ABSTRACT
Cryogenic processing is based on the principle that many materials exhibit brittle characteristics when their temperatures are reduced to low levels. Microgrinding equipment may be operated with the injection of a cryogen into the grinding chamber. Cryogenic processing relies on some principles to liberate the various fractions from a scrapped item. In cryogenic processing the scrapped items must have their temperatures reduced to their respective cold cracking temperatures just prior to being fed into a fragmentizer. Cryogenic processing has the advantage of yielding a high quality product. A few of the items processed with the cryogenic technique are: automotive-type tires, plastic wires, starters, generators, electric motors, plastic-metal laminates, electrical conductors, and plastic bleedings. Styrofoam, polyurethane, or insulated stainless steel or aluminum tanks can be used to contain the cryogen for the batch immersion freezing method. Cryogenic liquids which come in contact with the human skin cause severe freeze burns; therefore, proper safety procedures must be strictly adhered to.
