Page 225 - AJWEP-22-5

Rheological properties of coal gangue slurry

A B

C

Figure 4. Influence of three factors on the estimated marginal mean of slurry density: (A) Solid volume
concentration, (B) coal gangue particle size, and (C) fly ash‑to‑coal gangue mass ratio

at optimized viscosity ensures complete fracture filling Table 5. Significance analysis of influencing
with fewer boreholes, ultimately reducing drilling costs. factors on slurry viscosity

Factor Sum of DOF Average F‑value p‑value
3.1.2. Influence on slurry viscosity squared variance
The influences of the three factors on slurry viscosity deviations
are presented in Table 5. The p-values for factors A, A 42.833 2 20.432 17.333 0.001
B, and C were all below 0.01, indicating extremely B 32.375 3 17.685 12.163 0.002
significant differences. This finding demonstrates that
all three factors significantly affect slurry viscosity. C 51.147 6 12.113 8.812 0.003
Although factor C remained statistically significant, its Deviation 15.896 9 3.576
influence on viscosity was less pronounced compared Sum 17
to factors A and B. The order of influence of the three Abbreviation: DOF: Degrees of freedom.
factors on slurry viscosity is as follows: Solid volume
concentration > coal gangue particle size > fly ash-to- viscosity decreased from 9 to 5.5 mPa·s. This reduction
coal gangue mass ratio. is attributed to smaller particles having lower internal
The marginal means of each factor were employed friction angles and reduced interparticle friction, which
to analyze the variations in slurry viscosity under collectively reduce flow resistance. 21-23
the influence of individual factors, as illustrated in The fly ash-to-coal gangue mass ratio showed
Figure 5. Solid volume concentration exhibited a an approximately linear correlation with viscosity.
highly significant effect on viscosity. Increasing solid Increasing the coal gangue proportion raised the
concentration reduces particle spacing, altering their viscosity from 5 to 10.5 mPa·s. Fly ash particles are
arrangement and interactions, which leads to higher significantly finer than coal gangue particles; thus,
viscosity. 19,20 A clear inverse relationship was observed higher coal gangue content hinders particle mobility
between coal gangue particle size and slurry viscosity. and amplifies internal friction and viscosity. Notably,
24
As the particle size decreased from 50 mesh to 200 mesh, viscosity increased gradually at mass ratios of 7:3 and

Volume 22 Issue 5 (2025) 219 doi: 10.36922/AJWEP025210162