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Liu, et al.

A B

C

Figure 5. Influence of three factors on the estimated marginal mean of slurry viscosity: (A) Solid volume
concentration, (B) coal gangue particle size, and (C) fly ash‑to‑coal gangue mass ratio

3:7, suggesting that excessive coal gangue promotes role in determining the water bleeding rate. As the
particle agglomeration, thereby accelerating viscosity volume concentration increased, the water bleeding rate
buildup. Therefore, optimizing the fly ash-to-coal decreased significantly, which is attributed to the higher
gangue mass ratio is crucial to balancing the viscosity proportion of solid particles relative to water during
and injectability of the slurry. slurry preparation, thereby reducing bleed water. 25,26 A
near-linear relationship was observed between volume
3.1.3. Influence on water bleeding rate concentration and water bleeding rate. When the
The test results for the influence of the three factors on concentration increased from 50% to 70%, the average
the water bleeding rate are presented in Table 6. Factors water bleeding rate declined from 0.39 to approximately
A and C exhibited equivalent levels of significance 0.29 (Figure 6A).
(p<0.01), indicating extremely significant differences Coal gangue particle size exhibited minimal impact
and confirming that both solid volume concentration and on the water bleeding rate. Although finer particles (e.g.,
coal gangue mass proportion have a highly significant 100 mesh) slightly reduced water bleeding compared
impact on slurry water bleeding rate. In contrast, to coarser particles (50 mesh), the difference was
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factor B showed a higher p-value (i.e., less statistical negligible (Figure 6B). Coal gangue particles, due to
significance), indicating that its effect on the water their high density, initially experience strong resistance
bleeding rate was less pronounced compared to factors to water flow. However, as sedimentation progresses,
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A and C. The order of influence of the three factors the settling velocity decreases, resulting in similar water
on the water bleeding rate is as follows: solid volume bleeding rates across different particle sizes over time.
concentration = fly ash-to-coal gangue mass ratio > coal As illustrated in Figure 6C, the mass ratio of fly
gangue particle size. ash to coal gangue exhibited an approximately linear
The marginal means of the three factors were utilized relationship with the slurry water bleeding rate. As the
to examine their variations in the water bleeding rate proportion of coal gangue increased, the water bleeding
(Figure 6). Solid volume concentration plays a key rate decreased from 0.38 to approximately 0.28,

Volume 22 Issue 5 (2025) 220 doi: 10.36922/AJWEP025210162