Transcript Energy Transfer - Noadswood Science

Friday, April 8, 2016
Phytomining & Bioleaching
L.O: To understand the terms phytomining and bioleaching
Parys Mountain copper mines, Amlwch (Wales),
1989
What is the impact of this?
Copper mines in Wales
http://www.bbc.co.uk/wales/history/sites/themes/society/industry_co
pper.shtml
Electrolysis
•
Electrolysis is very expensive to complete and open cast mines
also have a massive ecological impact. Copper can be also be
obtained from copper salts using scrap iron, however in recent
years two new approaches have been made to extract pure
metals: •
Phytomining
•
Bioleaching
Phytomining
• Phytomining uses plants to absorb naturally occurring metal compounds
(including copper) when they grow
• Once a significant amount of metal compound has been absorbed the
plants are burned, producing ash which contains the metal compounds
• This method can also be used to
extract metals from contaminated
land
• Brassicas (cabbage family) can be
used to extract cadmium, cobalt and
nickel
• Look at the celery which has been
left in copper sulfate (blue leaves)!
Phytomining Practical
• Complete the practical to produce pure copper
1.
2.
3.
4.
5.
Brassica plants have been grown in conditions with large
amounts of naturally occurring metal compounds (specifically
copper)
The plants have subsequently been ‘ashed’ in the fume cupboard
Add sulfuric acid to the ash
Filter the mixture
Leave to dry and then displace using iron filings…
• What evidence is there that the
experiment has worked?
Displacement
• Adding the iron fillings to the copper sulfate solution will cause a
displacement reaction
• The iron is more reactive than the copper, displacing it to form iron sulfate
and copper
Bioleaching
• Bioleaching uses bacteria to produce leachate solutions that
contain metal compounds…
• Some bacteria can live by using the energy of the bonds between
sulfur and copper – in doing so this separates the metal from the
ore
• Bioleaching is extremely energy efficient, however it is very slow…
Metal Theft
• Metal theft is increasing in the UK – currently it is the fastest growing
theft
• This is because metal prices are steadily increasing (with the cost of the
raw materials / oil used for machinery to extract / power electrolysis)
• Recycling metals is a way to cheapen their overall cost…