12 LOGISTICSANDRITZ


Modern market-orientated de-inking processes


More efficient processes for de-inking print papers developed by Andritz are enabling better results to be achieved from the use of cheaper recovered materials. PPL reports


Pulp Paper & Logistics


paper, the range of paper grades that can be produced successfully is also expanding. Around 30 years ago, mechanical pulps began to be partly substituted by recovered paper stock in newsprint production. Today, almost all paper grades


A


are manufactured using 100 per cent recovered paper. Modern de-inking plants produce excellent pulps for high-grade writing and printing papers. The plant design depends on the impurities to


July/August 2015


s a result of the continual development in technologies for processing recovered


be removed and the cleanliness requirements in the final product – and puts a challenge to the suppliers of de-inking technologies. The goal is as always to produce deinked pulps with almost the same characteristics of virgin pulp, but at lower cost. Waste paper processing and de-inking plants are beneficial for economic reasons – regarding the costs of recovered paper as raw material – but above all in terms of environmental protection and climate compatibility. The raw material used has a substantial influence on the quality of the final paper product. Chemical pulp


offers optimum quality with regard to optical properties and paper strengths as well as the cleanliness of the end product, while secondary fibre pulp has advantageous features for the opacity, which is important for graphical papers. For sanitary papers, chemical pulp still provides the best quality parameters because this pulp has the necessary softness.


Recovered paper and contaminants The configuration of a de-inking process (DIP) plant is also determined by the contaminants entering the system with the


Figure 1: ANDRITZ FibreFlow drum pulper slushing office waste and old magazines


secondary fibre. Various process stages are needed to remove undesirable and non-fibre components (such as stickies and printing ink particles) from the pulp or reduce their content, but without harming the fibre material. The following main technological


process stages are necessary to improve the optical properties and treat contaminants in order to optimize the quality of the finished pulp as shown in Table 1:


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