Question
Describe the principle of froth floatations process. What is the role of stabilizer and of a depressant? Give one example of each.
Solution
Froth floatation process: This process is based on the fact that the sulphide ore particles are only moistened with oil, whereas oxide and gangue particles are moistened by water. For this, the powdered ore is mixed with water and a little pine oil and whole mixture is then stirred vigorously through rotating paddle by blowing compressed air. The oil forms a foam or froth with air. The ore particles stick to the froth and rises to the surface, while gangue are left in water. The froth is skimmed off, collected and allowed to subside to get concentrated ore. This is especially suitable for sulphide ores.
Fig. Froth floatation process.
(a) Role of stabilizer: Stabilizers are used to stabilize the froth. Examples: Cresols and aniline.
(b) Role of depressant: Depressants are used to prevent certain type of particles from forming the froth with bubbles.
Examples: NaCN can be used as a depressant in the separation of ZnS and PbS ore.
Fig. Froth floatation process.
(a) Role of stabilizer: Stabilizers are used to stabilize the froth. Examples: Cresols and aniline.
(b) Role of depressant: Depressants are used to prevent certain type of particles from forming the froth with bubbles.
Examples: NaCN can be used as a depressant in the separation of ZnS and PbS ore.
