Flotation separation of brucite and calcite in dodecylamine system enhanced by regulator potassium dihydrogen phosphate

To achieve efficient flotation separation of brucite and calcite, flotation separation experiments were conducted on two minerals using dodecylamine (DDA) as the collector and potassium dihydrogen phosphate (PDP) as the regulator. The action mechanism of DDA and PDP was explored through contact angle measurement, zeta potential detection, solution chemistry calculation, FTIR analysis, and XPS detection. The flotation results showed that when DDA dosage was 35 mg/L and PDP dosage was 40 mg/L, the maximum floating difference between brucite and calcite was 79.81%, and the selectivity separation index was 6.46. The detection analysis showed that the main dissolved component HPO₄²⁻ of PDP is selectively strongly adsorbed on the Ca site on the surface of calcite, promoting the adsorption of the main dissolved component RNH+ 3 of DDA on calcite surface, while brucite is basically not affected by PDP. Therefore, PDP is an effective regulator for the reverse flotation separation of brucite and calcite in DDA system.