Deinking, bleaching and treating process of waste paper

Abstract

The invention discloses a deinking, bleaching and treating process of waste paper, comprising the following steps of: (1) calculating water consumption and waste paper amount according to the paper pulp concentration of 12-20 percent, adding water into a high-concentration hydrapulper and heating the high-concentration hydrapulper to 70-90DEG C; (2) adding a deinking agent comprising the following substances by 100 parts on the weight of waste paper: 1-3.5 parts of sodium hydroxide, 1.5-4 parts of sodium silicate, 0.1-2 parts of alkylphenoxypolyethyleneoxyethanol, 0.1-2 parts of polyoxyethylene sorbitan monooleate, 0.5-8 parts of sodium dodecyl benzene sulfonate and then feeding the waste paper; (3) carrying out bleaching after operating for 20-25 minutes, adding an acid-alkali buffering agent and a chelating agent and then adding sodium hydrosulfite; and (4) adding hydrogen peroxide after continuing for 30-45 minutes and continuing for 30-50 minutes, carrying out screening, purifying, condensing, and defibrinating and making paper by a paper-making machine. The invention has the advantages that: the deinking and bleaching can be realized in a pulper by one step, so that the production efficiency and the whiteness and the quality of regenerated pulp can be improved; the whitenes can reach over 80 percent ISO; and the invention is especially suitable for producing various high-grade toilet paper.

Description

technical field [0001] The invention particularly relates to a waste paper deinking and bleaching treatment process which can realize waste paper deinking and bleaching in one go and is especially suitable for producing high-grade toilet paper. Background technique [0002] At present, the commonly used waste paper deinking and bleaching process steps are as follows: deinking in high-consistency hydraulic pulper, screening and purification, washing machine cleaning, concentrating machine concentration, bleaching in bleaching tank, refining machine refining, paper machine papermaking . In the existing process, deinking of waste paper is carried out by adding deinking agent into high-consistency hydraulic pulper, and bleaching of recycled pulp is carried out by adding bleaching agent into bleaching pool or other bleaching equipment, so regeneration and bleaching are completely independent. process. Especially for the bleaching of regenerated pulp, the regenerated pulp is gen...

AI Technical Summary

Problems solved by technology

In short, the whole bleaching process takes 6-8 hours, the bleaching time is long, and the production efficiency is low, which not only affects the pulp production, but also increases the production cost; at the same time, the use of hypochlorite bleaching not only consumes a lot of clean water, but also causes serious environmental pollution. Regenerated pulp has low strength and poor whiteness, and it is easy to produce dark gray and impure color

[0003] The invention patent with the patent number ZL01130080.9 discloses a bleaching method for waste paper deinked pulp. The bleaching process is to use a reduction bleaching composition composed of sodium dithionite and other components to perform one-time bleaching. The bleaching effect is not ideal. If you want to achieve higher whiteness, you need to add water-insoluble oil or solvent, but the pulp after adding oil or solvent has a peculiar smell, so it cannot be used as high-grade toilet paper.

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