Influence of malic acid, which acts as an impurity, on the crystallization kinetics of zinc lactate has been investigated in this work. Crystallization of zinc lactate with a linear cooling profile was carried out in a batch crystallizer and a population balance model was used to estimate the crystallization kinetics for each studied system by using the nonlinear optimization method. The predicted results related to the concentration profile of zinc lactate are in good agreement with the experimental data. The influence of malic acid on the crystallization of zinc lactate is discussed herein. (C) 2017 Elsevier B.V. All rights reserved.