C1 - Metals Flashcards
What is an ore?
Rocks that contain enough metal compounds that make it economically viable to extract the metal compound.
What is a native metal?
A metal that can be found uncombined in the Earth’s crust.
What is smelting?
Heating a metal ore to extract the metal.
Why is copper extracted from low-grade ores?
Copper ores are running out and there are no high-grade ores left.
Describe bioleaching.
Bacteria feed on low grade ores. A leachate is produced (this is a solution of copper ions). The leachate is either electrolysed or scrap iron is added to it.
Why is scrap iron used to extract copper from leachate?
Scrap iron is cheap. Iron is more reactive than copper and will displace the copper ions from the leachate.
Why is oxygen used to produce low-carbon steels?
Oxygen reacts with the carbon in pig iron to make carbon dioxide. This removes the carbon from the steel.
Why is it more expensive to extract titanium than iron?
Extracting titanium involves more steps than extracting iron. Larger amounts of energy are also needed. Argon is used in the process which is expensive.
Iron oxide is heated with carbon inside the blast furnace. What type of reaction takes place?
Reduction. Carbon removes the oxygen from iron oxide.
What is the equation for iron oxide reacting with carbon monoxide to make iron and carbon dioxide?
Fe2O3 + 3CO -> 2Fe + 3CO2
Describe how aluminium is extracted from bauxite.
Bauxite is mixed with cryolite to lower the melting point. The mixture is heated and electrolysed. Aluminium is
produces as well as carbon dioxide.
Why is it important to recycle aluminium cans?
To preserve aluminium ores, save 95% of energy compared to extracting it from bauxite. Reduce CO2 emissions.
What is phytomining?
Plants absorb copper ions from low-grade copper ores. The plants are harvested and burnt. The ash left behind is dissolved in sulphuric acid to produce copper sulphate solution. The copper sulphate solution is either electrolysed or scrap iron is added to displace the copper ions
What are the pros and cons of phytomining?
Pro: heat released during burning of plants can be used to heat houses or produce electricity. Plants absorb CO2 during photosynthesis. Cons:not continuous/Batch process so it takes a long time.
Describe the electrolysing of copper sulphate.
Copper sulphate is used as the electrolyte. Positive copper ions in the copper sulphate solution are attracted to the negative electrode where they take on 2 electrons and form copper atoms.
