Influence of slurry ionic composition on the wetting contact angle of scheelite during flotation in a closed water circuit

Determining the wetting contact angle is critical in beneficiation processes, as it characterizes the interaction between the collector reagent and the mineral surface within the slurry. This study presents a comparative analysis of changes in the contact angle under flotation enrichment conditions in an open circuit, a closed circuit with accumulation of major impurities, and a closed circuit with conditioned circulating water. Measurements were conducted using an OSA 15EC goniometer and analyzed with the SCA20 software. The relationship between contact angle and contact time was modeled using secondorder polynomial regression. Data on contact angle variation over time, both in the absence and presence of varying collector concentrations on the mineral surface, are provided for open and closed circuits with impurity accumulation and recycled water conditioning. Mathematical analysis revealed quantitative trends in the contact angle of scheelite wetting depending on water circulation conditions, collector concentration (tall oil), and contact time. The developed model accurately fits the experimental data, with high determination coefficients (R2) ranging from 0.98 to 1.0. The presence of competitive ions in the slurry significantly reduces collector efficiency during mineral flotation; however, preliminary conditioning of recycled water effectively mitigates this effect. Conditioning restores collector efficiency, promotes stable flotation complex formation, and consequently increases the yield and quality of the target concentrate while reducing losses.