SOURCE: FuseSchool, Minerals and ores - The extraction of minerals, available on YouTube (2013), Duration: 5:59 mins, URL: https://youtu.be/fZM_NF93gWo
See the other videos available on YouTube by FuseSchool:
Chemistry: Extraction using heat
Chemistry: Uses of Metals
Chemistry: Transition Metals
Chemistry: Alkali Metals (Group 2.)
Metal extraction
Key Concepts
- The Earth's crust contains many different rocks.
- Rocks are mixtures of minerals.
- A mineral can be either an element or a compound.
- A metal ore is a mixture of minerals containing the metal, and other materials in the rock, from which it is economically viable to extract the metal.
- A high grade ore produces a high yield of metal. A low grade order produces a low yield of metal.
- Most metal ores occur as a metal oxide, a metal sulfide or a metal carbonate.
- The more active (or reactive) a metal is, the more stable the compound it forms.
most reactive elements → → → → → → → → → → → → → → least reactive elements potassium > calcium > sodium > magnesium > aluminium > zinc > iron > nickel > tin > lead > copper > silver > platinum > gold most stable compounds → → → → → → → → → → → → → → least stable compounds - The more stable the compound is, the more energy is required to separate the metal in the metal ore.
most reactive elements → → → → → → → → → → → → → → least reactive elements most stable compounds → → → → → → → → → → → → → → least stable compounds potassium > calcium > sodium > magnesium > aluminium > zinc > iron > nickel > tin > lead > copper > silver > platinum > gold more energy to extract metal from ore → → → → → → → → → → → → → → less energy to extract metal from ore - The least active metals are found in nature as elements (native metals).
When the least active metals are found as compounds, they can be extracted from their ores by heating in air (roasting in air).
Moderately active metals can be extracted by heating their ores with a suitable reducing agent (thermal reduction).
Highly active metals can be extracted from their ores using electricity (electrolysis).
| most reactive elements | → → → → → → → → → → → → → → | least reactive elements | ||||||||||||||||||||||||
| most stable compounds | → → → → → → → → → → → → → → | least stable compounds | ||||||||||||||||||||||||
| more energy to extract metal from ore | → → → → → → → → → → → → → → | less energy to extract metal from ore | ||||||||||||||||||||||||
| potassium | > | calcium | > | sodium | > | magnesium | > | aluminium | > | zinc | > | iron | > | nickel | > | tin | > | lead | > | copper | > | silver | > | platinum | > | gold |
| electrolytic extraction | thermal reduction | native metals | ||||||||||||||||||||||||
| roasting ore in air | ||||||||||||||||||||||||||
- Metals that require the least amount of energy to extract, those that occur in nature as the element (native metals) were the first metals used by humans in ancient times.
Metals that require a moderate amount of energy to extract, that is, those that can be extracted by heating their ores, were the next to be used widely.
Highly reactive metals requiring huge amounts of energy to extract have only been used in more modern times.
| most reactive elements | → → → → → → → → → → → → → → | least reactive elements | ||||||||||||||||||||||||
| most stable compounds | → → → → → → → → → → → → → → | least stable compounds | ||||||||||||||||||||||||
| more energy to extract metal from ore | → → → → → → → → → → → → → → | less energy to extract metal from ore | ||||||||||||||||||||||||
| electrolytic extraction | thermal reduction | native metals | ||||||||||||||||||||||||
| roasting ore in air | ||||||||||||||||||||||||||
| potassium | > | calcium | > | sodium | > | magnesium | > | aluminium | > | > | iron | > | > | > | tin | > | > | copper | > | > | gold | |||||
| Elements isolated in the 19th Century | ← | Iron Age (1000 B.C. - 1 C.E.) |
← | Bronze Age - heating copper and tin ores (2300-1000 B.C.) |
← | Copper Age (3200-2300 B.C.) |
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SOURCE: AUS-e-TUTE, 22 June 2019, Metal Extraction Concepts Chemistry Tutorial, https://www.ausetute.com.au/metalextract.html
Mining: Exploration and Extraction
Extraction: Smelting Oxides
- Smelting Oxides: Carbon Reduction MethodVery active metals (Group 1, Group 2 and aluminium) require electrolysis to extract the metal while very inactive metals like gold and silver can occur in nature as the element so require no energy to extract the metal. Includes an example of extracting Lead from Cerussite.
Extraction: Smelting Sulfides
- Copper SulfidesAlthough copper can be found in nature as the uncombined element, it is often found in nature as compounds.
Electrolytic Extraction
- Copper: ElectrowinningElectrowinning refers to the process of using electrolysis to extract a metallic element from the compounds in its ore.
- Aluminium Production : Hall-Heroult CellPure alumina, Al2O3, is extracted from the mineral bauxite using hot concentrated sodium hydroxide solution in the Bayer Process.
- Sodium Production : Downs CellSodium metal can be extracted electrolytically from molten (fused) sodium chloride using a Downs Cell.
Refining Metals
- ElectrorefiningElectrorefining refers to the process of using electrolysis to increase the purity of a metal extracted from its ore (compound or mixture of compounds from which a metal can be extracted commercially).
Alloys
- Binary AlloysAtoms in a pure metal solid are arranged in a regular crystal lattice.
An alloy is a mixture of a metal with one or more other elements.
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