Ads
related to: sulfur dioxide bleaching wood pulp at home kit
Search results
Results From The WOW.Com Content Network
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. [1] These processes and chemistry are also applicable to the bleaching of non-wood pulps, such as those ...
The use of wood to make pulp for paper began with the development of mechanical pulping in the 1840s by Charles Fenerty in Nova Scotia [1] and by F. G. Keller [2] in Germany. Chemical processes quickly followed, first with Julius Roth 's use of sulfurous acid to treat wood in 1857, followed by Benjamin Chew Tilghman 's US patent on the use of ...
Dissolving pulp is mainly produced chemically from pulpwood in a process that has a low yield (30 - 35% of the wood). This makes up of about 85 - 88% of the production. [2] Dissolving pulp is made from the sulfite process or the kraft process with an acid prehydrolysis step to remove hemicelluloses. For the highest quality, it should be derived ...
It enabled the recovery and reuse of the inorganic pulping chemicals such that a kraft mill is a nearly closed-cycle process with respect to inorganic chemicals, apart from those used in the bleaching process. For this reason, in the 1940s, the kraft process superseded the sulfite process as the dominant method for producing wood pulp. [6]
It is used as such in some industrial dyeing processes to eliminate excess dye, residual oxide, and unintended pigments and for bleaching wood pulp. Reaction of sodium dithionite with formaldehyde produces Rongalite. Na 2 S 2 O 4 + 2 CH 2 O + H 2 O → NaHOCH 2 SO 3 + NaHOCH 2 SO 2. Thus is used in bleaching wood pulp, cotton, wool, leather and ...
Chemical pulping involves dissolving lignin in order to extract the cellulose from the wood fiber. The different processes of chemical pulping include the Kraft process, which uses caustic soda and sodium sulfide and is the most common; alternatively, the use of sulfurous acid is known as the sulfite process, the neutral sulfite semichemical is treated as a third process separate from sulfite ...
The Do's and Don'ts for Bleaching Your Hair at Home “First off, note the difference between overall color vs a retouch,” says Jackson. “If you are doing a color retouch, you should only ...
Elemental chlorine free (ECF) is a technique that uses chlorine dioxide for the bleaching of wood pulp.It does not use elemental chlorine gas during the bleaching process and prevents the formation of dioxins and dioxin-like compounds, carcinogens.