... -bentoniteMechanical castingGreencompression strength , Kpa≥50>50Hot wet strength,Kpa≥0.8-1.0>1.5-2.0Colloidindex,ml/15g±50-70 ... , 300min≤15.0<13Mud making rate,m3/t2.5-8.7<8.7 The refined Na-bentonite quality index ItemIndexWhiteness,%≥75Size,mesh300Colloidindex ... ,%≤10Sorption capacity,ml/g±≥20Mud making rate,m3/t2.5-8.7 Good quality low price bentonite clay