Resource 6: Elements found in Africa
Background information / subject knowledge for teacher
Elements found in Africa and their uses
(Abbreviations: DRC = Democratic Republic of Congo, RSA = Republic of South Africa)
|Element||Found where (figures in brackets represent the approximate proportion of current world reserves)||Uses|
|Jewellery, cell phones, calculators, personal digital assistants, global positioning system units (GPS) and satellites (as a lubricant – in the zero gravity of space oil-based lubricants would volatilise) and other small electronic devices. Most large electronic appliances such as television sets also contain gold. The electronic applications utilise gold’s excellent electrical conductivity. Gold is also widely used for dental fillings because of its lack of reactivity.|
|Aluminium||Guinea (as bauxite, 30%)||Aluminium is by far the most widely used non-ferrous metal: its uses are legion; it has excellent electrical and heat conductivity and strength to density ratio. This last property accounts for its many transport uses, including aerospace. It is also used in packaging; construction, e.g. window frames, roof and wall cladding; electrical transmission cables, cooking pans and utensils, drink cans and ships’ masts.|
|Manganese||RSA (77%)||Manganese is an essential component in many steels; including high tensile steel, which contains between 8 and 15% Mn. Manganese is also used to improve the corrosion resistance of the aluminium used to manufacture food cans.|
|Vanadium||RSA||Like manganese, vanadium is used mainly in alloy steels to improve their strength, such as high speed tool steel. Vanadium pentoxide is also an important catalyst in the industrial production of sulfuric acid by the contact process.|
|Diamond has a high resistance to corrosion and is the hardest naturally occurring substance known. Artificially produced industrial diamonds are used for applications that make use of the properties mentioned above; e.g. cutting and drilling tools in mechanical engineering, geological ore processing and crude oil exploration|
Zambia (3. 5%)
|Copper has excellent heat and electrical conductivity that explains its major applications in heating systems for pipework and as the conducting medium in electrical wiring. Copper is also alloyed with nickel to produce hardwearing and corrosion resistant coinage. This property also explains its use in roofing and construction; e.g. the Statue of Liberty is clad in copper about 12 mm thick.|
|Cobalt||Zambia||Permanent magnets. Cobalt is also used in alloy steels to produce so-called ‘super alloys’ that have extremely high strength even at temperatures approaching their melting points. This means that they are widely used in jet engines. The isotope cobalt-60 is a gamma-ray emitter and used in radiotherapy and medical equipment and food sterilisation.|
Zimbabwe (3. 4%)
|Chromium has extremely high corrosion resistance that explains its use in steel alloying. 14% chromium or above produces stainless steel. Chromium oxide is used in the manufacture of magnetic tape used in cassettes. In the past, chromium compounds were also widely used to make paints and pigments, such as chrome yellow, but are less so nowadays due to concerns about their long-term environmental effects.|
|Platinum group metals (PGMs) which include Platinum, Osmium, Iridium, Palladium, Rhodium and Ruthenium||RSA (58%)||The PGMs are all extremely resistant to corrosion. This and their bright, attractive lustre, explains their use in the manufacture of jewellery. They all have several stable oxidation states which makes them ideal for use as catalysts in many industrial processes. They are used in the manufacture of motor vehicle catalytic convertors.|
|Most uranium is used in the manufacture of nuclear weapon systems and nuclear reactors. However, relatively tiny amounts are also used in medical imaging and smoke detectors. Uranium accounts for about 5% of the world’s non-renewable energy sources.|
Questions that your students could consider
- Choose an element (e.g. aluminium, copper) and find out where it is mined and how it is extracted. What are the challenges and opportunities for local people?
- Choose an element that is mined in their country e.g. copper and find out about the history surrounding the industry. What are the lessons for the future?
- Open-cast mining – what is it and what are the environmental implications?
- Gold – what effect does the discovery of a valuable mineral have on a local area? How can the beneficial effects be maximised?
- Galamsey mining has become increasingly common amongst the youth in Ghana and other African countries. What are the dangers and environmental effects of this illegal activity?