Promotion effect of mechanical activation on the role of pyrite in chalcopyrite bioleaching

• Mechanical activation significantly reduces particle size and increases surface area and energy of chalcopyrite and pyrite, enhancing their reactivity. • The combined use of mechanically activated chalcopyrite and pyrite boosts copper extraction by 51.8% compared to non-activated mixtures, reaching 63.4%. • Pyrite's catalytic role in chalcopyrite bioleaching is activated by mechanical activation, providing additional oxidants and acting as a cathode in galvanic coupling. • A mechanistic model is proposed to explain how mechanical activation promotes pyrite's role in accelerating chalcopyrite bioleaching.