A Novel Ether Amine Reagent for the Low-Temperature Flotation Separation of KCl

The sylvite flotation production in western China still faces the issue of deteriorating efficiency in winter due to the low temperature. Based on the understanding of the molecular mechanism, an ether amine reagent was proposed for replacing the traditional composition of octadecylamine and 2-oil. The introduction of ether groups was determined to be effective for low temperature operation by decreasing the freezing point. The hydrogen bonds between ether groups and water molecules improved the foaming performance, which was verified by the froth experiments. Further molecular dynamics investigation showed that the ether diamine with a short carbon chain was more efficient for KCl separation, since it had two active groups and stronger penetration into the water for capturing the KCl particles. At a concentration as low as 2.5 × 10^–4 mol/L, the reagent achieved a KCl recovery of 93.66% at 0 °C, with a KCl grade of 80.48% in the flotation product.