COMPLEX STUDY, CHEMICAL AND MINERALOGICAL, OF THE RED MUD DUMPS RESULTS IN ROMANIAN ALUMINA PLANTS

11th International Multidisciplinary Scientific GeoConference SGEM2011, www.sgem.org, SGEM2011 Conference Proceedings/ ISSN 1314-2704, June 20-25, 2011, Vol. 1, 1101-1108 pp

ABSTRACT

The hydrometallurgical process for obtaining alumina by Bayer process bauxite is
getting significant amounts of red mud (0.8 - 2 t / t Al2O3). It is deposited in dumps
which can cause danger for environment mainly due to the alkali content ( pH = 8-13)
and small dimensisons of particles (less than 60 microns).

Chemical and mineralogical composition of red mud bauxite is closely related to type of
the bauxite used as raw material and processing conditions determined by some
peculiarities of applied technology (pressure, temperature, etc.). In Romania, a producer
of alumina and aluminum tradition for over 50 years, have been processed in time many
varieties of bauxite of internal origin and imported bauxites. Red mud is stored entirely
in dump type deposits.

This paper presents the results of the mineralogical study (x-ray diffraction, scanning
electronic microscopy, optical microscopy) and chemical analysis of different sorts of
red mud.

Keywords: red mud, bauxite, Bayer process