| 摘要 |
PCT No. PCT/AU90/00335 Sec. 371 Date Apr. 2, 1991 Sec. 102(e) Date Apr. 2, 1991 PCT Filed Aug. 7, 1990 PCT Pub. No. WO91/01989 PCT Pub. Date Feb. 21, 1991.Method for extracting tannins from bark and multi-stage apparatus suitable therefor. The method includes the steps of: contracting bark containing tannins with a first tannin enriched aqueous wash medium at elevated temperatures; separating the tannin-rich liquid extract by filtration including dewatering the resulting filter cake under pressure; washing the filter cake with a plurality of aqueous wash media at elevated temperatures; and separating the tannin enriched media after each washing stage by filtration including dewatering the filter cake under pressure; wherein each successive wash medium has a lower degree of tannin enrichment than the preceding wash medium.
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