Extraction by carbon
Metals less reactive than carbon, such as iron, are extracted by heating their oxide with carbon. The carbon takes the oxygen away.
Last updated
Analogy
The carbon is a more powerful magnet for oxygen than the metal.
Example
iron oxide + carbon-> iron + carbon dioxide2Fe2O3 + 3C -> 4Fe + 3CO2
In practice
Iron is made in a blast furnace by heating iron oxide with carbon.
Practice
Flashcards
- Which method extracts metals more reactive than carbon?Electrolysis.
Interview questions
- Explain why aluminium is extracted by electrolysis but iron can be extracted with carbon.
- Aluminium is more reactive than carbon
- Carbon cannot displace aluminium from its oxide
- Iron is less reactive than carbon
- Electrolysis needs a lot of electricity so it costs more
Questions people ask
What does the blast furnace do?
It is a tall furnace where iron ore, coke (carbon) and limestone are fed in at the top and hot air is blown in at the bottom. Carbon reacts with oxygen to give carbon monoxide, which removes oxygen from iron oxide to give molten iron.
Why is limestone added to the blast furnace?
Iron ore contains impurities such as sand, silicon dioxide. Limestone breaks down on heating to give calcium oxide, which reacts with the sand to make slag, a molten waste that floats on the iron. The slag can then be removed and often used in road building.