2562 RED MUD AS A STRATEGIC SECONDARY RESOURCE FOR CRITICAL MINERALS: COMPARATIVE CHARACTERIZATION AND POLICY IMPLICATIONS FROM INDIAN ALUMINA REFINERIES *Akash Padhan1, Biswajit Paul1 1Department of Environmental Science and Engineering, Indian Institute of Technology (Indian School of Mines), Dhanbad 826004, India. (*Presenting author: 22dr0008@iitism.ac.in) ABSTRACT Critical minerals are essential for clean energy technologies, advanced manufacturing, and national security. However, their supply chains are being limited by geological, environmental and geopolitical factors. As a result, interest has been increasing in secondary resources that can be used to provide supplements to primary mineral supply. Red mud, a voluminous by-product formed in the process of the production of alumina, is an environmental liability and a possible strategic resource since it is enriched with critical, technological and rare earth elements. This paper provides the comparative technical analysis of red mud samples retrieved in alumina refineries. These refineries relate to bauxite ores in the eastern Indian bauxite belt. The extensive characterization was done with X-ray fluorescence, inductively coupled plasma optical emission spectroscopy, X-ray diffraction, and field-emission scanning electron microscopy. The findings demonstrate high-source-related variability of chemical composition, mineralogy, and morphology. The highest enrichment of the analyzed elements is scandium. Its concentration, especially in the residue of one refinery has been high, making scandium a priority critical mineral that may be recovered. There are also other critical and rare earth elements, such as Gallium, vanadium, chromium, among others, although their concentrations are relatively lower. The results show that red mud must be referred to as a secondary resource which is specific to the refinery. This has significant consequences on critical mineral strategy, waste management and mineral policy. KEYWORDS Critical minerals, red mud, scandium, secondary resources, mineral policy 1. INTRODUCTION Critical Minerals and Strategic Materials are key to developing the new technologies of today (Vikentiev, 2023). These include new renewable energy systems, electric vehicles, advanced electronic devices and military hardware (Jaiswal et al., 2025; Kalantzakos, 2020). The demand for these materials has grown significantly over the past few years. As a result of this rapid growth there are significant risks emerging in relation to global supply chains. These risks arise due to both geological constraints, environmental limits and geopolitical concentrations of the resources required. Consequently, the goal of diversifying supply has become a major policy issue. Increasingly, the focus is turning toward secondary resources developed from mining and metallurgical waste products. It could potentially supplement primary supplies of critical materials (Kursunoglu, 2025). Red mud, often referred to as bauxite residue, is a primary byproduct of the Bayer process used to produce alumina (Hairi et al., 2015). An estimated 1-1.5 tons of red mud is generated for each ton of alumina (Al-Fakih et al., 2023). It is reported that an estimated 300 million tons of red mud is generated globally every year. As a result, the cumulative stockpile of red mud will be approximately 4 billion tons worldwide (Archambo & Kawatra, 2021; Swain, 2022). Despite the massive quantity of red mud available, recycling rates are extremely low with less than 2-3 percent currently being recycled. For the most part, red mud is simply dumped into landfills or stored in tailing ponds (Padhan &
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