Effect of age of the wood of eucalyptus in its chemical and pulpability, and bleachability and properties of the pulp / Efeito da idade da madeira de eucalipto na sua química e polpabilidade, e branqueabilidade e propriedades físicas da polpa

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

The concern about the quality of the wood that enters a cellulose factory has been focused on many studies, once the productive process and final product are under great influence of the original raw material. Considering the demand for younger trees, the effect of the age of the wood in the chemical constitution and the variables of the process, as well as the bleached pulp final characteristic, becomes a fact of great interest for the industries of the sector. The objective of this study was to characterize two Eucalyptus clones, Eucalyptus grandis (clone A) and Eucalyptus urograndis (clone B) both of different ages ( 1, 3, 5, 6, 7 and 8 years), as for the thin chemical composition and pulping, such the pulp bleachability and physical properties. For that the samples were collected in spots such as the climate and soil characteristics were homogeneous, preventing results variations due to these elements. Both chemical compositions of the clone samples suffered significant statistic variations due to the variation of their age. The concentration of the glicans, as well of the cellulose, tended to raise with the increase of the age of the tree. The concentration of xylans, and the others carbohydrates composing the hemicelluloses, tended to decrease with the increase of the age of the trees. The uronic acids, acetyl groups, lignin, ashes and the ratio S/G lessened with the maturing of the plants, while the extractive concentration increase. The basic density of the wood studied rose with the raise of the age. The 5 years samples presented the greatest pulping yield results for kappa 17.0 (RD17 – 54.7 and 55.0% for the A and B clones respectively). The RD17 presented correlation with the glican concentration. The HeXA’s quantity formed had no relation with the age of the trees, however it did related very well with the alkaline applied charge. The lesser total active chlorine consumption in the bleaching was obtained by the 5 year tree pulps, being 24.7 and 23.5 kg/adt for the clones A and B respectively and also these samples, presented the major bleachability values (0.47 for both). The brightness reversion and bleached pulp viscosity values were considered normal and within the acceptable patterns. The only samples that had final bleaching cost below US$ 40.00/adt were the ones originated from the 5 year wood. The refine energy consumption and tear index, both for the same traction index, were higher for older wood, in the other hand the air passage resistance, that tended to decrease with de increase of the age.

ASSUNTO(S)

influence of age quimica analitica wood chemistry bleachability polpabilidade química da madeira influência da idade pulpability branqueabilidade

ACESSO AO ARTIGO

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