Minerals and Ores: Natural materials
The Earth’s is the main source of minerals and ores. Most of the elements do not found Free State because of their reactive tendencies. Potassium, sodium, calcium, magnesium, aluminium, zinc, iron, lead etc are the metals found in combined state. Minerals are the natural materials in which the metals and their compounds are found in earth.
These ores contain good percentage of metal. Hence, we can say all minerals are not ores but all ores are the minerals.
Abundances of the metals in the Earth's Crust
Aluminium is the most abundant metallic element but iron has played a much greater role in human history and is an essential part of everybody, literally! Iron is one of 94 naturally occurring elements. It is a metallic material with a silver-grey colour and metallic lustre. Its Atomic Number is 26 and its symbol is Fe. Iron is found in all parts of the planet. It comprises about 5% of the Earth’s crust but is thought to make up perhaps as much as 80% of the planets core. There are four naturally occurring stable isotopes of iron with at least four unstable isotopes also known to exist.
Characteristics of a mineral
- It must occur naturally.
- It must be inorganic
- It must be a solid
- It must possess an orderly internal structure, that is, its atoms must be arranged in a definite pattern.
- It must have a definite chemical composition that may vary within specified limits."
Ores
Ores are those minerals from which metal are extracted conveniently and profitably.
Types of Ores
There are mainly four types of ores such as Oxides; Carbonate Ores; Sulphide; Halides Ores.
Types of Ores |
Name of Ores |
|
Oxides |
Aluminium |
Bauxite (Al2O3.2H2O) |
Copper |
Cuprites (Cu2O) |
|
Iron |
Hematite (Fe2O3) |
|
Tin |
Casseterite (SnO2) |
|
Carbonate Ores |
Calcium |
Limestone (CACO3) |
Zinc |
Calamine (ZnCO3) |
|
Iron |
Siderite (FeCO3) |
|
Sulphide |
Zinc |
Zinc blende (ZnS) |
Copper |
Copper glance (Cu2S) |
|
Lead |
Galena (PbS) |
|
Mercury |
Cinnabar (HgS) |
|
Halide Ores |
Sodium |
Rock Salt (NaCl) |
Fluoride |
Fluorspar (CaF2) |
|
Silver |
Horn silver (AgCl) |
Ores and Methods of Extraction of some Common Metals
Metals |
Occurrence |
Extraction method |
1. Lithium |
Spodumeme LiAl(SiO3)2 Lipidolite |
Electrolysis of fused LiCl/ KCl |
2. Sodium |
Rock salt (NaCl) |
Electrolysis of fused NaCl / CaCl2 |
3. Magnesium |
Carnallite (KCl.MgCl2.6H2O) Magnesium (MgCO3) |
Electrolysis of fused MgO or MgCl2 / KCl carbon reduction of MgO |
4. Calcium |
Limestone (CACO3) Dolomite (MgCO3.CaCO3) Gypsum (CaSO4) |
Electrolysis of fused CaCl2/ CaF2 |
5. Copper |
Cuprites (Cu2O) Copper glance (Cu2S)
|
Roasting of sulphide partially and reduction 1Cu2O + Cu2S+ 6Cu+SO2 |
6. Aluminum |
Bauxite (Al2O3.2H2O) Cryolite (Na2AlF6) |
Electrolysis of Al2O3 dissolved in molten Cryolite or in Na2AlF6 |
7. Zinc |
Zinc blende (ZnS) Zencite (ZnO) Calamine (ZnCO3) |
Roasting and then reduction with C
|
8. Lead |
Galena (PbS) |
Roasting of sulphide ore then reduction of the oxide
|
9. Iron |
Hematite (Fe2O3) Magnetite (Fe2O4) Siderite (FeCO3) Iron pyrite (FeS2) Limonite (Fe2O3.3H2O) |
Reduction with the help of CO and Coke in blast furnace, chemical reduction with CO, Calcination followed by reduction with CO. Roasting followed by reduction with CO. |