Determinação do teor de cinzas em dez espécies de madeiras amazônicas

Abstract

Wood is one of the materials most used by man due to its great variability, as for its physical and mechanical properties, as well its aesthetic characteristics. However, specific data on the quantitative chemical composition of Brazilian tropical species are scarce in the literature. These data can be found as percentages of extractives, ashes, lignin, for only a few tropical species, but for a large number of species, their quantification is still missing. The mineral compounds known as ashes provide information on the amount of inorganic substances, aiming at the energetic use of wood residues, some characteristics are fundamental, among them the ash content, to evaluate the feasibility of the use of this material. The objective of this work was to quantify the ash content in the wood of 10 Amazonian wood species. Samples were selected from 10 species of wood that are being exploited by Mil Madeiras Preciosas. Each wedge-shaped specimen was divided into two, one of which was used for ash analysis and the other for anatomical studies, the samples were then processed into sawdust in a knife mill. The ash content was determined by ASTM Standard D1102-84 (2007), using porcelain crucibles for calcination of samples in a muffle oven at a temperature of 580 ~ 600°C. Ashes contents found in all species are among the values considered accepts for tropical species. Of the species studied, only ‘jarana’ (Holopyxidium jarana) and ‘taxi amarelo’ (Sclerolobium paniculatum) did not have their previous identifications confirmed by the macroscopic analysis performed in the laboratory. These species were identified in this study as ‘jutaí café’ (Dialium guianense) and ‘taxi preto’ (Tachigali myrmecophila). The ash contents found in all species are among the acceptable values for tropical species, but the species ‘preciosa’ (Aniba canelilla), ‘louro itaúba’ (Mezilaurus itauba) and ‘jutaí pororoca’ (Martiodendron elatum) presented levels above 1.50%, therefore, patched its use for the production of charcoal.