Crystallization of potassium sulfate by cooling and salting-out using 1-propanol in a calorimetric reactor

TLDR: In this article, a study was made on a isothermal process for the crystallization of potassium sulfate as an alternative to the cooling process, which employed addition of 1-propanol to aqueous salt solutions to achieve the salting-out of the K 2 SO 4.

Abstract: A study was made on a isothermal process for the crystallization of potassium sulfate as an alternative to the cooling process. The process employs addition of 1-propanol to aqueous salt solutions to achieve the salting-out of the K 2 SO 4 . This work was carried out using an automated Mettler Toledo model RC1 reactor-crystallizer with 800 ml capacity, and controlled isothermally at 25°C to test the crystallization of K 2 SO 4 by addition of the alcohol, and from 50 to 10°C for the cooling crystallization. In both systems, the line of nucleation points was shown to be approximately parallel to the saturation curve, with an average width of 13°C or 3 % mass for crystallization by cooling, compared with 0.2 to 1 % by salting-out. In experiments on crystallization by cooling, the K 2 SO 4 crystals were 0.27 mm in mean size, showed 7 % agglomeration, and contained 8.5 % moisture. Crystals obtained by salting-out had a mean size of 0.79 mm, 28 % agglomeration, and 9-10 % moisture content. A crystal shape factor of approximately of 0.7 was obtained in both systems, apart from the agglomeration.