Extraction of metals Flashcards
Metals that are [ ] reactive than carbon have to be extracted using [ ] of [ ]
more
electrolysis
molten compounds
Why is electrolysis more expensive than reduction?
Uses a lot of energy
What is purified by electrolysis?
Copper
What is smelting?
ore being heated in a furnace
What is the issue with extracting copper by reduction with carbon?
Copper produced this way is impure - and therefore doesn’t conduct electricity very well. Not useful because copper is used to make electrical wiring
Why is electrolysis used with copper?
Purifies it - much better conductor
What is electrolysis?
The breaking down of a substance using electricity
What does electrolysis require?
A liquid to conduct the electricity, called the electrolyte.
What are electrolytes often made of?
Metal salt solutions made fro the ore or molten metal oxides
Why can the electrolyte conduct electricity?
Has free electrons
Electrons are taken away by the [ ] electrode and are given away by the [ ] electrode. As ions gain or lose electrons they become [ ] or molecules and are released.
Positive
Negative
Atoms
How is electrolysis is used to get copper?
1) Electrons are pulled off copper atoms at the positive electrode (anode) causing them to go into solution as Cu²⁺ ions.
2) Cu²⁺ ions near the negative electrode gain electrons and turn back into copper atoms
3) The impurities are dropped at the positive electrode as a sludge, whilst pure copper atoms bond to the negative electrode
What is the positive electrode whilst purifying copper through electrolysis?
Big lump of impure copper, which will disolve
What is the negative electrode whilst purifying copper through electrolysis?
Starts as a thin piece of pure copper and more pure copper adds to it.
What can be used to EXTRACT copper?
A displacement reaction
More reactive metals react more [ ] than less reactive metals
Vigorously
What will happen if you put a reactive metal into a solution of a dissolved metal compound? Why?
The reactive metal will displace the less reactive metal in the compound.
Because the more reactive metal bonds more strongly to the non-metal bit of the compound and pushed out the less reactive metal.
Scrap iron can be used to displace copper from [ ] - this is really useful because iron is cheap and copper is expensive. If some iron is put in a solution of copper [ ], the more reactive iron will ‘kick out’ the less reactive copper from the solution. You end with [ ] solution and copper metal
solution
sulphate
iron sulphate
If a piece of silver metal is put into a solution of copper sulphate… Why?
nothing happens
The more reactive metal (copper) is already in the solution
Why is it important to recycle copper?
The supply of copper-rich ores is limited.
The demand for copper is [ ] and this may lead to …
Growing
Shortages in the future
What 2 things are scientists looking into getting copper from?
Low grade ores (ores that only contain small amounts of copper)
From waste that is currently produced when copper is extracted
What are 2 new ways of extracting copper?
Bioleaching and Phytomining
What is bioleaching?
This uses bacteria to separate copper from copper sulfide. The bacteria get energy from the bond between copper and sulfur, separating out the copper from the ore in the process. The leachate (The solution produced by the process) contains copper which can be extracted.
What is phytomining
Growing plants in soil that contains copper. The plants can’t use or get rid of the copper so its gradually builds up in the leaves. The plants can be harvested, dried, and burned in a furnace. The copper can be collected from the ash left in the furnace.
What is 1 advantage to Bioleaching and Phytomining and 1 disadvantage?
Ad: smaller impact on the environment than traditional methods
Dis: They’re slow
