Metallurgy Flashcards
A metal is an element which ionizes by ____________, is thus an ________________.
electron loss,electron donor
Metallic atoms have __,__,_ valence electrons & tend to form :-
* ______________ on ionization,
*__________________
1,2,3
* positive ions ( cations)
* electrovalent compound.
Valency of a metal is the no. of electron______ per atom
lost
State any 5 important properties of metals
- Lustrous( exist in solid state)
- has high m.p and b.p
- high density
- high ductility
- it is malleable
- metals are good conductors of elec & heat
- good reducing agents
- forms electrovalent chlorides and at least one basic oxid.
A non metal is an element which ionizes by ___________, is thus an __________
electron gain, electron acceptor
Non metallic atoms have __,__,__or__ valence electrons& and tend to form
*_____________ on ionization
*______________ compounds
4,5,6 or 7
* negative ions
*electrovalent/covalent
what is a mineral ?
the compounds of various metals found in nature associated with their earthly impurities are called minerals
valency of a non metal is the no.of electrons ______________ per atom
gained
what is an ore ?
the naturally occurring metals from which metals can be extracted profitably and conveniently are called ores.
occurence of metals in a free or native state-
metals occurring in a free metallic form not acted upon by natural elements like constituents of air and water
occurence of metals in a combined state -
metals occurring in the form of compounds
what is metallurgy ?
the large scale process involved in extraction of pure metals from their respective ores is called metallurgy.
what is matrix
the rocky impurities including silica,mud etc. associated with the ore is called matrix
matrix is also known as
gangue
what is flux ?
the sub added to ore to get rid if matrix resulting in formation of a fusible compound - slag
the naturally occurring metals from which metals can be extracted profitably and conveniently are called
ores.
the compounds of various metals found in nature associated with their earthly impurities are called
minerals
the sub added to ore to get rid if matrix resulting in formation of a fusible compound - slag
flux
the rocky impurities including silica,mud etc. associated with the ore is called
matrix
the large scale process involved in extraction of pure metals from their respective ores is called
metallurgy
3 ores of aluminium
Bauxite, Cryolite, Corundum (trick - BCC)
3 ores of zinc
zinc blende, calamine, zincite
(trick - CZZ)
4 ores of iron
haematite, magnetite, iron pyrites, spathic iron ore
(trick - HIMS)
MAIN ore of aluminium
bauxite
MAIN ore of iron
haematite
what are the 4 steps involved in extraction of metals
step 1 - dressing of the ore
step 2 - conversion of conc. ore to its oxide
step 3 - reduction of metallic oxides to its metals
step 4 - electro-refining of impure metal
what are the methods used in extraction of metals step 1 process
~> hydrolytic method
~> magnetic separation
~> froth flotation method
~> chemical method
what are the methods used in extraction of metals step 2 process
> roasting
calcination
what are the methods used in extraction of metals step 3 process
- reduction by - electrolysis
- reduction by - reducing agents
- reduction by - thermal decomposition
reason for step 1 process
to convert impure ore to pure conc ore
reason for step 2 process
to convert the pure conc ore to its oxide - since oxides are easy to reduce
reason for step 3 process
to obtain impure metal from metallic oxide by reduction
reason for step 4 process
to obtain metal in its very pure form
_________________ depends on the position of the metal in the activity series of metals
method of reduction
which method is known as gravity separation method
hydrolytic method
separation of ore and gangue in hydrolytic method is due to
difference in density of particles
principle of separation of hydrolytic method
ores- denser- settles in grooves
gangue - lighter-washed down by water
magnetic separation involves separation of
– magnetic ORE from non magnetic GANGUE or
– non magnetic ORE from magnetic GANGUE or
explain the process of magnetic separation
=>the powdered ore is placed in conveyor belt
=> the MAGNETIC PARTICLES attracted to the magnetic wheel- separate from the non magnetic particles
froth flotation involves separation of ore and gangue by
preferential wetting
explain the process of froth flotation method
a tank containing the ore _ oil and water is agitated with air.
the ore separates above as a foam.
name :
1. process of heating the conc. ore in the PRESENCE OF EXCESS AIR to a high temp. before it is reduced to a metal
2. process of heating the conc. ore in LIMITED SUPPLY OF AIR or ABSENCE OF AIR at a room temp. just below its m.p or not sufficient to melt the ore
- ROASTING
- CALCINATION
2ZnS + 3O2 –>
2ZnO + 2SO2
2FeS2 + 11O2 –>
2Fe2O3 + 8SO2
ZnCO3 –>
ZnO + CO2
FeCO3 –>
FeO + CO2
On heating ZnCO3 [ zinc carbonate a residue of __________ is formed which is _______ when hot and __________ when cold
zinc oxide [ ZnO] , yellow, white
what are metals which gets reduced in the electrolysis step 3 of extraction of metals
reduction of K, Na, Ca, Mg, Al [ are top at activity series]
what are metals which gets reduced in the reducing agents in step 3 of extraction of metals
reduction of Zn, Fe, Pb, Cu
what are metals which gets reduced in thermal decomposition step 3 of extraction of metals
reduction of Hg, Ag
why are the metals from K to Al is used for electrolysis step 3 of extraction of metals ?
- are most electropositive
- have more affinity for o2
- metallic oxides cannot be reduced by reducing agents but can be reduced by ELECTROLYSIS
why are the metals from Zn to Cu is used to reduce by reducing agents in step 3 of extraction of metals ?
- are less electropositive
- have less affinity for o2
- metallic oxides can be reduced by reducing agents such as CO, H2.
why are the metals from Hg to Ag is used for thermal decomposition
in step 3 of extraction of metals ?
- are least electropositive
- least affinity for o2
- metallic oxides can be reduced by HEAT ALONE.
ZnO + C –>
Zn + CO
Fe2O3 + 3CO2 –>
2Fe + 3CO2
2PbO + C –>
2Pb + CO2
CuO + C –>
Cu + CO
CuO + H2 –>
Cu + H2O
2HgO —>
2Hg + O2
2Ag2O —>
4Ag + O2
which ore is used in step 1 of extraction of ALUMINIUM
Bauxite
What is chemical method ?
separation of ore and gangue by using chemicals such as NaOH
which method is used in step 1 of extraction of ALUMINIUM
chemical method using conc. soln. of NaOH.
Which process is used in step 1 of extraction of ALUMINIUM
BAEYER’S PROCESS
CONVERSION in step 1 of extraction of ALUMINIUM
Impure bauxite to pure alumina
give the products to the reactions when
Amphoteric oxide [ impure bauxite ] reacts with base [ NaOH ] at 150 degree C
it gives out salt [ NaAlO2 ] And Water
