Metals can be extracted from their ore through various processes depending on the reactivity of the metal. Less reactive metals can be manually separated from crushed ore, while more reactive metals require more energy-intensive processes like electrolysis or extraction in a blast furnace. In a blast furnace, ore, limestone flux and coke fuel are continuously fed into the top while hot air is blown into the bottom, allowing extraction of the metal in molten form from the bottom. Roasting is also used as a preliminary step, where sulfide ores are heated in air to transform the metal into an oxide and release sulfur dioxide gas. These processes can release toxic fumes and pollutants if not properly controlled.

1. Done by: Nazmus Shakib
Class : 8-A
Roll no: 31.007
Extraction of Metals.

2. What is a Metals?
Metal is a material that is typically hard, opaque, shiny, and has good
electrical and thermal conductivity. Metals are generally malleable that
is, they can be hammered or pressed permanently out of shape without
breaking or cracking as well as fusible .About 91 of the 118 elements in
the periodic table are metals, the others are nonmetals or metalloids.
Some elements appear in both metallic and non-metallic forms.
Astrophysicists use the term "metal" to collectively describe all elements
other than hydrogen and helium. In that sense, the metallicity of an
object is the proportion of its matter made up of chemical elements
other than hydrogen and helium.
Many elements and compounds that are not normally classified as
metals become metallic under high pressures; these are formed as
metallic allotropes of non-metals.

3. Some types of metals:
Potassium Sodium Lithium

4. Some types of metals:
Calcium Magnesium Aluminum

5. Reactivity series of metals:
In chemistry, a reactivity series is
an empirical, calculated, and
structurally analytical progression
of a series of metals, arranged by
their "reactivity" from highest to
lowest.It is used to summarize
information about the reactions of
metals with acids and water,
double displacement reactions
and the extraction of metals from
their ores.

6. Metals of low reactivity:
Most metals are found naturally in rocks called ores.
They are in compounds, chemically bonded to other
elements. However, the unreactive metals at the
bottom of the reactive series can be found as the
elements themselves.We say that they are found
native.
Some examples of metals with low reactivity are:
1. Gold,
2. Copper,
3. Silver and
4. Platinum.

7. Gold Silver Platinum
Some types of low reactivity
metals:

8. The highly reactive metals:
The highly reactive metals are the most difficult
to extract from their ores.These metals are
found in very stable compounds.
Reduction by carbon won’t work.You know
carbon’s place in reactivity series. It lies just
under aluminum.Therefore, carbon can’t
displace the highly reactive metals from their
ores.
However we have a way to get these metals. It’s
called electrolysis.

9. The highly reactive metals:
Once you have separated the metal compound
from the ore, the next 2 steps are:
1. Melt it, then
2. Pass electricity through it.
Both steps use a lot of energy.Therefore highly
reactive metals are expensive to extract.

10. Electrolysis:
In chemistry and manufacturing, electrolysis is a
technique that uses a direct electric current (DC) to
drive an otherwise non-spontaneous chemical
reaction.
Electrolysis is commercially important as a stage in
the separation of elements from naturally
occurring sources such as ores using an electrolytic
cell.The voltage that is needed for electrolysis to
occur is called the decomposition potential.

11. The word electrolysis comes from the Greek ἤλεκτρον "amber"
and λύσις "dissolution".
1785 – Martinus van Marum's electrostatic generator was used to
reduce tin, zinc, and antimony from their salts using electrolysis.
1800 –William Nicholson and AnthonyCarlisle (view also Johann Ritter),
decomposed water into hydrogen and oxygen.
1808 – Potassium (1807), sodium, barium, calcium and magnesium were
discovered by Sir Humphry Davy using electrolysis.
1821 – Lithium was discovered by WilliamThomas Brande who obtained
it by electrolysis of lithium oxide.
1833 – Michael Faraday develops his two laws of electrolysis, and
provides a mathematical explanation of his laws.
1875 – Paul Émile Lecoq de Boisbaudran discovered gallium using
electrolysis.
1886 – Fluorine was discovered by Henri Moissan using electrolysis.
1886 – Hall–Héroult process developed for making aluminium
1890 – Castner–Kellner process developed for making sodium hydroxide

12. Electrolysis is the passing of a direct electric current through an ionic
substance that is either molten or dissolved in a suitable solvent,
producing chemical reactions at the electrodes and separation of
materials.
The main components required to achieve electrolysis are:
An electrolyte: a substance, frequently an ion-conducting polymer that
contains free ions, which carry electric current in the electrolyte. If the
ions are not mobile, as in a solid salt then electrolysis cannot occur.

