Mother liquor

It is encountered in chemical processes including sugar refining.

[1] In crystallization, a solid (usually impure) is dissolved in a solvent at high temperature, taking advantage of the fact that most solids are more soluble at higher temperatures.

[2] An alternative to second cropping is continuous recycle of a portion of the mother liquors from one batch into in subsequent batches in which an increased product yield is expected, and also leads to an accumulation of impurities.

It can be shown that the impurity profile of the mother liquors, at moderate recycle levels (i.e. when x>1), quickly reaches a steady state according to (1 − xn +1)/(1 − x), where n is the number of times the process is operated and x is the fraction of mother liquors recycled (Fig.

[3] The aforementioned approach is idealised and assumes that the build up of impurities in the mother liquor does not exceed the impurity/impurities solubility.