2. Name ID
MD. Ubidullah Khokan 19-003
MD. Ashadul Islam 19-141
MD. Mahedy Hasan 19-272
Sudev Chakma 19-251
Zubayer Ahmed 19-257
Bijoy Dripto Acharjya 19-261
Submitted To-
Dr. Md. Zahangir Alam
Associate Professor
Department of Applied Chemistry &
Chemical Engineering
University of Dhaka
Submitted By-
4. METALLURGY
art and science of extracting metals from
their ores and modifying the metals for
use.
Study of the chemical, physical, and
atomic properties and structures of
metals and the principles whereby metals
are combined to form alloys.
5. HISTORY OF METALLURGY
A magic material
The first known metal was gold.
Gold is bright, incorruptible, malleable,
and appears in pure form in the beds of
streams.
The earliest surviving gold jewelry is from
Egypt in about 3000 BC.
6. HISTORY OF METALLURGY
The age of copper: from 7000 BC
From about 7000 BC a few neolithic
communities begin hammering copper
into crude knives and sickles.
azurite and malachite, two ores of
copper were found.
two significant steps in the development
of metallurgy:
- the casting of metal, by pouring it into
prepared moulds
- the smelting of mineral ores to extract
metal.
7. HISTORY OF METALLURGY
The age of bronze: from 2800 BC
The cast alloy of copper and tin is bronze
The technology of bronze is first developed in
the Middle East
The age of iron: from 1500 BC
A few iron objects dating from before 2000
BC have been found (beads, a ring, some
blades), but it is not until about 1500 BC that
the working of iron is done anywhere on a
regular basis.
The Hittites are the first people to work iron, in
Anatolia from about 1500 BC
8. HISTORY OF METALLURGY
The discovery of steel: 11th century BC
By the 11th century BC it has been discovered that iron can be much
improved. If it is reheated in a furnace with charcoal (containing carbon),
some of the carbon is transferred to the iron.
A new material- steel is produced
Cast iron in the east: 513 BC
The melting point of iron (1528°C) is too high for primitive furnaces.
The Chinese develop a furnace hot enough to melt iron, enabling them to
produce the world's first cast iron
9. HISTORY OF METALLURGY
Ironmasters of Coalbrookdale: 18th century
In 1709 Abraham Darby, an ironmaster
with a furnace at Coalbrookdale on the
river Severn, discovers that coke can be
used instead of charcoal for the smelting
of pig iron.
Iron bridge: 1779
in 1779 the world's first iron bridge, with a
single span of over 100 feet, is created
over the Severn just downstream from
Coalbrookdale.
10. HISTORY OF METALLURGY
Pudding and rolling: 1783-1784
Henry Cort invented a furnace which shakes the molten iron so that air
mingles with it. The technique which becomes known as pudding. Oxygen
combines with carbon in the metallic compound, leaving almost pure iron.
In the previous year he invented machine for drawing out red-hot lumps of
purified metal between grooved rollers, turning them into manageable bar.
His device is the origin of the rolling mills.
11. HISTORY OF METALLURGY
The 19th century
The large-scale production of
cheap steel.
The development of the open-hearth
furnace by William and Friedrich Siemens
in Britain and by Pierre and Émile Martin in
France.
The separation from their ores, on a
substantial scale, of aluminum and
magnesium.
Development of electrolytic cell for
producing cheaper sodium in 1886.
12. HISTORY OF METALLURGY
The 20th century
the introduction of fusion welding
The first practical oxyacetylene torch was
produced in 1901.
Striking an arc from a coated metal
electrode, which melts into the join, was
introduced in 1910.
In extractive metallurgy, the application of
chemical thermodynamics, kinetics, and
chemical engineering are introduced.
In physical metallurgy, the study of
relationships between macrostructure,
atomic structure and physical and
mechanical properties are developed.
14. EXTRACTIVE METALLURGY
Extractive metallurgy is the art of obtaining valuable metals from an ore or
metallic concentrate and refining the initial products into a purer form.
Metals can be found on the earth in several chemical forms such as natives
(gold, copper), oxides, sulphides, sulphates, carbonates, nitrates, and others.
The compound must be converted into a type that can be more readily
treated. Common practice is to convert metallic sulfides to oxides, sulfates,
or chlorides; oxides to sulfates or chlorides; and carbonates to oxides.
