Possible strategies for red mud neutralization and dealkalization from the alumina production industry: a review for Indonesia

The production of alumina from bauxite ore results in a byproduct of red mud with an alkaline characteristic and high salinity. Red mud has limited applications due to issues of permits for its mobilization. This lack of utilization of red mud has increased the burden on red mud disposal facilities at alumina plants. This review provides an up-to-date overview of bauxite processing, red mud characteristics, and management in Indonesia using both scientific articles and data from a representative alumina industry in Indonesia. The various methods for red mud neutralization and dealkalization that have been investigated in previous research are also presented to assess potential future research directions. Of the many red mud neutralization and dealkalization processes reported, the combination of calcification and carbonation is considered to have potential for development. In addition to reducing alkali contents and avoiding pH rebound, carbonation processes can reduce carbon dioxide emissions. The use of calcium-rich waste for red mud calcification is also provides interesting opportunities for future work, although further consideration is needed regarding the effect of impurities and the mineralogy of calcium-rich waste on the red mud dealkalization process. Finally, an overview of the civil engineering and construction use of red mud after calcification and carbonation is described, proposing ways in which large quantities of red mud from alumina plants can be utilized to reduce the burden on red mud disposal facilities.