Bleaching of wood pulp
WebNov 13, 2010 · During kraft pulping, some lignin fragments undergo condensation reactions and form alkali-stable but acid-labile bonds with carbohydrates. Treatment of pulp with an acid can be useful in easy removal of a part of the residual lignin in unbleached kraft pulps. The acid treated pulp can be subsequently bleached by one of the regular bleaching … Web42 Technologies for Reducing Dioxin in the Manufacture of Bleached Wood Pulp Box 4-A—What Is Pulp “Brightness’y?How Is It Measured? “Brightness’ is the reflecting …
Bleaching of wood pulp
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WebJan 29, 2024 · Sr. Sales & Marketing manager. Valmet. Jun 2014 - Apr 20242 years 11 months. Responsible for sales of capital projects in the … WebABSTRACT. This paper summarizes the review of developments in the area of ozone-based elemental chlorine free (ECF) and total chlorine free (TCF) bleaching of wood and non-wood pulps. Focused areas of review are reaction mechanism of ozone with carbohydrates and lignin, effect of process conditions maintained during ozone bleaching on pulp ...
Webbleaching wood pulp pulp wood Prior art date 1972-04-11 Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.) Expired Application number CA897360A Inventor H. Andrews Douglas E. Mallet Samuel WebChemical pulp bleaching is accomplished with various compounds containing chlorine or oxygen and alkali extractions in several stages. Fig. 19.3 indicates why several stages …
Bleaching 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 … See more Brightness is the amount of incident light reflected from paper under specified conditions, usually reported as the percentage of light reflected, so a higher number means a brighter or whiter paper. In the US, the See more Mechanical pulp retains most of the lignin present in the wood used to make the pulp and thus contain almost as much lignin as they do cellulose and hemicellulose. It would be impractical to remove this much lignin by bleaching, and undesirable since one of the big … See more The bleaching of chemical pulps has the potential to cause significant environmental damage, primarily through the release of organic materials into waterways. Pulp mills are almost always located near large bodies of water because they … See more Hydrogen peroxide and sodium dithionite are used to increase the brightness of deinked pulp. The bleaching methods are similar for … See more Chemical pulps, such as those from the kraft process or sulfite pulping, contain much less lignin than mechanical pulps, (<5% compared to … See more • Johan Richter – inventor of the continuous process for bleaching wood pulp • Paper chemicals See more WebThe paper pulp production process can be divided roughly into three stages: wood handling, fiber processing, and drying and packaging. 1. Wood handling. Wood is first debarked and cut into small chips for more …
WebPrevious editions of The Bleaching of Pulp have provided comprehensive information on the technology used to bleach wood pulps. The 5th edition will continue this tradition as the premiere industry text on bleaching technologies but will be more focused on the modern industrial processes with less emphasis on fundamental science. New or more …
WebThe bleaching agents and the sequence in which they are used depend on a number of factors, such as the relative cost of the bleaching chemicals, type and condition of the pulp, desired brightness of the paper to be produced, and sometimes in response to environmental guidelines and regulations. Bleaching of mechanical pulp is much different north by northwest eva marie saintWebMar 1, 2015 · Incorporation of ozone after oxygen delignification stage followed by bleaching with D 0 E OP D sequence significantly improved the brightness and … how to report someone for pirating moviesWebBleaching of chemical pulp. Valmet’s modern bleaching processes and bleach plant design for both hardwood and softwood pulps are focused on pulp quality, efficiency and … how to report someone for withholding mail