METALLURGY Metallurgy The extraction of metals from their ores and refining it is known as metallurgy.

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