Abstract: Enhanced methods for separating of overlapping density porous materials are provided. The methods of the invention exploit the differences in the porosity of porous feed materials compared to that of the solid plastics. In the first stage, air is forced out of the pores of a porous feed material. In the second stage, a solution, having the appropriate density, is forced into the pores. This increases the density of the porous material relative to the density of the solid plastics. As a result, the porous material can be made to sink, while the solid plastics continue to float.

Abstract: An elutriation column is installed in a separation tank. The elutriation column includes a vertical separation column having a first side feed arm and a second side overflow arm spaced above the first side feed arm. Water is forced upwardly through the vertical separation column at a controllable velocity. A solid feed mixture is fed through the first side feed arm to the vertical separation column. Water from the tank rising in the vertical separation column at the controlled velocity causes targeted floater materials to move upwardly in the vertical separation column and heavier sinker materials to continue to sink. The floater materials flow from an outlet in the side of the separation tank into the recovery tank. At a discharge, lower end of the vertical separation column, the heavier sinker materials are removed from the separation tank. A mechanism is provided for purging undesirable materials that can cause plugging from the feed arm.

Abstract: An elutriation column is installed in a separation tank. The elutriation column includes a vertical separation column having a first side feed arm and a second side overflow arm spaced above the first side feed arm. Water is forced upwardly through the vertical separation column at a controllable velocity. A solid feed mixture is fed through the first side feed arm to the vertical separation column. Water from the tank rising in the vertical separation column at the controlled velocity causes targeted floater materials to move upwardly in the vertical separation column and heavier sinker materials to continue to sink. The floater materials flow from an outlet in the side of the separation tank into the recovery tank. At a discharge, lower end of the vertical separation column, the heavier sinker materials are removed from the separation tank. A mechanism is provided for purging undesirable materials that can cause plugging from the feed arm.

Abstract: Enhanced methods for separating of overlapping density porous materials are provided. The methods of the invention exploit the differences in the porosity of porous feed materials compared to that of the solid plastics. In the first stage, air is forced out of the pores of a porous feed material. In the second stage, a solution, having the appropriate density, is forced into the pores. This increases the density of the porous material relative to the density of the solid plastics. As a result, the porous material can be made to sink, while the solid plastics continue to float.