The hydrothermal precursors in the ‘‘Lime Dust–Drilling Mud’’
(LD–DM) and ‘‘Lime Dust–Dam Sludge’’ (LD–BS) mixtures were
burned at various temperatures (800, 900, 1000 and 1100 C) with
a heating rate of 5 C/min. The burned products were rapidly
cooled by air-quenching and then analyzed using the conventional
‘‘glycerin alcohol’’ method, to determine the amount of free lime in
belite cements. The results of this analysis are given in Fig. 4. The
reduced amount of free lime (2% for burning temperatures of
1000 and 1100 C) shows the quasi-complete combination
between slaked lime and other oxides, indicating the optimum
burning temperature. A fast decrease in free lime content with
burning temperature was observed between 800 and 1000 C in
both hydrothermal mixtures. However, from 1000 C, the variation
in the amount of free lime was small. This temperature (1000 C)
was chosen for further belite cement synthesis.