| 摘要 |
PROBLEM TO BE SOLVED: To provide a viscosity-reducing agent for a black liquor, which can significantly reduce a viscosity of the black liquor.SOLUTION: The viscosity-reducing agent is added to a black liquor in a black liquor concentrating step for concentrating the black liquor that is a by product in production of kraft pulp, and comprises at least one substance selected from the group consisting of urea, quaternary ammonium salt and alkanolamine. In addition, a method for concentrating the black liquor is also disclosed, which comprises a step of adding at least one substance selected from the group consisting of urea, quaternary ammonium salt and alkanolamine to the black liquor that is a byproduct in the production of kraft pulp to concentrate the black liquor. |
