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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 ]
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 ...
SBB (C2S) construction: 1 - Coating 2 - Bleached chemical pulp 1 - Coating Not drawn to scale. Solid bleached board (SBB) or solid bleached sulphate (SBS) is a virgin fibre grade of paperboard.
The bleaches used to remove unwanted fungal stains from wood include two-part peroxide bleach and solutions of sodium hypochlorite. [27] The former is particularly effective at removing the natural colour of wood before it is recoloured with pigmented stains or dyes. [27] Oxalic acid is particularly effective at removing iron stains from wood. [27]
Mechanical pulping is the process in which wood is separated or defibrated mechanically into pulp for the paper industry. The mechanical pulping processes use wood in the form of logs or chips that are mechanically processes, by grinding stones (from logs) or in refiners (from chips), to separate the fibers.
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.
Solid unbleached board, also known as SUB, is a grade of paperboard typically made of unbleached chemical pulp. Most often it comes with two to three layers of mineral or synthetic pigment coating on the top and one layer on the reverse side. Recycled fibres are sometimes used to replace the unbleached chemical pulp. [1]
A pulp mill in Rauma, Finland Woodchips for paper production. A pulp mill is a manufacturing facility that converts wood chips or other plant fiber sources into a thick fiber board which can be shipped to a paper mill for further processing. Pulp can be manufactured using mechanical, semi-chemical, or fully chemical methods (kraft and sulfite ...