Polyvinyl Chloride (PVC).  Oversized second grade material.  Agglomerates or lumps, maximum size 2-3" down to 1/2-1/4".  All are plus 4 mesh.

PROBLEM:

Slurry grind in water to 100% minus 4 mesh (3/16"). 

RESULTS:

10% by weight PVC in water.  Recirculated at 100 gpm.  All lumps easily ground to 100% minus 4 mesh.

AB MIXER:

Model 6 x 3, toothed impeller/liner, 10 HP, 1800 RPM, 3/16" grid.  Recirculating to tank.