16. EXTRACTIVE METALLURGY
Mineral processing
Mineral processing involves crushing,
grinding, and concentration.
Pyrometallurgy
Pyrometallurgy involves the treatment of
ores at high temperature to convert ore
minerals to raw metals, or intermediate
compounds for further refining.
17. EXTRACTIVE METALLURGY
The processes of Pyrometallurgy are-
Roasting- in which compounds are converted at temperatures just below
their melting points.
smelting- All the constituents of an ore or concentrate are completely
melted and separated into two liquid layers, one containing the valuable
metals and the other the waste rock.
Refining- The final procedure for removing the last small amounts of impurities
left after the major extraction steps have been completed.
19. EXTRACTIVE METALLURGY
Conversion-
Because not all ores and concentrates are found naturally in a form that is
satisfactory for leaching, they must often be subjected to preliminary
operations. For example, sulfide ores, which are relatively insoluble in sulfuric
acid, can be converted to quite soluble forms by oxidizing or sulfatizing
roasts.
A second popular treatment for converting sulfides is pressure oxidation, in
which the sulfides are oxidized to a porous structure.
20. EXTRACTIVE METALLURGY
Leaching
Dissolution of the valuable metals into the aqueous solution.
Oxides are leached with a sulfuric acid or sodium carbonate solvent.
sulfates can be leached with water or sulfuric acid.
Ammonium hydroxide [NH4OH] is used for native ores, carbonates, and
sulfides, and sodium hydroxide [NaOH] is used for oxides. Cyanide solutions
are a solvent for the precious metals, while a sodium chloride solution
dissolves some chlorides.
Two methods of leaching:
simple leaching
pressure leaching
21. EXTRACTIVE METALLURGY
Recovery
the solution from leaching operations is treated in a variety of ways to
precipitate the dissolved metal values and recover them in solid form.
These include-
electrolytic deposition- Insoluble anodes, and cathodes are inserted into a
tank containing leach solution. As current is passed, the solution dissociates,
and metal ions deposit at the cathode. This common method is used for
copper, zinc, nickel, and cobalt.
22. EXTRACTIVE METALLURGY
Recovery continue….
chemical precipitation- a displacement reaction takes place in which a
more active metal replaces a less active metal in solution. For example, in
copper cementation iron replaces copper ions in solution.
changing the acidity of a solution is a common method of precipitation.
24. PHYSICAL METALLURGY
Physical metallurgy is the science of making useful products out of metals.
Metal parts can be made in a variety of ways, depending on the shape,
properties, and cost desired in the finished product.
The cost of a finished part is often determined more by its ease of
manufacture than by the cost of the material.
Usually a metal part has the same properties throughout.
25. PHYSICAL METALLURGY
Structures and properties of metals
Metallic crystal structures-
Metals are used in engineering structures (e.g., automobiles, bridges, pressure
vessels) because, in contrast to glass or ceramic, they can undergo appreciable
plastic deformation before breaking.
This plasticity stems from the crystalline structure of metal and the nondirectional
nature of the bond between the atoms.
In the most ductile metals, atoms are arranged in a close-packed manner.
aluminum, copper, nickel, gamma iron, gold, and silver are face-centred cubic
structured.
alpha iron, tungsten, chromium, and beta titanium are body-centred cubic
structured.
26. PHYSICAL METALLURGY
Physical Property
Good electrical conductors and heat
conductors.
Dense – Most metals have high density.
Malleable - can be beaten into thin
sheets.
Ductile - can be stretched into wire.
Solid at room temperature (except Hg).
Sonorous – Metals make a ringing sound
when they are struck.
Possess metallic luster.
Have high melting and boiling point.
Opaque as thin sheet.
27. PHYSICAL METALLURGY
Chemical Property
Usually have 1-3 electrons in their outer shell.
Lose their valence electrons easily.
Almost any metal will oxidize in air, the only exception is gold.
Are good reducing agents.
Have lower electronegativities.
28. PHYSICAL METALLURGY
Alloy
Almost all metals are used as alloy.
Alloy is the solid solution of tow or more metals.
Alloys have properties superior to pure metal.
29. PHYSICAL METALLURGY
Reasons for making Alloy
To improve the strength and hardness of metals.
To improve the appearance of metals.
To improve the resistance of metal against corrosion and rusting.
