How should phytomining and bioleaching be evaluated for a particular ore source?
Compare them with traditional extraction, using evidence to weigh benefits and drawbacks and decide when each method is suitable.
AQA GCSE Combined Science: Trilogy (8464) — Chemistry — Higher · 5.10.1.4
Revise AQA GCSE Combined Science: Trilogy (8464) — Chemistry — Higher specification point 5.10.1.4, Alternative methods of extracting metals (HT only), with free active-recall flashcards. Flip through the set or review every question and answer below.
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How should phytomining and bioleaching be evaluated for a particular ore source?
Compare them with traditional extraction, using evidence to weigh benefits and drawbacks and decide when each method is suitable.
What grade of ore can biological extraction methods be useful for?
Low-grade ores.
How can biological extraction reduce the handling of rock?
It can reduce the amount of rock that must be dug up, moved and disposed of.
What five factors may be considered when evaluating biological metal extraction, if data are available?
What resource limitation applies to metal ores?
They are a finite resource.
How is the availability of high-grade copper ores changing?
They are becoming harder to find.
What is a low-grade metal ore?
An ore containing little useful metal compared with the amount of unwanted rock.
Why is traditional mining and extraction less attractive for low-grade copper ores?
Large quantities of rock must be dug up, moved and disposed of to obtain relatively little copper.
What advantage do alternative copper extraction methods offer for low-grade sources?
They can extract copper while reducing the need for large-scale rock removal.
What is bioleaching?
A method of extracting metal from low-grade ores using bacteria.
How does bioleaching make metal available for recovery?
Bacteria act on the ore, producing a leachate containing metal compounds. The metal can then be recovered from the solution.
Which conventional ore-processing steps does bioleaching avoid?
Removing huge amounts of rock and mechanically concentrating the ore.
What are the two main methods for recovering copper from solutions of its compounds?
Displacement using scrap iron and electrolysis.
How does scrap iron recover copper from a solution of copper compounds?
Iron is more reactive than copper, so it displaces copper from the solution, depositing copper metal.
How does electrolysis recover copper from a solution of copper compounds?
An electric current causes copper ions to gain electrons and form copper metal.