# Question 68ce1

May 5, 2017

Aluminium by Hall Heroult process

#### Explanation:

For extraction of Aluminum generally Hall Heroult process is generally used in industries

Process is :
Bayer's process
1) the Alumina ore is treated with NaOH at high pressure and temperature to form $N a A l {O}_{2}$
$A {l}_{2} {O}_{3} + N a O H = 2 N a A l {O}_{2}$
2)This $N a A l {O}_{2}$ solution is then recrystallized with $A l {\left(O H\right)}_{3}$ to form $A l {\left(O H\right)}_{3}$ crystals
3)This $A l {\left(O H\right)}_{3}$ crystals are heated to form pure Alumina
$2 A l {\left(O H\right)}_{3} = A {l}_{2} {O}_{3} + 3 {H}_{2} O$
Hall Heroult process
1) initially the Alumina $A {l}_{2} {O}_{3}$ obtained by Bayer's process is taken in a steel container acting as cathode
2) The Alumina is added to Cryolite solution($N {a}_{3} A l {F}_{6}$) which decrease melting point of Alumina to nearly 960°C#
3)Then the graphite electodes(Anode) are inserted and operating at high voltage we get Aluminium at Anode of 99.95%purity.
$2 A {l}_{2} {O}_{3} + 3 C = 4 A l + 3 C {O}_{2}$ in electrolysis

May 5, 2017

Titanium by Krolls process

#### Explanation:

Titanium is generally produced by Krolls process

Ilmentite ore is reduced in presence of coke in a fluidised bed reactor
This reaction produces $T i C {l}_{4}$
$T i C {l}_{4}$ is reacted with Mg to form $T i$
$T i C {l}_{4} + 2 M g = 2 M g C {l}_{2} + T i$
This Titanium​ is then vacuum refined to produce Pure Titanium ,as the unrefined Titanium has no use commercially due to presence of $M g C {l}_{2}$in Titanium Sponge