The Bayer process is used for refining bauxite to smelting grade alumina (A
l2O3), the precursor to aluminium. The process was developed and patented b
y Karl Josef Bayer 110 years ago, and has become the cornerstone of the alu
minium production industry worldwide. Production of alumina reached 46.8 me
gatonnes (Mt) worldwide by the end of 1997, with Australia the worlds large
st producer of bauxite and refiner of alumina with just under 30% of world
production. Although the refining process is well established and the basic
theories underpinning it are well defined, the fundamental chemistry of th
e Bayer process is not well understood. Of particular interest to industria
l and academic researchers alike, is the chemistry of the Bayer process sol
ids-aluminium trihydroxide, 'red mud' and sodium oxalate. The surface chemi
stry of these solids is of great industrial importance as the refining indu
stry experiences significant restrictions due to limitations imposed on the
process by surface chemical reactions. Of scientific interest is the conce
ptual advancement of our knowledge and understanding of the nature of surfa
ces under extreme (non-ideal) conditions. A review of the current literatur
e relating to these important Bayer process solids is thus presented. While
not exhaustive, the review is thorough and aims to familiarise the reader
with current levels of understanding regarding the nature of Bayer process
solids surfaces under Bayer process conditions, and the significant roles t
hese solids play in the overall efficiency of the refining process. It is h
oped that this review will provide a useful starting point for researchers
new to the area of Bayer process research, whilst also stimulating further
fundamental research in this economically and scientifically significant ar
ea. (C) 1999 Elsevier Science B.V. All rights reserved.