| 摘要 |
<p>The invention relates to a process and an installation for processing secondary plastics made up of various thermoplastic polymers as such or mixed, with a view to recycling them. According to the invention, the process comprises the plastification of the polymeric solid in the presence of water while stirring continously, under certain conditions of temperature and pressure, until obtaining a liquid phase water-polymer emulsion which is then filtered and the effluent is subjected to a rotational atomization under pressure, in the presence of a descending internal side circuit of cool water, the tangential speed imparting to the liquid film a rotation motion being higher than 10 m/s, preferably of 100...180 m/s at a rotative speed of 3,500...5,000 rpm, the atomized material coming in contact with the cool water film, so that the solidification of the polymer occurs, said polymer being entrained downwards by the cool water film and subjected to continous stirring and then to a centrifugal separation, so that the resulting water can be decontaminated and recycled while the wet polymer is dried and cyclone-separated in order to be stored. The claimed installation for applying the process comprises some thermally insulating autoclaves (2) with pressurized stirring using an inert gas, which communicate with a storing vessel (11) provided with heating and stirring means, some periodically operating valves (8) being mounted in connection with said vessel (11) and, depending on the level and pressure, there are also provided some mechanical filters (7) mounted on the autoclaves (2), an atomizer (18) having an atomizing disk (17) and a system for cooling and circulating the cooled water, and a suspension vessel (29) and a continuously operating centrifuge (35) and a fluidized-bed dryer (46), the polymer powder dried with preheated gas from some blowers (50 and 51) being finally stored in a dry powders storage bunker (59).</p> |
