Papermaking fiber recovery pulp purification treatment process
By combining heavy sand separator, pulp screener, thermal dispersion treatment and light sand separator, the paper fiber recycled pulp is processed sequentially, which solves the problem of excessive dust in the paper fiber recycled pulp, improves the yield of good pulp, reduces production costs and extends the service life of equipment.
Patent Information
- Application Number
- CN202511236951.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-01
- Publication Date
- 2025-10-24
AI Technical Summary
Existing technologies are difficult to effectively remove dust from recycled papermaking fiber pulp, which makes its reuse difficult and leads to serious waste of resources. In addition, existing treatment methods are inefficient and costly.
A combined process of heavy sand separator, pulp screener, thermal dispersion treatment and light sand separator is used to sequentially process paper fiber recycled pulp, and to carry out step-by-step synergistic purification of different types of impurities.
It significantly improves the yield of good pulp, reduces production costs, extends equipment lifespan, reduces resource waste, and aligns with the concept of sustainable development.
Smart Images
Figure FT_1 
Figure FT_2 
Figure FT_3
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to a kind of papermaking fiber recovery pulp purification treatment process, belong to papermaking waste recovery technical field. BACKGROUND
[0002] In the production process of pulp board, after screening and deslagging, the slurry is discharged with white water, and then recovered by a cylinder screen. However, there are many problems in the recovered waste white slurry, which contains resin, sand, impurities and a lot of dust, which leads to its sale at a lower price (about 1 dry ton of waste white slurry is recovered per day). Due to the presence of these dusts, the reuse of waste white slurry faces great challenges, and also causes waste of resources.
[0003] From the composition of waste white slurry, the black viscose particles entrained therein are mixed with inorganic salts such as calcium and silicon to form a mass, which is not easy to separate, which further increases the difficulty of purification treatment. At present, methods such as flotation, screening and washing are used to remove fine impurities from waste white slurry, but all have some shortcomings. The flotation method has poor removal effect on impurities closely combined with fibers, and the chemical reagent affects the quality of fibers; the screening method is difficult to remove small particles and irregular small impurities that can pass through the screen, and the efficiency decreases with the increase of slurry concentration and impurities; the washing method consumes a large amount of water resources, and if there is no recycling system, it will increase the cost, and the cleaning effect of impurities closely combined with fibers is limited. These shortcomings show that a single technical means cannot effectively solve the problem of high dust content in waste white slurry, and a new comprehensive treatment method or improvement of existing technology is needed to improve the feasibility of waste white slurry recycling. Under the current demand of papermaking production, an effective method is urgently needed to reduce the dust content in waste white slurry, so as to facilitate its recycling. This not only helps to improve the economic benefit of enterprises and reduce resource waste, but also meets the concept of sustainable development. SUMMARY
[0004] In view of the defects in the prior art, the present application aims to provide a papermaking fiber recovery slurry purification treatment process, which adopts a combined treatment process of heavy sand remover, screen pulp machine, heat dispersion treatment and light sand remover, and purifies the papermaking fiber recovery slurry through coordination. The recovery slurry is treated in sequence to solve the problem of difficult reuse of recovery slurry due to high dust content and improve the yield of good slurry.
[0005] In order to achieve the above technical purpose, the present application provides a papermaking fiber recovery slurry purification treatment process, which comprises the following sequential steps: using a heavy sand remover to treat the papermaking fiber recovery slurry, then screening it through a screen pulp machine, then heat dispersing the screened recovery slurry, and finally treating it through a light sand remover.
