MADE TO BE MADE AGAINCHEMISTRY FOR A CIRCULAR ECONOMYMetals 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

Can you name another alloy?

AlloysAluminium commonly used as an alloy of 93% Al mixed with Si and Fe

How do the iron and silicon atoms

make aluminium stronger?

Aluminium and titanium

Task 1: Aluminium and titanium

Aluminium TitaniumName of oreHow it is extracted

Physical properties

Uses

Complete the table. How much can you remember?

Task 1: Aluminium and titanium

Aluminium TitaniumName 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, overhead power cables, saucepans, cooking foil and cans

Fighter aircraft, artificial hip joints and pipes in nuclear power stations

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

End of life

Manufacture

Use

Recycle

Extract

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 elementB.A compoundC.An oreD.A solution

Quiz time: question 2

2. Aluminium is extracted by…

A.ReductionB.DistillationC.Thermal decompositionD.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-make-dispose’

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.

Research this prod

uct on the

internet. Explain

why

plantbottle packag

ing is a

‘technical nutrien

t’. Comment

on the impact of t

his choice

on the environment

. Consider

biological nutrien

t based

packaging.