CN106801356A - A kind of method that maize straw normal pressure prepares high yield pulp1 fluting medium slurry - Google Patents

Abstract

A kind of method that maize straw normal pressure prepares high yield pulp1 fluting medium slurry, is related to a kind of preparation method of fluting medium slurry.The present invention is to solve, substantially all using high temperature, high pressure, medicine high treatment maize straw, existing in existing pulp and paper industry, pulping yield is low, and the problem that waste liquid cannot be processed.Method：First, maize straw is sent into pulverizer, the stalk that will be crushed first with centrifugal blower sends into high-speed oscillating sieve, then by cyclopneumatic separator so that skin is separated with marrow, obtains maize straw skin raw material；2nd, maize straw skin raw material is impregnated in NaOH solution；3rd, high yield pulp1 fluting medium slurry will by the maize straw skin raw material roll mill grinding of dipping, be obtained.This method obtains pulping yield high under conditions of whole normal pressure, and yield has reached more than 75%.The present invention is applied to fluting medium field.

Description

A method for preparing high-yield corrugated base paper pulp from corn stalks under normal pressure

technical field

The invention relates to a preparation method of pulp for corrugated base paper.

Background technique

Corrugated boxes, as a traditional and essential packaging container, have been used for hundreds of years and are deeply favored. Corrugated cardboard is the raw material for making corrugated cartons, and corrugated base paper is one of the important components for the production of corrugated cardboard. Corrugated base paper requires good fiber bonding strength, smooth paper surface, good tightness and stiffness, and requires a certain degree of elasticity to ensure that the made carton has shock resistance and pressure resistance. The corrugated base paper currently produced is divided into 6 types according to the pulping mode: American waste, American waste + national waste, American waste + straw pulp, national waste + straw pulp, American waste + national waste + straw pulp and all straw pulp. Using #11 American waste to produce high-strength corrugating base paper, or using high-quality wheat straw as raw material to produce high-strength corrugating base paper using non-polluting pulping technology plus #11 American waste to produce high-strength corrugating base paper can produce high-quality corrugating base paper, but due to the sharp increase in demand for American waste in the domestic market , the U.S. waste market has experienced a situation of shortage of supply and rising prices. Using American waste (and Russian waste, Japanese waste, European waste) and national waste as raw materials can only produce some corrugated base paper with low strength requirements. The quality of the corrugated base paper produced from national waste is reduced due to repeated recycling of raw materials, and only medium and low corrugated base paper can be produced.

The price of American waste remains high due to the influence of international factors, and production companies need to properly store, pack and stack it, and prevent rain and ventilation; before shredding waste paper, it must be unpacked and sorted, due to the complex composition of waste paper, debris More, the selection is not only time-consuming, laborious and inefficient, but also pollutes a lot. However, if American waste is not selected, the corrugated base paper produced will have the problem of poor paper quality to varying degrees.

Corn stalks are a by-product of my country's main crop corn, with an annual output of up to 250 million tons. At present, most of the corn stalks are burned on the spot, which not only causes a lot of waste of straw resources, but also causes huge pollution to the environment. The fiber component in corn straw mainly exists in the outer skin of the rice straw, which has high strength and good toughness, and its performance is similar to that of reed, so it should be a good material for making paper. However, in the pulp and paper industry, corn stalks are basically processed by chemical pulping at present. The processing process is high temperature, high pressure, high chemical, low pulping yield, and the waste liquid cannot be treated. Therefore, corn stalks have not been used in the preparation of corrugated base paper.

Contents of the invention

The present invention aims to solve the problems that corn stalks are treated with high temperature, high pressure and high chemicals in the existing pulping and papermaking industry, and the pulping yield is low, and the waste liquid cannot be treated. Method of pulping corrugated base paper.

The method for preparing high-yield corrugated base paper pulp from corn stalks under normal pressure of the present invention comprises the following steps:

1. Send the corn stalks into the pulverizer and crush them to a particle size of 1-2 cm. First, use a centrifugal fan to send the crushed straws to a high-speed vibrating screen to make the materials in a suspended or semi-suspended state. With the help of a cyclone separator, due to the different densities of light materials such as skin and pith, the light parts such as skin and pith are separated to obtain corn stalk skin raw materials;

2. Under normal pressure, soak the corn stalk husk raw material in NaOH solution;

3. Grinding the impregnated corn stalk raw material with a double-roller mill to obtain high-yield pulp for corrugated base paper.

