摘要
Cemented paste backfill(CPB)is one of the effective methods for resource utilization of tailings,but the high cost of ordinary Portland cement(OPC)limits its utilization.Considering the poor performance of Na_(2)CO_(3)-activated binders,in this work,supplementary materials,including CaO,MgO,and calcined layered double hydroxide(CLDH),were used to modify their properties with the aim of finding an alternative binder to OPC.Isothermal calorimetry,X-ray diffraction,and thermogravimetric analyses were conducted to explore the reaction kinetics and phase assembles of the binder.The properties of the CPB samples,such as flowability,strength development,and heavy metal immobilization effects,were then investigated.The results show that the coupling utilization of MgO and CLDH showed good performance.The strength of the Mg_(2)-CLDH_(3) sample was approximately 2.94 MPa after curing for 56 d,which was higher than that of the OPC-based sample.Moreover the cost of the modified Na_(2)CO_(3)-activated binder was lower than that of the OPC-based binder.Modified sample showed satisfactory heavy metal immobilization effects.These findings demonstrate that carbonate-activated binder modified by supplementary materials can be suitable in CPB.
基金
financially supported by the Key Laboratory of the Ministry of Education on Safe Mining of Deep Metal Mines,Northeastern University (No.2017SMDM-KFA01)
the Fundamental Research Funds for the Central Universities (No.N2101043)。
