| 摘要 |
The removal of undesired constituents or impurities from solids, preferably introduced and removed as a slurry, is effected by counter-current flow of the solids and a washing agent introduced into a washing zone where at least a portion of the washing agent is introduced at a point intermediate the introduction of the solids or slurry and the point of introduction to the zone of the initial washing agent. By controlling the temperature of the washing agent, the plural introduction creates a plurality of temperature interfaces within the washing zone, thus increasing efficiency by, in effect, increasing the number of washing or extraction stages present in the zone. In one embodiment a slurry of polyolefin or polymer, e.g. polypropylene, is washed with a solvent, e.g., substantially pure propylene liquid.
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