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Copper in health
 Extracting copper 
Metals are found as ores buried in the Earth's crust. So how do we get to the final metal? There are three main stages.
  • mining
  • extraction
  • purification.

Let's look at each of these in more detail.

Photo of copper mine
Picture 4. A copper mine. The size of the trucks in the picture give an idea of the scale.
The copper ore has to be dug from the ground. The ore contains some copper mineral and lot of waste rock. The copper mine in picture 4 produces 6 tonnes of copper from every 1000 tonnes of ore.

An ore has to be changed chemically into the metal. This process is called reduction. How this is done, and how much it costs, depends upon the metal's reactivity (see reactivity properties). In general, the more reactive the metal, the harder it is to extract it from its ore.
Metal ore Reactivity Primary
aluminium found mainly as the ore bauxite high electrolysis
iron extracted from the ore medium blast furnace
copper various ores low roasting in air

Interactive graphic
Interactive graphic
5. Laboratory apparatus for electrolysis.
Many metals are impure when they are extracted from their ores. Impurities have to be removed. Copper is purified by electrolysis. In this process copper is transferred from an impure anode to the cathode of an electrolytic cell. The insoluble impurities fall to the bottom. The copper produced by this process is 99.99% pure copper.

This is similar to the electrolysis that is done in a school lab.

Question 2
a) i. The copper mine in picture 4 produces 6 tonnes of copper for every 1000 tonnes of ore. What mass of copper (in Kg) could be obtained from 50 tonnes of a ore?
[1 tonne = 1000 Kg]
ii. How much waste will this produce?
(Write the answer in Kg).
b) Sodium is more reactive than aluminium. What method would have to be used to extract sodium from its ore – rock salt?
c) Mercury is less reactive than copper. Which method would be suitable for its extraction?
d) Zinc is extracted from its ore, zinc blende, by heating in a blast furnace with coke. What does this tell you about its reactivity?
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