Waste paper deinking pulp chlorine-free bleaching method

Abstract

A waste paper deinking pulp chlorine-free bleaching method includes preparing A solution, which contains the components with the following weight percentage: 6 to 8 percent of EDTA, 7 to 10 percent of sodium polyacrylate, 6 to 9 percent of DTPA, 8 to 12 percent of hydroxyethylidene diphosphonic acid, 5 to 8 percent of DTPMPA, and residual deionized water; preparing a bleaching solution, which proportionally mixes sodium hydroxide, sodium silicate, hydrogen peroxide and A solution; directly mixing waste paper deinking pulp and bleaching solution according to 1:1-1.1 weight ratio under certain conditions in the hydrogen peroxide bleaching section; finally bleaching for 60 to 90 minutes. The waste paper deinking pulp chlorine-free bleaching method can prevent the reaction between metal ions and hydrogen peroxide and reduce the catalytic decomposition of hydrogen peroxide and the consumption of sodium silicate so as to prevent sodium silicate from forming dirt and system plant fiber from twisting, reduce flocculation and achieve dispersion effect and better bleaching effect.

Description

technical field [0001] The invention relates to a chlorine-free bleaching method of waste paper deinked pulp. Background technique [0002] Newspapers and office waste paper are important renewable resources, and the recycling of waste paper is an effective way to solve the shortage of resources, energy waste and serious pollution faced by the paper industry. The recycled pulp after waste paper is shredded, because the whiteness of the paper is reduced in the process of shredding and deinking, so the bleaching of waste paper deinked pulp has always been an important issue in the paper industry. Waste paper is a mixture of different fibers, dyes, sizing agents, fillers, etc. Waste paper deinking pulp is more difficult to bleach than virgin pulp. Hydrogen peroxide is a commonly used chlorine-free oxidative bleaching agent. The main decomposition products are water and oxygen. Its use can reduce environmental pollution, but compared with bleaching virgin pulp, it is less effec...

AI Technical Summary

Problems solved by technology

Hydrogen peroxide is a commonly used chlorine-free oxidative bleaching agent. The main decomposition products are water and oxygen. Its use can reduce environmental pollution, but compared with bleaching virgin pulp, it is less effective when used in waste paper deinking pulp. Moreover, metal ions will decompose hydrogen peroxide during the bleaching process in alkaline, reducing the bleaching effect