[0006] The present application adopts the combined treatment process of heavy sand remover, screen pulp machine, heat dispersion treatment and light sand remover to purify the papermaking fiber recycled pulp, adopts the characteristics of each treatment process point, and combines the characteristics of the impurities in the recycled pulp after papermaking, and the step-by-step and cooperative treatment is targeted, so that the problem that the recycled pulp cannot be reused due to dust is solved, and the yield of good pulp is greatly improved. First, the heavy sand remover treatment. The heavy dust in the recycled pulp wraps inorganic salt, which is easy to settle due to its large mass. If not treated first, the subsequent process will be disturbed. The heavy sand remover separates the heavy dust from the pulp by centrifugal force and other physical principles, providing a pure starting condition for subsequent treatment. Then, the screen pulp machine is screened. After the heavy sand removal, the larger particle impurities are the main treatment object. After the heavy dust is removed, the screen pulp machine screens the larger particle impurities, which cannot pass through the screen hole and are intercepted. If the order is not correct, the heavy dust may block the screen hole or mix with the larger particle impurities, affecting the screening effect. Under certain circumstances, if the recycled pulp needs to be treated to the level of dissolving pulp, heat dispersion treatment is required. After the previous treatment, the impurities are relatively simple, and the heat dispersion treatment is more effective. The mechanism includes thermal and chemical processes, first pressure filtration, then deoxidation heat treatment, heating to break the chemical bond with impurities, and then air floatation treatment, bubbles adhere to impurities to make them float and be removed. If the impurities are not effectively removed before heat dispersion treatment, the treatment effect will be disturbed. Finally, the light sand remover treatment. After the previous steps, the light dust is the main impurity. The light sand remover separates the light dust by physical separation. Because most of the other impurities have been removed, the light dust can be accurately separated. If the order is not correct, the light dust will mix with other impurities, affecting the treatment effect. This combination process can effectively purify various impurities, maximize the efficiency of each step from the mechanism, improve the yield of good pulp, improve the utilization value of recycled pulp, reduce the cost and improve the production efficiency.
[0007] As a preferred scheme, the papermaking fiber recycled pulp is a purified recycled pulp which has been treated by a sand removal system and a closed screening system and then subjected to sedimentation treatment.
[0008] As a preferred scheme, the specific steps of the heat dispersion treatment are: after pressure filtration of the recycled pulp, deoxidation heat treatment is performed, then the pulp is diluted with water and compressed air is introduced for air floatation treatment.
[0009] As a preferred scheme, the dryness of the recycled pulp after pressure filtration is 18-28%.
[0010] As a preferred scheme, the deoxidation heat treatment is performed at a temperature of 100-150℃ for 2-8min.
[0011] As a preferred scheme, the gas flow rate of the air floatation treatment is 2.5-5.6kg / h.
[0012] As a preferred scheme, the heavy sand remover processes the papermaking fiber recycled pulp under the conditions of a pulp concentration of 0.5-1.5% and a rotating speed of 1500-3000 rpm.
[0013] As a preferred scheme, the screening aperture is 0.11-0.17 mm.
[0014] As a preferred scheme, the pulp concentration is 0.5-1% when the light sand remover is used.
[0015] Compared with the prior art, the technical scheme of the present application has the following innovative and beneficial technical effects: 1) The present application processes the impurities in the papermaking recycled pulp according to their characteristics, first uses a heavy sand remover to process heavy dust, and then sequentially uses a screen machine, a hot dispersion treatment and a light sand remover. This sequence is mainly due to the existence of mutual influence of various impurities. Compared with the prior art, this processing technology is more systematic, especially when it is processed to the dissolving pulp level, the hot dispersion treatment is arranged after the screening, which can better deal with special impurities because part of the interfering impurities have been removed in the previous steps. This process sequence comprehensively covers various impurities and accurately purifies the recycled pulp, thereby significantly improving the yield of good pulp, far exceeding the lower yield of the prior art due to incomplete processing or unreasonable sequence.
[0016] 2) Unlike the prior art which focuses on the treatment of part of the impurities, the present application can comprehensively treat various impurities. This targeted treatment has the beneficial effect of reducing costs. For example, processing impurities in a reasonable order can avoid damage to subsequent equipment such as a screen machine by heavy dust, reduce equipment maintenance and replacement costs, and prolong the service life of the equipment. At the same time, accurate treatment of impurities avoids unnecessary energy consumption due to impurity interference, eliminates the need for repeated treatment of pulp, and reduces overall production costs. BRIEF DESCRIPTION OF DRAWINGS
[0017] Figure 1 The figure is a process flow diagram of the papermaking fiber recycled pulp purification treatment of Example 1.
[0018] Figure 2 The figure is a physical picture of the waste papermaking fiber recycled pulp.
[0019] Figure 3 The figure is a physical picture of the good pulp obtained in Comparative Example 1.
[0020] Figure 4 The figure is a physical picture of the good pulp obtained in Comparative Example 2.
[0021] Figure 5 The figure is a physical picture of the good pulp obtained in Comparative Example 3.
[0022] Figure 6 The figure is a physical picture of the good pulp obtained in Comparative Example 4.
