Leaching Bollman extractor

In Fig. 12.8-2a an enclosed moving-bed bucket elevator device is shown. This is called the Bollman extractor. Dry flakes or solids are added at the upper right side to a perforated basket or bucket. As the buckets on the right side descend, they are leached by a dilute solution of oil in solvent called half miscella. This liquid percolates downward through the moving buckets and is collected at the bottom as the strong solution or full miscella. The buckets moving upward on the left are leached countercurrently by fresh solvent sprayed on the top bucket. The wet flakes are dumped as shown and removed continuously. 

Figure 12.8-2. Equipment for moving-bed leaching [a) Bollman bucket-type extractor, (b) Hildebrandt screw-conveyor extractor.

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