Interactions of the phases containing calcium and aluminium as a part of red mud with ammonium hydrofluoride

I.S. Medyankina, L.A. Pasechnik, V.M. Skachkov, S.P. Yatsenko, V.G. Bamburov
The Institute of Solid State Chemistry of the Ural Branch of RAS

DOI: 10.26456/pcascnn/2017.9.307

Abstract: Fluorination processes of calcium, aluminum and iron phases in the composition of alumina production red mud using ammonium bifluoride to develop conditions of separation multicomponent materials and extract the valuable products have been considered in this paper. It is found that interaction of Al₂O₃ and 3CaO · Al₂O₃ · 6H₂O as a part of red mud with ammonium hydrofluoride takes place the formation of ammonium fluoroaluminates and their decomposition to simple fluoride under the elevated temperatures. Calcium containing phases are the most active components and already at the initial moment of contacting the reaction mixture are decomposed with the fluorite CaF₂ formation which in the presence of fluorine-containing aluminum compounds at a temperature above 400°C is a part of calcium cryolite CalAlF₅. The research allows to justify the direction of sequential processes to separate phase components of red mud after their fluorination.
Keywords: red mud, bauxite residue, tricalcium aluminate, ammonium hydrofluoride, ammonium fluoromellate, industrial waste, fluorination.

Bibliography link:
Medyankina, I.S. Interactions of the phases containing calcium and aluminium as a part of red mud with ammonium hydrofluoride / I.S. Medyankina, L.A. Pasechnik, V.M. Skachkov et al. // Physical and chemical aspects of the study of clusters, nanostructures and nanomaterials: Interuniversity collection of proceedings / Ed. by V.M. Samsonov, N.Yu. Sdobnyakov. – Tver: TSU, 2017. – I. 9. – P. 307-316.

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