Crystallization of Salt Solutions on Surface of Droplet and Layer

Resumo

The evaporation and crystallization of a droplet and a thin layer of aqueous solutions of LiBr and LiCl salts on a heated wall with a temperature T_w = 86°C were studied experimentally. Crystallization curves were obtained for a wide range of initial salt concentrations. For the first time it was shown that for different C₀₁ values the crystallization rates J_cr were different; the J_cr curve was nonlinear. With C₀₁ decreasing, the supersaturation at the onset of crystallization increased, because of different induction times with respect to the generation of the first active crystallization center. It is known for relatively large crystals that heat transfer influences the rate of crystallization. Processing of the experimental data with due account of the basic thermophysical parameters shows that supersaturation also affects the crystal growth. The crystallization rate in a thin layer is significantly higher than in a droplet. It was found that description of crystallization in a droplet should take into account strong anisotropy of the crystallization.