| 摘要 |
<p>Mixed fractions of polypropylene and polyethylene obtained from recycling plants cannot be separated by hydrocyclone separation units due to the virtually identical density of the polymers. In known process for separation and recovery of thermoplastics from plastic waste, the use of different temperatures for step-wise heating is proposed, but there is no practicable solution to the problem of separation of parts which have already started to melt from the parts which have not yet undergone thermal deformation. In order to separate polymer mixtures of the small particle size from the polymers having approximately the same specific gravity, but having different melting points, the polymer mixture is heated batchwise in a high-speed mixer by friction or jacket (mandrel) heating as far as softening and agglomeration of the polymer particles having the lower melting points, the mixture is subsequently fed to a cooling mixer, and, after cooling, is separated in a separation unit into agglomerate and undeformed particles.</p> |
