Recycling Bauxite Waste for the Mineral Industry: Phase Transformations and Microstructure During Sintering

Raw materials of mineral industries are mainly in the form of ore, which generate fine mineral particles during the extraction, comminution and transport which are primarily regarded as non-recyclable waste. The aim of this paper is to develop and characterize materials using recycled fine particles of bauxite sintered at high temperature at a laboratory scale for the calcium aluminate industry. To use these recycled materials as raw materials, the physico-chemical transformations during high-temperature processing are described. Phase transformations as a function of temperature were determined by XRD, and optical and electronic microscopies were utilized to observe microstructures. Materials with different particle size distributions showed different chemical reactivity as a function of particle size. The optimization of particle size distribution makes it possible to substitute synthetic bricks for bauxite ore using recycled fine particles of bauxite.