13. A direct current (DC) electrical supply: provides the energy
necessary to create or discharge the ions in the electrolyte.
Electric current is carried by electrons in the external circuit.
Two electrodes: electrical conductors that provide the physical
interface between the electrolyte and the electrical circuit that
provides the energy.
Electrodes of metal, graphite and semiconductor material are
widely used. Choice of suitable electrode depends on chemical
reactivity between the electrode and electrolyte and
manufacturing cost.

14. Roasting ores:
Roasting is a step of the processing of certain ores. More specifically, roasting is a
metallurgical process involving gas–solid reactions at elevated temperatures with the goal
of purifying the metal component(s). Often before roasting, the ore has already been
partially purified, e.g. by froth floatation. The concentrate is mixed with other materials to
facilitate the process.The technology is useful but is also a serious source of air pollution.
Roasting consists of thermal gas–solid reactions, which can include oxidation, reduction,
chlorination, sulfation, and pyrohydrolysis. In roasting, the ore or ore concentrate is
treated with very hot air.This process is generally applied to sulfide minerals. During
roasting, the sulfide is converted to an oxide, and sulfur is released as sulfur dioxide, a gas.
For the ores Cu2S (chalcocite) and ZnS (sphalerite), balanced equations for the roasting
are:
2 Cu2S + 3O2 → 2 Cu2O + 2 SO2
2 ZnS + 3 O2 → 2 ZnO + 2 SO2
The gaseous product of sulfide roasting, sulfur dioxide (SO2) is often used to produce
sulfuric acid. Many sulfide minerals contain other components such as arsenic that are
released into the environment.

16. Blast furnace:
A blast furnace is a type of metallurgical furnace used for smelting to produce
industrial metals, generally iron, but also others such as lead or copper.
In a blast furnace, fuel, ores, and flux (limestone) are continuously supplied through
the top of the furnace, while a hot blast of air (sometimes with oxygen enrichment) is
blown into the lower section of the furnace through a series of pipes called tuyeres,
so that the chemical reactions take place throughout the furnace as the material
moves downward.The end products are usually molten metal and slag phases tapped
from the bottom, and flue gases exiting from the top of the furnace.The downward
flow of the ore and flux in contact with an up flow of hot, carbon monoxide-rich
combustion gases is a countercurrent exchange and chemical reaction process.
In contrast, air furnaces (such as reverberatory furnaces) are naturally aspirated,
usually by the convection of hot gases in a chimney flue. According to this broad
definition, bloomeries for iron, blowing houses for tin, and smelt mills for lead would
be classified as blast furnaces. However, the term has usually been limited to those
used for smelting iron ore to produce pig iron, an intermediate material used in the
production of commercial iron and steel, and the shaft furnaces used in combination
with sinter plants in base metals smelting.

17. Blast furnace:
Up until the early 20th century, roasting was started by burning wood on
top of ore.This would raise the temperature of the ore to the point
where its sulfur content would become its source of fuel, and the
roasting process could continue without external fuel sources. Early
sulfide roasting was practiced in this manner in "open hearth" roasters,
which were manually stirred (a practice referred to as "rabbling") using
rake-like tools to expose unroasted ore to oxygen as the reaction
proceeded.
This process would release large amounts of acidic, metallic, and other
toxic compounds. Results of this include areas that even after 60-80
years are still largely lifeless, often exactly corresponding to the area of
the roast bed, some of which are hundreds of metres wide by kilometres
long.

19. Blast furnace:
Blast furnaces existed in China from about 1st
century AD and in theWest from the High Middle
Ages.They spread from the region around Namur in
Wallonia (Belgium) in the late 15th century, being
introduced to England in 1491.
The fuel used in these was invariably charcoal.The
successful substitution of coke for charcoal is widely
attributed to Abraham Darby in 1709.The efficiency
of the process was further enhanced by the practice
of preheating the combustion air (hot blast),
patented by James Beaumont Neilson in 1828.