Category Archives: pulp bleaching

Hydrogen peroxide bleaching

Hydrogen peroxide is a total chlorine free (TCF) bleaching agent. It is appropriate for chemical, mechanical and recycled pulp to achieve a wide range of brightness. It has both oxidizing and reducing properties which is pH depended. The chemical formula of this bleach is H2O2. Pure Read more

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Chlorine dioxide bleaching

Chlorine dioxide is an oxidizing agent for pulp bleaching. The chemical formula of this chlorine dioxide bleach is ClO2. It is a yellowish-green gas, bad odor and liquefied in 11⁰C which is red in color. It is an ECF (elemental chlorine-free) bleaching process which is currently most Read more

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Hypochlorite bleaching

Hypochlorite bleach is an oxidizing agent. There are two types of hypochlorite bleaching agent that are used in pulp and paper industries such as calcium hypochlorite and sodium hypochlorite. Generally, this stage is placed after chlorination and alkali extraction stages. It can be single stage Read more

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Alkaline extraction stage for pulp bleaching

Alkaline extraction stage is essential after chlorination bleaching stage is to remove chlorinated and oxidizing lignin products from the pulp. It is also help to reactivate the remaining lignin for the next oxidation stage. All the chlorinated lignins are not soluble in the water. About 40-42% Read more

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Chlorination bleaching process

Chlorination bleaching is the second stage of the pulp bleaching process. It is the cheapest bleaching agent for eliminating lignin. Elemental chlorine (EC) reacts selectively with the non carbohydrate compounds. It is another significant delignification process. It ruptures the lignin bonds and Read more

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Oxygen delignification process

Oxygen Delignification is one of the most significant and well proven pulp bleaching process for ECF (elemental chlorine free) and TCF (total chlorine free) bleached pulp production. It is the first stage of the bleaching process; in this case oxygen and alkali are used to eliminate a portion of Read more

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Pulp Bleaching Sequences

Globally, there are several bleaching sequences are shown in different pulp mills to achieve the bleaching action. Different chemicals are used in each stage usually with washing between two stages to removes products. The preference of bleaching sequences depends on many things such as pulp Read more

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What is bleaching of pulp

The objective of pulp bleaching is to produce white pulp. Unbleached pulps are not suitable for manufacturing of high grade of white paper. Since all the processing pulp brightness is very low, especially Kraft pulp. The sulfite pulping process produces comparatively bright chemical pulps, while Read more

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