Chalcopyrite hydrophobicity evaluated by contact angle: influence of pH and mixed thiophosphate collectors

Chalcopyrite hydrophobicity plays a central role in copper flotation and is governed by surface chemistry and interfacial phenomena.In this study, contact angle measurements were used to evaluate the natural hydrophobicity of chalcopyrite and compare it with that of spodumene, apatite, and calcite under controlled pH conditions.The effect of a dithiophosphate (DTP) collector and a mixed dithiophosphate-monothiophosphate (DTP/MTP) system on chalcopyrite wettability was also investigated.Chalcopyrite exhibited the highest natural contact angle among the minerals studied, while apatite and calcite were strongly hydrophilic.Increasing pH enhanced the contact angle of all minerals.Both DTP and DTP/MTP increased chalcopyrite hydrophobicity, but the mixed collector achieved similar contact angles at significantly lower concentrations.These results indicate a cooperative adsorption mechanism consistent with the literature, in which chemisorption of DTP and physisorption of MTP generate a denser and more efficient hydrophobic surface film.Contact angle analysis is demonstrated to be a rapid and cost-effective tool for predicting flotation behavior.