| 摘要 |
The invention relates to a method which enables the reliable and pure separation of aromatic polymers that are precipitable by acidification, as found in particular in waste water from cellulose production, from an alkaline solution. In order to achieve good separability, in particular by filtration, the polymers are precipitated by reducing the pH value at a relatively low temperature, typically between 15 and 60 ~C, before then reheating the dispersion until it converts to a filterable form, typically between 50 and 90 ~C. The product thus separated by filtration, for example, can be washed and then dried at high temperature, in particular up to 110 ~C, without its turning black.
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