Sulphate pulping

Tall oil rosin is obtained from crude tall oil obtained from the Kraft (sulphate) pulping of various coniferous trees in the paper manufacturing industry. During the Kraft pulping process the fatty acids and the resin acids from the coniferous wood are saponified by the alkaline medium. On concentration of the resulting pulping liquor, the sodium soap of these mixed acids rises to the surface from where they are skimmed out. By acidification of this material with sulphuric acid, the crude tall oil is obtained. Fractional steam distillation of the crude tall oil allows the separation of the tall oil fatty acids and the tall oil rosins [21]. 

Five cellulose samples were used microcrystalline celluloses (Munkteli, Avicell and Thermocell), cellulose from sulphate pulping process (Taircdl), and recycled Kraft-pulp (IFAB UKP, Sweden). The method for preparation of microcrystalline Thermocell cellulose was developed at IWCh, Latvia [13],... 

Sulphate Liquor.—One ton of sulphate pulp which is used for the manufacture of Kraft paper produces about 2,000 gal. of liquor which is to be concentrated from 10 to 20°B6. Usually a double or triple effect of the horizontal type is used for this purpose, and the capacity is from 2 to 2K gal. per square foot according to the steam pressure. The concentration of this 20°B6, liquor is continued... 

Evaporators for the recovery of soda or sulphate pulp liquors must be washed frequently in order to remove the scale which is formed by the organic matter in the liquor. 

K Nilsson, H Norrstrom, and A Teder. Absorption Bands in Electronic Spectra of Lignins. Part IV. Lignins from Sulphate Pulping of Birch. Svensk Papperstidn. 75 733-738, 1972. 

G Brunow, T Bus, GE Miksche. Reactions of Sulphur during Sulphate Pulping. Acta Chem Scand 26 1117-1122, 1972. 

Practically the only commercial successful innovations made by Finnish chemists in the early 20th century were related to tall oil soap and some other byproducts of woodpulping. The Finnish scholar Alfons Hellstrom discovered two more natural terpenes from juniper resin, invented methods for distilling tall oil under vacuum from sulphate pulping waste, and developed commercially applicable processes for the manufacture of tall oil soap and the use of rosin acids from tall oil for paper sizing. Such distillations of tall oil became an important industry not only in Finland but also in many other countries. By 1939, the sales of tall oil soap conquered a third of the Finnish detergent market. ... 

Pulping of hgnocellulosic materials results in fibres termed pulps. Pulping of wood can generally be divided into mechanical and chemical pulping or mixtures of both types. In chemical pulping, nowadays the alkaline Kraft sulphate pulp process is predominant compared to the sulphite process. 

Kraft process (Kraft or sulphate pulping) describes a technology for conversion of wood into wood pulp consisting of almost pure cellulose fibres. 

Sulphate pulp n. Paper pulp made from wood chips cooked under pressure in a solution of caustic soda and sodium sulphide. 

Fregert S, Gruvberger B, Heijer A (1972) Sensitization to chromium and cobalt in processing of sulphate pulp. Acta Derm Venereol 52 221-224... 

Colophony (rosin) is a resin obtained from different species of coniferous trees. There are three types of colophony, depending on the method of recovery gum rosin, wood rosin and tail-oil rosin. Gum rosin is obtained from various species of living pine trees. The trees are tapped for oleoresin, which is then distilled to obtain turpentine as the distillate and gum rosin as the distillation residue. Wood rosin is produced from old pine stumps. Tail-oil rosin is obtained as a by-product in the sulphate pulping of coniferous wood. The supply of pine stumps for the production of wood rosin is decreasing and, today, the major types produced are gum rosin and tail-oil rosin. In technical literature, the term colophony corresponds to gum rosin. In dermatological literature, tail-oil rosin and wood rosin are also included in the term colophony , since the resins contain the same major chemical components and allergens and are used in various technical products, regardless of the source. In American literature, the term rosin is more frequently used. 

Potassium dichromate, 0.5% petrolatum (sulphate pulp, Fregert et al. 1972)... 

Unbleached kraft (sulphate) pulp has a lignin content of 3 to 5% which, after oxygen delignification, can be decreased to approximately 1.5%, or a kappa value of 8 to 10 (indicator of residual lignin). 

Holmbom B, Ekman R 1978 Thll oil precursors of scots pine and common spruce and their change during sulphate pulping. Acta Acad Abo, Ser B 38(3) 11 pp... 

Until about 1940, approximately equal amounts of chemical pulp were made by these two processes. Sulphate pulp had the advantage of giving... 

There are three routes by which naval stores are produced. The oldest method is the tapping of living trees to cause a flow of oleoresin. The second method is removal of naval stores by solvent extraction. The latter process now has replaced steam distillation as a means of recovering turpentine. In the United States, the latest and now the most important route is kraft (sulphate) pulping of pine, during which turpentine and tall oil are recovered as by-products of kraft pulp manufacture. A fourth process, no longer used in the United States, is recovery of turpentine and pine oils by the destructive distillation of pine wood. ... 

Paavllalnen, L. (1991). Influence of morphological properties of softwood fibres on sulphate pulp fibre and paper properties, in Proceedings of the International Paper Physics Conference. Atlanta, GA TAPPI Press, pp. 383-95. 

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