CN117344561A - Method for preparing high-whiteness high-strength needle-leaf machine pulp - Google Patents

Abstract

The invention belongs to the technical field of chemi-mechanical pulp preparation, in particular to a method for preparing high-whiteness high-strength needle-leaf chemi-mechanical pulp, which comprises the following steps: raw material preparation: selecting a high-quality needle She Songshu, cutting the needle She Songshu into small sections of 10-12 cm, cleaning the needle She Songshu, and selecting the high-quality needle She Songshu, wherein the bark is required to be smooth and flawless so as to ensure the quality and purity of the pinus pinnatifida; selecting proper branches, which are not suitable for making paper pulp; the invention can effectively soften the fibers of conifer through alkali boiling treatment, and improve the flexibility and plasticity of the fibers. Meanwhile, impurities such as lignin and pectin in the fiber can be destroyed by alkali cooking treatment, so that the whiteness and strength of the paper pulp can be improved; the needle Duan Posui is crushed into fine fibers in a mechanical crushing mode, so that the surface area and the contact area of the fibers can be increased, the binding force and the adhesive force between the fibers are improved, and the strength and the stability of paper pulp are improved.

Description

Method for preparing high-whiteness high-strength needle-leaf machine pulp

Technical Field

The invention relates to the technical field of chemi-mechanical pulp preparation, in particular to a method for preparing high-whiteness high-strength needle-leaf chemi-mechanical pulp.

Background

Chemi-mechanical pulp is a pulp obtained by treating a vegetable fibre raw material by chemical pretreatment and mechanical milling. In particular, this pulping process removes some of the hemicellulose from the wood chips by mild pretreatment, such as chemical impregnation or cooking, leaving lignin less or essentially undissolved, but softening the intercellular layer. And then, the softened wood chips or grass sheets are ground by a disc grinder, so that the fibers are separated into paper pulp.

The purpose of chemi-mechanical pulp is to make paper, which pulp is called mechanical pulp. If a certain chemical treatment is performed before refining, the resulting pulp is called chemimechanical pulp.

The conifer is short in fiber and low in strength, and can influence the quality of paper when directly used for papermaking. Therefore, it is necessary to perform a slurrying treatment; however, the traditional needle blade pulping method has the problems of low whiteness, poor strength, high production cost and the like, and seriously influences the quality and the production benefit of paper.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a method for preparing high-whiteness high-strength needle-leaf machine pulp, which solves the problems of low whiteness, poor strength and high production cost.

In order to achieve the above purpose, the present invention provides the following technical solutions: a method for preparing high-whiteness high-strength needle-leaved machine pulp, comprising the following steps:

(1) Raw material preparation: selecting a high-quality needle She Songshu, cutting the needle She Songshu into small sections of 10-12 cm, cleaning the needle She Songshu, and selecting the high-quality needle She Songshu, wherein the bark is required to be smooth and flawless so as to ensure the quality and purity of the pinus pinnatifida; selecting proper branches, which are not suitable for making paper pulp;

(2) And (3) alkali cooking: heating and boiling the cleaned needle Duan Fangru in 2% -3% sodium hydroxide solution for 30 min to fully soften the fibers; in the process, the sodium hydroxide can effectively remove impurities such as lignin, resin and the like, and soften the fiber, so that the subsequent bleaching and pulping processes are easier;

(3) Mechanical crushing: the needle leaf segments subjected to alkali boiling treatment are put into a pulping machine, a proper amount of water and a crushing element are added, the needle leaves Duan Posui are made into fine fibers through high-speed rotation and impact, and in the crushing process, a proper amount of water is added to play a role in lubrication, so that friction among the fibers is reduced, and the crushing and the fine fibers are facilitated; meanwhile, the added water can also help to clean impurities and residual alkali liquor on the surface of the fiber, so that the quality and purity of the paper pulp are improved;

(4) Bleaching: adding 10% -20% hydrogen peroxide bleaching agent into the crushed fiber, heating and stirring for 30 minutes to remove lignin and other impurities in the fiber, so as to improve the whiteness of the fiber, wherein the hydrogen peroxide bleaching agent can effectively remove lignin and other impurities in the fiber, improve the whiteness and purity of the fiber, and the heating and stirring can promote interaction between the bleaching agent and the fiber, so that the impurities are easier to remove;

(5) Washing and drying: the bleached fiber is washed clean, residual chemical substances and moisture are removed, then drying treatment is carried out, and the chemical substances and moisture on the surface of the fiber can be removed by washing, so that the quality and purity of paper pulp are improved; the cleaning with clear water can be carried out for multiple times to fully remove residual substances; meanwhile, the drying treatment can remove the moisture in the fiber, so that the paper pulp is drier and more stable;

(6) And (3) fiber screening: the dried fibers are subjected to screening treatment, and classified and stored according to the required fiber length and quality, the screening treatment can remove the fibers with too long or too short length, so that the fiber length of the paper pulp is more uniform, the quality and purity of the paper pulp are improved, and the classification and storage are carried out according to the required fiber length and quality, so that the requirements of different paper making can be better met, and the quality and production efficiency of the paper are improved;

(7) And (3) pulp manufacturing: the screened fibers are subjected to filter pressing to remove filter pressing shapes, so that the dryness is improved, the fibers with different lengths and qualities are mixed according to a certain proportion, the more comprehensive fiber characteristics and paper properties can be obtained, and the adhesive force between the fibers can be increased by adding a proper amount of water and a gelling agent, so that the paper pulp is more stable and uniform; after being stirred uniformly, the paper pulp can be used for producing various different kinds of paper.

