Recovery of sulphate from spinning baths

Sodium sulphate can be eiystallised as Glauber s salt. Therefore, the spinning bath solution is led to multiple stage thiekeners to raise the concentration of Na2S04. There, water is vaporised to saturation point and erystallisation takes place. 

By recrystallising in melting pots and evaporation of the crystal water in crystallisers, a pulp of sodium sulphate is obtained. 

This pulp is centrifuged and dried at 450 °C in a drying tower by direct heating with a natural gas burner. Another teehnique for drying is the usage of a tumble dryer and a subsequent separation in a cyclone. 

Generally applicable for sulphate reduction. If a further reduction of sulphate is necessary, the technique described in Section 12.7.7 can be applied. 

Example plants Lenzing and Glanzstofif, AT Reference literature 

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