Extracting metals Flashcards
what is an ore
a rock that contains metals or their compounds where it will contain enough metal for it to make extraction economical
what is a low-grade ore
rocks that don’t have enough metal to make extraction worthwhile
how do metals corrode
when they react with substances around them, such as air and water
why are some metals found in their native state in the earth’s crust
because they are not reactive and do not combine with other elements
what are the 2 ways to chemically extract metals
- electrolysis of a molten compound
- reduction of its oxide using carbon
what 5 metals can be extracted using the electrolysis method
potassium
sodium
calcium
magnesium
aluminium
what elements can be extracted using the reduction method and why
metals less reactive than carbon, zinc iron copper
how are metals extracted using the reduction method
metal oxide and carbon is reacted inside a blast furnace to produce a metal and carbon monoxide or carbon dioxide
how are metals extracted using the electrolysis reaction
the metal oxide is dissolved in a molten cryolite, which reduces the temperature needed for electrolysis. as the current passes through aluminium ions gain electrons and are reduced to aluminium atoms at the cathode. at the anode, oxide ions lose electrons and form oxygen gas
what method is used to counteract the running out of high-grade iron ores
using scrap iron
what is the word equation where scrap iron is used to extract copper from copper salts
iron + copper sulfate –> iron sulfate + copper
what is the benefit of using low-grade ore
more common as most high-grade ores have already been used
what are 3 cons of low-grade ores
- less profitable
- use more energy
- produce more waste when used
what are 2 ways of using biological metal extractions
phytoextraction
bioleaching
what happens in phytoextraction
the roots of a plant absorb metal compounds, the plant concentrates the metal compounds in its shoots and leaves. the plant is then burned and ash will contain the metal compound
what happens in bioleaching
using bacteria to extract metal by oxidizing compounds and releasing metal ions
what is the leachate
the solution that bacteria produce in bioleaching
what are 3 cons of extracting materials
uses up limited recources
uses a lot of energy
damages the environment
what are 5 pros of recycling metals
metal ores will last longer
less energy is needed
fewer quarries and mines are needed
less noise and dust are produced
less land is needed
what are 3 drawbacks of metal recycling
used metal items must be collected and transported to the recycling centre
different metals must be sorted
will save different amounts of energy depending on the metal
what is LCA
a life cycle assessment of a product is a “cradle to grave” analysis of its impact on the environment
what are the 4 stages of an LCA
obtaining raw material
manufacturing the product
using the product
disposing of the product
give 5 pieces of data that an LCA will need
the use of energy
the release of waste materials
transport and storage
whether the raw materials are renewable or non-renewable
whether the product can be recycled or reused
ho the product is disposed of
