| 摘要 |
The invention proposes a process which enables separation of aromatic polymers which can be precipitated by acidification, as can be found especially in waste water from cellulose production, from an alkaline solution in a reliable manner and in pure form. To achieve good separation capacity, especially by filtration, it is proposed that the polymers be precipitated by reducing the pH at a relatively low temperature, typically between 15 and 60.degree.C, and the dispersion be subsequently reheated until it passes into filterable form, typically between 50 and 95.degree.C. The product separated in this way for example by filtration can be washed and can be dried at a high temperature, especially up to 110.degree.C, without becoming black.
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