2. Introduction to blast furnace
•A blast furnace is a type of metallurgical furnace used for smelting to produce industrial
metals, primarily pig iron, from iron ore.
•It operates on the principle of chemical reduction whereby carbon monoxide converts to
iron oxides to elemental iron.
•Primarily the fuel used in blast furnace is ‘COKE’.
3. Role of coke in blast furnace:
Coke is primarily carbon and act as a
fuel to maintain the high temperature
required in the blast furnace, which
can reach up to 2000° C.
The combustion of coke produces heat
and carbon monoxide, which is
essential for the smelting process.
Reduction in blast furnace:
Fe2O3+3CO→ 2Fe+3CO2
4. Production of coke using coke oven:
Coking process and coke oven:
The coking process involves heating coking coal in the absence of air to drive off
volatile compounds. This is done in coke ovens, which are special ovens designed to
withstand high temperature.
5. Physical and chemical properties of coke
Appearance:
Coke is grey, hard and
porous material.
Composition:
It consists of high
carbon content
with few impurities
Density:
True density is
around 1.80-
1.95g/cm3 ,and
apparent density is
0.88-1.08g/cm3.
Porosity:
Typically between
35-55%
Thermal properties:
Has a high ignition
temperature of
450-650° C and good
thermal confuctivity
Reactivity:
Coke has low
reactivity with gases
and liquids, making
it stable at high
temperature
7. Advances in Eco-friendly coking technologies
Recent advancements in eco-
friendly coking technologies
have focused on the treatment
of coking wastewater, which
poses a serious threat to the
presence of refractory
substances.
Integrated treatment methods,
including biological methods
with a special focus on “bio-
augmentation”, have
emerged as effective solution
for managing coking
wastewater.
Additionally, “microwave
technology” is being explored
for its potential in treating
coking wastewater.
Benefit of bio-augmentation in coking process
9. conclusion
Role and importance of coke in industries worldwide:
Blast Furnaces in Iron & Steel Industry:
Coke is a major input factor in blast furnaces, accounting for
approximately 60% of hot metal cost.
Its quality, including factors like size fraction, ash content, carbon content,
reactivity, granulometry, moisture content, and strength after reaction,
significantly impacts blast furnace performance.
Thermal Role: Coke provides the bulk of the energy and process heat required
for the iron-making process.
Chemical Role: It furnishes the necessary reduction potential in the form of
carbon monoxide for the reduction process and supplies the required carbon
for carburizing the liquid hot metal.
Iron Production:
Oven coke (sized between 40 to 100 millimeters or about 1.5 to 4 inches) is used
worldwide in blast furnaces to produce iron.
Smaller quantities of coke are also employed in other metallurgical processes,
such as the manufacture of ferroalloys, lead, and zinc, as well as in kilns for lime
and magnesia production.
10. Steelmaking Process:
Coke has a dual role in steelmaking:
Heat Provider: It supplies the heat needed to melt the iron ore.
Oxygen Stealer: When burnt, it removes oxygen from the iron ore, leaving
behind pure iron.
In the coking plant, coal is heated in the absence of oxygen to around 1250°C,
resulting in coke formation.
Historical Development:
The evolution of coke making has been continuous since the latter half of the
19th century.
Innovations in coke oven design, such as beehive ovens, gunflue, half-divided,
four-divided, twin flue, and cross-over systems, have contributed to the present-
day coke oven technology.
Worldwide annual coke production stands at approximately 350 million tonnes,
with India contributing around 12 million tonnes
