Alternative methods of extracting metals (HT only)
- The Earth’s resources of metal ores are limited.
- Copper ores are becoming scarce and new ways of extracting copper from low-grade ores include phytomining, and bioleaching. These methods avoid traditional mining methods of digging, moving and disposing of large amounts of rock.
- Phytomining uses plants to absorb metal compounds. The plants are harvested and then burned to produce ash that contains metal compounds.
- Bioleaching uses bacteria to produce leachate solutions that contain metal compounds.
- The metal compounds can be processed to obtain the metal. For example, copper can be obtained from solutions of copper compounds by displacement using scrap iron or by electrolysis.
- Students should be able to evaluate alternative biological methods of metal extraction, given appropriate information.