The depression of copper-activated pyrite in flotation by biopolymers with different compositions

• Biopolymers’ adsorption on copper-activated pyrite formed Cu-biopolymer complex.
• Formation of Cu-biopolymer complex inhibited xanthate adsorption on pyrite surface.
• The structure feature of biopolymer played a significant role in pyrite depression.
• Higher molecular weight led to higher adsorption amount and pyrite depression.
• Functional groups influenced biopolymers’ ability to inhibit xanthate adsorption.