METALLURGY
Metallurgy
• The extraction of metals from their ores and refining it is known as metallurgy
rem ova l o f g an g u e
e le ctro m a gn e tic s e pe ra tio n
fro th fl o a tio n
H yd ra u lic w a s h in g
P h ys ica l m e th o d
L e a ch in g
C h e m ica l m e th o d
E n rich m e n t o f th e o re
R o a s tin g C a lc in a tio n
C o n ve rs io n o f th e o re in to s u ita b le fo rm
E le ctro ly tic re du ctio n ( N a ,M g .. . . . )
B y h e a tin g w ith C ( Z n ,F e )
B y h e a tin g ( H g )
R e du ctio n
E le ctro ly tic re fi n in g ( C u , H g ,A U )
D is tilla tio n ( Z n , H g )
L iqu a tio n ( S n ,P b )
R e fi n in g
M e ta llu rg y
ENRICHMENT OF ORE
• Process used for removal of the “GANGUE”
• GANGUE – Soil, Sand and Earthy Impurities
Enrichment processes
• Hydraulic washing
Froth Floatation
Electromagnetic separation
Chemical Method
• Dissolve ore + Hot and Conc. NaOH
• Al2O3 + 2NaOH -> 2NaAlO2+H2O
• Filter it- add dil HCl
• NaAlO2 + 2H2 O + HCl - Al(OH)3 + NaCl
• Filter the ppt wash,dry and Ignite
• 2Al(OH)3 - Al2O3 + 3H2O
• Pure Bauxite is obtained
REDUCTION
• Conversion of concentrated ore into a more suitable form
• Roasting -- Heating the Sulphide ore in presence of air to form an Oxide ore
• 2ZnS+3O2 2ZnO + 2SO2
• Calcination -- Heating the Carbonate ore in the absence of air to form an Oxide ore
• ZnCO3- ZnO + CO2
Reduction
• Low in the reactivity series ----
• Heating ---- e.g..2HgS + 3O2 2HgO +2SO2
• 2HgO(S) - 2Hg + O2 (g)
• Middle in the reactivity series
• Heating with C (Smelting)
• ZnO + C --Zn + CO
• High up in the reactivity series Electrolytic reduction
REFINING
• LIQUATION:
Used for metals having low M.P. Pb,Sn
Metal
(low M.P.)
Impurity(High M.p.)
Hearth
REFINING
• DISTILLATION
• Metals used are Volatile - Hg ,Zn
• The impure metal is heated in a retort.
• The Pure metal distils over and is condensed in a receiver.
• The impurities are left behind in the retort
k
• ELECTROLYTIC REFINING
• Metals used are ---Cu,Zn,Sn,Ni,Ag,Au…
CuSO4 + H2SO4
