| 摘要 |
<p>The invention relates to reprocessing of waste paper in a de-inking process with a flotation downstream of at least one further purification stage. The invention is characterised by the following features: a) the flotation (32) takes place in a plurality of stages; b1) at the latest after the third flotation stage, the flotation scum (33) accumulated until then is taken off and purified by means of a pressure relief flotation (39) which produces at least clear water (43) and, separately from the latter, the sludge containing the contaminants (46, 48), whereupon the sludge - if appropriate after further thickening - is discharged from the paper treatment process, or b2) first the coarse contaminants and then the fibres are separated from the sludge (33) of the flotation stages - except the last two - in one or two screening devices (36, 37) and the contaminants are at least largely precipitated from the fraction or fractions (38') low in fibres as sludge by pressure relief flotation (39), and the fibre-containing fraction (44) and the clear water (43) from the pressure relief flotation are recycled to a point upstream of the flotation unit (32). <IMAGE></p> |
