reuse and recycling

• advantages of recycling:

  • less quarries and mines needed to extract finite reserves of metal ores
  • less crude oil to be extracted as raw material for making plastics
  • less energy for recycling compared with making new product from natural resources, so emission of greenhouse gases reduced
  • amount of waste disposed in landfill reduced
• disadvantages of recycling:

  • collection and transport of used items needs organisation, workers, vehicles and fuel
  • can be difficult to sort different metals
  • sorted metal need to be transported to where can be turned into ingots
• • earth's supply of metal ores limited
  • so need to be extracted from lowgrade ores
• phytomining:

  • plants absorb copper ions through their roots

  1. plants are grown on soil that contains copper
  2. the plants absorb copper through roots and concentrate ions in cells
  3. plants harvested and burnt in furnace
  4. ash left behind contains copper which can be extracted through electrolysis and displacement using iron
• phytomining is slow but:

  • reduces need to obtain new ore by mining
  • conserves limited supplies of high-grade ores
  • reduces amount of rock waste that must be disposed of after traditional mining
• bioleaching:

  • bacteria used to break down copper compounds in ore to soluble copper compounds
  • copper seperated from ore
  • leachate is acidic solution produced which has copper ions
  • extracted from displacement or electrolysis
• • for displacement, scrap iron used to displace copper
  • scrap iron cheaper than copper
• • copper is finite
  • can be extracted from low grade ores
  • low grade ores are ores without much copper in