Obtaining and using metals 2.0

Question 1

what are the 4 main stages of a life-cycle assessment?

Answer 1

• obtaining the raw materials needed
• manufacturing the product
• using the product
• disposing of the product at the end of its useful life

Question 2

what considerations are there related to raw materials in the life-cycle assessment? (2)

Answer 2

• using up limited resources such as ores and crude oil

- damaging habitats through quarrying, mining, or felling trees

Question 3

what considerations are there related to manufacture in the life-cycle assessment? (2)

Answer 3

• using up land for factories

- the use of machines and people

Question 4

what considerations are there related to disposal in the life-cycle assessment? (2)

Answer 4

• using up land for landfill sites

- whether any or all of the product can be recycled or reused

Question 5

why does phytoextraction work?

Answer 5

Plants absorb mineral ions through their roots

Question 6

describe the process of phytoextraction: (5)

Answer 6

• plants are grown on a low-grade ore that contains lower amounts of metal
• the plants absorb metal ions through their roots and concentrate these ions in their cells
• the plants are harvested and burnt
• the ash left behind contains a higher concentration of the metal than the original ore
• the ash is processed to obtain the metal

Question 7

describe the advantages and disadvantages of phytoextraction: (3)

Answer 7

advantages:

• reduces the need to obtain new ore by mining
• conserves limited supplies of more valuable ores with higher metal content

negative:
-is it a slow process

Question 8

Suggest reasons why phytoextraction decreases the damage done to the environment. (2)

Answer 8

• reduce the need for mining

- do not destroy natural habitats

Question 9

how does the process of bioleaching work?

Answer 9

Certain bacteria can break down low-grade ores to produce an acidic solution containing metal ions

Question 10

what is the acidic solution produced from bioleaching called?

Answer 10

leachate

Question 11

advantages and disadvantages of bioleaching: (2)

Answer 11

advantages:
- does not need high temperatures

disadvantages:
-produces toxic substances, including sulfuric acid, which damage the environment.