Residual textile fibre content in granulates
Transcription
Residual textile fibre content in granulates
Printed within the framework of Imprim’ Vert on recycled paper - In its quality of issuerof papers, Aliapur adheres to the eco-body Ecofolio for their recycling. Residual textile fibre content in granulates Aliapur’s R&D department has developed a reliable and reproducible process for determining textile fibre content in batches of end-of-life-tyre granulates. This process is currently being used to help in establishing an AFNOR standard. Residual textile fibre content in granulates Definition Mass fraction of textile fibres contained in a laboratory sample of granulates obtained from end-of-life tyres. Reference value Residual content of loose textile fibres in granulates of between 0% and 0.3% in weight. Origin of the textile fibres The percentage of fibres in end-of-life tyres is between 0% and 6% of the weight of the tyres, depending on whether they are from truck tyres or passenger car tyres. Composition of an end-of-life truck tyre Composition of an end-of-life passenger car tyre Mass fraction Mass fraction Rubber between 75% and 80% Rubber between 80% and 85% Wire between 10% and 15% Wire between 20% and 25% Textile fibres 5% For end-of-life tyres to be integrated into the various industrial production processes and thus recycled, they must be of constant and optimum quality. After the various shredding phases, the textile fibres are removed from the granulates by aspiration. The presence of fibres in the end-of-life tyre granulates can be a problem in certain applications, for example visually, or when the granulates are incorporated into binding agents that the fibres tend to absorb. It is thus important to ensure that the textile fibre content is as low as possible. Industrial production of granulates + Shred Granulates with maximum 0.3% textiles fibres + Wire with between 3 and 50%* of rubber Textile fibres with between 20 and 50%* of rubber * depending on which industrial process is used Method recommended and studied by Aliapur At Aliapur’s request, the BRGM1 adapted the ASTM D5603 – 01 standard to measure the textile fibre content in a 500 g sample of granulates. In addition to the loose textile fibres, the laboratory technicians identified and weighed the visible textile fibres still bound to the granulates. The laboratory confirmed the repeatability and reproducibility of this method. Illustration of the general principle 500 g of granulates Remove from each sieve: balls of loose textile fibres, n textile fibres bound to granulates, n granulates. n ELT granulates Sifter Operating method Masses Granulates Sieve 1 m1 G Loose fibres Bound fibres m1 FLoose m1 FBound Sieve 2 m2 G m2 FLoose m2 FBound Sieve 3 m3 G m3 FLooses m3 FBound Sieve 4 m4 G m4 FLoose m4 FBound Sieve 5 m5 G m5 FLoose m5 FBound Sieve 6 m6 G m6 FLoose m6 FBound n First of all, carry out particle size distribution analyses in accordance with the standard XP T 47-752. Remark: this characterization can be carried out in parallel with the particle size distribution analysis of the products. n Manually remove from each sieve the loose textile fibres, as well as any textile fibres bound to granulates (visible with the naked eye). n Then weigh on scales the bound textile fibres, the loose textile fibres, the remaining granulates for each particle size category. Results The measurements carried out on a dozen products obtained from the sampling plan in accordance with the “Samples and sampling” sheet, and from four different sites (samples of 500 g of granulates) give fibre content values of between 0% and 0.3% in weight. Measurements of the bulk density of fibres produced the following values: from 0.12 to 0.13 g/cm3 (standard NF EN ISO 61 – Plastics – Determination of apparent density of moulding material that cannot be poured from a specified funnel. (1) Bureau de Recherches Géologiques et Minières. The concentration of granulates still bound to textile fibres (visible with the naked eye) varies between 0% and 5.4%. Studying the different products analysed revealed the presence of granulates bound to fibres essentially in granulates of more than 2 mm; below this particle size, the concentration was very low. This operating method is currently the subject of a study with a view to establishing an AFNOR standard. Conclusion The processes for separating out textile fibres used in granulation factories make it possible to attain extremely low free-textile content, or even no fibres. The measurements obtained give values for the residual fibre content of between 0% and 0.3% in weight. References n Projet de norme expérimentale à l’étude – Pneus usagés non réutilisables (PUNR) – Détermination du taux de fibres textiles dans les granulats issus de PUNR à l’issue de procédés de granulation – Méthode basée sur une séparation manuelle après tamisage mécanique des produits. n ASTM D5603 – 01 Standard Classification for Rubber Compounding Materials – Recycled Vulcanizate Particulate Rubber. Sample sites Reference studies “Échantillonnage et caractérisation de granulats de pneus usagés non réutilisables – BRGM pour le compte d’Aliapur – Juillet 2006”. n “Échantillonnage et caractérisation de granulats de pneus usagés non réutilisables en vue de la comparaison de différents procédés de granulation – BRGM pour le compte d’Aliapur – Février 2007”. n “Analyses de granulats, de fibres textiles et de fibres métalliques issus du broyage de PUNR véhicules légers (VL) et poids lourds (PL) – LRCCP pour le compte d’Aliapur – Juin 2005”. n The studies carried out by Aliapur used a variety of batches of ELT granulates from four European granulation factories using different processes and raw materials. These batches correspond to the main products marketed by these sites. The four sites from which the samples were taken collectively represent the main configurations of what can be found in terms of processes and types of tyre used. Aliapur used a wide variety of products for its analyses, guaranteeing an overall view of the sector and good representativeness of the results. n n n n 1 Factory 1: successive shredding of truck tyres. F actory 2: successive shredding of passenger car tyres. F actory 3: shredding by crushing of truck and passenger car tyres. F actory 4: cryogenics followed by shredding of truck and passenger car tyres. 2 4 3 Editorial coordination: R&D Aliapur - Graphic Coordination: communication Aliapur - Design/production: Crayon Bleu - Photo credits:Aliapur DR, Michel Djaoui – March 2010 Printed within the framework of Imprim’ Vert on recycled paper - In its quality of issuerof papers, Aliapur adheres to the eco-body Ecofolio for their recycling. Standards ALIAPUR - Research & Development 71, cours Albert Thomas - 69003 Lyon - FRANCE Tel: +33 (0)4 37 91 43 20 - Fax: +33 (0)4 78 54 67 14 www.aliapur.fr - [email protected] Used tyre recovery in France