copper from deep in the ground. sl m2. five stages: open pit mining pit crusher 0.6% cu froth...
Post on 21-Dec-2015
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Five stages:• Open Pit mining
• Pit crusher 0.6% Cu
• Froth floatation 30% Cu
• Smelting 90.4% Cu
• Electrolytic refining 99.98% Cu
% by mass = mass of element in 1 mole of compound x 100
Mr of compound
CuFeS2
Mr = 64+56+32+32 = 184
% by mass = 64 x 100 = 35%
184
Open Pit mining.Bingham Canyon
Low grade copper
Quantities huge
Shavings tested
Dynamite used
Waste to tips
Froth Floatation
Collector (oil) molecules attach themselves to the chalcopyrite grains.
The grains are now water-repellent.
Air bubbles attract the grains.
Froth produced and is pumped away to smelter.
•Detergent
•Oil
•Water
•Tailings
0.6%
30%concentrating
Smelting• First stage involves
– Silica– Oxygen– Concentrate
• Cu2S made
•Most important stage involves Cu2S / air / furnace
•Cu2S(l) + O2(g) 2Cu(l) + SO2(g)
Cu2S + O2 2Cu + SO2
0 -2
-2 +4
+1 0
O
S
Cu
Oxidised or reduced?
reduced
oxidised
reduced
What mass of copper could be obtained by reducing 1kg of copper (I) sulphide?
Cu2S + O2 2Cu + SO2
What mass of copper could be obtained by reducing 1kg of copper (I) sulphide?
160 128
Moles in
1kg
1 mol 2 mol
Mass in question
Mass in
Underline
160 160
0.800kg
Electrolytic Refining99.4% 99.98%
The copper anodes are already 99.4% copper!
The copper cathodes will be 99.98% copper!
e-e-Cu
e- e-
Anode + - Cathode
Cu2+Cu
Cu
Cu2+
CuCu2+
•Describe what is happening at the anode.
•Write an equation.
•Is this oxidation or reduction?
e-e-Cu
e- e-
Anode + - Cathode
Cu2+
Cu2+Cu
Cu
Cu2+
CuCu2+
•Describe what is happening at the cathode.
•Write an equation.
•Is this oxidation or reduction?
e-e-Cu
e- e-
Anode + - Cathode
Cu2+Cu
Cu
Cu2+
CuCu2+
•Write an equation.
Cu(s) Cu2+(aq) + 2e-
•Is this oxidation or reduction?
Oxidation
e-e-Cu
e- e-
Anode + - Cathode
Cu2+
Cu2+Cu
Cu
Cu2+
CuCu2+
•Write an equation.Cu2+(aq) + 2e- Cu(s)
•Is this oxidation or reduction?
Reduction