MADE TO BE MADE AGAIN
CHEMISTRY FOR A CIRCULAR ECONOMY
Metals in a circular economy, Part 1
Lesson objectives:
• Give reasons for the uses
of aluminium, titanium
and their alloys.
• Explain the importance of
materials recovery.
• Discuss the limitations of
aluminium recycling and
how product design could
be improved.
What do you think this image means?
Aluminium and titanium
Extraction
Aluminium and titanium exist in the earth as ores.
Most aluminium exists as aluminium oxide in bauxite.
Most titanium exists as titanium dioxide often in combination
with other metals like iron (ilmenite).
Unlike iron, they cannot be extracted from their oxides by
reduction with carbon. WHY NOT?
Extraction from the ores by electrolysis is expensive because:
• the process has many stages
• large amounts of energy are needed
Aluminium and titanium
Properties and uses
Low density = light weight = soft
• Commonly used as alloys to increase strength
Corrosion resistant
• A thin layer of oxide on the surface stops corrosion by H2O + O2
Uses:
• Aluminium: aircraft, trains, overhead power cables, saucepans,
cooking foil and cans
• Titanium: fighter aircraft, artificial hip joints and pipes in nuclear
power station
Aluminium and titanium
Alloys
Aluminium commonly used as an alloy of 93% Al mixed with Si
and Fe
Task 1: Aluminium and titanium
Aluminium
Name of ore
How it is extracted
Physical properties
Uses
Complete the table. How much can you remember?
Titanium
Task 1: Aluminium and titanium
Aluminium
Titanium
Name of ore
Bauxite
(aluminium oxide)
(Al2O3)
Rutile (TiO2)
Ilmenite (FeTiO3)
How it is extracted
Electrolysis
(many processes, uses a lot of energy)
Physical properties
Soft, low density, light, corrosion resistant
(used as alloys)
Uses
Aircraft, trains,
Fighter aircraft, artificial
overhead power
hip joints and pipes in
cables, saucepans,
nuclear power stations
cooking foil and cans
Task 2: The lifecycle of a can
Metals like aluminium can be viewed as technical nutrients which
we need to make the products we use. We need to design out waste
so that the nutrients are recovered
Task 2: The current lifecycle of a can
Organise your cards around the wheel to illustrate the lifecycle
of an aluminium can.
Task 2: The current lifecycle of a can
Use
Extract
End of life
Manufacture
Recycle
Task 3: Why recycle?
Turn over your cards. Sort them into two groups to explain why
recycling aluminium is better than extracting it from its ore.
Recycling is a good idea but in a linear system it simply slows down the
loss of valuable materials.
Task 4
1) Look at the cards from the previous exercise.
2) What would have to change to make aluminium
recovery work better?
3) Write a letter to a packaging company describing the
advantages to the industry of adopting clean
‘technical’ and ‘biological’ materials flows.
Quiz time: question 1
1. Bauxite is an example of…
A.An element
B.A compound
C.An ore
D.A solution
Quiz time: question 2
2. Aluminium is extracted by…
A.Reduction
B.Distillation
C.Thermal decomposition
D.Combustion
Quiz time: question 3
3. Aluminium cannot be extracted from aluminium oxide using carbon
because…
A.Aluminium is more reactive than carbon
B.The density of aluminium is too low
C.Carbon is higher in the reactivity series than aluminium
D.Aluminium is covered in a layer of aluminium oxide
Quiz time: question 4
4. Aluminium is often recycled. Which answer(s) are true and which
indicate(s) that aluminium production is still essentially ‘take-makedispose’
A.Recycling of short cycle products (cans, packaging) is always
wasteful even at high recycling rates.
B.World aluminium production from bauxite is increasing year on
year.
C.Recycling reduces the amount of energy used to make aluminium
and makes it cheaper than extracting from bauxite.
D.Recycled aluminium is not suitable for all uses of the metal.
Homework
Coca-Cola is developing a bottle called PlantBottle as an
alternative to aluminium cans. It is currently made from
30% plant material and the company’s aim is to make a
bottle from 100% plant-based waste.