Process for producing high-strength cardboard paper from waste cartons

Abstract

The process for producing the high-strength cardboard paper from the waste cartons is characterized by comprising the following specific steps: step 1, pretreating the waste cartons with alkali liquor; 2, the pretreated waste paper is conveyed to a paper shredder to be shredded, and water is added in the shredded process to prepare paper pulp; step 3, adding water filtering enzyme into the prepared paper pulp, and modifying paper-making industrial pulp fibers through enzyme treatment; 4, feeding the paper pulp subjected to enzyme treatment into a white water tank, diluting with white water, and carrying out coarse screening and fine screening purification on the diluted paper pulp to finally obtain good paper pulp; 5, feeding the good paper pulp into a disc mill type heat dispersion machine to inactivate the water filtering enzyme; sixthly, the pulp is fed into a pulp flowing box, wet paper sheets are obtained through net forming and vacuum dewatering on a net part, the wet paper sheets are further dewatered through a pressing part and then dried through a drying part, and dry paper sheets are obtained. Alkali liquor treatment is added to improve the pulp purification rate, and enzyme treatment is added to improve the paper strength.

Description

Technical Field

[0001] The invention relates to the technical field of boxboard production technology, and in particular to a process for producing high-strength boxboard paper from waste cartons. Background Art

[0002] As people's environmental awareness increases, the modern papermaking industry is gradually transforming from a traditional high-pollution industry to a green industry with typical circular economy characteristics, using recycled waste paper as the main raw material to remake paper. China's packaging paper industry has maintained a sustained high-speed growth trend in recent years, but China's papermaking fiber resources are relatively scarce, and the supply capacity can no longer meet the needs of capacity expansion. Waste paper has become the most important resource for the development of China's papermaking industry.

[0003] The main steps of waste paper recycling are as follows: first, waste paper is processed into pulp. This process involves soaking waste paper in water; then breaking it into fine fibers. Pulp is the main raw material for papermaking, which will be screened and purified to remove impurities; the purified pulp will be used to make new paper, and then through pressing and drying, the pulp fibers will form paper with a certain strength and flexibility.

[0004] However, in the existing recycling and reproduction process, due to the presence of some stickies in the waste paper, the impurity rate of the pulp made from the waste paper is high, and it is not easy to remove the stickies after the waste paper is crushed into pulp, resulting in poor strength of the paper produced; in addition, due to the low interweaving and bonding ability between the fibers in the pulp made from waste paper, the strength of the produced boxboard is also low. Summary of the invention

[0005] In view of the above technical problems, the present invention provides a process for producing high-strength boxboard paper from waste cardboard boxes. The waste paper is soaked in alkali solution before being sent to a shredder to make pulp, which helps to filter out some stickies in the waste paper during screening and improve the purification rate of good pulp; and Ruichen water filter enzyme is added to the pulp made from waste paper for enzyme treatment to achieve fiber modification in the pulp and improve paper strength. White water is used in the production process and the effluent wastewater is recycled and reused, saving water costs and clean water resources.

[0006] To achieve the above object, the technical solution of the present invention is as follows:

[0007] The process of producing high-strength boxboard paper from waste cartons is characterized by the following specific steps:

[0008] In the first step, waste paper is pretreated by alkali solution;

[0009] In the second step, the pre-treated waste paper is transported to the shredder for shredding, and water is added during the shredding process to make pulp;

[0010] In the third step, water-removing enzymes are added to the prepared pulp to modify the pulp fiber of the paper industry through enzyme treatment;

[0011] The fourth step is to send the enzyme-treated pulp into a white water tank, dilute it with white water, and purify the diluted pulp by coarse screening and fine screening to finally obtain good pulp;

[0012] The fifth step is to send the good pulp into a disc mill heat disperser to inactivate the water filter enzyme;

[0013] In the sixth step, the paper is sent to the headbox, and then formed on the wire section, and vacuum dehydrated to obtain a wet paper sheet. The wet paper sheet is further dehydrated by the pressing section, and then dried by the drying section to obtain a dry paper sheet.

[0014] Specifically, in step 1, the waste paper is transported to an alkali solution treatment pool and soaked in the alkali solution of the alkali solution treatment pool. The alkali solution is a solution of sodium hydroxide and water, and the concentration is 0.5-1%, and the soaking time is 0.5-1 hour.

[0015] Specifically, the water-filtering enzyme in step three is Ruichen water-filtering enzyme, and stirring is carried out after adding the water-filtering enzyme, and the stirring time is 20-30 minutes. The pulp fiber of the papermaking industry is modified by enzyme treatment to achieve fiber modification, increase fiber fibrillation, and improve fiber bonding strength, which is conducive to the long fiber adsorption of an appropriate amount of fine fibers, reduces mesh clogging, promotes dehydration, and restores and enhances the fiber swelling ability, thereby improving paper strength.

[0016] Specifically, the coarse screening in step 4 uses a vibrating screen or a pressure screen device to screen out and remove large impurities in the slurry, such as bark, stones, etc. in the slurry, and the coarse screen is arranged before the high-concentration cleaner, which can effectively reduce the burden of the high-concentration cleaner and subsequent screening equipment, and improve production efficiency and slurry quality.

