Metal Extraction

Question 1

What is a metal ore?

Answer 1

A rock containing enough metal to make it worthwhile extracting the metal from it

Question 2

In many cases the ore of a metal is an ….

the ore of aluminium is …

Answer 2

oxide

bauxite - aluminium oxide

Question 3

How are metals extracted from their ores?

Answer 3

Using a chemical reaction

Question 4

Why do the economics of metal from ore extraction change with time? (2)

Answer 4

If market price of the metal drops it might not be worth extracting it, or it might be worth increasing extraction if price increases
As tech improves it might become possible to extract metals previously unextractable so now might be worth money

Question 5

What are the two ways metals are extracted from their ores?

Answer 5

Reduction

Electrolysis

Question 6

What do some ores have to do before the metal is extracted?

Answer 6

Be concentrated to get rid of the unwanted rocky material

Question 7

What can electrolysis also be used for besides extracting metals?

Answer 7

Purifying them

Question 8

How are some metals extracted through reduction?

Answer 8

The oxygen is removed by reacting the metal oxide ore with carbon to leave the metal and carbon dioxide

Question 9

What determines whether the metal can be extracted with carbon?

Answer 9

Its place on the reactivity series

Question 10

If the metal is less reactive than carbon it will be….

If it is more reactive it will be …

Answer 10

extracted using reduction with carbon

extracted by electrolysis

Question 11

What is the bad thing about electrolysis for a company?

Answer 11

It’s expensive

Question 12

How do metals more reactive than carbon have to be extracted?
Example…

Answer 12

by electrolysis of its molten compound.

aluminium

Question 13

Why is electrolysis more expensive than reduction with carbon?
Example:

Answer 13

It uses a lot of energy

Very high temperatures are required to melt aluminium oxide which is very expensive

Question 14

How is copper extracted from its ore? describe…

Answer 14

Reduction … easily, in a furnace which is heated which is called smelting

Question 15

Why is impure copper unuseful?

What’s used to purify it?

Answer 15

It contains impurities which stops it conducting electricity well which is bad as it’s used to make electrical wiring
Electrolysis

Question 16

What does electrolysis mean?

Answer 16

The breaking down of a substance by splitting it with electricity

Question 17

What does electrolysis require?

Answer 17

A liquid to conduct the electricity called the electrolyte

Question 18

What does the electrolyte have and what do these do?

Answer 18

Free ions that conduct electricity

Question 19

What happens to electrons at the positive electrode? then at the negative electrode?
So what happens to the ions?

Answer 19

They are taken by the +ve and given away by the -ve

They gain or lose electrons and so become atoms or molecules and are released

Question 20

How do you use electrolysis to get copper? (describe)

1. Electrons and the +ve electrode
2. -ve electrode
3. Impurities
4. What is the electrolyte?

Answer 20

Electrons are taken of copper atoms at the positive electrode causing them to go into the solution as Cu2+ ions
Cu2+ ions near the -ve electrode gain electrons and turn back into copper atoms
The impurities are dropped under the +ve electrode as sludge whilst pure copper atoms bond to the -ve electrode.
Copper II sulphate solution containing Cu2+ ions

Question 21

What can also be used to extract copper?

Answer 21

A displacement reaction

Question 22

What will happen if you put a reactive metal in a solution of a dissolved metal compound?
What can be sued to displace copper from copper sulphate solution?

Answer 22

The reactive metal will displace the less reactive metal

Iron

Question 23

Why is it important to recycle copper? (2)

Answer 23

The amount of copper rich ores is limited

Demand is growing and this may lead to shortages in the future

Question 24

What are the two ways scientists have come up with to extract copper from low grade ores or the ground?
What is the advantage and disadvantage to these techniques?

Answer 24

Phytomining
Bioleaching
They have a smaller impact on the environment than traditional methods but they are slow

Question 25

What is phytomining? (4 stages)

Answer 25

Growing plant in soil that contains copper
The plants can’t use or get rid of the copper so it eventually builds up in their leaves
The plants are harvested dried and burned in a furnace
The copper can be collected from the ash left in the furnace

Question 26

What is bioleaching? (3 stages)

Answer 26

Bacteria is used to separate copper from copper sulphide
The bacteria get energy from the bond between copper and sulphur separating, separating the copper from the ore in the process
The leachate, the solution produced contains copper, this can be extracted through filtering.

Question 27

Why is mining for metal ores good? (4)

Answer 27

Useful products can be made
It provides local people with jobs
This brings money into the area
So facilities such as hospitals and infrastructure can be improved

Question 28

Why is mining for metal ores bad? (4)

Answer 28

It causes noise
Scarring of the landscape
Loss of habitats
Deep mine shafts can be dangerous for a long time after the mine is abandoned

Question 29

Why is mining for metals bad?

Answer 29

It uses a lot of energy which requires the burning of fossil fuels

Question 30

Why is burning fossil fuels for mining bad? (4)

Answer 30

They are running out so it’s important to conserve them
It contributes to acid rain
Global dimming
and Climate change

Question 31

Why is recycling metals good in relation to fossil fuels?
and energy?
and for the earth’s resources?
and for pollution?

Answer 31

It uses only a small fraction of the energy required to mine ores and extract new metal
it’s cheaper as it uses less
there is a finite amount of metal ores so it conserves these
It cuts down the amount of rubbish sent to landfills that take up space and pollute the environment.