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Project

Autoclave processing for valorizing residues from metallurgical industries – AVAREST

The Bayer process is by far the prevailing process for the production of alumina, and its core unit operation is the high temperature digestion of bauxites in autoclaves. Operations in high temperature and pressure are an integral part of many industrial processes and deliver materials used e.g. in construction, automotive, and aerospace. Understanding this core similarity, we developed a hydrothermal process to treat the residues from the Bayer process (bauxite residue, also knows as red mud), that delivered water-insoluble monoliths with zeolites as a major reaction product. This process was then tested for other formulations. In all cases, the results are very promising: the end-materials are durable, of high strength, high specific surface, with most of the heavy metals immobilised. This patent-pending process is now being upscaled, and granular materials, but also boards of max 1 m x 2 m will be produced for further testing in real-life conditions and applications. This will ultimately increase the market and technology readiness level, but part of this trajectory is to find an optimum balance between overall cost and performance. As the correlations are manifold, we apply optimal experimental design methodology with machine learning modules to optimize the raw materials’ formulations in combination with the processing parameters, for the best performance per application. Both process and product are highly interesting for related disciplines like metallurgical, chemical, civil and architecture engineering, and will be the basis for established and future industrial collaborations and international projects.
Date:4 Jan 2021 →  3 Jan 2024
Keywords:autoclave processing, hydrothermal curing, residue valorization, zeolites, design of experiments
Disciplines:Biology and other natural sciences, Materials recycling and valorisation, Numerical analysis, Destructive and non-destructive testing of materials