| 摘要 |
<p>The subject matter of the present invention is a method and a device for removing printing ink from waste paper stock. The invention is aimed, in particular, at improving the efficiency of the flotation process used for the removal of printing ink. According to the present invention waste paper stock, which contains printing ink as an impurity, is treated in such a way that the waste paper stock is divided into a coarser and a finer pulp fraction, of which only the finer fraction is subjected to flotation and, after de inking, combined with the coarser waste paper stock. The method is characterised in that the above-mentioned stages are repeated in order to improve the cleaning effect. The device according to the invention is in turn characterised in that fractionating appliances 2 are arranged in the coarser waste paper stock feed lines, which appliances form the coarser and the finer fractions and from which appliances the finer fraction is conveyed via feed lines 4 to flotation appliances 3, which are provided with froth outlet ducts 9, following which the cleaned, de-inked finer fraction is conveyed via feed lines 6, 7 to feed and outlet lines 1, 5, 8 of the fractionating appliances 2, which contain coarser pulp. <IMAGE></p> |
