Comparing production methods

{Electrolysis - want in molten state -> from solid to molten state

• high temperature = more energy}

—> the extraction method used depends upon the metal’s position in the reactivity series.

—> in principle, any metal could be extracted from its compounds using electrolysis.
—> however, large amounts of electrical energy are needed to do this, so electrolysis is expensive.

—> if a metal is less reactive than carbon, it can be extracted from its compounds by heating with carbon.

{MOST reactive}

K Potassium
Na Sodium
Ca Calcium
Mg Magnesium
Al Aluminium
C Carbon
Zn Zinc
Fe Iron
Sn Tin
Pb Lead
Cu Copper
Ag Silver
Au Gold
Pt Platinum

{LEAST reactive}

Electrolysis

—> Key features of the method :

• elements are formed at cathode & anodes
• electricity is used for decomposition

—> It is more expensive than reduction because :

• anodes need to be replaced
• large amount of energy needed to go from solid to molten
• high temperatures
• electrodes need replacing

—> The metals that are extracted this way and why :

• aluminium -> electrolysed
• more reactive than carbon

Reduction

—> Key features of the method :

• high temperatures
• batch process
• additional substances, e.g. metals are involved in the reduction process
• inert substance required

—> The metals that are extracted this way and why :

• titanium can’t be electrolysed
• titanium carbode forms which is brittle

—> a series of operations are carried out over a period of time in a separate, identifiable item or part of material

—> extraction of Ti

—> time consuming - is constantly stopped and restarted to clean etc.

—> flexibility - can change products

—> trial and error opportunities

—> more labour required - transfer of products to the next stage

—> all operations occur at the same time and the material being processed is not divided into identifiable positions

—> extract ion of brine and Al

—> time efficient - does not need to be stopped

—> less flexible

—> self sufficient - not much labour is required

—> large investment required