1. ( The wood is first ignited over a bed of sand.

2. When the wood starts burning properly, the coke is thrown from the top to the well at a
predetermined height of about 40 inches. This makes a 40-inch coke bed.
3. Then the combustion begins in the coke bed using fire from the burning wood and air
from the trees.
4. At this time, aerial explosions have flown at lower than normal rates to provoke coke.
5. When the coke starts to burn properly after about 3 hours of burning, alternating layers
of limestone, pig iron, and coke are charged until it reaches the level of the charging
door.
6. At this time, an air blast is carried out at a normal blowing rate, and combustion occurs
more rapidly in the coke bed.
7. All the oxygen from the air blast is consumed by combustion in the combustion zone.
8. The chemical reaction that occurs is C + O2 -> CO2 + Heat.
9. It is an exothermic reaction, and the temperature in the combustion zone varies from
1150 to 1850 ° Celsius.
10. The portion of the coke bed above the combustion zone is a reducing zone.
11. This region prevents oxidation of the metal charge while leaving it over and through.
12. Ho carbon dioxide goes up through this region; some of it is reduced by the following
reaction, CO2 + C -> 2CO
13. The zone of dilution of iron above the zone is a melting zone where solid iron is
converted into molten iron.
14. This molten iron falls down through the coke bed and collects in the well.
15. In this region, sufficient carbon compacts are extracted by the molten metal and are
characterized by the following chemical reaction: – 3 Fe + 2 CO -> Fe3 C + CO2
16. Above the melting zone, there is a preheating zone, where the inward gases are
preceded by and the temperature of this zone is about 1900 degrees Celsius.
17. In addition to limestone, fluorspar and soda ash are also used as flux materials.
18. The main function of the flux is to remove impurities from the iron and protect the iron
from oxidation.
19. For normal blast rates, the first molten iron appears in the tap hole within 5 to 10 minutes
after the start of the air blast.
20. The charging door remains closed until the metal melts.
21. The content of the charge goes down as the melting proceeds.
22. The rate of charging, i.e., the rate of adding layers of charge, is equal to the rate of
melting. The furnace is kept throughout the process.
23. When the melting process is over and no more molten irons are required, the charge
feeders stop, and the air blast also stops.
24. The bottom plate opens when the prop is removed, and the slag is removed.
25. The copula furnace is generally not used for more than 4 hours but may be used for 10
hours of continuous operation.
26. The cupola furnace operates on a simple principle that produces carbon dioxide and
heat from the combustion of coke and causes iron to melt.
27. Iron melts when it flows downwards.)
(Spark Arrester
Spark arrester is conical in shape which is located at the top most of the
furnace. It is made of sheet metal and steel structures which is attached to
the cylindrical body of the furnace. The main function of spark arrester is to
arrest sparks produced in the chamber. It has some opening at the top which
helps smoke to escape from the furnace.
Charging Door
In cupola furnace, there is an opening with hinged door attached at suitable
height where operator can feed metals, coke, scrap iron, pig iron and flux
into the furnace with the help of charging cranes. These doors are made up
of steels and lined with fire resistant material.
Charging Floor
Changing floor or charging stage is a platform made for operators where
they can feed charges of metal, flux and coke inside the furnace via charging
door either manually or by using charging cranes and buckets. It is always
built around the furnace at suitable height (always below the charging door).
Steel structures are always used to build and construct charging stage
around the furnace.
Air Blast Inlet Pipe
Air blast inlet pipe or air supply duct is connected to blower and wind box at
bottom of the furnace. The main function of air blast inlet pipe is to pass the
air from blower to windbox of the furnace.
Wind Box
Wind box or wind belt is a circular steel jacket which connects the air blast
inlet pipe from the motorised blower and the cylindrical shell of the furnace.
Tuyeres & Peep Holes
Tuyers are the small holes present in a circular pattern all around the
cylindrical shell in the bottom region where wind box is present. The main
function of the tuyers is to supply the air from wind box and blower to the
combustion chamber. Peep holes are made radially on the wind box towards
the tuyers holes which helps operators to see and examine the combustion
process inside the chamber.
Slag Spout
Slag spout is a narrow opening which can be found at the bottom edge of
furnace to discharge impurities in the form of slag from the combustion
chamber.
Tapping Spout
Similar to slag spout, tapping spout is positioned at lower part of furnace
which helps to discharge molten metal from the combustion chamber.
Drop Bottom
Drop Bottom in cupola is mostly used for cleaning, maintenance and
repairing the furnace interiors. It is usually a hinged or drop bottom doors
positioned at the bottom of the furnace which helps to discharge last molten
metal in between the support legs.
Bottom Prop
Bottom prop or Prop bar is used as an additional support at the bottom of the
furnace to prevent the opening of drop bottom doors. It is made of a sturdy
material to withstand mechanical stress and high temperature that come
from combustion zone.
Support legs & Foundation
Support legs and floor foundation plays a major role by supporting the entire
furnace structure. Supports are often made up of durable and heat resistant
 material to withstand mechanical & thermal stress and to evenly distribute
weight of the structure during its operation.
Cylindrical Shell
The cupola’s vertical structure is covered by a thin cylindrical steel about 6
to 12mm thickness. The inner side is lined with refractory bricks with is made
up of silica oxide acid and alumina. Sometimes tamping clays are also used
along with refractory bricks for lining the inner circumference.)

