How is glycerol separated from spent-lye in the soap industry?

Which technique is used for the separation of a compound present in an aqueous solution?

Chromatography is a valuable method for the separation,isolation,purification,and identification of the constituents of a mixture. It is based on the general principle of:

On heating,some solid substances change from solid to vapour state without passing through liquid state. The technique used for the purification of such solid substances based on the above principle is known as

Give the answer of the following questions in short:
$(i)$ When is simple distillation used?
$(ii)$ When is fractional distillation used?
$(iii)$ Which liquid is obtained first in fractional distillation?
$(iv)$ Which liquid is cooled first in fractional distillation?
$(v)$ What happens in the fractional column?

Glycerol boils at $290\,^oC$ with slight decomposition. Impure glycerin can be purified by: