Crystallization of zinc lactate in presence of malic acid

• Published in: Journal of crystal growth Vol. 312; no. 19; pp. 2747 - 2755
• Main Authors: Zhang, Xiang-Yang, Févotte, Gilles, Zhong, Liang, Qian, Gang, Zhou, Xing-Gui, Yuan, Wei-Kang
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15-09-2010; Elsevier
• Subjects: A1. Impurities; A1. Industrial crystallization; A1. Purification; B1. Malic acid; B1. Zinc lactate; Chemical and Process Engineering; Condensed matter: structure, mechanical and thermal properties; Crystallization; Crystals; Engineering Sciences; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; Gibbs equations; Impurities; Malic acid; Mathematical models; Nucleation; Physics; Solid-solid transitions; Solubility, segregation, and mixing; phase separation; Specific phase transitions; Supersaturation; Zinc lactate; B1. Malic acid; B1. Zinc lactate; A1. Impurities; A1. Industrial crystallization; A1. Purification; Particle size; Purification; Cooling rate; Metastable states; Crystallization; Solubility; Crystal seeds; Steady state; Heat treatments; Zinc; Malic acid; Impurities; Zinc lactate; Industrial crystallization
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2010.06.005

The influence of malic acid, which acts as an impurity on the cooling crystallization of zinc lactate is investigated in this paper by monitoring the relative supersaturation and the number of crystals during crystallization. The presence of malic acid increases the solution solubility and makes the metastable zone wider; it also changes the habit of the crystal. The purity of the final products is shown to be influenced by the amount and size of seed crystals, cooling rate, seeding temperature and final temperature, but appears to depend mainly on the particle size and level of supersaturation. Residual supersaturation thresholds are observed that depend on the final temperature. A model is proposed to predict the steady-state supersaturation value from the final temperature at a given impurity concentration. This model is based on Kubota and Gibbs equations.