Metals and Metallurgy Summary
1. Metals are hard substances. They are ductile, malleable, sonorous and good conductors of heat and electricity. Metals are electropositive in nature.
2. Non-metals are brittle and electronegative in nature.
3. An ore is a rock mineral from which a metal can be obtained profitably.
4. Metallurgy is the science of extracting useful metals from their ores, refining them and preparing them for use.
5. Concentration is the removal of impurities from the ore.
6. Roasting means to convert the concentrated ore into its oxide by heating in a current of air so as to remove the moisture and volatile impurities.
7. Calcinations is heating of the ore in the absence of air.
8. Smelting is a reduction process in which the metal oxide is finally changed into metal.
9. Slag is a glassy waste which is actually calcium silicate.
10. Gangue is the impurity that settles down in the froth flotation process.
11. Alloys are homogeneous mixture of two or more metals or a metal and non-metal combined in a definite proportion.