Q. Beneficiation of Ores?
Most of the ores available in nature contain large amounts of impurities, i.e. gangue. Direct extraction of metals from the ores by metallurgical processes is uneconomical and technically difficult. Therefore, the ores should be processed first by some cheaper methods which remove the gangue partly or wholly. The pre treatment of ores by cheaper methods, based mainly on physical properties and without bringing out any major chemical change in the ore, is known as beneficiation or concentration of the ore or ore dressing. Beneficiation of ores results in saving the cost of the transportation, fuel, fluxing agents and increased production.
The methods used for beneficiation of ores are based on differences in such properties of ores and gangue as colour, lustre, size, density, and wet ability by water or oil. The simplest method of ore beneficiation consists of hand picking of ore particles, which is based on difference in colour, lustre or shape and size of ore particles and gangue. Hand picking can be adopted in areas where labour is cheap. However, this method is outdated and is practised only in very specific cases when other methods are not possible, e.g., hand picking of diamonds from gravel and clay.