Biological methods of extraction

• The Earth's supply of metal ores is limited, making it harder to find and mine high-grade copper ores
• Alternative methods to extract metals from low-grade copper ores include biological methods using living organisms
• Phytomining (or phytoextraction) involves plants absorbing metal ions through their roots, concentrating them in their cells, then being harvested and burnt to produce an ash containing metal compounds
• Phytomining is slow but reduces the need to obtain new ore by mining, conserves limited supplies of high-grade ores, and reduces the amount of rock waste that must be disposed of after traditional mining
• One disadvantage of phytomining is that it is a slow process
• Bioleaching uses bacteria to break down low-grade ores to produce an acidic solution containing metal ions, but it produces toxic substances, including sulfuric acid, which can damage the environment
• Iron, being more reactive than copper, can displace copper from the leachate in bioleaching processes, providing a cost-effective way to produce copper
• Copper compounds can also be dissolved and the solution electrolysed to produce copper metal