Yes, it is possible to separate calcium (Ca) and barium (Ba) by selective precipitation of their sulfates. The principle behind this separation method is based on the differences in the solubility of calcium sulfate (CaSO4) and barium sulfate (BaSO4) in water.
Calcium sulfate (CaSO4), commonly known as gypsum, has a higher solubility in water compared to barium sulfate (BaSO4). This difference in solubility allows for selective precipitation of the sulfates by adjusting the conditions to favor the formation of one sulfate over the other.
Here's an explanation of the separation process:
- Formation of Calcium Sulfate Precipitate: First, the mixture containing both calcium and barium ions in solution is treated with a source of sulfate ions, such as sulfuric acid (H2SO4) or sodium sulfate (Na2SO4). The addition of sulfate ions leads to the formation of insoluble calcium sulfate (CaSO4) precipitate due to its limited solubility in water:
Ca2+ (aq) + SO4^2- (aq) → CaSO4 (s)
The formed calcium sulfate precipitate can be separated from the solution by filtration or centrifugation.
Barium Sulfate Remains in Solution: Barium sulfate (BaSO4), on the other hand, remains in the solution as it is highly insoluble in water. Since barium sulfate does not precipitate under these conditions, it can be separated from the calcium sulfate precipitate.
Recovery of Barium Sulfate: To recover the barium sulfate, the solution can be further processed by removing any remaining solid impurities, followed by evaporating the water to concentrate the barium sulfate. Once the concentration is sufficient, the barium sulfate can be collected by filtration or centrifugation.
In this way, selective precipitation of calcium sulfate allows for the separation of calcium and barium ions present in the initial solution. It is important to note that precise control of experimental conditions, such as pH, temperature, and concentration, is necessary to achieve effective separation and obtain pure precipitates.