National Mineral Resources University (University of Mines) (Russia):

Brichkin V. N., Professor, Doctor of Engineering Sciences, kafmetall@mail.ru

Dubovikov О. А., Associate Professor, Ph. D. in Engineering Sciences

Nikolayeva N. V., Lecturer, Ph. D. in Engineering Sciences, opiopi@bk.ru

Besedin А. А., Postgraduate, kafmetall@mail.ru

Major aluminium smelters all over the world still use Bayer process, patented about 120 ago, for aluminium production from bauxite. As a result of aluminium smelters operation, waste is produced (red mud), which mostly consists of oxides of iron, aluminium, titanium and some other useful metals. These wastes are finely-ground materials, containing large quantities of valuable components, and, while recovery of most of them may be economic, they also contain strong caustic, which produces a negative impact upon environment. At present time, the quantities of accumulated wastes (due to unavailability of recycling) amount to hundreds of million tons. Actually, there are several alternatives for red mud recycling, but first strong caustic needs to be removed from it. Thickening and filtration processes are applied to achieve that. Filtration is applied for solid phase separation from solution in dense slurries, as well as for clarification of solutions, containing negligible quantity of solid particles. The article presents the results of red mud sample filtration studies under different conditions. The experiments showed, that red mud dewatering forms an integral part of its efficient recycling and is characterized by a complex relationship between process indices and actual operating conditions. With that, pressure filtration permits to obtain filter cake with moisture content up to 32.8 % at the temperature about 20 °С.

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