[0017] Specifically, the fine screening in step 4 is to convey the slurry after the coarse screening to the high-concentration cleaner, and use the centrifugal principle of the high-concentration cleaner to remove impurities with density different from the slurry, and then pass through an ultrasonic sorting screen or a high-frequency vibration screen to remove small particle impurities in the slurry.

[0018] Specifically, in the step 5, the temperature of the material fed into the disc mill heat disperser is controlled at 110-115° C., and the pH value is controlled at 6.5-7.0.

[0019] Specifically, in step six, the waste water removed by vacuum after forming on the net and the waste water removed by squeezing in the pressing part are transported to the filtering equipment for recycling and reuse.

[0020] Beneficial effects of the present invention:

[0021] The present invention soaks the waste paper in alkali solution before feeding it into the shredder to make pulp, which helps to filter out some stickies in the waste paper during screening, improves the purification rate of good pulp, and further improves the strength of the produced boxboard paper;

[0022] The present invention adds Ruichen water filter enzyme to the pulp made of waste paper for enzyme treatment, thereby modifying the fibers in the pulp, increasing the fiber separation and brooming, improving the fiber bonding force, facilitating the long fibers to absorb a proper amount of fine fibers, reducing mesh blockage, promoting dehydration, and restoring and improving the fiber swelling ability, thereby improving the paper strength;

[0023] The present invention uses white water in diluting the slurry, which saves clean water resources and reduces water costs. The waste water vacuumed out after forming on the net and the waste water squeezed out by the pressing part are transported to the filtering equipment for recycling and reuse, saving water costs. DETAILED DESCRIPTION

[0024] The technical solution of the present invention is described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] Example 1

[0026] The process of producing high-strength boxboard paper from waste cartons is characterized by the following specific steps:

[0027] In the first step, waste paper is pretreated by alkali solution;

[0028] In the second step, the pre-treated waste paper is transported to the shredder for shredding, and water is added during the shredding process to make pulp;

[0029] In the third step, water-removing enzymes are added to the prepared pulp to modify the pulp fiber of the paper industry through enzyme treatment;

[0030] The fourth step is to send the enzyme-treated pulp into a white water tank, dilute it with white water, and purify the diluted pulp by coarse screening and fine screening to finally obtain good pulp;

[0031] The fifth step is to send the good pulp into a disc mill heat disperser to inactivate the water filter enzyme;

[0032] In the sixth step, the paper is sent to the headbox, and then formed on the wire section, and vacuum dehydrated to obtain a wet paper sheet. The wet paper sheet is further dehydrated by the pressing section, and then dried by the drying section to obtain a dry paper sheet.

[0033] Specifically, in step 1, the waste paper is transported to an alkali solution treatment pool and soaked in the alkali solution of the alkali solution treatment pool. The alkali solution is a solution of sodium hydroxide and water with a concentration of 0.5-1% and a soaking time of 0.5-1 hour.

[0034] Specifically, the water-filtering enzyme in step three is Ruichen water-filtering enzyme, which is added and stirred for 20-30 minutes. The enzyme treatment realizes fiber modification, increases fiber fibrillation, improves fiber bonding strength, is conducive to long fibers adsorbing an appropriate amount of fine fibers, reduces mesh clogging, promotes dehydration, and at the same time restores and enhances fiber swelling ability, thereby improving paper strength.

[0035] Specifically, in step 4, the coarse screen uses a vibrating screen or a pressure screen device to screen out and remove large impurities in the slurry, such as bark, stones, etc. in the slurry, and the coarse screen is arranged before the high-concentration cleaner, which can effectively reduce the burden of the high-concentration cleaner and subsequent screening equipment, and improve production efficiency and slurry quality.

[0036] Specifically, the fine screening in step 4 is to convey the slurry after the coarse screening to the high-concentration cleaner, and use the centrifugal principle of the high-concentration cleaner to remove impurities with density different from the slurry, and then pass through an ultrasonic sorting screen or a high-frequency vibration screen to remove small particle impurities in the slurry.

[0037] Specifically, in step 5, the temperature of the material fed into the disc mill heat disperser is controlled at 110-115° C., and the pH value is controlled within the range of 6.5-7.0.

[0038] Specifically, in step six, the waste water vacuumed out after the net forming and the waste water squeezed out by the pressing part are transported to the filtering equipment for recycling and reuse.

