| 摘要 |
A method of separating a portion of acrylonitrile-butadiene-styrene (ABS) from a mixture containing ABS and for separating a portion of ABS and polycarbonate (PC) from a mixture of plastics containing ABS and PC is disclosed. The method includes shredding and/or granulating the mixture of plastics containing ABS and PC to provide a selected particle size; dispersing the shredded mixture of plastics in a first aqueous solution having a specific gravity of 1.04±0.01 g/cc, a pH in the range of 11.5±0.8 and a surface tension of 34±4 dynes/cm wherein a first reject fraction floats and a first retained fraction sinks, separating the first reject fraction from the first aqueous solution, introducing the first retained fraction into a second aqueous solution having a specific gravity of 1.09±0.01 g/cc and a pH in the range of 11.5±0.8 and a surface tension of 34±4 dynes/cm wherein a first product fraction floats and a second retained fraction sinks, separating the first product fraction from the second aqueous solution with the second retained fraction, introducing the second retained fraction into a third aqueous solution having a specific gravity of 1.16±0.01 and a pH in the range of 11.5±0.8 and a surface tension of 34±4 dynes/cm wherein a second reject fraction floats and a third retained fraction sinks, separating the second reject fraction from the third aqueous solution with the third retained fraction, introducing the third retained fraction into a fourth aqueous solution having a specific gravity of 1.203±0.002 and a pH in the range of 11.5±0.8 and a surface tension of 34±4 dynes/cm wherein a second product fraction floats and a third reject fraction sinks, and thereafter separating the second product fraction from the third reject fraction, wherein the first and second product fractions after drying are not less than about 96% ABS and PC. A method of separating polypropylene and polyethylene from each other from a mixture of plastics containing polypropylene and polyethylene is also disclosed. The method includes shredding and/or granulating the mixture containing polypropylene and polyethylene to provide a selected particle size; dispersing the shredded mixture in an aqueous solution having a specific gravity 0.91 to 0.93 g/cc, a surface tension of 34±2 dynes/cm and a pH of 8.5 to 0.5 wherein the polypropylene floats and the polyethylene sinks, and separating the polypropylene from the polyethylene.
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