2.2. Whitening of bauxite tailings
In the experiment, two process routes were employed to whiten
bauxite tailings, which are pre- and post-reaction calcinations. The
former is that the milled bauxite tailings firstly is calcined at 600 °C
for 2 h in flowing air to eliminate the organic matter, then react with the phosphoric acid to get whitened bauxite tailings; the latter is
that the milled tailings firstly react with the phosphoric acid, then calcined
in flowing air to eliminate the organic matter, finally bauxite
tailings was whitened.