Delignification of bamboo (Bambusa procera acher) -: Part 2.: Characterisation of kraft black liquors from different cooking conditions

Bamboo (Bambusa procera acher) was delignified in a laboratoryscale digester by conventional kraft pulping under varying conditions. Pulps with kappa numbers in the range 12.9-56.3 and viscosities in the range 871-1319 ml g(-1) were obtained. The chemical composition of the corresponding black liquors was analysed with respect to their main organic and inorganic constituents. The results indicated that the dry solids of the black liquor contained 40-44% lignin, 20-24% aliphatic carboxylic acids, 4-7% polysaccharides and the residual matter (about 30%) consisted mainly of inorganic constituents. Of the monosaccharide moieties detected in the polysaccharides, xylose was predominant, suggesting that xylan was a major hemicellulose constituent in the black liquor. The effect of effective alkali, sulphidity and H-factor of the cook on the formation of the individual constituents in the black liquor is also discussed.