1. S.E.S.POLYTECHNIC
SOLAPUR
By- Prof. M.S.KHED

2. Metals and Alloys
Hardness: Hardness is the ability of the metal to resist wear or abrasion and penetration.
Ductility: It is the property of the metal by which it can be stretched in length without breaking.
Malleability: It is the property by which a metal can be hammered into shapes without cracking and rolled in to sheets:
Toughness: The property of metal to resist repeated shocks or vibrations.
Brittleness: It is the property of a metal which does not permit permanent deformation without breakage.
Tenacity: Tenacity of a metal is measured by weight which its wire can support.
Tensile strength: It is the ability to carry the load without breaking.

3. Weldability: It is the process of uniting two pieces of metal by means of heat, by bringing their ends together in the molten state.
Mechinability: It is property due to which a material can be easily cut by cutting tools to produce a desired shape and surface finish on its surface.
Casting: The process of pouring molten metal into mould and allowing it to solidify is known as casting.
Forging: The process of giving predetermined shape to piece of metal at sufficiently high temperature when metal is in the plastic state is known as forging.
Extrusion: The process by which a piece of metal is reduced in cross section by forcing it to flow through a die orifice under high pressure is known as extrusion process.
Brazing: A method of joining metal surfaces by introducing molten non ferrous alloy with melting point above 400oc between them.
Soldering: : A method of joining metal surfaces by introducing molten non ferrous alloy with melting point below 400oc between them.

4. Metals are one of the two major classifications of elements (non-metals being the other).
Almost all metals are found in the combined state as compounds on the crust of the earth. This is due to their high reactivity.
However, there are few exceptions. Such as gold, silver, copper, platinum and bismuth, which are found in the free state, due to their low reactivity. 
Aluminium is the most abundant metal in the earth's crust, followed by iron and calcium.   

5. Classification of ores
Types of Ores
Ores occur in the form of compounds. These compounds are generally oxides, sulphides,
carbonates or halides. 
Classification of ores  
Type of ore
Metals
Compound (in the ore)
Oxide Ores
Aluminium
Bauxite - Al2O3, 2H2O
Copper
Cuprite - Cu2O
Iron
Haematite - Fe2O3
Magnetite - Fe3O4
Sulphide Ores
Iron Pyrite - FeS
Copper Glance - Cu2S
Copper Pyrites - CuFeS2
Zinc
Zinc Blende - ZnS 
Carbonate Ores
Calcium
Limestone - CaCO3
Calamine - ZnCO3
Halide Ores
Sodium
Rock Salt - NaCl
Fluorspar - CaF2

6. Extraction of Metals - Metallurgy The compounds of various metals found in nature as ores are mixed with impurities like sand and rock. The various processes involved in the extraction of metals from their ores and their subsequent refining are known as metallurgy. An overview of various processes involved during metallurgy is given below.

7. Steps involved in extraction of metal form its ores Crushing: a)The ores obtained from the mines is in the form of big lumps. b) These lumps are crushed into suitable size particles. Concentration Of ores The process of removal of gangue or matrix form the ore is known as concentration.

8. Metallurgy : The various processes involved in the extraction of metals from their ores econoimically and profitably are known as metallurgy.
Ores Those minerals from which the metals can be extracted profitably are called ores.
Gangue or Matrix The rocky impurities, including silica and earthly particles, present in an ore are called gangue or matrix.
Minerals The natural materials in which the metals or their compounds occur in the earth are called minerals.

9. Main process
Sub-process
1. Concentration of the ore     (removal of unwanted      metals and gangue to      purify the ore).
a. Hydraulic washing.  b. Gravity separation.  c. Froth floatation.  d. Magnetic separation.  e. Chemical separation.
2. Conversion into metal     oxide. 
a. Calcination for carbonate ore.  b. Roasting for sulphide ore.
3. Reduction of metal oxide to     metal.
a. Roasting - mercury (Hg) is produced by roasting     Cinnabar (HgS) in air.  b. Reduction - using highly reactive         elements. Example: aluminium reduces manganese     dioxide to manganese.  c.  Electrolytic reduction - highly reactive elements,     such as sodium and mercury, are obtained by     electrolytic reduction when the metal is deposited     at cathode.
4. Refining of impure metal     into pure metals.
a. Electrolytic refining - of copper, gold, tin, lead,     chromium, nickel, etc.  b. Liquation process - for tin, lead and bismuth. c. Distillation process - for zinc, mercury.  d. Oxidation process - for iron.

10. Hydraulic Washing (Gravity Separation
Concentration of the ore 1. Hydraulic washing process (Gravity separation)  This process separates the heavier ore particles from the lighter gangue particles.
This is done by washing them in a stream (jet) of water over a vibrating, sloped table with
grooves. Denser ore particles settle in grooves. Lighter gangue particles are washed away.   
Hydraulic Washing (Gravity Separation

11. 2. Froth floatation process : In this process, separation of the ore and gangue particles is done by preferential wetting.
This process is generally used for sulphide ores of copper, lead and zinc. The finely
powdered ore is mixed with water and a suitable oil in a large tank. A current of
compressed air agitates the mixture.  The ore particles are wetted by oil and forms a
froth at the top, which is removed. The gangue particles wetted by water settle down.
Ore preferentially wetted by oil is removed as froth. Gangue wetted by water is removed
after it settles down.   
Froth Floatation 

12. 3. Magnetic separation process This process is used in the extraction of metals which exhibit magnetic properties. For example,
in the extraction of iron, crushed magnetite ore (iron) particles are separated using their
magnetic property. The pulverized ore is moved on a conveyor belt. Electro-magnetic wheel
of the conveyor attracts only the magnetic particles into a separate heap.  Eg.Tinstone contain
magnetic impurities.  
Only the magnetic particles are attracted by the magnetic wheel. These particles fall separately
into a different heap as shown in the diagram. 
Magnetic Separation 

13. There are three practice questions below this that you need to answer after watching the video.
Process of separating metal from ore is called
magnetic separation
floatation process
metallurgy
cyclone separation
2. Naturally occurring metallic compounds are called
metalloids
minerals
hard solids
soft solids
3. In magnetic separation, magnets are used to separate
mineral and gangue
metal and mineral
metal and gangue
iron and steel