| Describe Phytoextraction and it's Process | It Makes use of plants absorbing mineral ions through their roots:
1) plants are grown on a low-grade ore
2) plants absorb metal ions through their roots and concentrate these ions in their cells
3) then are harvested and burnt
4) the ash left behind contains metal compounds
Process is slow but:
- reduces the need to obtain new ore by mining
- conserves limited supplies of high-grade ores
- reduces the amount of rock waste that must be disposed of after traditional mining |
| What is the Process & Conditions of Bioleaching | 1) Certain bacteria can break down low-grade ores to produce an acidic solution containing copper ions. The solution is called a leachate and the process is called bioleaching
2) Bioleaching does not need high temperatures but it produces toxic substances, including sulfuric acid, which damage the environment |
| What is a Life Cycle Asessment? | Analysis of a manufactured product on the environment (eg, use of energy, transport of materials and the release of waste substances into the environment): |
| What is Stage 1 of a Life Cycle Assesment? | 1) RAW MATERIALS:
come from the Earth's crust, atmosphere or oceans, or are due to living organisms, include:
- using up limited resources such as ores and crude oil
- damaging habitats through quarrying, mining, or felling trees |
| What is Stage 2 of a Life Cycle Assesment | 2) MANUFACTURE:
- using up land for factories
- the use of machines and people |
| What is Stage 3 of a Life Cycle Assesment | 3) USE:
- impact of a product on the environment during its use, depends on the type product
- Eg, wooden chair - v/little impact, car- high impact |
| What is Stage 4 of a Life Cycle Assesment | 4) DISPOSAL:
Impacts on environment:
- using up land for landfill sites
- whether any or all of the product can be recycled or reused |
| What are the Advantages of Recycling? | ADVANTAGES:
- saves most energy
- reduces the impact on the environment.
- fewer quarries and mines needed to extract finite reserves of metal ores
- less crude oil needs to be extracted from the crust as a raw material for making plastics
- less energy is needed for recycling compared with making a new product from natural resources, so the emission of greenhouse gases is reduced
- amount of waste that is disposed of in landfill is reduced |
| What are the disadvantages of Recycling? | DISADVANTAGES:
- collection and transport of used items needs organisation, workers, vehicles and fuel
- can be difficult to sort different metals from one another
- the sorted metal may need to be transported to where it can be turned into ingots
Amount of sorting depends on:
- purity of the mixture of metals/materials
- How pure you want the final material to be (copper wires need v/high purity ∴ waste copper will need processing, but construction steel doesn't need high purity |
