PPH KRYSTIAN

Preparation of paper pulp

The paper industry has been using waste paper as a raw material for paper production for a very long time, however, in recent years, due to the dynamic development of civilization, there has been a large increase in the production of paper products. The upward trend in consumption contributes to increased production while at the same time increasing waste. Poland's integration with the European Union causes many changes in Polish environmental legislation and forces the necessity of obtaining and processing waste paper. It is a potential source of very valuable paper fibres, suitable after de-inking for the manufacture of high-quality woodfree papers and sanitary cellulose tissue paper.The key issue here is the preparation of the raw material, i.e. waste paper pulp, which must have appropriate properties - the pulp must be properly dispersed, de-inked and bleached. It is a product of the re-pulping process of waste paper. For this reason, it is a secondary, qualitatively heterogeneous intermediate product, depending both on the type and degree of printing and contamination of the paper or cardboard from which it is made and the method of its cleaning and re-pulping. The properties of the recycled pulp depend on the properties of the raw material (waste paper), whereby paper made from waste paper or lack of own pulp is always weaker than the raw material itself, whose fibres, once dried, lose some (20-40%) of their swelling capacity, conditioning proper binding of the fibres.The paper is made mainly of vegetable fibres; only insignificant quantities are made of animal, mineral or metallic fibres. Knowledge of the morphological, chemical, physical and physico-chemical properties of the fibres is essential for understanding their behaviour in paper production processes and their influence on the properties of the finished product.