| 摘要 |
<p>Solid catalyst is separated from suspension in a solution of olefin polymer by introducing polymer solution, solvent and suspended catalyst to a first centrifuging zone maintained under superatmospheric pressure, removing from this zone as product a first stream comprising a catalyst-free polymer solution, removing a second stream containing catalyst, solvent and polymer, introducing this second stream to a second centrifuging zone maintained under superatmospheric pressure, removing from this zone a quantity of material containing polymer, solvent and a small amount of catalyst, recycling the material to the first centrifuging zone and removing from the second zone a stream comprising solvent concentrated in catalyst. The polymer solution may be introduced to the first zone after cooling to below the temperature at which polymer begins to precipitate therefrom, while the temperature of the stream entering the second zone may be increased above this point. Specified olefins are ethylene, propylene, butylene, and copolymers with butadiene and isoprene, preferably being polymerized using chromium oxide, containing hexavalent chromium, with silica, alumina, zirconia, thoria and silica-alumina. Apparatus for carrying out the process is described. Specifications 790,195 and 804,641 are referred to.</p> |