Compared with the prior art, the invention has the following beneficial effects:

the fiber of conifer can be effectively softened by alkali boiling treatment, and the flexibility and plasticity of the fiber are improved. Meanwhile, the alkali cooking treatment can damage lignin, pectin and other impurities in the fiber, which is beneficial to improving the whiteness and strength of the paper pulp.

The needle Duan Posui is crushed into fine fibers in a mechanical crushing mode, so that the surface area and the contact area of the fibers can be increased, the binding force and the adhesive force between the fibers are improved, and the strength and the stability of paper pulp are improved.

Energy consumption and noise pollution in the crushing process can be reduced through the crushing element, and the crushing effect and the production efficiency can be improved.

Impurities and pigments in the fiber can be further removed through bleaching treatment, and the whiteness and purity of the paper pulp are improved.

Residual chemical substances and moisture in the paper pulp can be removed through washing and drying treatment, and the quality and the service performance of the paper pulp are improved.

The fiber sorting and storage device has the advantages that the fibers with different lengths in the paper pulp can be sorted and stored through fiber sorting, the quality and the use effect of the paper pulp are improved, the matching use of the fibers can be carried out according to the requirements of different paper sheets, and the diversity and the functionality of the paper sheets are improved.

Detailed Description

The following will clearly and completely describe the technical solutions in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

Examples

The present invention provides the following embodiments:

(1) Raw material preparation: selecting a high-quality needle She Songshu, cutting the needle She Songshu into small sections of 10-12 cm, cleaning, keeping straight without damaging bark during cutting, putting the cut needle sections into clear water, adding a proper amount of cleaning agent, lightly cleaning with a brush or a high-pressure water gun to remove dirt and impurities on the surface, avoiding damaging fibers and bark during cleaning, ensuring the cleaning of water quality and avoiding polluting the fibers;

(2) And (3) alkali cooking: heating and boiling the cleaned needle Duan Fangru in 2% -3% sodium hydroxide solution for 30 min to fully soften the fibers;

specifically, the cleaned needle Duan Fangru is heated and boiled for 30 minutes by steam in a sodium hydroxide solution with the concentration of 2% -3%, and simultaneously, the needle Duan Junyun is heated and fully softened by continuous stirring, the temperature and the pressure are controlled in the heating process, the needle segment is prevented from being burnt or the sodium hydroxide is prevented from being decomposed and losing efficacy due to the over-high temperature, and after the needle segment is boiled, the needle segment is fished out of the sodium hydroxide solution and is washed by clean water, so that the residual alkali liquor and impurities are removed;

(3) Mechanical crushing: putting the needle leaf segment subjected to the alkaline cooking treatment into a pulping machine, adding a proper amount of water and a crushing element, and turning the needle leaf Duan Posui into fine fibers through high-speed rotation and impact;

the refiner generally adopts horizontal rotation type, and the inner wall is attached with breaking elements such as blades, hammer sheets and the like, and breaks the needle blade sections in a high-speed rotation mode, so that the refiner is further provided with an impact device for impacting and flushing the fibers through high-pressure water flow to ensure that the fibers are finer and more uniform.

(4) Bleaching: adding 10% -20% hydrogen peroxide bleaching agent into the crushed fiber, heating and stirring for 30 minutes to remove impurities such as lignin in the fiber and improve the whiteness of the fiber;

the specific heating temperature and stirring time depend on the type and amount of hydrogen peroxide bleaching agent, the characteristics of the fibers and the quality requirements of the pulp, and generally, the heating temperature can be between 60 and 80 ℃ and the stirring time can be between 20 and 40 minutes;

(5) Washing and drying: washing the bleached fiber, removing residual chemical substances and moisture, and then drying;

to avoid damage to the fibres or incomplete evaporation of water due to excessive temperatures, vacuum drying is used to avoid this.

(6) And (3) screening fibers: screening the dried fibers, and classifying and storing the fibers according to the length and quality of the fibers;

the screening treatment adopts 170 mesh screens and 2000-rotation speeds to control the fiber length and remove impurities, and classification and storage are also classified and identified according to the specific condition of the paper pulp and the quality requirement of the paper pulp so as to facilitate subsequent use and management.

(7) And (3) pulp manufacturing: and (3) carrying out filter pressing on the screened fibers to remove filter pressing shapes and ensure the dryness to be improved.

Finally, it should be noted that: the foregoing description is only a preferred embodiment of the present invention, and the present invention is not limited thereto, but it is to be understood that modifications and equivalents of some of the technical features described in the foregoing embodiments may be made by those skilled in the art, although the present invention has been described in detail with reference to the foregoing embodiments. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (1)

1. A method for preparing high-whiteness high-strength needle-leaved machine pulp, which is characterized by comprising the following steps:

(1) Raw material preparation: selecting a high-quality needle She Songshu, cutting the needle She Songshu into small sections of 10-12 cm, sieving, filtering, and washing;

(2) And (3) alkali cooking: heating and boiling the cleaned needle Duan Fangru in 2% -3% sodium hydroxide solution for 30 min to fully soften the fibers;

(3) Mechanical crushing: putting the needle leaf segment subjected to the alkaline cooking treatment into a pulping machine, adding part of hydrogen peroxide and a crushing element, and turning the needle leaf Duan Posui into fine fibers through high-speed rotation and impact;

(4) Bleaching: adding 10% -20% hydrogen peroxide bleaching agent into the crushed fiber, heating and stirring for 30 minutes to remove impurities such as lignin in the fiber and improve the whiteness of the fiber;

(5) Washing and drying: washing the bleached fiber, removing residual chemical substances and moisture, and then drying;

(6) And (3) fiber screening: screening the dried fibers, and classifying and storing the fibers according to the length and quality of the fibers;

(7) And (3) pulp manufacturing: and (3) carrying out filter pressing on the screened fibers to remove filter pressing shapes and ensure the dryness to be improved.