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<p>Copper tailings (CTs) are a solid waste with large stockpiles and significant environmental risks. Their low pozzolanic reactivity and high mineral crystallinity limit their high-value utilization. Conventional single activation methods such as mechanical, thermal, or chemical treatments are generally insufficient to significantly enhance the reactivity of CTs, particularly due to the high energy consumption associated with thermal activation. In this study, a microwave-mechano-chemical synergistic activation method was adopted. The optimal activation conditions were determined using response surface methodology (RSM) to improve activation efficiency, reduce energy consumption, and enable large-scale utilization of CTs in construction materials. The results show that under microwave irradiation at 420 W, ball milling for 120&#xa0;min, and a CaO dosage of 4%, mortar with 30% cement replacement by activated CTs achieved a 28 d compressive strength of 34.52&#xa0;MPa and an activity index of 79.45%. Compared with mortar containing unactivated CTs, the compressive strength and activity index increased by 17.15&#xa0;MPa and 39.47%, respectively. Microwave irradiation induces thermal stress due to differences in dielectric constants among CTs mineral phases, leading to the formation of surface microcracks. Ball milling further refines particle size and facilitates the penetration of CaO into newly formed surfaces after particle fragmentation, thereby enhancing the dissolution of active components such as Al, Si, and Ca. The synergistic effects of these processes significantly improve the pozzolanic activity of CTs. This research offers novel approaches for CTs activation and resource use.</p>

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Effect of microwave and mechano-chemical synergistic activation on the reactivity of copper tailings and the properties of cementitious materials

  • 期刊论文

  • 发表日期：

    2026年7月6日

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  • Jingzhi Peng,
  • Zhihong Wu,
  • Hui Li,
  • Jin Wang,
  • Rui Li,
  • Haitao Hui

摘要

Copper tailings (CTs) are a solid waste with large stockpiles and significant environmental risks. Their low pozzolanic reactivity and high mineral crystallinity limit their high-value utilization. Conventional single activation methods such as mechanical, thermal, or chemical treatments are generally insufficient to significantly enhance the reactivity of CTs, particularly due to the high energy consumption associated with thermal activation. In this study, a microwave-mechano-chemical synergistic activation method was adopted. The optimal activation conditions were determined using response surface methodology (RSM) to improve activation efficiency, reduce energy consumption, and enable large-scale utilization of CTs in construction materials. The results show that under microwave irradiation at 420 W, ball milling for 120 min, and a CaO dosage of 4%, mortar with 30% cement replacement by activated CTs achieved a 28 d compressive strength of 34.52 MPa and an activity index of 79.45%. Compared with mortar containing unactivated CTs, the compressive strength and activity index increased by 17.15 MPa and 39.47%, respectively. Microwave irradiation induces thermal stress due to differences in dielectric constants among CTs mineral phases, leading to the formation of surface microcracks. Ball milling further refines particle size and facilitates the penetration of CaO into newly formed surfaces after particle fragmentation, thereby enhancing the dissolution of active components such as Al, Si, and Ca. The synergistic effects of these processes significantly improve the pozzolanic activity of CTs. This research offers novel approaches for CTs activation and resource use.