52-55 - Extracting Metals Flashcards
What is an ore?
A rock containing enough metal to make its extraction economical
Why is gold found in the earth?
It’s not very reactive
How might the profitability of metal extraction change?
The price for a metal could rise or drop
Technology could make extraction cheaper
What are the two ways of extracting metals from ores?
Reduction
Electrolysis
What is reduction?
When carbon replaces the oxygen in a metal oxide
How is iron oxide extracted?
Reduced with carbon in a blast furnace
Why do some metals have to be extracted with electrolysis?
More reactive than carbon
What are the issues with electrolysis?
Expensive because of the energy it takes
Transport of waste rock is expensive
Why does copper need to go through electrolysis?
It is impure after reduction and doesn’t conduct electricity
What is an electrolyte?
A liquid that conducts electricity
Often a metal salt solution
What is the charge of an anode?
Positive
What is the charge of a cathode?
Negative
What are the steps of electrolysis?
Anode pulls copper atoms into solution to form Cu2+ ions
These ions gain electrons at the cathode, become copper atoms
Impurities form a sludge by the anode
What is the cathode in electrolysis?
A thin piece of pure copper
What is the anode in electrolysis?
A lump of impure copper which dissolves
What is displacement?
When a more reactive metal replaces a less reactive metal in a compound
Why should copper be recycled?
There are few copper-rich ores
Shortages may occur in the future
What is bioleaching?
Bacteria gets energy from copper sulfate bond
Separates two elements
Excretes copper leachate
What is leachate?
The solution produced in bioleaching
What is phytomining?
Grow plants in soil containing copper
Plant is burned
Copper collected from ashes
What are the disadvantages of phytomining and bioleaching?
They’re slow
Why is it important to recycle metals?
Saves money
Saves energy
Saves resources
Reduces landfill pollution
How much energy does it take to recycle copper?
15% of what is needed to extract copper
Which metals are extracted with electrolysis?
Those more reactive than carbon
Why do metals need to be extracted from their ores?
Ores contain compounds
