Flotation, a widely used mineral separation technique, is influenced by the chemical environment of the pulp, which often contains a variety of dissolved metal ions. These ions can have both positive and negative impacts on the flotation process. In silicate flotation systems, certain metal ions are released from minerals, potentially modifying surface properties and altering the flotation behavior of minerals. This study explores the role of calcium ions in the flotation separation of phlogopite and quartz, focusing on how these ions affect the adsorption capacity of collectors and influence flotation recovery. Calcium ions, released from phlogopite during flotation, were found to significantly enhance the adsorption of collectors on the quartz surface, improving flotation recovery, especially under alkaline conditions. The sequence of calcium ion interaction with the mineral surfaces plays a crucial role in the flotation process, with prior exposure to calcium ions providing a stronger activation effect. The optimal flotation performance was achieved using a mixed collector system (DDA-NaOL) at pH 8, which demonstrated a recovery difference of 59.19% between phlogopite and quartz. These findings highlight the activation role of calcium ions in improving flotation selectivity and offer valuable insights into the underlying mechanisms of calcium ion activation in flotation processes.