Separation of Plastics by Flotation.
U S Pat 4 167 477 Sept 11 1979 :
Individual components of mixtures of plastics, e.g., polystyrene and polyamides, were separated by flotation using sodium silicate as a wetting agent and fatty amines as promoters. Thus, 1 lb of a granular mixture containing equal amounts of polystyrene and 2 different grades of nylon was added to a flotation cell containing 1.2 Gal 0.1 pct aqueous sodium silicate. Passing air through gave a primary float consisting of 100 pct polystyrene in a yield of 92.5 pct of the total polystyrene added. The tailings were separated using aeromine 3037 (c17 primary amine acetates) and hcl, almost completely separating the 2 nylon grades.
U.S. Pat. 4,167,477; Sept. 11, 1979; Chem. Abstr. 90:122,444B