The flotation agent is an important collector in the production of potassium chloride and is brought into the crystallization stage with the reflux of the mother liquor. Octadecylamine Hydrochloride (ODA), 1-Dodecylamine Hydrochloride (DAH) and Sodium 1-dodecanesulfonate (SDS) were selected to study their effect on the nucleation of potassium chloride. Focused Beam Reflectance Measurement was used to collect the nucleation-induced periods of KCl in the presence of flotation agents at different supersaturations. Then, empirical equations, classical nucleation theory and growth mechanism equations were employed for data analysis. It was found that the presence of flotation agents increased the nucleation sequence m, and m(ODA) > m(SDS) > m(DAH) > m(H2O). In addition, the interfacial energy data obtained using classical nucleation theory suggest that the flotation agents used in our paper promoted the homogeneous nucleation of KCl (reduced from 5.3934 mJ·m-2 to 5.1434 mJ·m-2) and inhibited the heterogeneous nucleation of KCl (increased from 2.8054 mJ·m-2 to 3.6004 mJ·m-2). This investigation also revealed that the growth of potassium chloride was consistent with the 2D nucleation-mediated growth mechanism, and the addition of flotation agent did not change the growth mechanism of potassium chloride. Finally, the particle size distribution results were exactly consistent with the order of nucleation order m. The study of nucleation kinetics and growth mechanisms of different flotation agents on potassium chloride can provide guidance for optimizing the production process of potassium chloride and developing new flotation agents.
Keywords: crystallization; flotation agent; growth mechanism; nucleation kinetics; potassium chloride.