Refrigeration of bulk materials - using liquid nitrogen to cool waste copper wire etc. to allow subsequent sepn. from plastics etc.

摘要

A process for the continuous refrigeration of granular or particulate materials in bulk uses several currents of cooling gas. At least one flows in the same direction as the movement of the bulk material and at least one in the opposite direction, the algebraic sum of the pressure differences being zero or slightly positive in the direction of the material movement. Appts. comprises a vertical, thermally insulated, tunnel down which the material travels by gravity and circuits joining into the tunnel at various levels to introduce the refrigeration gases. Process is useful for the recovery of materials such as copper from electric cables or aluminium from products which include rubber or plastic. The cooling cause the materials to become brittle so that they can be crushed and separated.