Extracting Metals
Metals are extracted from ores by reduction or electrolysis.
About this topic
How a metal is extracted depends on its reactivity. Unreactive metals such as gold and silver are found native, as uncombined metals. Metals below carbon in the reactivity series, such as iron, zinc and lead, are extracted from oxides by reduction with carbon or carbon monoxide. Reactive metals above carbon, such as aluminium, sodium and magnesium, require electrolysis of molten compounds.
In the blast furnace, iron(III) oxide, coke, limestone and hot air are used. Coke burns to give carbon dioxide, then carbon monoxide: C + O2 gives CO2, CO2 + C gives 2CO. Carbon monoxide reduces the ore: Fe2O3 + 3CO gives 2Fe + 3CO2. Limestone decomposes to calcium oxide, which reacts with silica impurities to form slag. Aluminium comes from bauxite, purified to aluminium oxide, dissolved in molten cryolite to lower the melting point from over 2000 to about 950 degrees Celsius and electrolysed with carbon electrodes; it needs huge amounts of electricity, so recycling saves 95 percent of the energy. Copper is purified by electrolysis.
Mining has environmental costs, such as habitat destruction, waste rock and carbon dioxide, so recycling metals is important.
A misconception is that all metals are extracted by heating with carbon, but aluminium is too reactive for that. Another is that iron from the blast furnace is pure; it contains about 4 percent carbon and is brittle, so it is converted to steel.
Key ideas
- Reactive metals need electrolysis
- Iron is reduced by carbon in a blast furnace
- Recycling saves energy
Quick check
Use cases: where Extracting Metals helps
- Homework: review the key idea behind Extracting Metals before you start a problem set.
- Exam revision: use the quick check to test whether you can recall Extracting Metals without notes.
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- Teaching a friend: explain Extracting Metals in your own words, then compare your version with the key ideas.
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Frequently asked questions
What is Extracting Metals?
Metals are extracted from ores by reduction or electrolysis.
What will I learn in Extracting Metals?
Reactive metals need electrolysis. Iron is reduced by carbon in a blast furnace. Recycling saves energy.
Is Extracting Metals part of Chemistry?
Yes. It is one of 150 Chemistry topics on LearnViz HighSchoolEdu, with 3 key ideas, a live animation and a quick check.
Does the Extracting Metals lab work on a phone or tablet?
Yes. The animation resizes to fit your screen and supports touch, so you can drag, tap and slide with your finger.
How should I study Extracting Metals?
Read the summary and key ideas first, play with the interactive lab to see the idea in motion, then answer the quick check. If you get a question wrong, go back to the key idea it tests.
Do I need an account, and is my progress saved?
No account is needed. Marking a topic as learned is saved in your own browser, so it stays on that device and is not sent to a server.