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Upgrading recycled fibres by appropriate treatments during stock preparation

Virgin and recycled fibres, used for the production of paper-based boards, are damaged during their lifetime by various treatments. By applying enzymatic treatment or optimising chemical, physico-chemical and mechanical treatments during the recycling process, this project proposes to restore fibre properties to enable the manufacture of paper and board with a higher mechanical strength. The phenomena of fibre degradation and restoration will be studied using new methods and tools, to contribute to a better understanding of these mechanisms, and to give recommendations to the paper industry on how to prevent or limit fibre degradation. The result will be an improvement in fibre quality after multiple recycling, and the outcome will be an increase in the recycling rate of packaging materials.

The objectives of this project are:
1) to study the phenomena that cause fibre weakening during paper recycling
2) To develop solutions to restore the mechanical properties of the recycled fibres and understand the mechanism of the restoration.
This project deals with recycling brown grade fibre for the production of corrugated paper. Fundamental data on the mechanical properties and morphological, ultrastructural and topochemical parameters of the various types of fibres will be gathered. However, before developing new fibre treatments, it is necessary to quantify in which phases of the process the mechanical strength of the fibres is affected.

Progress to Date
Fractionation allows the separation of pulp into various fractions, to which are applied specific treatments: refining for long fraction and enzymatic treatment on short fraction.
This encouraging technique has been performed on an industrial scale after validation on a pilot plant scale.

The results of the pilot plant scale trials and characterisation have shown that:
1. Double fractionations are efficient for producing various types of pulps that are easily treated separately: short fraction by enzyme, medium fraction and long fraction by MC-refining.
2. Short fraction: decrilling (removal of fines), performed by washing (fine/fibre separation), followed by fine enzymatic treatment before remixing, is an encouraging method for increasing short fraction drainability. The restoration of pulp properties was limited but significant. The yield can be maintained by reintroducing the fines fraction.
3. Medium and long fractions: MC-refining is particularly efficient for developing the mechanical properties of these fractions with limited detrimental effects (there was a low decrease in drainability, but the fibre length remained constant).


Scientist responsible for the project

Dr ALAIN Cochaux
Domaine Universitaire Box 251
38044 Grenoble CEDEX 9
France - FR

Phone: +33 4 76 15 40 65
Fax: +33 4 76 15 40 16


Project ID QLRT-1999-01071
Organisation Centre Technique de l'Industrie des papiers, carton et celluloses
Area 5.3.2
Start date 01 January 1999
Duration (months) 36
Total cost 2 266 845 €
Total EC contribution   1 133 422 €
Status Complete
Web address of the project

The partners

  • Voith Sulzer Paper Technologystoffafbereitung GM, Germany - DE

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