Feasibility of preparing red mud-based cementitious materials: Synergistic utilization of industrial solid waste, waste heat, and tail gas Zhaofeng Li a, * , Jian Zhang a , Shucai Li a , Chunjin Lin a , Yifan Gao a , Chao Liu a a Geotechnical and Structural Engineering Research Center, Shandong University, Jinan, Shandong, 250061, China article info Article history: Received 22 June 2020 Received in revised form 27 October 2020 Accepted 29 October 2020 Available online xxx Handling editorCecilia Maria Villas B^ oas de Almeida Keywords: Red mud-based cementitious materials Waste heat Tail gas Carbonation disposal High-temperature disposal Synergy theory abstract In order to address the environmental problems caused by red mud and other industrial by-products, a new concept was proposed to use red mud to prepare cementitious materials by incorporating other solid wastes, waste heat, and tail gas. The feasibility of this synergistic concept was verified by laboratory-scale tests, and the effect of tail gas and waste heat on solid wastes was revealed by FTIR (Fourier transform infrared spectroscopy), XRD (X-ray diffraction), and SEM-EDS (Scanning electron microscopy-Energy Dispersive Spectroscopy), and the key device for carbonation disposal was devel- oped. The results showed that the cementitious reactivity of industrial solid wastes can be improved by carbonation disposal of tail gas. The cementitious reactivity of Sintered red mud, coal gangue, fly ash, and Bayer red mud was increased by 49.8%, 4.4%, 9.5% and 18.9%, respectively. The multi-solid waste system with Bayer red mud, steel slag, carbide slag, aluminum ash, and flue gas desulfurization gypsum can generate high performance red mud-based cementitious materials (RCM) with a compressive strength of 8.8 MPa at 1 d under the circumstance of high temperature disposal. And RCM consists of 2CaO$SiO 2 , 3CaO$Al 2 O 3 , and CaO$(Al 2 O 3 þ Fe 2 O 3 ). In addition, the mechanical strength and soundness of RCM can be improved by the carbonation of tail gas. This innovative concept provides a way for the mass utilization of red mud along with other solid wastes, waste heat and tail gas through the relevant cementitious materials for use in transportation construction, and shed light on the cleaner production of industry. © 2020 Published by Elsevier Ltd. 1. Introduction Ordinary Portland cement (OPC) is widely used in construction engineering, and about 3.95 billion tons of OPC produced in 2018. However, high energy consumption and large CO 2 emissions of OPC production do not meet the needs of ecological construction (C. Chen et al. 2010, M. Schneider et al. 2011). Environmental protec- tion has become an issue of great concern to the entire world (Hughes, R.M. et al. 2016). Researchers are actively searching for substitutes to OPC based materials. As a result of industrial development and urbanization, billions tons of industrial wastes are generated annually. According to statistics of Prospect of global solid waste treatment from the Inter- national Solid Waste Association and International Environmental Technology Center, the world produces 7e10 billion tons of solid wastes, which including red mud, fly ash, metallurgical slag (blast furnace slag, steel slag, nickel slag, etc.), flue gas desulfurization ash, various tailings, etc.. Among the various industrial solid wastes, red mud, which is a solid powder waste discharged during the production of alumina, is difficult to utilize than other by-products because of its high alkalinity and heavy metal content (M. A. Khairul et al. 2019). The large amounts of stored red mud has caused tremendous harm to the environment, but also contains tremen- dous market potential for its utilization. So far, red mud was mostly used as absorbent for waste water (Xin Li et al., 2020), rare metals extraction Rivera et al., 2018, and cementitious material prepara- tion (M. A. Khairul et al. 2019). However, the utilization rate of red mud is relatively lower than that of other solid wastes, such as fly ash and blast furnace slag. Therefore, it is urgent to find an efficient way to deal with red mud. As an effective way to utilize red mud in large quantities, cementitious materials have been a hot topic over the past few Abbreviations: SRM, Sintered red mud; BRM, Bayer red mudm; BFS, Blast furnace slag; CG, Coal gangue; FA, Fly ash; SS, Steel slag; RCM, Red mud-based cementitious material; OPC, Ordinary Portland cement; FGD, Flue gas desulfuriza- tion ash; XRD, X-ray diffraction; SEM, Scanning electron microscopy; FTIR, Fourier transform infrared spectroscopy; XRF, X-ray fluorescence; EDS, Energy Dispersive X-Ray Spectroscopy. * Corresponding author. E-mail address: lizf@sdu.edu.cn (Z. Li). Contents lists available at ScienceDirect Journal of Cleaner Production journal homepage: www.elsevier.com/locate/jclepro https://doi.org/10.1016/j.jclepro.2020.124896 0959-6526/© 2020 Published by Elsevier Ltd. Journal of Cleaner Production xxx (xxxx) xxx Please cite this article as: Z. Li, J. Zhang, S. Li et al., Feasibility of preparing red mud-based cementitious materials: Synergistic utilization of industrial solid waste, waste heat, and tail gas, Journal of Cleaner Production, https://doi.org/10.1016/j.jclepro.2020.124896