Waste paper deinking process method

Abstract

The invention relates to a waste paper deinking process method, which comprises the processes of pulping, high-concentration sand removal, rough screening, low-concentration sand removal, pre-flotation, fine screening, concentration, heat dissipation, bleaching, post flotation and pulp formation, wherein the pulping process comprises the steps that waste paper and water are placed in a drum pulping machine; 0.1 to 0.8 percent of deinking agent, 0.1 to 0.8 percent of sodium silicate, 0.1 to 0.8 percent of sodium hydroxide and 0.01 to 0.1 percent of surfactant based on the oven dry weight of the waste paper are added into the drum pulping machine; the pulp concentration is controlled to be 3 to 20 percent, the temperature is 20 to 70 DEG C, the pulping time is 10 to 30 minutes, then broken deinked pulp is obtained, and nano silicon dioxide is added into the deinked pulp, wherein the nano silicon dioxide adsorbs ink particles; and because of high specific area of the nano silicon dioxide, the adsorption probability of the nano silicon dioxide and the ink particles is increased, and the small ink particles and gooey particles undergo flocculation to form big particles, which is favorable for flotation and removal.

Description

technical field [0001] The invention relates to a process method for deinking waste paper, which belongs to the technical field of pulping and papermaking. Background technique [0002] At present, waste paper has become an important source of the paper industry, and its proportion is increasing. The recycling of waste paper is an effective way to solve the three major problems faced by the paper industry, such as shortage of raw materials, energy shortage and serious pollution. Deinking is The key to recycling waste paper. [0003] At present, the methods used for waste paper deinking include mechanical method, chemical method and biological enzyme method. [0004] Due to the advent of new technologies such as pressureless printing and electrostatic printing, the types of inks are also increasing, such as UV-curable inks, laser printing inks, flexographic printing inks, etc. These inks are the main reason for the difficulty of deinking. These ink particles become very sma...

AI Technical Summary

Problems solved by technology

[0005] Traditional chemical deinking has the following problems: low pulp whiteness, high residual ink content, high paper dust, high content of fine stickies, etc. At present, the deinking workshop uses traditional chemical deinking, and its pulp Average whiteness 59.90% ISO, average residual ink content 315.56ppm, average sticky content 414.10ppm

[0006] The large stickies in the deinking pulp cannot pass through the sieve gap of 0.10-0.15 mm, and can be mostly removed by the screening equipment in the workshop. The fine stickies can pass through the screen gap of 0.10-0.15 mm, but cannot be effectively removed by the screening equipment, and will When the deinked pulp enters the papermaking workshop, this kind of fine stickies re-flocculates to form large stickies, which brings many problems to the papermaking workshop. Stickies are viscous substances derived from recycled fibers, and most of them have negative charges.

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