INFLUENCE OF RECOVERED PAPER QUALITY ON RECYCLED PULP PROPERTIES

Statistical data show that a further increase of recovered paper (RP) supply to European paper mills could come mainly from increasing and improving household collection. However, it is generally accepted that an extended collection from households is always detrimental to RP quality. The low quality of recovered paper is determined by the high content of unusable materials consisting of non-paper components and unwanted paper and board (paper and board that does not conform to RP grade definition). In this study, the effects of unwanted paper and board (p&b) on recycled pulp properties are analysed for RP grades 1.11 and 1.04, originated from household collection. In the case of deinking RP grade 1.11, it was shown that even a low content (3-5%) of brown packaging p&b strongly affects the optical properties of deinked pulp, by decreasing brightness and by increasing the number and size of specks, due to brown fibre flakes. In the case of packaging RP grade 1.04, the increasing content of graphic paper results in lower freeness, higher ash and short fibre contents and lower mechanical strength of recycled pulp.