Further, the corn stalk husk raw material obtained in step 1 is firstly pretreated, and then subjected to the next step of impregnation treatment. The specific method of the pretreatment is as follows: washing the corn stalk husk raw material with water at 50-60° C., steaming it under normal pressure for 20-30 minutes, and finally feeding it into a screw extrusion deflaking machine for extruding and deflaking.

Further, the mass concentration of the NaOH solution in step 2 is 2%-10%.

Further, the dipping temperature in step 2 is 80-120° C., and the dipping time is 40-60 minutes.

Further, the slurry separated by the twin-roll mill in Step 3 is also sent to a high-consistency refiner for refining. Since the high-consistency refining hardly cuts the fibers, the fiber separation effect is good, and the pulping quality will be greatly improved.

Principle of the present invention:

In the present invention, the corn stalks are fed into the pulverizer, and light parts such as skin and pith are peeled off under the action of shearing and impacting, and are pulverized into a certain particle size. Under the action of the centrifugal fan, the crushed material enters the high-speed vibrating screen, making the material in a suspended or semi-suspended state. With the help of a cyclone separator, due to the different densities of light materials such as skin and pith, the light parts such as skin and pith are separated.

Beneficial effects of the present invention:

The method of the present invention uses peeled corn stalks as raw materials, and the pith of corn stalks is mostly miscellaneous cells, which do not contribute to the quality of paper, but will cause poor paper quality. Therefore, the present invention removes the pith of corn stalks, and then Preparation of pulp for corrugated base paper. A high pulping yield is obtained under the condition of normal pressure throughout the whole process, and the yield reaches more than 75%, which is more than 50% higher than the 50% yield of corn stalk chemical pulping.

Moreover, the fracture length of the corrugated base paper prepared with this high-yield corrugated base paper pulp reached 1.318-2.224 km, the ring pressure index reached 6.62-13.02 mN m/g, and the quality was good (under the same conditions, using market waste paper The prepared corrugated base paper has a breaking length of 2.13km and a ring pressure index of 6.19mN·m/g). The whole process of the method of the invention is under normal pressure, breaks away from the high-pressure environment, reduces production risks and investment in equipment, saves energy consumption, and reduces production costs.

Since no other chemical additives are added in the method of the invention, the difficulty of waste liquid treatment is greatly reduced. The waste liquid generated after the double-roller grinding in the third step of the method can be extracted and recycled to save water resources; it can also be collected for fermentation and composting.

Due to the low pulping yield of corn stalks, it has not been used to prepare corrugated base paper. The invention improves the pulping yield of corn stalks, uses the corn stalks to prepare corrugated base paper, and overcomes technical prejudice.

The method of the invention makes up for the problem that my country's current high-quality corrugated base paper production relies heavily on foreign imported waste paper, and turns waste into treasure, realizes resource recovery and reuse, and alleviates the problem of air pollution.

detailed description

The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any combination of the specific embodiments.

Specific implementation mode 1: In this implementation mode, the method for preparing high-yield corrugated base paper pulp from corn stalks under normal pressure includes the following steps:

1. Send the corn stalks into the pulverizer and crush them until the particle size is 1-2cm. First, use the centrifugal fan to send the crushed straws to the high-speed vibrating screen to make the materials in a suspended or semi-suspended state, and then use the cyclone separator to make the skin and Separating the pith to obtain the corn stalk husk raw material;

2. Under normal pressure, soak the corn stalk husk raw material in NaOH solution;

3. Grinding the impregnated corn stalk raw material with a double-roller mill to obtain high-yield pulp for corrugated base paper.

Specific embodiment 2: The difference between this embodiment and specific embodiment 1 is that the corn stalk husk raw material obtained in step 1 is pretreated first, and then the next step of dipping treatment is carried out; the specific method of the pretreatment is: use 50 ~ The corn stalk husk raw material is washed with water at 60°C, steamed under normal pressure for 20-30 minutes, and finally sent to a screw extrusion deflaking machine for extrusion and deflaking. Others are the same as in the first embodiment.

Embodiment 3: This embodiment is different from Embodiment 1 in that: the mass concentration of NaOH solution in step 2 is 2%-10%. Others are the same as in the first embodiment.

