Kraft processProcess of converting wood into wood pulp A kraft paper mill in The Pas, Manitoba Woodchips for paper production The kraft pulping process, or simply kraft or sulfate process (spelling, sulphate in the U.K. and older literature) is a preeminent industrial process for conversion of wood into wood pulp, a product that consists of almost pure cellulose fibres, the main component of paper.[not verified in body] The process name is derived from the Swedish and German word Kraft, meaning "strength" in this context, due to the characteristic strength of the kraft paper produced using the process.
Bleaching of wood pulpBleaching of wood pulp is the chemical processing of wood pulp to lighten its color and whiten the pulp. The primary product of wood pulp is paper, for which whiteness (similar to, but distinct from brightness) is an important characteristic. These processes and chemistry are also applicable to the bleaching of non-wood pulps, such as those made from bamboo or kenaf.
Pulp (paper)Pulp is a fibrous lignocellulosic material prepared by chemically, semi-chemically, or mechanically isolating the cellulosic fibers of wood, fiber crops, waste paper, or rags. Mixed with water and other chemicals or plant-based additives, pulp is the major raw material used in papermaking and the industrial production of other paper products.
Soda pulpingSoda pulping is a chemical process for making wood pulp with sodium hydroxide as the cooking chemical. In the Soda-AQ process, anthraquinone (AQ) may be used as a pulping additive to decrease the carbohydrate degradation. The soda process gives pulp with lower tear strength than other chemical pulping processes (sulfite process and kraft process), but has still limited use for easily pulped materials like straw and some hardwoods.Sulfite processThe sulfite process produces wood pulp that is almost pure cellulose fibers by treating wood chips with solutions of sulfite and bisulfite ions. These chemicals cleave the bonds between the cellulose and lignin components of the lignocellulose. A variety of sulfite/bisulfite salts are used, including sodium (Na+), calcium (Ca2+), potassium (K+), magnesium (Mg2+), and ammonium (NH4+).
PaperPaper is a thin sheet of matted cellulosefibers. Largely derived from lignocellulose, paper is created from a pulp dissolved into a slurry that is drained and dried into sheets. Different types of paper are defined by constituent fiber, paper pulp, sizing, coating, paper size, paper density and grammage.
Sodium hydroxideSodium hydroxide, also known as caustic soda and, more generically, as lye, is an inorganic compound with the formula NaOH. It is a white solid ionic compound consisting of sodiumcationsNa and hydroxideanionsOH. As a strong nucleophile, it is frequently used in SN2 reactions. Sodium hydroxide is a highly corrosivebase and alkali that decomposes lipids and proteins at ambient temperatures, and may cause severe chemical burns at high concentrations.
AnthraquinoneAnthraquinone, also called anthracenedione or dioxoanthracene, is an aromaticorganic compound with formula C14H8O2. Several isomers exist but these terms usually refer to 9,10-anthraquinone (IUPAC: 9,10-dioxoanthracene) wherein the keto groups are located on the central ring. It is used as a digester additive to wood pulp for papermaking. Many anthraquinone derivatives are generated by organisms or synthesised industrially for use as dyes, pharmaceuticals, and catalysts.
PapermakingPapermaking is the process of manufacturing paper and cardboard, which are widely used for printing, writing, and packaging, and numerous other purposes. Today almost all paper is made using industrial machinery, while handmade paper survives as a specialized craft and a medium for artistic expression.
BrightnessBrightness is an attribute of visual perception in which a source appears to be radiating/reflecting light. In other words, brightness is the perception dictated by the luminance of a visual target. The perception is not linear to luminance, and relies on the context of the viewing environment (for example, see White's illusion).
Substance (chemistry)In chemistry, a substance is a unique form of matter with constant chemical composition and characteristic properties. Chemical substances may take the form of a single element or chemical compounds. If two or more chemical substances can be combined without reacting, they may form a chemical mixture. If a mixture is separated to isolate one chemical substance to a desired degree, the resulting substance is said to be chemically pure.*As an Amazon Associate I earn from qualifying purchases.