Chapter 19:Extraction of Metals
- The Earth’s crust contains metals and metal compound
- [ ] such as gold, copper, iron oxide and aluminium oxide
- A metal ore is a rock that contains enough of the metal to make it worthwhile extracting
- They have to be extracted from their ores through processes
- [ ] such as electrolysis, using a blast furnace or by reacting with more reactive material
- Obtaining from ores is a reduction process
- Middle order metals like iron are extracted by reducing with carbon in the blast furnace.
- [ ] Blast furnace uses three raw materials (coke ,limestone and iron) .
- [ ] Coke burns to produce carbon monoxide and heat producing Pig Iron-
- Iron ore+ carbon monoxide ➡️iron + carbon dioxide
- Limestone ➡️lime + carbon dioxide
- Lime + sand ➡️calcium silicate
- Aluminium ore is called bauxite .
- [ ] The bauxite is purified to produce aluminium oxide.
- [ ] The extraction is done by electrolysis.
- [ ] The ions in the aluminium oxide must be free to move so that electricity can pass through it
Rusting
- Reaction of iron with air /oxygen and water to form rust.
- Rusting is a redox process.
- You can prevent it by panting or coating with oil or grease, metal or electroplating.