Synergistic strengthening mechanism of Ca²⁺ - Sodium silicate to selective separation of feldspar and quartz

Enhancing the selectivity of flotation reagents is of utmost importance to improve the effectiveness of separation. In this study, a combined inhibitor was used utilizing Sodium silicate (SS) and Ca²⁺ to separate quartz and feldspar in near-neutral pulp. Selective inhibition of the combined inhibitor was assessed by micro-flotation experiments. And a series of detection methods were used to detect differences in the surface properties of feldspars and quartz after flotation agents and to put forward a synergistic strengthening mechanism. The outcomes were pointed out that pre-mixing combined inhibitors were more effective than the addition of Ca²⁺ and SS in sequence under the optimal proportion of 1:5. A concentrate from artificial mixed minerals that was characterized by a high quartz grade and a high recovery was acquired, and was found to be 90.70% and 83.70%, respectively. It was demonstrated that the combined inhibitor selectively prevented the action of the collector and feldspar from FT-IR and adsorption capacity tests. The results of XPS indicated that Ca²⁺ directly interacts with the surface of quartz to increase the adsorption of collectors. In contrast, the chemistry of Al on the feldspar surface was altered by combined inhibitor, with Na⁺ and Ca²⁺ taking the place of K⁺. It is possible that the composite inhibitor forms a hydrophilic structure, which prevents the adsorption of the collector on the surface of feldspar by interacting with the Al active site. The combination of Ca²⁺ and SS synergically strengthens the difference of collecting property between quartz and feldspar by collector, thus achieving the effect of efficient separation.