A mixture of powdered salt and sugar can be separated by the process of winnowing.

Explanation

Evaporation (the process of converting a liquid into a vapour) can separate the sugar and salt solution, and if the water is entirely evaporated. We will receive separated sugar from the combination while if we dissolve the solution in alcohol, we will get salt while sugar will be dissolved in alcohol. We can't use the winnowing process to separate the powdered salt and sugar since it separates the heavier and lighter components of a combination while it forms a homogenous solution ( composition is uniform throughout the mixture).

As a result, the assertion is incorrect.

Farmers employ this procedure to remove lighter husk particles from heavier grain seeds. It is an ancient agricultural technology for separating grains that was invented by ancient societies.