Embodiment 4: The difference between this embodiment and Embodiment 1 is that the mass concentration of NaOH solution in step 2 is 4%-8%. Others are the same as in the first embodiment.

Embodiment 5: This embodiment is different from Embodiment 1 in that: the mass concentration of NaOH solution in step 2 is 6%. Others are the same as in the first embodiment.

Embodiment 6: This embodiment is different from Embodiment 1 in that: in step 2, the dipping temperature is 80-120° C., and the dipping time is 40-60 minutes. Others are the same as in the first embodiment.

Embodiment 7: This embodiment is different from Embodiment 1 in that: in step 2, the immersion temperature is 100° C., and the immersion time is 50 minutes. Others are the same as in the first embodiment.

Embodiment 8: This embodiment is different from Embodiment 1 in that: the slurry separated by the twin-roll mill in step 3 is sent to a high-consistency refiner for refining. Others are the same as in the first embodiment.

The following examples of the present invention are described in detail, and the following examples are implemented on the premise of the technical solution of the present invention, and detailed implementation schemes and specific operating procedures are provided, but the protection scope of the present invention is not limited to the following implementation example.

Example 1:

In this embodiment, the method for preparing high-yield corrugated base paper pulp from corn stalks under normal pressure is carried out according to the following steps:

1. The corn stalks are fed into the pulverizer, and the light parts such as skin and pith are peeled off under the action of shearing and impact, and crushed into a certain particle size. Under the action of the centrifugal fan, the crushed material enters the high-speed vibrating screen, making the material in a suspended or semi-suspended state. With the help of a cyclone separator, due to the different densities of light materials such as skin and pith, the light parts such as skin and pith are separated. Obtain the raw material of corn stalk husk; wash the raw material of corn stalk husk with water at 50-60°C, steam at normal pressure for 20-30 minutes, and then send it to a screw extrusion deflaking machine for extrusion and deflaking;

2. Immerse the corn stalk husk raw material for 40 minutes in a NaOH solution with a mass concentration of 2% and an immersion temperature of 80° C. under normal pressure;

3. Grinding and separating the impregnated corn stalk raw material with a double-roller mill to obtain high-yield pulp for corrugated base paper.

The pulping yield of this embodiment is 89.32%. Using the high-yield corrugated base paper pulp of this embodiment, the broken length of the corrugated base paper made on the laboratory paper machine is 1.318km, and the ring pressure index is 5.06mN m/g .

Example 2:

In this embodiment, the method for preparing high-yield corrugated base paper pulp from corn stalks under normal pressure is carried out according to the following steps:

1. The corn stalks are fed into the pulverizer, and the light parts such as skin and pith are peeled off under the action of shearing and impact, and crushed into a certain particle size. Under the action of the centrifugal fan, the crushed material enters the high-speed vibrating screen, making the material in a suspended or semi-suspended state. With the help of a cyclone separator, due to the different densities of light materials such as skin and pith, the light parts such as skin and pith are separated. Obtain the raw material of corn stalk husk; wash the raw material of corn stalk husk with water at 50-60°C, steam at normal pressure for 20-30 minutes, and then send it to a screw extrusion deflaking machine for extrusion and deflaking;

2. Immerse the corn stalk husk raw material for 45 minutes in a NaOH solution with a mass concentration of 5% and an immersion temperature of 120° C. under normal pressure;

3. Grinding and separating the impregnated corn stalk raw material with a double-roller mill to obtain high-yield pulp for corrugated base paper.

The pulping yield of this embodiment is 81.51%. Using the high-yield corrugated base paper pulp of this embodiment, the corrugated base paper made on the laboratory paper machine has a fracture length of 2.169 km and a ring pressure index of 9.76 mN m/g .

Example 3:

In this embodiment, the method for preparing high-yield corrugated base paper pulp from corn stalks under normal pressure is carried out according to the following steps:

1. The corn stalks are fed into the pulverizer, and the light parts such as skin and pith are peeled off under the action of shearing and impact, and crushed into a certain particle size. Under the action of the centrifugal fan, the crushed material enters the high-speed vibrating screen, making the material in a suspended or semi-suspended state. With the help of a cyclone separator, due to the different densities of light materials such as skin and pith, the light parts such as skin and pith are separated. Obtain the raw material of corn stalk husk; wash the raw material of corn stalk husk with water at 50-60°C, steam at normal pressure for 20-30 minutes, and then send it to a screw extrusion deflaking machine for extrusion and deflaking;

2. Immerse the corn stalk husk raw material in NaOH solution with a mass concentration of 10% and an immersion temperature of 100° C. for 55 minutes under normal pressure;

3. Grinding and separating the impregnated corn stalk raw material with a double-roller mill to obtain high-yield pulp for corrugated base paper.