To lower the melting point of metal.
31. PHYSICAL METALLURGY
Casting
Casting consists of pouring molten metal
into a mold, where it solidifies into the
shape of the mold.
The process was well established in the
Bronze Age (beginning. 3000 BC)
It is particularly valuable for the
economical production of complex
shapes, ranging from mass-produced
parts for automobiles to production of
statues, jewelry, or massive machinery.
32. PHYSICAL METALLURGY
Casting Process
Sand-casting
Sand-casting is widely used for making cast-iron and steel parts of medium
to large size
sand combined with a binder such as water and clay is packed around a
pattern to form the mold.
Metal molds
molds are made from metal.
33. PHYSICAL METALLURGY
Casting Process Continued….
Investment casting
In investment casting a mold is made by drying a refractory slurry on a
pattern made of wax or plastic.
A series of layers is applied and dried to make a ceramic shell, and the
pattern is then melted or burned out to provide the mold.
This process allows the mass production of parts with more complex shapes
and finer surface
Centrifugal casting
Centrifugal casting forces the metal into a mold by spinning it.
It is used for the casting of small precious-metal objects
34. PHYSICAL METALLURGY
MetalWorking
Metalworking is the process of working with metals to create individual parts,
assemblies, or large-scale structures.
- these can be divided into five broad groups:
1) Rolling
Rolling is a metal forming process in which metal stock is passed through
one or more pairs of rolls to reduce the thickness and to make the thickness
uniform.
- More than 90 percent of the aluminum, steel, and copper produced is rolled
at least once in the course of production.
35. PHYSICAL METALLURGY
2) Extrusion
Extrusion is the process by which long straight metal parts can be produced.
The cross-sections that can be produced vary from solid round, rectangular, to L
shapes, T shapes.
Extrusion is done by squeezing metal in a closed cavity through a tool, known as a
die using either a mechanical or hydraulic press.
3) Drawing
Drawing consists of pulling metal through a die.
4) sheet metal forming
5) Forging
Forging is the shaping of a piece of metal by pushing with open or closed dies.
37. POWDER METALLURGY
Powder metallurgy (P/M) consists of making solid parts out of metal powders
and and using them to make finished or semi-finished products.
Used when
• melting point is too high .
• reaction occurs at melting .
• too hard to machine.
• very large quantity.
39. POWDER METALLURGY
Powder production
The most common method of producing
metal powders is atomization of a liquid.
Here a stream of molten metal is broken
up into small droplets with a jet of water,
air, or inert gas such as nitrogen or argon.
Different shapes produced Will affect
compaction process significantly
40. POWDER METALLURGY
Blending or mixing
Blending means mixing powder of the same chemical composition but different
sizes.
Mixing means combining powders of different chemistries.
Except for powders, some other ingredients are usually added:
Lubricants: to reduce the particles-die friction
Binders: to achieve enough strength before sintering
Deflocculants: to improve the flow characteristics during feeding
Elemental or pre-alloyed metal powders are first mixed with lubricants or other alloy
to produce a homogeneous mixture of ingredients
Blending and mixing are accomplished by mechanical means.
42. POWDER METALLURGY
Powder compaction
Pressing process
Blended powders are pressed in dies under high pressure to form them into
the required shape.
Produces a “Green” compact
Size and shape of finished part (almost)
Not as strong as finished part – handling concern
44. POWDER METALLURGY
Sintering
Green compacts are heated in a controlled-atmosphere furnace to allow
packed metal powders to bond together
Transforms compacted mechanical bonds to much stronger metal bonds.
45. POWDER METALLURGY
Finishing Operations
to improve properties, finishing processes are needed:
• Cold restriking, resintering, and heat treatment.
• Impregnation of heated oil.
• Infiltration with metal (e.g., Cu for ferrous parts).
• Machining to tighter tolerance.
Plating, Painting
47. APPLICATION POWDER METALLURGY
Electrical Contact materials
Sliding Electrical Contacts
Heavy-duty Friction materials
Self-Lubricating Porous bearings
Carbide, Alumina, Diamond cutting tools
Structural parts
Cermets
Hard and Wear Resistant Tools
Refractory Material Products
THESE COMPONENTS ARE
USED IN AIR & SPACE
CRAFTS, HEAVY
MACHINERY, COMPUTERS,
AUTOMOBILES, etc…
