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.

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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?

Aluminium and titanium Alloys Aluminium commonly used as an alloy of 93% Al mixed with Si and Fe How do the iron and silicon atoms make aluminium stronger?

Task 1: Aluminium and titanium Name of ore How it is extracted Physical properties Uses Complete the table. How much can you remember?

Task 1: Aluminium and 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, 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… An element A compound An ore A solution

Quiz time: question 2 2. Aluminium is extracted by… Reduction Distillation Thermal decomposition Combustion

Quiz time: question 3 3. Aluminium cannot be extracted from aluminium oxide using carbon because… Aluminium is more reactive than carbon The density of aluminium is too low Carbon is higher in the reactivity series than aluminium 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’ Recycling of short cycle products (cans, packaging) is always wasteful even at high recycling rates. World aluminium production from bauxite is increasing year on year. Recycling reduces the amount of energy used to make aluminium and makes it cheaper than extracting from bauxite. 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 product on the internet. Explain why plantbottle packaging is a ‘technical nutrient’. Comment on the impact of this choice on the environment. Consider biological nutrient based packaging.