1. It is mainly used to convert pig irons to molten irons.

2. More types of cast irons are produced from this furnace-like malleable and grey cast
iron.
3. The copper base alloy is also manufactured by this device.

Ưu

 Simple and robust design.

 Easy and economical to operate.
 Wide range of metal alloys such as pig iron, nodular cast iron, white cast iron
and copper-based alloys also can be melted.
 Cupolas can be operated continuously with multiple production cycles.
 Cupolas are highly efficient and gives high output.
 It can operate and withstand even at high temperatures.
 cupolas have longer operational life
 Less floor space is required.

Nhược

 it emits lot of pollutants in the atmosphere which causes environmental

concerns.
 it is very hard to control the temperature in this furnace.
 it is difficult to repair when there is a damage
 Safety training should be given to operators to operate such industrial
furnaces.

1.1. Electric arc furnace

Charging the Furnace

you first feed the furnace with materials like scrap metal, pig iron, or graphite. With the
help of large metal manipulators, you place the electrodes into the furnace and make
sure that the material touches the electrodes.

Creating the Arc

After charging the furnace, the process of starting the electric arc involves creating a
high voltage between the electrodes. This electric arc also produces heat to increase
the temperature of the electric arc furnace above 3000 F (1650 C).

The arc, meanwhile, ionizes the material surface to produce plasma that simultaneously
melts the raw materials underneath.

In this phase, one has control of the intensity of the arc in order to regulate the
temperature. The efficiency of an electric arc furnace is based on the fact that you are
able to control the conditions under which various materials can be melted without
losing much energy or time.

· Melting and Refining

In the melting phase, you have to control the temperature of the electric arc furnace to
ensure that the raw materials melt properly. In this process, you purify the molten metal
or graphite by adding chemicals so as to eliminate any unwanted matter. It is critical for
making high-quality products in electric arc furnace technology because you can make
certain specific adjustments of the melt at this step.

· Tapping the Molten Metal

After the raw materials have been melted and even refined, you go ahead to tap the
furnace and get the molten material. Molten metal or graphite is carefully poured into
ladles or molds depending on the successive stage of your manufacturing line.

After tapping, you get ready for the next smelting operation by cleaning and recharging
the furnace as might be required.
999999999999

ứng dụng

o Steel production from scrap metal.

o Recycling of steel and other metals.
o Production of ferroalloys like Fe-Mn and Fe-Si.
o Melting non-ferrous metals.
o Versatile in various metallurgical processes.
o Efficiently converts scrap into high-quality steel products.

Ưu điểm

o Energy Efficiency: EAFs are more energy-efficient than traditional blast furnaces,
o Versatility: They can melt a wide range of scrap materials, including steel, iron,
and non-ferrous metals, making them versatile for recycling and alloying
processes.
o Environmental Benefits: EAFs produce fewer greenhouse gas emissions
compared to conventional steelmaking processes, contributing to reduced carbon
footprint and air pollution.
 o Faster Melting: EAFs have the ability to quickly reach high temperatures,
resulting in shorter processing times compared to other methods.
o Precision Control: Operators have precise control over the melting process,
allowing for better quality control and the production of specific alloys with
desired properties.

Nhược

o Higher Operating Costs: EAFs consume a significant amount of electricity,

resulting in higher operating costs,
o Dependence on Electricity: Power interruptions or fluctuations can disrupt
operations and lead to downtime.
o Limited Capacity: EAFs are typically smaller in capacity compared to traditional
blast furnaces, Scrap Quality: The quality and composition of scrap metal used in
EAFs can vary, which may affect the quality and consistency of the steel
produced.
o Emissions: emit pollutants such as dust, particulate matter, and nitrogen oxides,
which can be a concern for air quality and environmental regulations.

