Method for bleaching natural color pulp

A technology for uncolored pulp and oxygen delignification, which is applied in the field of pulp and paper making, can solve the problems of difficult system control, high production risk, environmental protection restrictions, etc., and achieves shortened production time, low production cost, and strong environmental friendliness. Effect

Inactive Publication Date: 2010-10-27
CHINA NAT PULP & PAPER RES INST CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Compared with the single-stage hypochlorite bleaching method and the CEH method, this method has higher production efficiency and better pulp quality; since elemental chlorine is not used, the pollution is reduced; Chlorine, the system control is more difficult, prone to explosion, and the production risk is greater; and because chlorine dioxide inevitably contains a certai...

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] The present embodiment adopts the mixed bamboo material that raw material is yellow bamboo, support green bamboo, westerly wind bamboo, Diaoyuci, Zhitianci, cotton bamboo. Raw materials are cooked into pulp by kraft pulping process. The slurry viscosity used is 1200ml / g, the whiteness is 34.2%ISO, and the kappa value is 13.90. Good pulp adopts two-stage oxygen delignification conditions for oxygen delignification treatment, the pulp is not washed between the two stages of oxygen delignification, and the first-stage oxygen delignification conditions are: sodium hydroxide 3%, magnesium sulfate 0.5% , oxygen pressure 0.7MPa, temperature 80°C, time 30min; second stage oxygen delignification conditions: sodium hydroxide 1%, magnesium sulfate 0.3%, oxygen pressure 0.4MPa, temperature 90°C, time 40min; after oxygen delignification The slurry after plain is washed with hot water at 80°C, the pH of the washed slurry is 7.5, and the slurry is subjected to alkali treatment streng...

Embodiment 2

[0022] Present embodiment adopts raw material to be the mixed bamboo material of Ci bamboo, yellow bamboo, mian bamboo, hemp bamboo. Raw materials are cooked into pulp by kraft pulping process. The slurry viscosity used is 1234ml / g, the whiteness is 33.5% ISO, and the kappa value is 14.2. The good pulp is firstly treated with oxygen delignification under the conditions of two stages of oxygen delignification, the pulp is not washed between the two stages of oxygen delignification, and the first stage of oxygen delignification is used as: sodium hydroxide 2.5%, magnesium sulfate 0.5 %, oxygen pressure 0.8MPa, temperature 60°C, time 40min; the second oxygen delignification conditions are: sodium hydroxide 1.5%, magnesium sulfate 0.3%, oxygen pressure 0.4MPa, temperature 90°C, time 45min; after oxygen delignification After lignification, the slurry is washed with hot water at 80°C, and the pH of the washed slurry is 8. The slurry is subjected to hydrogen peroxide-enhanced alkali...

Embodiment 3

[0024] The raw material used in this embodiment is uncolored wheat straw pulp from a domestic factory. The slurry used had a viscosity of 972ml / g, a whiteness of 33.9% ISO, and a kappa value of 16.6. First, the fine pulp is subjected to oxygen delignification treatment under single-stage oxygen delignification conditions. The single-stage oxygen delignification conditions are: sodium hydroxide 2.5%, magnesium sulfate 0.5%, oxygen pressure 0.8MPa, temperature 60°C, time 45min; After oxygen delignification, the slurry is washed with hot water at 80°C, the pH of the slurry is 8 after washing, and the slurry is subjected to alkali treatment strengthened by oxygen and hydrogen peroxide. The conditions are: 2% sodium hydroxide, 0.05% magnesium sulfate, over Hydrogen oxide 1%, oxygen pressure 0.7MPa, temperature 90°C, time 60min; after alkali treatment, the material is washed with 80°C hot water, and the washed slurry is subjected to ozone bleaching. The ozone bleaching conditions ar...

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Abstract

The invention discloses a method for bleaching natural color pulp. The method adopts the bleaching flows of oxygen delignification (O), alkali extraction (E), ozone bleaching (Z) and hydrogen peroxide bleaching (P), wherein the oxygen delignification can be divided into single section or two sections; the alkali extraction process can adopt the reinforcing treatment of hydrogen peroxide or oxygen and hydrogen peroxide; and the hydrogen peroxide bleaching section comprises normal-pressure hydrogen peroxide bleaching and oxygen reinforced hydrogen peroxide bleaching. The bleaching flow uses the chemicals such as oxygen, hydrogen peroxide, ozone, alkali and the like, and does not use any chlorine-containing bleaching agent. The bleaching flow of the invention is efficient and simple, and is suitable for the natural color pulp of various materials of between 5 and 40 kappa valences. The obtained bleached pulp can be used for making various paper. The waste water produced by the method has no AOX, and can be directly recycled to a washing or digesting section of the natural color pulp. The method improves the product quality and production efficiency, reduces the energy consumption, has strong environment friendliness, obviously reduces the production cost, and has remarkable economic benefit and social benefit.

Description

technical field [0001] The invention relates to a method for bleaching natural color pulp in the field of pulp and papermaking. Background technique [0002] As we all know, pulping and bleaching is the most polluting section in the papermaking industry. Different pulping and bleaching methods are often used, and the degree of pollution varies. At present, cooking and pulping black liquor can achieve better pollution control effect through alkali recovery; however, there is still no good treatment method for bleaching wastewater; especially for bleaching wastewater containing elemental chlorine bleaching method. Because it contains a large amount of organic halides (AOX), especially dioxins, furans and other substances with teratogenic and carcinogenic effects, it is difficult to treat wastewater, the treatment cost is high, and the pollution is serious and long-lasting after direct discharge or simple treatment. . The use of advanced, low-pollution or non-polluting bleach...

Claims

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Application Information

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IPC IPC(8): D21C9/16D21C3/02
Inventor 陈彬
Owner CHINA NAT PULP & PAPER RES INST CO LTD
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