Accession Number : AD0712273

Title :   THE COLOUR OF UNBLEACHED SULPHATE PULP,

Corporate Author : SVENSKA TRAFORSKNINGSINSTITUTET STOCKHOLM

Personal Author(s) : Norrstrom,Hans

Report Date : 11 MAR 1969

Pagination or Media Count : 12

Abstract : A study has been made of the factors in the wood, the pulping and subsequent operations that have a bearing on the colour of unbleached sulphate pulp. The colour of the pulp was determined by the C.I.E. tristimulus method and is reported in the units dominant wavelength and excitation purity. The brightness of the pulps was also measured. Spruce and pine pulps differed in colour as did those from pine sapwood and heartwood. The addition of bark decreased the brightness but had only a slight effect on colour. The Kappa number influenced the colour of the pulp more than the residual alkali of the black liquor but both had an appreciable effect on brightness. Elevated sulphidity and the addition of polysulphide gave a higher dominant wavelength, while the inclusion of black liquor in the cook affected only the brightness. The colour and brightness were dependent on the pH of the process water and the concentration and species of the metal ions present. The brightness also varied according to the washing method. (Author)

Descriptors :   (*WOOD PULP, COLORS), BRIGHTNESS, SULFATES, PH FACTOR, SULFIDES, SOLUTIONS(MIXTURES), SWEDEN

Subject Categories : Wood, Paper and Related Forestry Products
      Mfg & Industrial Eng & Control of Product Sys

Distribution Statement : APPROVED FOR PUBLIC RELEASE