3 induction Furnace

1. Working Principle

 The heating element generates heat, which is transferred to the crucible. The material
inside the crucible absorbs this heat and gradually reaches its melting point.
 Once the material becomes molten, it is ready for pouring into molds or containers to
achieve the desired shape.
 The furnace can be tilted or equipped with a tapping mechanism to pour the molten
material effectively.

Faraday’s Law describes how a magnetic field interacts with an electric circuit to
generate an electromotive force, a phenomenon known as electromagnetic induction.4,5

Therefore, once a piece of conducting material — such as a charge or load within a

furnace — is placed in an alternating magnetic field, an electric current is generated. As
the current flows, it meets resistance and dissipates energy as heat via the Joule Effect.
ứng dụng

 Alloy manufacturing, where induction stirring provides optimal uniformity and

flexibility.
 Aluminum melting, where induction melting minimizes the energy required to
convert alumina into aluminum and its alloys.
 Investment casting, where air and vacuum furnaces are used.
 Shrink-fitting, annealing, and brazing.

Ưu

Induction furnace is more efficient and melting process is clean.

Induction also ensures a more controlled melting process as compared to other kinds of
metal melting.
cupolas emit many pollutants, specifically dust, making induction a cleaner and safer way to
melt cast iron.
Another thing is that induction furnaces do not require an arc or combustion, making the
temperature safer to work with.
In Induction furnace, operation is faster and more efficient. The electromagnetic stirring
action creates a homogeneous mixture of the liquid metals..

Nhược

There is only one big negative feature. An induction furnace does not have a refining
capacity
 4. Crucible

Working of a Crucible Furnace

The working of a Crucible Furnace involves heating the material inside the crucible until it
reaches its melting point. The heating element generates heat, which is transferred to the
crucible, causing the material inside it to heat up and eventually melt.

As the material melts, it turns into a liquid state and becomes more viscous, making it easier
to pour into a mold or container. The temperature inside the crucible is maintained until the
material has fully melted, after which it is removed from the furnace and poured into a mold
or container to take the desired shape.

The working of the crucible furnace can be controlled by adjusting the heat generated by
the heating element or by using a temperature control system. The size and design of the
crucible furnace can also impact the working process and the time required to melt the
material.

Construction of a Crucible Furnace

A Crucible Furnace consists of two main parts: a heating element and a crucible. The
heating element can be an electric or gas burner, and it generates heat that is transferred to
the crucible. The crucible is a container made of a material that can withstand high
temperatures such as graphite, clay, or silicon carbide.

The crucible is placed in the heating element, and the material to be melted is placed inside
the crucible. The heating element generates heat, which is transferred to the crucible,
causing the material inside it to melt. The furnace is designed to retain heat and maintain
the required temperature until the material inside the crucible has melted.
 Ưu điểm

1. Versatility: Crucible furnaces can be used to melt a wide range of materials,

including metals, alloys, glass, and ceramics.
2. Precise temperature control: crucible furnaces can maintain a precise
temperature, making them ideal for applications that require accurate temperature
control.
3. High melting temperatures: Crucible furnaces can reach very high temperatures,
making them suitable for melting materials with high melting points, such as tungsten
and platinum.
4. Compact size: Crucible furnaces are available in a range of sizes, making them
ideal for small-scale applications or for use in laboratories.
5. Cost-effective crucible furnaces are relatively inexpensive and require minimal
maintenance
6. Easy to use: Crucible furnaces are relatively simple to operate and do not require
extensive training or specialized skills.

Nhược điểm

1. Limited capacity: Crucible furnaces have a limited capacity and can only melt a certain
amount of material at a time
2. Energy consumption: Crucible furnaces can consume a significant amount of energy to
reach the high temperatures required for melting materials.
3. Environmental impact: The use of crucible furnaces can produce emissions and
pollutants
4. Material compatibility: Some materials may not be suitable for melting in a crucible
furnace due to their chemical composition or physical properties.
Safety risks: Crucible furnaces operate at high temperatures and can pose safety risks to
workers if not used correctly
ứng dụng

1. Metallurgy: Crucible furnaces are commonly used in metallurgy for melting and
casting metals and alloys..
2. Glass manufacturing: Crucible furnaces are used in the manufacturing of glass,
Ceramics: Crucible furnaces are used in the production of ceramics, particularly for
small-scale production and for firing ceramics at high temperatures.
3. Jewelry making: Crucible furnaces are used by jewelers for melting and casting
precious metals such as gold and silver.
4. Research and development: research and development in materials science,
chemistry, and engineering.
5. Dental laboratories: melting and casting dental alloys