Additives for Deinking

Newspapers, weekly and monthly magazines, brochures and office papers are used as raw material to produce graphic papers, tissue or the top ply of white board. In the deinking process first the printing ink has to be detached from the paper surface then the released ink has to be removed from the pulp slurry, either by flotation or by washing or by a combination of the two. Whereas in Europe flotation is most commonly used and washing is only used for special deinked pulp (DIP) qualities, in North America washing is more common. 

The effiuent/white water quality has to be controlled very exactly. COD increases with increasing pH. For flotation deinking of recovered paper the total chemical costs have a relatively high proportion of 15-20% of the overall DIP production costs. Yield rates up to 93 % for newsprint production are attainable. 

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