| 摘要 |
<p>A treatment method which can remove particles of impurities as effectively as possible without requiring excessively high apparatus cost or operationally related complexity is provided. As a method for removing impurities from an aqueous fibrous suspension(S), particularly from a waste paper suspension, comprising: carrying out a fractionation process(3) for forming a fine fraction(F) and a coarse fraction(G); subjecting the fine fraction to flotation; and dispersing the coarse fraction, a method for removing impurities comprises treating at least a portion of the coarse fraction together with the fine fraction in a selective flotation step(1) after performing a dispersion process(4). The fine fraction is concentrated into short fibers, and the coarse fraction is concentrated into long fibers in the fractionation process. The selective flotation step for treating the fine fraction and the at least a portion of the coarse fraction is a first selective flotation process.</p> |
