Is washing necessary after crystallization?
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Is washing necessary after crystallization? How exactly should the washing be carried out? Should it be done by slurry washing or by submerging the material for washing? Also, do impurities remain when the crystals grow larger?
It is determined based on the requirements for product quality and the composition of the original liquid. A small amount of crystals can also be used for experiments; after washing and recrystallization, tests can be conducted for comparison. Manufacturers decide which specifications of products to offer based on customer demands and pricing considerations
Currently, there is an impurity residue remaining after two crystallizations, at 20 ppm; it’s not clear whether this arises from the heating and dissolution during recrystallization or from the fact that washing was not carried out
How should it be washed? Spray washing or slurry washing?
If high purity is required, pulping and washing are recommended, at the cost of yield loss； If the requirement for impurity content is not high, spray washing can be used. However, the aforementioned premise suggests that experimental data should be used as evidence; otherwise, it is all just theoretical talk.