Then, the flotation of LCC, MCC and HCC was conducted in saline water. Combustible recovery and ash recovery as a function of
flotation time are shown in Fig. 3. Again, the flotation of HCC was
very poor in saline water although the combustible recovery was
increased to 28%. However, saline water significantly increased
the flotation of LCC and MCC with combustible recovery being
more than 80%. A comparison of Figs. 2 and 3 indicates that a synergy occurred between saline water and clay minerals in increasing
both combustible recovery and ash recovery. As shown in these figures, when the clay content was increased from 7% in LCC to 12% in
MCC, combustible recovery increased by 2% and ash recovery by
1.8% when de-ionised water was used. When saline water was
used, combustible recovery increased by 6% and ash recovery
increased by 7%. In fact, the additional clay minerals facilitated
the recovery of both combustible and mineral matter in particular
in saline water