Transcript Metals and the Environment

Metals and the Environment
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Links to the 2011 specifications
AQA
C1.3.1 – Extracting metals
Edexcel
Topic 4 – Obtaining and using metals
OCR Gateway
C2c – Metals and alloys
How Science Works
The content in this presentation can help illustrate how scientists:
• use appropriate methodology to answer scientific questions and solve scientific problems
• evaluate the use of contemporary scientific and technological developments and their
benefits, drawbacks and risks
• consider how and why decisions about science and technology are made, including
those that raise ethical issues, and about the social, economic and environmental effects
of such decisions.
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Bioleaching
New mining techniques can decrease the effects of metal
extraction on the environment.
In bioleaching, metal ores are
dissolved in a solution then
mixed with certain bacteria.
Depending on the type of
bacteria, different metals will be
‘leached’ from the ores into the
solution, ready for electrolysis or
a displacement reaction.
Bioleaching uses less energy
than traditional extraction and
does not produce waste gases.
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Phytomining
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Extracting copper
Copper extracted from its ore
by bioleaching or phytomining
is impure. In order to purify the
copper, it must be dissolved in
an acid, such as sulfuric acid,
then electrolysis carried out.
The copper from the copper
sulfate solution is attracted to
the pure copper negative
electrode. Titanium is used for
the positive electrode.
Copper can also be extracted from solutions of copper sulfate
by carrying out a displacement reaction using scrap iron.
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