[0023] Figure 7 The good pulp sheet obtained from Comparative Example 5 is shown in the figure. DETAILED DESCRIPTION
[0024] The technical solutions of the present application will be further described below in combination with the specific embodiments of the present application. It should be noted that the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application; these embodiments are only for better understanding the present application, rather than limiting the scope of the present application.
[0025] Unless otherwise specified, all the reagents and raw materials used in the present application are commercially available products or products prepared by known methods.
[0026] Example 1 Figure 1 The process flow chart of the present example is shown below: the recycled pulp for papermaking is sent into a heavy sand separator at a feeding concentration of 1% and a rotating speed of 2000 rpm, then the recycled pulp treated by the heavy sand separator is screened by a screen pulp machine with a pore size of 0.14 mm, then the screened recycled pulp is subjected to pressure filtration to make the dryness of the recycled pulp after pressure filtration reach 23%, then the recycled pulp after pressure filtration is subjected to deoxygenation heat treatment at a temperature of 120℃ and a treatment time of 5 min, then the recycled pulp is dispersed by stirring with hot water at 80℃, then the recycled pulp is diluted to a concentration of 1%, then compressed air is introduced for air floatation treatment and the gas flow rate of the air floatation treatment is controlled to be 4 kg / h, and finally the recycled pulp after heat dispersion treatment is sent into a light sand separator at a feeding concentration of 0.8% for treatment to obtain good pulp.
[0027] Comparative Example 1 In the present comparative example, only heat dispersion separation method is used to treat the recycled pulp, and the treatment is as follows: the recycled pulp for papermaking is subjected to pressure filtration to a dryness of 23%, then the recycled pulp is heated to 120℃ in a laboratory oxygen removal reaction kettle, the heating time is 5 min, then the recycled pulp is dispersed by stirring with hot water at 80℃, then the recycled pulp is diluted to a concentration of 1%, and then compressed air is introduced for air floatation treatment and the gas flow rate of the air floatation treatment is controlled to be 4 kg / h.
[0028] Comparative Example 2 In the present comparative example, only screening method is used to treat the recycled pulp, and the treatment is as follows: the recycled pulp for papermaking is diluted with water to a concentration of 1%, then the recycled pulp is dispersed by stirring, and then the recycled pulp is screened by a screen pulp machine with a pore size of 0.14 mm.
[0029] Comparative Example 3 In the present comparative example, only NOSS residue removal separation method is used to treat the recycled pulp, and the treatment is as follows: the recycled pulp for papermaking is diluted with water to a concentration of 0.8%, then the recycled pulp is fully stirred, and then the recycled pulp is treated by a light residue removal device.
[0030] Comparative Example 4 The comparative example 4 uses multiple processing steps as follows: the papermaking fiber recycled pulp is filtered and dewatered to a dryness of 23%, then heated to 120°C in a laboratory oxygen removal reactor for 5 minutes, then dispersed by stirring with 80°C hot water, diluted to a concentration of 1%, air floated by introducing compressed air and controlling the air flow rate to 4 kg / h, the recycled pulp is diluted to a concentration of 1% with water, then dispersed by stirring, then screened by a screen with a pore size of 0.14 mm, and finally the recycled pulp is diluted to a concentration of 0.8% with water, fully stirred, and then treated by a light degritting device.
[0031] Comparative Example 5 The comparative example 5 uses multiple processing steps as follows: the papermaking fiber recycled pulp is diluted to a concentration of 1% with water, then dispersed by stirring, then screened by a screen with a pore size of 0.14 mm, the papermaking fiber recycled pulp is diluted to a concentration of 0.8% with water, fully stirred, and then treated by a light degritting device, the papermaking fiber recycled pulp is filtered and dewatered to a dryness of 23%, then heated to 120°C in a laboratory oxygen removal reactor for 5 minutes, then dispersed by stirring with 80°C hot water, diluted to a concentration of 1%, air floated by introducing compressed air and controlling the air flow rate to 4 kg / h.
[0032] The good pulp obtained by processing the recycled pulp of Example 1 and Comparative Examples 1-5, and the untreated recycled pulp is sheeted and the dust amount is measured as shown in Table 1, and the sheet physical picture is shown in Figures 2-7 .
