Aluminum is an important basic raw material for national economic development. The alumina industry is expanding rapidly due to the increasing demand for aluminum. Bauxite residue, also known as red mud, is a high saline-alkaline solid waste generated by alumina production. The global inventory of bauxite residue reached 5 billion tons in 2021, increasing by approximately 200 million tons per annum (Ke et al. 2021). Due to its low utilization ratio (< 1%), large amounts of bauxite residue are stacked in disposal areas, which may cause a series of environmental safety issues including water pollution, soil salinization, heavy metal pollution and crop loss (Bray et al. 2018). In 2010, a bauxite residue reservoir dam breached causing an unprecedented ecological disaster in Hungary (Enserink 2010). Since 2010, there have been several incidents of dam failure around the world, restricting the sustainable development of the aluminum industry. Disposal and utilization of bauxite residues became the focus of global attention.

Bauxite residue contains a large amount of aluminum, iron, and silicon with high pH, fine particles and large specific surface area. These properties should be regarded as a promising secondary resource for large-scale utilization. Furthermore, ecological disposal is still a promising strategy to eliminate the negative environmental risks of stacked bauxite residue (Xue et al. 2022). During the last 20 years, scholars published 4949 peer-reviewed papers on bauxite residue-related studies. The number of bauxite residue-related publications increased from 84 to 2002 to 594 in 2021. The major topics include ecological rehabilitation of bauxite residue, valuable elements extraction, building materials preparation, and environmental application (Nguyen et al. 2022).

This special issue in the Bulletin of Environmental Contamination and Toxicology (BECT) is a collection of reviews and research papers on the subject of ecological disposal and large-scale utilization of bauxite residue. Recent research involving the intersection of environmental engineering, metallurgy, soil science and material science is highlighted to present the latest advances in ecological disposal and large-scale utilization of bauxite residue. In this issue of the Bulletin of Environmental Contamination and Toxicology includes three focused reviews and 25 research articles, with a focus on bauxite residue in the fields of (1) soil formation and ecological disposal, (2) environmental application, (3) building materials preparation, and (4) valuable elements extraction. The above 28 papers demonstrate the requirement and directions for further research to develop practical and sustainable strategies for ecological disposal and large-scale utilization of bauxite residue.

Ecological disposal is the most promising way to reduce the potential risks of the disposal areas in the surrounding environment. Among them, soil formation process is the critical point for revegetation. In the field of soil formation and ecological rehabilitation (6 papers), Zhang et al. demonstrated the necessity of ecological rehabilitation for reducing heavy metal pollution on the disposal areas. Guo et al. developed a novel strategy using functional microorganisms and demonstrated the application potential of penicillium oxalicum on dynamic changes of soil-formation indicators in bauxite residue. In the field of environmental application using bauxite residue, we have received 8 papers with three sub-topics including wastewater treatment, flue gas desulfurization, and soil remediation. Zhao et al. prepared a new bauxite residue/fly ash composite material and reported its effects on phosphate removal by a combination of physical adsorption, chemical adsorption and chemical precipitation. Zhou et al. provided a new preparation way of bauxite residue-based adsorbent using polyethylene glycol-modified bauxite residue and used to remove low concentration of carbonyl sulfide in the flue gas. Three papers explored the application potential of bauxite residue as raw material in the production of cement, bricks and blocks. Zhang et al. designed a specific mortar material from industrial solid wastes including bauxite residue, fly ash, and iron tailings, and demonstrated that the developed specific mortar material was environmentally acceptable and feasible as 3D printable construction material. In the field of recycling of bauxite residue, Zhang et al. used the iron-containing stripping solution generated during resource recycling of bauxite residue to produce battery-grade FePO4·2H2O product and realize the high-value use of iron from bauxite residue. Wang et al. developed a high-pressure hydrothermal reduction method to separate and recover sodium, aluminum, and iron in high-iron bauxite residue in one step in an alkaline hydrothermal system. With the exception for metallurgical application, bioleaching also has its unique effects on the extraction of valuable metals. Qu et al. performed a continuous mode of bioleaching to investigate the leaching efficiency of Titanium (Ti) from bauxite residue using Penicillium tricolor.

Overall, this special issue covers major research topics of bauxite residue, which reflects the aspiration to realize large-scale utilization and control environmental risks of bauxite residue through the cross fusion of multi-disciplines. We hope that the content in this special issue will inspire the related workers towards more research breakthroughs in the area and also foster increased interdisciplinary collaboration. We are grateful to Prof. Erin Bennett and the editorial team of Bulletin of Environmental Contamination and Toxicology for their great efforts to make this special issue possible. The full projects (42,030,711, 42,077,379, 42,177,391) supported by the National Natural Science Foundation of China have been vital for the research discussed in this publication. We would like to express our gratitude to the 2nd International Conference on the Ecological Restoration and Disposal of Bauxite Residue organized in Changsha, China on November 27–28, 2021. More than 80 specialists and scholars attended this conference, and an in-depth discussion on large-scale utilization and ecological disposal of bauxite residue was conducted. Meanwhile, future directions including ecological disposal, environmental application, building materials preparation, and valuable elements extraction were pointed out. Finally, we would like to take this opportunity to thank all the co-authors and the reviewers who have made important contributions to this special issue.