Revision: Class 12 >> General Principles and Processes of Isolation of Elements NEET (UG) General Principles and Processes of Isolation of Elements

At some places, minerals contain a very high percentage of a particular metal, and the metal can be profitably extracted from it. These minerals are called ores.

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Ores are those minerals from which metals are extracted commercially at a comparatively lower cost and with minimum effort.

The elements or compounds, which occur naturally in the earth’s crust, are known as minerals.

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Minerals are the naturally occuring compounds of metals which are generally mixed with other substances such as soil, mud, sand, silica (Si02) limestone, rocks, etc. These earthly impurities are called gangue or matrix.

The minerals which contain high percentage of atom and from which a metal can be extracted conveniently and profitably are called ores, e.g. bauxite is an ore of aluminium.

The naturally occurring chemical substances in the earth’s crust, containing inorganic salts, solid silicons, matte, etc., obtainable by mining, are called minerals, e.g. bauxite and kaolinite.

The science and technology regarding the extraction of metals from ores and their purification for use is called metallurgy.

Ore: Those minerals from which a metal can be extracted profitably are called ores.

Charge: The mixture of materials fed into a furnace to extract a metal is called charge.

Mineral: The naturally occurring compounds of metals which are generally mixed with earthy such as soil, sand, limestone and rocks are known as minerals.

The product obtained by the combination of gangue with flux is called slag.

The substance added to get rid of gangue in the extraction of metal is called flux.

Roasting is the process of heating concentrated ore to a high temperature in the presence of air. The process is usually carried out for sulphide ores.

The impurities (sand, silt, soil, gravel, etc.) present in the ore are called gangue.

If an ore is a carbonate or a hydrated oxide, it is heated in the absence of air to a temperature that is high but insufficient to melt the ore. The process is known as calcination.

Minerals from which metals can be extracted profitably are known as ores.

If minerals contain a very high percentage of a particular metal and the metal can be profitably extracted from it. These minerals are called ores.

Most of the elements occur in nature as in combined state as minerals. The chemical composition of minerals is fixed.

• Metals occur in either the free or combined state, depending on their reactivity.
• Metals are grouped as low, medium, or highly reactive, and each group has a different extraction method.
• Ores have impurities called gangue, which are removed before extraction.
• Low-reactive metals are extracted by heating alone; medium-reactive metals require roasting or calcination, followed by reduction.
• Highly reactive metals (such as Na, Mg, and Al) are extracted by electrolysis.
• Metals are purified by electrolytic refining, where pure metal deposits at the cathode and impurities form anode mud.

• Reactive metals occur in combined form (as oxides, sulphides, etc.), while unreactive metals like gold and silver occur in the free state.
• Minerals are natural metal compounds; those from which metals can be extracted economically are called ores, and impurities present in ores are called gangue.
• The complete process of extracting and purifying metals from ores is called metallurgy.