[0033] Table 1 Good pulp rate and sheet dust amount of Example 1 and Comparative Examples 1-5
[0034] From Table 1 and Figures 2-7It can be seen that the amounts of dust in the good pulp obtained by using a single treatment method in Comparative Examples 1-3 are relatively large, and the good pulp rate is also relatively low. This is mainly because the recycled pulp contains not only relatively light dust such as resin and hot-melt material, but also heavy dust such as inorganic salt wrapped in calcium and silicon. Therefore, in order to achieve pulp purification, multiple treatment methods must be combined. Although Comparative Examples 4 and 5 use multiple technical methods, the main difference compared with Example 1 is the order of treatment, but the good pulp rate and the amount of dust are quite different. This is mainly because in Example 1, the heavy sand remover treatment and the screen pulp machine screening are performed in the early stage, which can remove the heavy dust (such as inorganic salt wrapped in calcium and silicon) in the recycled pulp. However, Comparative Example 4 does not have these steps, and directly performs pressure filtration and heat treatment operations. This results in the presence of heavy dust in the system during subsequent air flotation treatment, screen pulp machine screening, and light sand remover treatment. For example, heavy dust can affect the combination efficiency of bubbles and light dust in air flotation treatment, because the presence of heavy dust can interfere with the fluid dynamics in the air flotation process, making it difficult for bubbles to effectively capture light dust. Moreover, during screen pulp machine screening and light sand remover treatment, heavy dust can form more complex combinations with fibers or clog the screen and sand remover equipment, affecting the removal effect of these devices on impurities, and thus affecting the good pulp rate. Although the screening and light sand remover treatment in Comparative Example 5 can remove some impurities, it is not thorough enough for the heavy dust present in the recycled pulp. Compared with Example 1, Example 1 effectively removes heavy dust through the heavy sand remover, laying a good foundation for subsequent treatment. However, the heavy dust in Comparative Example 5 is not thoroughly removed in the early stage, which affects the subsequent pressure filtration, heat treatment, and air flotation processes. For example, during pressure filtration, heavy dust can be compressed with fibers, making it more difficult for impurities to separate from fibers during subsequent heat treatment. During air flotation treatment, the presence of heavy dust can also affect the movement of bubbles and the removal efficiency of light dust, ultimately affecting the good pulp rate and the amount of sheet dust. Therefore, the various treatment steps in Example 1 are mutually synergistic, and the heavy sand remover and screen pulp machine screening in the early stage remove heavy dust, providing a good foundation for subsequent deoxidizing heat treatment, air flotation treatment, and light sand remover treatment to remove light dust and further optimize the good pulp, thereby obtaining a high good pulp rate and a low sheet dust amount.
[0035] The above examples are only used to better explain the principles and practical applications of the present application, so that those skilled in the relevant art can better understand and utilize the present application, and do not limit the patent scope of the present application. Any equivalent transformation made using the content of the present application is within the scope of the patent protection of the present application.
Claims
1. A process for the purification of papermaking fiber recovery pulp, characterized in that, The method comprises the following steps in sequence: treating the papermaking fiber recycled pulp by a heavy sand remover, screening the recycled pulp by a pulp screen, then heat dispersing the screened recycled pulp, and finally treating the recycled pulp by a light sand remover.
2. A process for the purification of papermaking fibre recovery pulp according to claim 1, characterised in that, The heat dispersing treatment comprises the following steps: deoxidizing and heat treating the recycled pulp after pressure filtration, diluting the pulp with water, and then air floating the pulp by compressed air.
3. A process for the purification of papermaking fibre recovery pulp according to claim 2, characterised in that, The dryness of the recycled pulp after pressure filtration is 18-28%.
4. A process for the purification of papermaking fibre recovery pulp according to claim 2, characterised in that, The deoxidizing and heat treating is performed at a temperature of 100-150 DEG C for 2-8 min.
5. A process for the purification of papermaking fibre recovery pulp according to claim 4, characterised in that, The air floating is performed at a gas flow rate of 2.5-5.6 kg / h.
6. A process for the purification of papermaking fibre recovery pulp according to claim 1, characterised in that, The recycled pulp is treated by the heavy sand remover at a pulp concentration of 0.5-1.5% and a rotating speed of 1500-3000 rpm.
7. A process for the purification of papermaking fibre recovery pulp according to claim 6, characterised in that: The screened recycled pulp has a pore size of 0.11-0.17 mm.
8. A process for the purification of papermaking fibre recovery pulp according to claim 4, characterised in that, The pulp concentration is 0.5-1% when the recycled pulp is treated by the light sand remover.