The increasing scarcity of freshwater has driven interest in using non-conventional water sources in mineral flotation, yet their complex ionic composition adversely affects flotation performance. Variations in water chemistry, particularly the presence of divalent cations, influence cationic quartz flotation. This study investigates the impact of water quality and source on cationic quartz flotation in the context of phosphate ore processing. Single-mineral flotation tests using seawater, recovered process water, and reverse osmosis-treated water were conducted, supported by total organic carbon, zeta potential, and contact angle measurements. Ca 2+ and Mg 2+ ions were identified as the key ions competing for adsorption on quartz surfaces, reducing amine collector adsorption and quartz recovery. Total organic carbon measurements showed a significant reduction in amine adsorption on quartz in the presence of these divalent cations. Consistently, zeta potential measurements indicated a progressive decrease in the potential shift induced by amine addition with increasing Ca 2+ and Mg 2+ concentration, reflecting weakened amine–quartz interactions, which were further confirmed by contact angle measurements. Mitigation strategies involving EDTA complexation and mixing water streams effectively restored flotation performance. These findings elucidate the mechanisms by which divalent cations depress quartz flotation and provide practical guidance for integrating non-conventional water sources in phosphate beneficiation, thereby promoting sustainable water management practices.
Abbou et al. (Tue,) studied this question.