Improving the slurryability of high ash coal by blending anthracite of different particle size range

Hydraulic transportation of lignite and high ash coal (HAC) is economically unviable due to their poor slurryability and stability. The study suggests and shows how the proper selection of appropriate size range and proportion of anthracite for blending can aid in the economical preparation of highly concentrated HAC slurry. Fine (+0-53 & mu;m), coarse (+53-106 & mu;m), and coarser (+106-150 & mu;m) anthracite particles were added to the HAC sample. The proportion of anthracite particles was varied in the range of 10-40% (by weight), to obtain 12 blended tetra-modal samples. To determine the optimum size range and proportion of anthracite, the stability and rheological characteristics of both tri-modal HAC and blended tetra-modal coal samples were assessed. The addition of a fine anthracite sample (+0-53 & mu;m) has an adverse impact on the rheological characteristics. The optimum size range and proportion of anthracite particles for enhanced slurryability and low apparent viscosity are found to be +106-150 & mu;m and 30%, respectively. Optimal blending yields a 68% maximum solid concentration slurry. By taking advantage of both the tetra-modal particle size distribution and anthracite's high slurryability characteristics, the maximum achievable solid concentration of HAC slurry increases by 17%.