Extracting metals and making alloys
Ores are naturally occurring rocks that contain metal or metal compounds in sufficient amounts to make it worthwhile extracting them. Most everyday metals are alloys.
The Earth's crust contains metals and metal compounds such as gold, iron oxide and aluminium oxide but when found in the Earth they are often mixed with other substances. To be useful, they have to be extracted from whatever they are mixed with.
Ores are mined. They may need to be concentrated before the…