| 摘要 |
PROBLEM TO BE SOLVED: To provide a pulp washing agent more sufficiently extracting lignin from a pulp raw material, to provide a method for producing pulp, and to provide a method for washing the pulp. SOLUTION: The pulp washing agent contains effective amounts of a chelating compound and a water-soluble polymer. The lignin extraction is improved by adding the pulp washing agent to a washing zone 212 and a pulp washing part 30. Furthermore, the ratio of the amount of the added water-soluble polymer to the chelating compound is preferably increased as the pulp washing agent is added on the upstream side of the washing zone 212 and the pulp washing part 30. COPYRIGHT: (C)2009,JPO&INPIT
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