Sulfate pulping process

Terpenes, specifically monoterpenes, are naturally occurring monomers that are usually obtained as by-products of the paper and citms industries. Monoterpenes that are typically employed in hydrocarbon resins are shown in Figure 2. Optically active tf-limonene is obtained from various natural oils, particularly citms oils (81). a and P-pinenes are obtained from sulfate turpentine produced in the kraft (sulfate) pulping process. Southeastern U.S. sulfate turpentine contains approximately 60—70 wt % a-pinene and 20—25 wt % P-pinene (see Terpenoids). Dipentene, which is a complex mixture of if,/-Hmonene, a- and P-pheUandrene, a- and y-terpinene, and terpinolene, is also obtained from the processing of sulfate Hquor (82). 

The most commonly used reinforcement for high pressure decorative and industrial laminates is paper (qv). The strong substrate layers, or filler, are kraft paper. Kraft is a brown paper made from a sulfate pulp process (8). It consists of both short cellulose fibers from hardwoods and long fibers from conifers. The long fibers impart most of the wet strength required for resin saturation processes. 

Trees, especially conifers, contain tall oils. Tall oil is not isolated dkecfly tall oil fatty acids are isolated from the soaps generated as a by-product of the sulfate pulping process for making paper. Refined tall oil fatty acids are obtained by acidification of the soaps, followed by fractional distillation to separate the fatty acids from the rosin acids and terpene hydrocarbons that also are present in the cmde tall oil fatty acids (see Carboxylic acids Fatty ACIDS FROMTALL OIL). 

Trees, especially conifers, contain tall oils. Tall oil is not isolated directly tall oil fatty acids arc isolated from the soaps generated as byproducts of the sulfate pulping process for making paper. 

Simonson, R. (1963). The hemicellulose in the sulfate pulping process, Part 1, The isolation of hemicellulose fractions from pine sulfate cooking liquors. Sven. Papperstidn. 66, 839-845. 

A partly synthetic analog of the oil-based paints are the alkyd resins. The alkyds are esters formed from alcohols and acids through transesterification reactions. A direct source of unsaturated fatty acids is frequently used, for example, tall oil from the sulfate pulping process. 

When coniferous wood is pulped in the strongly alkaline Kraft pulping process, also called the sulfate pulping process , the predominant chemical pulping process today, the resin and fatty acids are converted into sodium soaps, and are after cooking recovered as so-called sulfate soap from the surface of the pulping liquor, the black liquor. The sulfate soap is a lamellar crystalline phase where the resin and fatty acids form the lamellae, and neutral components, such as sterols, are included between the lamellae [7],... 

Rotary kilns and, to a lesser extent, Fluo-SoHds kilns are used to calcine a wet precipitated calcium carbonate filter cake in the kraft or sulfate paper-pulp process (15). Lime is regenerated for use as a causticization reagent in recovering caustic soda for pulp digestion. Losses in lime recovery are replaced by purchased lime (see Paper Pulp). 

Kraft Process. The dominant chemical wood pulping process is the kraft or sulfate process. The alkaline pulping Hquor or digesting solution contains about a three-to-one ratio of sodium hydroxide, NaOH, and sodium sulfide, Na2S. The name kraft, which means strength in German,... 

Manufacture. The oldest method for producing Na2S is by the reduction of sodium sulfate with carbon in a refractory oven at 900—1000°C. Whereas this method is no longer used commercially in the United States, a variation is used to produce sodium sulfide captively during kraft pulp processing to replace lost sodium and sulfur values that were initiated into the system by merchant-suppHed sodium sulfide. In this method, sodium sulfate is added to the system in the recovery furnace, where it is reduced by carbon from the wood pulp to produce sodium sulfide. 

Lignin is removed from wood by both the sulfate and soda paper pulp processes, and limited amts have been recovered from these sources and other wood waste. It has been used as a component of Dynamites, and has been nitrated... 

The oleoresinous exudate or "pitch of many conifers, but mainly pines, is the raw material for the major products of the naval stores industry. The oleoresin is produced in the epithelial cells which surround the resin canals. When the tree is wounded the resin canals are cut. The pressure of the epithelial cells forces die oleoresin to the surface of die wound where it is collected. The oleoresin is separated into two fractions by steam distillation. The volatile fraction is called gum turpentine and contains chiefly a mixture of monoterpenes but a smaller amount of sesquiterpenes is present also. The nonvolatile gum rosin 5 consists mainly of llie dilerpenuid resin acids and smaller amounts of esters, alcohols and steroids. Wood turpentine, wood rosin and a fraction of intermediate volatility, pine oil are obtained together by gasoline extrachon of the chipped wood of old pine stumps. Pine oil is largely a mixture of the monoterpenoids terpineol. borneol and fenchyl alcohol. Sulfate turpentine and its nonvolatile counterpart, tall oil, 5 are isolated as by-products of the kraft pulping process. Tall oil consists of nearly equal amounts of saponified fatty acid esters and resin acids. 

There were good intentions when a small chemical terminal in Savannah, Georgia, that supplied the paper and pulp industry decided to change their product mix. Their terminal was to be converted from handling all nonflammable chemicals to storing large quantities of flammable crude sulfate turpentine (CST). Crude sulfate turpentine is an impure form of turpentine produced as a byproduct of the Kraft pulping process. It is classified as a Class IC flammable liquid. 

Wood is converted into pulp by mechanical, chemical, or semichemical processes. Sulfite and kraft (sulfate) are the common chemical processes, and neutral sulfite is the principal semichemical process (NSSC). Coniferous wood species (softwoods) are the most desirable, but the deciduous, broad-leaved species (hardwoods) have gained rapidly in their usage and constitute about 25 percent of pulp-wood. Table 28.2 summarizes the conditions utilized with the various pulping processes,... 

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