Utilization of cement kiln dust (CKD) to enhance mine tailings-based geopolymer bricks: Fid-Bau Portal

Utilization of cement kiln dust (CKD) to enhance mine tailings-based geopolymer bricks

Ahmari, Saeed / Zhang, Lianyang

Highlights ► Studied enhancement of MT-based geopolymer bricks with CKD. ► Inclusion of CKD significantly improves UCS and durability of MT-based geopolymer bricks. ► Enhancement is mainly related to provision of Ca, Si and Al, elevated alkalinity and fineness of CKD.

Abstract This paper studies the feasibility of enhancing the physical and mechanical properties and the durability of copper mine tailings (MT)-based geopolymer bricks with cement kiln dust (CKD). The effects of CKD content (0–10%), sodium hydroxide (NaOH) concentration (10 and 15M) and initial water content (12–20%) on unconfined compressive strength (UCS), water absorption, and weight and strength losses after immersion in water are studied. To shed light on the mechanism for the contribution of CKD to geopolymerization, microscopic and spectroscopic techniques including scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy are used to investigate the micro/nanostructure and the elemental and phase composition of geopolymer brick specimens. The results show significant improvement of UCS and durability when CKD is used. Water absorption, however, slightly increases due to the hydration of Ca in the added CKD. The enhancement of UCS and durability is attributed to the improving effect of CKD on dissolution of aluminosilicate species, formation of CaCO3, and integration of Ca into the geopolymer gel.