon monoxide and hydrogen, coming from reformed natural gas, syngas or coal. Iron ore is used mostly in pellet and/or lumpy form.
What are the 4 types of iron ore?
There are four main types of iron ore deposit: massive hematite, which is the most commonly mined,
magnetite, titanomagnetite, and pisolitic ironstone
. These ores vary in colour from dark grey, bright yellow, or deep purple to rusty red.
What is ore of Aluminium?
Bauxite
is the most common aluminum ore. Approximately 98% of primary aluminum production is based on bauxite.
What is extraction of iron?
Iron is extracted from
iron ore in a huge container called a blast furnace
. Iron ores such as haematite contain iron(III) oxide, Fe
2
O
3
. The oxygen must be removed from the iron(III) oxide in order to leave the iron behind.
Which reaction occurring in the blast furnace is an acid base reaction?
One of the raw materials which is fed into the Blast Furnace is limestone, an almost pure form of calcium carbonate. Limestone decomposes in the hot furnace to give
calcium oxide
, which is a base. Calcium oxide joins with acidic impurities in the ore, to make a salt.
Why Calcium carbonate is used in blast furnace?
The Chemistry of the blast furnace. … Limestone is calcium carbonate (CaCO
3
) and it is added to the blast furnace to remove the impurities in the iron ore, as mentioned above.
Calcium carbonate is decomposed by heat in the furnace to give calcium oxide (quicklime) and carbon dioxide
.
How is marble formed?
Marble forms
when sedimentary limestone is heated and squeezed by natural rock-forming processes
so that the grains recrystallize. If you look closely at a limestone, you can usually see fossil fragments (for example, bits of shell) held together by a calcite matrix.
What is limestone chemical formula?
Limestone consists of calcium carbonate, which has the chemical formula
CaCO
3
.
What is pig iron used for?
Pig iron is a solid form of hot metal, obtained from iron ore or scrap recycling, and it is processed with blast furnace or electric arc furnace. Pig iron is used as a
raw material for iron steel making
and most of this material was imported.
What is CSR and CRI of coke?
Coke reactivity to carbon dioxide (CRI) determines percent weight loss of coke, as a result of carbon dioxide action on the coke sample in temperature 1100°C. The coke strength after reaction (CSR) determines
>10 mm grain amount yield
obtained after mechanical tumbling of coke after reaction with carbon dioxide.
What is M10 coke?
The coke is removed, screened and replaced in the drum and subjected to a further 400 revolutions in the drum. The test is based on the ISO 556 standard. M40 – the percentage material remaining +40mm round hole after 100 revolutions. M10 – the percentage material –
10mm round hole after 100 revolutions
.
What is CSR in metallurgical coke?
Coke
Strength after Reaction
(CSR) refers to coke “hot” strength, generally a quality reference in a simulated reaction condition in an industrial blast furnace.
What is the function of limestone in the iron process?
The main function of limestone in the extraction of iron from haematite is
as a flux
. Limestone is used as a flux to remove the impurities and dirt from haematite. Limestone decomposes in a hot furnace and forms calcium oxide (CaO). Iron is extracted from its ore, haematite, in a blast furnace.
How is pig iron formed?
Pig iron, also known as crude iron, is an intermediate product of the iron industry in the production of steel which is
obtained by smelting iron ore in a blast furnace
.
What is slag formula?
The slag can generally be expressed by the formula
FeSNa
2
S(O)
. Both reactions 9.5 and 9.6 are heterogeneous and endothermic in nature.
What is slag example?
Slag is waste matter separated from metal during smelting. An example of slag is the
iron and silica that is removed during copper and lead smelting
. … An example of to slag is for the heat of copper smelting to remove the iron and silica from the copper.
What is iron and steel slag?
Iron and steel slags are
coproducts of iron and steel manufacturing
. In the production of iron, the blast furnace is charged with iron ore, fluxing agents, usually limestone and dolomite, and coke as fuel and the reducing agent.
What is steel made of?
steel,
alloy of iron and carbon
in which the carbon content ranges up to 2 percent (with a higher carbon content, the material is defined as cast iron).
What is the meaning of sponge iron?
Definition of sponge iron
:
iron in porous form or containing many voids
specifically : crude iron made by subjecting the oxide ore to a reducing gas without melting.
How is nickel pig iron?
Nickel pig iron is made of
low-grade nickel ore, coking coal, and a mixture of gravel and sand as an aggregate
. … Impurities are then removed via smelting and sintering processes and the resulting nickel pig iron contains four to 13 percent pure nickel.
What color is rod iron?
It’s
a muted black with grey and blue undertones
that soften it up so it is not a harsh black. It is lighter than a true black, therefore it is more flexible and can be used in a wide variety of spaces. From cabinets to exteriors and window trim, Wrought Iron is a popular paint color and it’s easy to see why.
What is steel and alloy of?
Fundamentally, steel is an
alloy of iron with low amounts of carbon
. … Alloy steels are made of iron, carbon and other elements such as vanadium, silicon, nickel, manganese, copper and chromium. Alloy steel. When other elements comprising metals and non-metals are added to carbon steel, alloy steel is formed.
What is difference between iron and cast iron?
Wrought Iron is iron that has been heated and then worked with tools. Cast Iron is iron that has been melted, poured into a mold, and allowed to solidify. The fundamental distinction between cast iron and wrought iron is
in how they are produced
.
