Continuous Crystallization 

There are two kinds of continuous crystallization, vacuum evaporating crystallization and vacuum cooling crystallization, determined by the solubility curve.

If the solubility curve is smooth, means solubility changes little along with temperature rising, we select vacuum evaporating crystallization, eg. Sodium chloride, sodium sulfate, ammonium sulfate, calcium chloride and etc;

If the solubility curve is steep, we select vacuum cooling crystallization, eg. Potassium chloride, potassium nitrate, copper sulfate, magnesium sulfate and etc.

Process Principle

        Evaporating crystallizer is getting part of solvent evaporated and making the solution oversaturated, thus the crystals would be separated out.

        There are various types of evaporating crystallizers, and according to the flow type,  it could be divided into 2 types: mother liquor circulating type and crystal slurry (mother liquor+ crystals) circulating type. Mother liquor circulating type is able to get good quality crystals during evaporation, as the crystals is separated from the mother liquor and grows bigger at the bottom of the crystallizer, is generally adopted in case good quality crystals was requred. And crystal slurry circulating type is more simple in structure and lower in construction cost, is widely adopted in case there was solids produced during evaporation and no requirements on crystal size. 

Application Scope

        Evaporating crystallizer has been widely adopted in petrochemical industry, chlroine alkali chemical industry, fine chemical and etc, for wastewater treatment and production, and has successful application on sodium chloride, barium chloride, sodium sulfate, sodium sulfite, ammonium chloride, magnesium sulfate, magnesium nitrate, calcium chloride and etc.

System Configuration

Triple-effect evaporating crystallizer consists of Effect I/II/III heating chambers, Effect I/II/III separating chamber (crystallizer), forced circulating pumps, material delivery pumps, vacuum pump, operation platsform and electrical control system. 

The effect number of system could be designed accordingly based on treatment capacity, evaporating capacity, energy supply cost at site and etc.