Colloidal properties of octadecylamine hydrochloride and the wettability of KCl crystal surface in different saturated salt solutions

Froth flotation is still an efficient technique for KCl production from low grade and complex systems containing various ions. In this work, the colloidal properties of one common collector, octadecylamine hydrochloride (ODA), in different saturated salt solutions at different temperature are investigated systematically. The results show that the turbidity of salt solutions increased substantially with the concentration of ODA increasing and the ODA colloidal particles aggregate seriously in the presence of MgCl2. Compared with ODA aqueous solutions, the surface activity and the critical aggregate concentration (CAC) of ODA became lower in saturated salt solutions. With the increase of MgCl2 percentage, the CAC values of ODA solution decreased gradually, while the CAC value of KCl-MgCl2 saturated solution was the lowest. The temperature has a great influence on the turbidity and surface activity of ODA aqueous solution, however, the effect is slight in saturated salt solutions. In addition, the salt solutions with MgCl2 result in lower contact angle on KCl crystal surface indicating that the adsorption of ODA molecules can be inhibited in the salt solutions with MgCl2. (C) 2016 Elsevier B.V. All rights reserved.