Biological methods of metal extraction - Higher
There are some alternative methods to extract Shiny element that is a good conductor of electricity and heat, and which forms basic oxides. that use living Living entity, eg animals, plants or microorganisms.. These have advantages and disadvantages compared to the usual The process of obtaining a metal from a mineral, usually by reduction or electrolysis. methods.
Phytoextraction
Plants absorb metal Electrically charged particle, formed when an atom or molecule gains or loses electrons. through their roots. Using plants to absorb metal compounds from the ground through their roots. The plants are then burned to produce an ash containing a high concentration of the metal compounds. is not yet used to extract metals for commercial purposes but it does help remove toxic metals from contaminated soil (for example around old mines).
In the future, when supplies of higher grade A rock containing enough quantities of a mineral for extraction to be possible. have run out, metals could be extracted by burning the plants to produce ash. The ash would contain a higher The concentration of a solution tells us how much of a substance is dissolved in water. The higher the concentration, the more particles of the substance are present. of the metal than the soil.
Question
Explain why phytoextraction is not currently used by mining companies for extracting metals.
Phytoextraction only produces a small quantity of metal and is very slow. Mining companies can make more money from other methods of extraction.
Bioleaching
Certain Single-celled microorganisms, some of which are pathogenic in humans, animals and plants. Singular is bacterium. found in the spoil heaps of old mines, can Chemical substances are oxidised by the addition of oxygen, removal of hydrogen or the removal of electrons. metal sulfide ores. These bacteria work best in acidic conditions so the spoil heaps are sprayed with acid.
Copper(II) sulfate solution is produced and is carefully collected.
This solution is called a leachate and the process is called Using bacteria to extract metals from their ores..
Copper may be extracted from the copper(II) sulfate by a A reaction that occurs when a more reactive element replaces a less reactive element in a compound. with iron or The decomposition (breakdown) of a compound using an electric current..
A disadvantage of bioleaching is that it introduces Poisonous. substances, including sulfuric acid, into the environment