Sink-float separation is the dividing of two commingled polymers or materials of different specific gravities. Here is a routine example - a silo of glass-filled polycarbonate is accidentally contaminated when a tanker load of polypropylene is blown into that silo. These two materials have different densities, or specific gravity. PRS will use a liquid solution of a density that is between the two commingled materials, causing one to sink and the other to float. These two polymers can now be effectively separated. This process will separate almost any two materials of different densities; ground metal, rocks, paper, plastics, etc.