Extraction of Metals

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What are metals often found with?
Sulphur or Oxygen
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What are rocks called with a high percentage of metals?
Ores
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What are the most abundant metals in the Earth's crust?
Aluminium and Iron
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What are Sulphides converted to before extraction?
Oxides
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what is the equation for turning Zinc into an oxide?
2ZnS + 3 O2 ----------> 2ZNO + 2SO2
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What can Sulphur dioxide cause?
Acid Rain
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What can happen to the Sulphur dioxide?
It can be collected and converted to Sulphuric acid in controlled conditions
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What is this equation?
SO2 + H2O + 1/2 O2 ----------> H2SO4
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What is Coke?
It is an impure form of carbon
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How is it obtained?
Heating coal in the absence of air
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Why is carbon not used sometimes?
The reaction with carbon is so high that the process is uneconomic
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What happens with reactive metals when reacted with carbon?
Carbides form
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What else is also used as a reduction agent?
Hydrogen
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What reaction is hydrogen used in?
The reduction of Tungsten
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How does the extraction of Iron occur?
Using coke and tall brick towers, called blast furnaces that are up to 70m high
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How much iron can a blast furnace produce daily?
10,000 tonnes a day
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What happens at the bottom of the furnace?
Coke burns in a blast of hot air
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What is heat generated by?
a exothermic reaction so that temperature is around 2000K
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what is formed from this reaction?
CO2
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Which then reacts with what? to form what?
excess carbon to form CO
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What is CO?
It is a reducing agent
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What does it reduce?
Iron oxide
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to produce?
Molten Iron
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What is wrong with using Carbon?
CO2 is a greenhouse gas and CO is toxic
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Why cant Tungsten be extracted by carbon?
It forms a Carbide
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What is wrong with using hydrogen?
There are risks of explosionand problems with storing it because it is flamable
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What are three advantages of using hydrogen?
No pollution, readily available, will give higher purity than carbon
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Why is titanium a valuable metal?
It is abundant, low density, corrosion resistant, extracted by reaction with a more reactive metal
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what is the first step in extracting titanium?
TiO2(solid) is converted to TiCl4(liqiud) at 900degrees
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What is the second step in extracting Titanium?
TiCl4 is purified by fractional distillation in an Ar atmosphere
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What is the third step in extracting titanium?
Extracted by Mg or Na in an Ar atmosphere at 1300K
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Why is a batch process expensive?
Energy is lost when reactor is cooled down after stopping
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Why else is the production of Titanium expensive?
The expensive cost of Na and Mg and high temps are needed at both stages
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When is electrolysis used?
When a reactive metal can't be extracted by the reduction of carbon
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Why is electrolysis not used sometimes?
When the metal needs to be pure
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What state must the aluminium oxide be in for electrolysis?
It must be molten
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Where is aluminium dissolved?
Into the molten cryolite(lowers the melting point of the aluminium oxide)
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What happens without the use of cryolite?
Aluminium oxide melts at too high temperature which makes the process uneconomic
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What is the electrode reaction at the cathode?
al3+3e- ---------> Al
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What is the electrode reaction at the anode?
2O2- -------> O2 + 4e-
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What recycling metals do?
Saves resources, creates less waste and scrap removed from countryside or landfill
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How much energy does recycling aluminium save?
uses less than 5% of energy
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What are the disadvantages of recycling metals?
cost assossiated with collecting, sorting and transporting metals
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How is copper often extracted?
With the use of scrap iron
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How is the aqueous solution of copper made?
By reacting the ore with sulphuric acid
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Compared with high temperatures of carbon what does this do?
uses less energy, work with lower grade ores and would work with low quality scrap iron
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Other cards in this set

Card 2

Front

What are rocks called with a high percentage of metals?

Back

Ores

Card 3

Front

What are the most abundant metals in the Earth's crust?

Back

Preview of the front of card 3

Card 4

Front

What are Sulphides converted to before extraction?

Back

Preview of the front of card 4

Card 5

Front

what is the equation for turning Zinc into an oxide?

Back

Preview of the front of card 5
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