Metals and their uses SPEC Flashcards
What is an ore?
rock
contain enough metal economical to extract
How are metals extracted?
Ores mined
(may be concentrated: copper)
metal extracted and purified
How is gold extracted and why?
It is unreactive metals
found in the Earth, metal itself
physical methods
How can metals that are less reactive than carbon be extracted from their oxides
reduction with carbon
carbon removes oxygen from their oxides
eg: iron oxide reduced in
blast furnace to make iron
How is aluminium extracted and what is the disadvantage of this?
Electrolysis of molten aluminium oxide (molten compounds)
because more reactive than carbon
large amounts energy needed
–> expensive
How can copper be extracted from copper-rich ores?
Smelting: heating ores in a furnace
Purified by electrolysis
Disadvantage of traditional way of mining copper?
Smelting + purifying copper
high amount of heating + electricity
Environmental
Supply limited
Copper-rich ores being depleted
Why are new ways of extracting copper from low-grade ores being researched?
limit the environmental
impact of traditional mining
What is phytomining?
Plants absorb metal compounds
Burned to
produce ash
Contains the metal compounds
What is bioleaching?
uses bacteria
leachate solutions
contain metal compounds
Phytomining + bioleaching produces copper compounds (solutions of copper salts). How is copper obtained from this?
electrolysis
displacement using scrap iron (more reactive than copper)
Aluminium and titanium cannot be extracted from
their oxides by reduction with carbon. Current
methods of extraction are expensive because?
many stages in the processes
large amounts of energy needed
Why should we recycle metals?
Extracting them uses limited resources
extracting expensive in terms
of energy + effects on the environment
