II.2.2.1. Decantation
Decantation is the method of separating the components of a heterogeneous solid-liquid or liquid-liquid mixture based on the large difference between their densities.
a) For solid-liquid components with much different densities, decantation with the aid of a wand is used (when the solid sits at the bottom of the liquid).
b) For liquid-liquid components with different densities and which are immiscible (they do not dissolve in each other), decantation with a separatory funnel is used.
Required Materials:
2 Berzelius glasses, wand, separating funnel (with tap), water, oil, sand, stand.
Experiment description:
- Using the wand, pour the liquid part of the mixture into the separatory funnel. The sand remains in the glass.
- Open the valve of the separatory funnel so that the water with the higher density will flow into the glass, and the oil with the lower density will remain in the separatory funnel.
- What do you notice?
By decantation, I separated the sand from the water with oil, with a stick, then I separated the water from the oil with a funnel with a tap.
Experiment conclusion:
By decantation, we separated the components of a heterogeneous solid-liquid or liquid-liquid mixture, based on the difference between their densities.
1. Obtaining potable water in large decantation basins, where solid impurities settle to the bottom of the decantation basins and the water is clarified and purified (cleaned) mechanically.
2. Separation of the 2 components of slaked lime: lime water and milk of lime.
