Cobalt extraction: when geology met biology
Image A: Element distribution map showing the tunnels that the microbes have created.
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It is often said that two heads are better than one. In this instance, the Museum’s ores research team hope that the expertise of two disciplines – geology and biology – will help develop a new, environmentally-friendly technique for the extraction and recovery of cobalt from its ore. How are they doing this? By using microbes!
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Cobalt – what’s the point?
As a ‘critical element’ cobalt is considered to be crucial for the development of technology in modern society.
It may surprise you, but cobalt has an abundance of uses. For example, it is used in turbine blades (e.g. jet engines); specialised magnets (e.g. Alnico) and is a vital ingredient in rechargeable batteries. Basically, cobalt is a big deal in your everyday life.
So, what’s the problem?
Problem one: around 55,000 tonnes of cobalt are produced globally each year but despite we Europeans consuming 30 per cent of cobalt’s global production, less than 0.1 per cent is produced within Europe (Herrington, 2013). This places Europe in a vulnerable position if anything affects cobalt’s supply chain.
Problem 2: Cobalt is nearly always produced as a by-product of mining for copper and nickel (the Bou-Azzer mine in Morocco being the exception). As a result, processing for cobalt is difficult and can involve using an undesirable cocktail of sulphuric acid, hydrogen sulphide, ammonia and hydrochloric acid (BGS, 2009). As delicious as that sounds, it’s probably best that we start looking into new extraction methods.
Welcome on stage: bio-leaching
Bio-leaching seeks to use microbes to recover metals from their ores – and that’s just the sort of leading-edge research our Museum scientists like to get involved in.
Munch, munch, munch…
As microbes are tiny, our scientists used a technique called ‘Energy Dispersive Spectroscopy’ (EDS) to visualise how effective the microbes were at bio-leaching. EDS bombards a sample with a focused beam of electrons. The X-ray spectrum produced reveals the sample’s chemical composition i.e. what elements are present. This information can then be used to make element distribution ‘maps’ – such as image A, which shows the tunnels that the microbes have created in cobalt-bearing pyrite (pink). The waste that the microbes produce (gypsum) is lime green. This image shows that the microbes are happily munching their way through the ore, liberating cobalt into solution. The liberated cobalt can then be reprecipitated as a useable compound.
We’re still a long way away from using bio-leaching as an alternative ore processing method, but our Museum scientists are well equipped for this adventure.
Visit window twenty to read more about cobalt in the ore collection.
References
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As a ‘critical element’ cobalt is considered to be crucial for the development of technology in modern society.
It may surprise you, but cobalt has an abundance of uses. For example, it is used in turbine blades (e.g. jet engines); specialised magnets (e.g. Alnico) and is a vital ingredient in rechargeable batteries. Basically, cobalt is a big deal in your everyday life.
So, what’s the problem?
Problem one: around 55,000 tonnes of cobalt are produced globally each year but despite we Europeans consuming 30 per cent of cobalt’s global production, less than 0.1 per cent is produced within Europe (Herrington, 2013). This places Europe in a vulnerable position if anything affects cobalt’s supply chain.
Problem 2: Cobalt is nearly always produced as a by-product of mining for copper and nickel (the Bou-Azzer mine in Morocco being the exception). As a result, processing for cobalt is difficult and can involve using an undesirable cocktail of sulphuric acid, hydrogen sulphide, ammonia and hydrochloric acid (BGS, 2009). As delicious as that sounds, it’s probably best that we start looking into new extraction methods.
Welcome on stage: bio-leaching
Bio-leaching seeks to use microbes to recover metals from their ores – and that’s just the sort of leading-edge research our Museum scientists like to get involved in.
Munch, munch, munch…
As microbes are tiny, our scientists used a technique called ‘Energy Dispersive Spectroscopy’ (EDS) to visualise how effective the microbes were at bio-leaching. EDS bombards a sample with a focused beam of electrons. The X-ray spectrum produced reveals the sample’s chemical composition i.e. what elements are present. This information can then be used to make element distribution ‘maps’ – such as image A, which shows the tunnels that the microbes have created in cobalt-bearing pyrite (pink). The waste that the microbes produce (gypsum) is lime green. This image shows that the microbes are happily munching their way through the ore, liberating cobalt into solution. The liberated cobalt can then be reprecipitated as a useable compound.
We’re still a long way away from using bio-leaching as an alternative ore processing method, but our Museum scientists are well equipped for this adventure.
Visit window twenty to read more about cobalt in the ore collection.
References
- Herrington, R., 2013. Road map to mineral supply, Nature Geoscience, 6, 892-894
- British Geological Survey. 2009. Commodity Profile: Cobalt. Mineral Profiles. p.1-19
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