What is the froth floatation method?

 The froth floatation method is based on the two opposite properties, hydrophilic and hydrophobic, of the particles. The particles of the metal sulphides, due to their hydrophobic property, get wetted mainly with oil, while due to the hydrophilic property the gangue particles get wetted with water. By applying these properties certain ores are also concentrated using the froth floatation method. In this method the finely ground ore is put into a big tank containing ample amount of water. Certain vegetable oil such as pine oil eucalyptus oil, is added in the water to form the froth. Pressurised air is blown through the water. There is an agitator rotating around its axis in the centre of the floatation tank. The agitator is used as per the requirement. Bubbles are formed due to the blown air. A foam is formed from oil, water and air bubbles together, due to the agitation, which rises to the surface of water and floats. That is why this method is called the froth floatation process. Particles of certain sulphide ore float with the foam on water as they preferentially get wetted by the oil. For example, this method is used for the concentration of zinc blend (ZnS) and copper pyrite (CuFeS₂).