Dielectric constants of coal-water slurries at 750 MHz

Measurements of the real portion of the dielectric constant of coal-water slurries at 750MHz are reported. Slurries of 40–65wt% of either Illinois No. 6, Utah bituminous or Texas lignite coals over the temperature range 11–71 °C were studied. The dielectric constant was independent of coal type and particle size within experimental error. The measured values of dielectric constants agreed with those predicted by the Looyenga equation: $\text{?′}\text{= ?′}{}^{\mathrm{<mtext>1</mtext><mtext>3</mtext>}}{}_2\text{+ φ(?′}{}^{\mathrm{<mtext>1</mtext><mtext>3</mtext>}}{}_1\text{??′}{}^{\mathrm{<mtext>1</mtext><mtext>3</mtext>}}{}_2\text{)]}{}^3$ where: $\text{?′}$, the mean value of the dielectric constant; ?′₁, the dielectric constant (3.8) of the dry coal; ?′₂, the dielectric constant of water; φ, the volume fraction of coal.