The pulping yield of this embodiment is 80.69%. Using the high-yield corrugated base paper pulp of this embodiment, the corrugated base paper made on the laboratory paper machine has a fracture length of 2.224km and a ring pressure index of 13.02mN m/g .

Example 4:

In this embodiment, the method for preparing high-yield corrugated base paper pulp from corn stalks under normal pressure is carried out according to the following steps:

1. The corn stalks are fed into the pulverizer, and the light parts such as skin and pith are peeled off under the action of shearing and impact, and crushed into a certain particle size. Under the action of the centrifugal fan, the crushed material enters the high-speed vibrating screen, making the material in a suspended or semi-suspended state. With the help of a cyclone separator, due to the different densities of light materials such as skin and pith, the light parts such as skin and pith are separated. Obtain the raw material of corn stalk husk; wash the raw material of corn stalk husk with water at 50-60°C, steam at normal pressure for 20-30 minutes, and then send it to a screw extrusion deflaking machine for extrusion and deflaking;

2. Immerse the corn stalk husk raw material for 60 minutes in a NaOH solution with a mass concentration of 3% and an immersion temperature of 110° C. under normal pressure;

3. Grinding and separating the impregnated corn stalk raw material with a double-roller mill to obtain high-yield pulp for corrugated base paper.

The pulping yield of this embodiment is 87.75%. Using the high-yield corrugated base paper pulp of this embodiment, the broken length of the corrugated base paper made on the laboratory paper machine is 1.406km, and the ring pressure index is 6.68mN m/g .

Claims (8)

1. A method for preparing high-yield corrugated base paper pulp under normal pressure from corn stalks, characterized in that the method may further comprise the steps: 1. Send the corn stalks into the pulverizer and crush them until the particle size is 1-2cm. First, use the centrifugal fan to send the crushed straws to the high-speed vibrating screen to make the materials in a suspended or semi-suspended state, and then use the cyclone separator to make the skin and Separating the pith to obtain the corn stalk husk raw material; 2. Under normal pressure, soak the corn stalk husk raw material in NaOH solution; 3. Grinding the impregnated corn stalk raw material with a double-roller mill to obtain high-yield pulp for corrugated base paper. 2. A method for preparing high-yield corrugated base paper pulp from corn stalks under normal pressure according to claim 1, characterized in that the corn stalk husk raw material obtained in step 1 is first pretreated, and then subjected to the next step of impregnation treatment; The specific method of the pretreatment is as follows: washing the corn stalk husk raw material with water at 50-60° C., steaming it under normal pressure for 20-30 minutes, and finally feeding it into a screw extrusion deflaking machine for extruding and deflaking. 3. The method for preparing high-yield corrugated base paper pulp from corn stalks under normal pressure according to claim 1, characterized in that the mass concentration of NaOH solution in step 2 is 2% to 10%. 4. The method for preparing high-yield corrugated base paper pulp from corn stalks under normal pressure according to claim 1, characterized in that the mass concentration of the NaOH solution in step 2 is 4% to 8%. 5 . The method for preparing high-yield corrugated base paper pulp from corn stalks under normal pressure according to claim 1 , wherein the mass concentration of the NaOH solution in step 2 is 6%. 6 . The method for preparing high-yield corrugated base paper pulp from corn stalks under normal pressure according to claim 1 , characterized in that in step 2, the dipping temperature is 80-120° C., and the dipping time is 40-60 min. 7 . The method for preparing high-yield corrugated base paper pulp from corn stalks under normal pressure according to claim 1 , wherein the dipping temperature in step 2 is 100° C. and the dipping time is 50 minutes. 8. A method for preparing high-yield corrugated base paper pulp from corn stalks under normal pressure according to claim 1, characterized in that the slurry separated by double-roller grinding in step 3 is also sent to a high-consistency refiner Medium refining.