Element distribution of grading in red mud at different temperatures based on TIMA and EDS analysis.

In this paper, element distribution patterns of red mud particles with different grading temperatures were explored based on TIMA and EDS, and alkali removal performance of different particle sizes under high temperature grading was compared. The results show that non-clay phases in the particles coagulate with the clay phases of different sodium contents during stacking process, thus forming a mixture phase containing clay phase and other impurities. The potential of grading utilization of red mud is displayed by process mineralogy studies. The elements and phases of different particle sizes of red mud cannot be effectively separated by grading at room temperature. Due to high-temperature grading, red mud is divided into three particle sizes, namely, a (above 100 μm), b (38-100 μm), and c (below 38 μm), with Na2 O contents of 3.25%, 2.31%, and 8.13%, respectively, decreasing to 1.00%, 0.27%, and 2.99% after alkali removal. The different elements and phases of red mud can be effectively separated by high-temperature grading, which promotes the classification of different particle sizes and the comprehensive utilization of red mud.