BACKGROUND　Significant　efforts　have　been　devoted　to　examine　the　adsorption　of　flotation　surfactants　in　both　mechanistic　studies　and　process　implementations.　However,　quantitative　electrochemical　methods　for　flotation　surfactant　adsorption　examination　have　not　been　well-established,　despite　of　their　low-cost,　accurate,　in-situ　nature.　RESULTS　In　this　paper,　voltametric　measurement　was　proven　to　quantitatively　examine　the　adsorption　of　activating　copper　and　lead　ions　onto　a　pyrite　surface.　The　activation　was　achieved　by　abrading　minerals　in　a　heavy-metal-bearing　solution　and　the　measurements　were　performed　by　transferring　the　minerals　to　a　solution　free　of　those　heavy　metals.　This　provided　a　simple　but　realistic　simulation　of　the　mineral　grinding　process　and　simplified　the　adsorption　quantification　by　excluding　any　other　irrelevant　electrochemical　reactions　near　the　surface.　Reliable　electrochemical　impedance　spectroscopy　(EIS)　upon　adsorption　with　convincing　physical　models　for　interpreting　the　interfacial　structures　also　were　obtained　in　this　paper.　The　additional　pseudocapacitive　behaviour　of　the　copper　sulfide　surface　layer　led　to　an　increased　capacitance　of　the　measured　EIS.　A　resistive　but　ion-permeable　xanthate　adsorption　layer　exhibited　its　own　relaxation　process.　Voltammetry　and　impedance　studies　showed　that　cyanide　competed　with　both　copper　and　lead　for　their　adsorption,　whereas　lead　activation　showed　greater　tolerance　to　cyanide　than　copper　did.　CONCLUSION　Electrochemical　methods　have　been　established　to　examine　the　adsorption　of　copper,　lead　and　xanthate　onto　pyrite　surface,　in　relation　to　various　flotation　conditions,　which　exhibited　significant　implication　to　the　flotation　of　pyritic　gold　ore　using　cyanide-bearing　water.　(c)　2020　Society　of　Chemical　Industry