Please give the physical methods of ore separation?

Physical Methods of Ore Separation

(a)        Gravity separation: The separation is based on the difference in the specific gravities of the gangue and the ore particles. The powdered ore is agitated with water or washed with a running stream of water of sand. The heavy ore particles settle down while the lighter particles of sand, clay etc are washed away,

(b)       Electromagnetic Separation: When one component .either the ore or impurity is magnetic in nature, this method can be used for separation. A magnetic separator consisting of a belt moving on two rollers is used. One of which is a strong magnet. The powdered ore is dropped on the belt from one end
(non - magnetic) and at the other end (magnetic), the magnetic particles are attracted and fall nearer the roller while non - magnetic particles fall away from the roller.

(c)        Froth Floatation Process: This method is used for the concentration of the sulphide ores. The method is based on the preferential wetting properties with the frothing agent and water. The powdered ore is added to water containing pine oil (frothing agent) and sodium, ethyl xanthate (collecting agent). A vigorous stream of air is now passed through, which thoroughly agitates the mixture and disposes the oil into colloid sized panicles. As a result of this, the sulphide particles of the ore stick to the o.il droplets and rise to the surface in the form of froth supported by air bubbles. Water wets the gangue particles which sink to the bottom.