Today, most sugar factories operate with approximately linear cooling curves. The cooling rate is about 1 K/h. Such a slow cooling rate leads to crystallization periods lasting more than 40 h. Because of the dependence of the crystallization rate on the purity, temperature and superaturation, the cooling crystallization of after-product magma can become shorter only through regressive cooling. The cooling rate can be very high at temperatures between 80 and 60 ºC (> 10 K/h). Below 55 ºC the cooling rate must be less than 1 K/h.

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