1. IN HEAVY-MEDIA SUSPENSION PROCESSES FOR THE FRACTIONATION AD RECOVERY OF COMMINUTED MATERIALS WHEREIN THE COMMINUTED MATERIALS ARE CHARGED INTO A SLIME-CONTANING HEAVY-MEDIA SUSPENSION MAINTAINED AT A SPECIFIC GRAVITY INTERMEDIATE BETWEEN THE SPECIFIC GRAVITIES OF THE COMPONENTS OF THE COMMINUTED MATERIALS WHEREBY A FLOAT AND A SINK PRODUCT IS FRACTIONED, THE IMPROVEMENT COMPRISING ADDING TO SAID HESVY-MEDIA SUSPENSION SODIUM HEXAMETAPHOSPHATE IN AN AMOUNT BETWEEN ABOUT 0.008 AND ABOUT 0.2 PERCENT BY WEIGHT OF THE SOLIDS IN SAID SUSPENSION.