| 摘要 |
<p>In the preparation of used paper (RP) with a wood content, it is cleaned before the heating stage (2) in a suspension. The suspension is divided into two fiber fractions with one fraction rich in wood matter and with a significantly higher wood content than the other fraction. The high-wood content fraction is passed to a stage (1) for water to be extracted to be passed as thick matter (S) to the heating stage (2). The used paper material is subjected to hot shearing forces, before division into fractions, followed by a sufficiently strong cooling action to give the fibers the behavior to divide into the two fractions. The heating stage (2) for the thick matter (S) is at a temp. of /-150 deg C, combined with a shear force working (3), where the thick matter (S) is dispersed (3) and kneaded. The thick matter (S) is held at a temp. of at least 100 deg C or at least 130 deg C during the shear force actions (3). The heating stage (2) is held at an absolute pressure of at least 2 bar, with the shear force actions through the outflow from the overpressure zone. The added chemicals (CH,CH'), to break down the material, contain NaOH and/or Na2CO3 and/or Na2S or they contain CaO, MgO and/or NaOH and/or NH4OH/SO2. The chemicals contain an organic solvent, and especially alcohols. After a dwell time, for the chemicals (CH,CH') to act, the material is passed through a washing stage (4) where the lignin content is removed. In addition, dirt particles are washed out, such as ink and stickies, and the like.</p> |
