Enhancing KCl Grade via Decomposition Solution Regulation in Cold Decomposition-Direct Flotation of Carnallite

The "cold decomposition-direct flotation" method is presently the predominant technique for KCl production from carnallite ore. However, this process has been hindered by the interactions between NaCl and KCl, resulting in suboptimal product purity and the potassium recovery rate. This study investigated the influence of the decomposition solution's composition on the concentrate grade of KCl. Initially, flotation tests with NaCl and KCl mixtures revealed that fine and newly formed NaCl adversely affected concentrate grade of KCl. Subsequently, we investigated the effects of NaCl, KCl, and MgCl 2 solutions as decomposition solution on the grade of KCl flotation concentrates. The results showed that higher MgCl 2 concentrations significantly increased particle size and concentrate grade of KCl. Additionally, experiments with diluted decomposition mother liquor (the triple-saturation point E) demonstrated that lower dilution ratios enhanced concentrate grade of KCl, suggesting that the decomposition mother liquor can be adjusted to an appropriate concentration for the decomposition of carnallite ores in industrial applications. This study provides valuable insights for addressing the challenges of low concentrate grade and the inefficient utilization of carnallite ore.