Browsing by Author "Bouiri, Baya"

Filter results by typing the first few letters
Now showing 1 - 4 of 4
  • No Thumbnail Available
    Item
    Blanchiment de la pâte fibreuse pour transformation chimique
    (2010) Bouiri, Baya
    L’alfa (Stipa tenacissima) est une graminée vivace très répandue en Afrique du Nord et au sud de l’Espagne. Les propriétés de ses fibres foliaires (souplesse, finesse teneur en cellulose) font de ce végétale une précieuse source de matière première pour l’industrie papetière. En raison de la longueur courte de sa fibre, le papier de l’Alfa prend bien les caractères d’imprimerie. Dans cette étude, deux pâtes cellulosiques kraft de différentes compositions chimiques ont été produites, l’une à partir de l’Alfa originale et l’autre de l’Alfa traité préalablement par l'acide dilué. La pulpe kraft de ce dernier a été blanchie par les séquences de blanchiment sans chlore brute : DEPD et DEDP. Le rendement, l’indice Kappa, la brillance et la teneur en α-cellulose des pulpes blanchies et écrues ont été déterminées. Il a été montré que l’Alfa prétraité se cuit plus facilement que l’originale et sa pulpe subissant la séquence de blanchiment DEDP à atteint des taux supérieurs en brillance (94.8 % de norme ISO), en α-cellulose (96,8 %) avec un rendement de 93.6 %, comparé avec celle blanchie avec la séquence DEPD qui a une brillance de 92,8 % de norme ISO, une teneur en α–cellulose de 95,1% avec un rendement de 83.2 %. D'autre part, les propriétés physico-mécaniques de la pulpe n'ont pas été réduites considérablement par le processus de blanchiment. La longueur de rupture, l’indice de déchirure et de l'éclat des feuilles étaient acceptables. Par conséquent, la pulpe spéciale produite à partir de l’Alfa pu être considéré comme matière non seulement pour les papiers de haute qualité mais aussi pour le traitement chimique
  • No Thumbnail Available
    Item
    Elemental chlorine-free bleaching halfa pulp
    (Elsevier, 2010) Bouiri, Baya; Amrani, Moussa
  • No Thumbnail Available
    Item
    Elemental chlorine-free delignification of kraft pulp produced from halfa (stipa tenacissima)
    (2011) Bouiri, Baya; Amrani, Moussa
    Halfa, also known as Stipa tenacissima, is grown in North Africa and south Spain. Due to its short fibre length, paper from halfa retains its bulk and takes block letters well. In this study halfa was evaluated for bleached pulp production. Two cellulose pulps with different chemical compositions were pulped by the conventional Kraft process. One from original halfa material and the other from halfa pretreated by diluted acid. The pulp produced from halfa pretreated with diluted acid was bleached by elemental-chlorine-free sequences DEPD and DEDP. The yield, Kappa number, brightness and α-cellulose content of the bleached and unbleached pulps were evaluated. The results show that during the chemical pulping process, the treated halfa cooked more easily than the original halfa. The treated halfa pulp also showed very good bleaching, reaching a brightness level of 94.8% ISO, a yield of 93.6% and α-cellulose content of 96.8% with the DEDP bleaching sequence as compared to an 83.2% ISO brightness level, 92.8% yield and 95.1% α-cellulose content for pulp bleached with the DEPD bleaching sequence. On the other hand, the physicalmechanical properties of the pulp were not notably reduced by the bleaching process. The breaking length, tear and burst index of the paper sheets were acceptable. Therefore, the halfa material could constitute a worthwhile choice for cellulosic fiber supply
  • No Thumbnail Available
    Item
    Production of dissolving grade pulp from alfa
    (2010) Bouiri, Baya; Amrani, Moussa
    Alfa, also known as Stipa tenacissimaI or "halfa", is grown in North Africa and south Spain. Due to its short fiber length, paper made from alfa pulp retains bulk and takes block letters well. In this study alfa was evaluated for bleached pulp production. Two cellulose pulps with different chemical compositions were pulped by a conventional kraft process. One sample was taken from the original alfa material and another from alfa that had been pretreated by diluted acid. The pulp produced from the pretreated alfa was bleached by the elemental-chlorine-free sequences DEPD and DEDP. The yield, Kappa number, brightness, and α-cellulose content of bleached and unbleached pulps were evaluated. The results showed that during the chemical pulping process, treated alfa cooked more easily than the original alfa. The treated alfa pulp also showed very good bleaching, reaching a brightness level of 94.8% ISO with a yield of 93.6% at an α-cellulose content 96.8(%) with a DEDP bleaching sequence, compared to 83.2% ISO brightness level, 92.8% yield, and 95.1% α-cellulose content for bleached pulp with a DEPD bleaching sequence. Therefore, this alfa material could be considered as a worthwhile choice for cellulosic fiber supply