Revision: General Principles and Processes of Isolation of Elements Chemistry HSC Science (General) 12th Standard Board Exam Maharashtra State Board

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

OR

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.

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.

OR

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

• 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.