[0039] Example 2

[0040] The waste paper is transported to the alkali solution treatment pool and soaked in the alkali solution of the alkali solution treatment pool. The concentration of the alkali solution is 0.5% and the soaking time is 1 hour. Then the soaked waste paper is transported to the shredder for shredding. The shredding time is 15 minutes. White water is added during the shredding process to make pulp. Then Ruichen water filter enzyme is added to the pulp to achieve fiber modification, increase fiber fibrillation, improve fiber bonding, and facilitate long fibers to absorb an appropriate amount of fine fibers, reduce mesh blockage, promote dehydration, and restore and enhance fiber swelling ability, thereby enhancing paper strength. After adding Ruichen water filter enzyme to the pulp, the slurry is evenly stirred by a stirrer. The stirring time is 30 minutes before sending it into white water. The pulp is sent to a high-concentration cleaner, where the centrifugal principle is used to remove impurities with a density different from that of the pulp. The pulp is then passed through a high-frequency vibrating screen to remove small particle impurities. The pulp after screening and purification is sent to a disc mill heat disperser, where the temperature is kept stable at 110-115°C and the pH value is kept within the range of 6.5-7.0 to inactivate the enzyme in the pulp. The pulp is then sent to a headbox, where it is formed on the screen, and vacuum dehydrated to obtain a wet paper sheet. The wet paper sheet is further dehydrated through a pressing section, and then dried in a drying section to obtain a dry paper sheet.

[0041] Example 3

[0042] The waste paper is transported to the alkali solution treatment pool and soaked in the alkali solution of the alkali solution treatment pool. The concentration of the alkali solution is 2% and the soaking time is 0.5 hours. Then the soaked waste paper is transported to the shredder for shredding. The shredding time is 20 minutes. White water is added during the shredding process to make pulp. Then Ruichen water filter enzyme is added to the pulp to achieve fiber modification, increase fiber fibrillation, improve fiber bonding, and facilitate long fibers to absorb an appropriate amount of fine fibers, reduce mesh blockage, promote dehydration, and restore and enhance fiber swelling ability, thereby enhancing paper strength. After adding Ruichen water filter enzyme to the pulp, the slurry is evenly stirred by a stirrer. The stirring time is 20 minutes before sending it into white water. The pulp is sent to a high-concentration cleaner, where the centrifugal principle is used to remove impurities with a density different from that of the pulp. The pulp is then passed through a high-frequency vibrating screen to remove small particle impurities. The pulp after screening and purification is sent to a disc mill heat disperser, where the temperature is kept stable at 110-115°C and the pH value is kept within the range of 6.5-7.0 to inactivate the enzyme in the pulp. The pulp is then sent to a headbox, where it is formed on the screen, and vacuum dehydrated to obtain a wet paper sheet. The wet paper sheet is further dehydrated through a pressing section, and then dried in a drying section to obtain a dry paper sheet.

[0043] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. The process of producing high-strength cardboard paper from waste cardboard boxes is characterized by: The specific steps are as follows: In the first step, waste paper is pretreated by alkali solution; In the second step, the pre-treated waste paper is transported to the shredder for shredding, and water is added during the shredding process to make pulp; In the third step, water-removing enzymes are added to the prepared pulp to modify the pulp fiber of the paper industry through enzyme treatment; The fourth step is to send the enzyme-treated pulp into a white water tank, dilute it with white water, and purify the diluted pulp by coarse screening and fine screening to finally obtain good pulp; The fifth step is to send the good pulp into a disc mill heat disperser to inactivate the water filter enzyme; In the sixth step, the paper is sent to the headbox, and then formed on the wire section, and vacuum dehydrated to obtain a wet paper sheet. The wet paper sheet is further dehydrated by the pressing section, and then dried by the drying section to obtain a dry paper sheet.

2. The process for producing high-strength boxboard from waste cartons according to claim 1 is characterized in that In the step 1, the waste paper is transported to an alkali solution treatment tank and soaked in the alkali solution of the alkali solution treatment tank. The alkali solution is a solution mixed with sodium hydroxide and water, and the concentration is 0.5-1%, and the soaking time is 0.5-1 hour.

3. The process for producing high-strength boxboard from waste cartons according to claim 1, characterized in that The water-filtering enzyme in step three is Ruichen water-filtering enzyme. After adding the water-filtering enzyme, stirring is carried out for 20-30 minutes. The pulp fiber of the papermaking industry is modified by enzyme treatment to achieve fiber modification, increase fiber fibrillation, improve fiber bonding strength, facilitate long fibers to absorb an appropriate amount of fine fibers, reduce mesh clogging, promote dehydration, and restore and enhance fiber swelling ability, thereby improving paper strength.

4. The process for producing high-strength boxboard paper from waste cartons according to claim 1, characterized in that In the fourth step, the coarse screening is performed by using a vibrating screen or a pressure screen to screen out and remove large impurities in the slurry.

5. The process for producing high-strength boxboard paper from waste cartons according to claim 1, characterized in that The fine screening in step 4 is to convey the slurry after the coarse screening to the high-concentration cleaner, and use the centrifugal principle of the high-concentration cleaner to remove impurities with density different from the slurry, and then pass through an ultrasonic sorting screen or a high-frequency vibration screen to remove small particle impurities in the slurry.

6. The process for producing high-strength boxboard paper from waste cartons according to claim 1, characterized in that In the step 5, the temperature of the product fed into the disc mill heat disperser is controlled at 110-115° C., and the pH value is controlled at 6.5-7.

0.

7. The process for producing high-strength boxboard paper from waste cartons according to claim 1, characterized in that In the step six, the waste water vacuumed out after the net forming and the waste water squeezed out by the pressing part are transported to the filtering equipment for recycling and reuse.