Collect. Czech. Chem. Commun. 1986, 51, 2481-2488

Mathematical modelling of salt purification by recrystallization. Countercurrent arrangement

Benitto Mayrhofera, Jana Mayrhoferováb, Lubomír Neužila and Jaroslav Nývltc

a Department of Chemical Engineering, Prague Institute of Chemical Technology, 166 28 Prague 6
b Institute of Physics, Czechoslovak Academy of Sciences, 180 40 Prague 8
c Institute of Inorganic Chemistry, Czechoslovak Academy of Sciences, 160 00 Prague 6


The paper presents a simple model of recrystallization with countercurrent flows of the solution and the crystals being purified. The model assumes steady-state operating conditions, an equilibrium between the outlet streams of each stage, and the same equilibrium temperature and distribution coefficient for all stages. With these assumptions, the model provides the basis for analyzing the variation in the degree of purity as a function of the number of recrystallization stages. The analysis is facilitated by the use of a diagram constructed for the limiting case of perfect removal of the mother liquor from the crystals between the stages.