Waste glue recovery system in viscose filament yarn production system

Abstract

The utility model discloses a waste glue recovery system in a viscose filament yarn production system, which comprises a waste glue collecting tank A for collecting and temporarily storing waste glue, a pre-filtering unit and a stepped filtering unit, and the waste glue collecting tank A is arranged on the rear side of a station of a viscose filtering section; the waste glue collecting tank A is connected with a feeding port of the pre-filtering unit through a conveying pipe I. The pre-filtering unit is arranged on the rear side of a station of the waste glue collecting tank A. The pre-filtering unit is connected with a feeding port of the stepped filtering unit through a conveying pipe II, and the stepped filtering unit is arranged on the rear side of a station of the pre-filtering unit; the stepped filtering unit is connected with a defoaming section in the viscose filament yarn production system, and a continuous passage for producing, treating and recycling the waste glue is formed among the viscose filtering section, the waste glue collecting tank A, the pre-filtering unit, the stepped filtering unit and the defoaming section. According to the utility model, through a plurality of filter combination forms, impurities in the waste rubber with multiple pulp types are intercepted in a grading manner for multiple times and then are reused in filament production.

Description

Technical Field

[0001] The utility model relates to the technical field of viscose filaments in the textile industry, in particular to a waste rubber recovery system in a viscose filament production system. Background Art

[0002] In terms of cost, the production of viscose filament industry uses coniferous wood pulp, hardwood pulp, bamboo pulp and other multi-pulp mixed pulps. That is, in the viscose filament multi-pulp production system, there are large differences in the indicators of different varieties of pulp. For example, the fiber length of coniferous wood pulp is 3 to 5 times that of hardwood pulp. Bamboo pulp and recycled pulp have a higher content of heterogeneous fibers due to the characteristics of raw materials. The combined use of multiple pulps will lead to the problem of poor uniformity of yellowing reaction, and the direct reaction in the later process is the increase of filtration waste rubber. Among them, the waste rubber is generated in the viscose filtration section, and the sources mainly include: KKF filter backwash waste rubber (80%), plate and frame filter disassembly and washing cavity rubber (15%), KKF filter equipment maintenance filter replacement cavity rubber (5%). Among them, the filtration system produces a large amount of waste rubber, and contains a high number of particles, ash, unswollen fibers and large particles of chemical fiber dust. It is difficult to purify it with simple filtration methods, and the recovery value is low, and it needs to be discharged regularly. It not only causes environmental pressure, but also a waste of resources. Therefore, it is necessary to study a waste rubber recovery system applied to the filament multi-slurry production system, which can effectively reduce the pulp and alkali costs of the filament.

[0003] At present, the treatment of viscose filament waste rubber mainly includes the following methods:

[0004] 1. Through a butterfly separator. The insoluble impurities in the waste rubber are separated by a butterfly separator and then enter the viscose staple fiber production system. The disadvantage is that the economic efficiency of recycling waste rubber into staple fiber is lower than that of recycling into filament, and the filament and staple fiber need to be in production at the same time, which has certain limitations;

[0005] 2. Filtration and recovery by plate and frame filter. The waste rubber volume of multi-slurry system is relatively large, and the impurity content is higher (the number of particles is usually > 50,000 / ml). Using plate and frame filter to process waste rubber will cause the filter to clog quickly, require many dismantlings, waste a lot of viscose, and the disassembly and assembly of plate filter is a high-labor-intensity operation, with high labor costs;

[0006] 3. KKF ​​filter filtration and recycling. Directly using KKF filter to filter waste rubber will produce more secondary waste rubber, causing waste. Because the waste rubber has high viscosity, many impurities, and extremely poor filtering performance, the amount of waste rubber filtered per unit time is very small (less than 0.5 cubic meters / hour). The KKF filter cannot guarantee the backwashing pressure during automatic backwashing, thus failing to achieve the backwashing effect and unable to perform normal filtration. Therefore, it is difficult to choose KKF automatic filter for filtration.

[0007] In addition, Chinese patent literature has disclosed a method for recycling waste rubber in viscose production (patent announcement number: CN105369394B). This scheme is to pre-treat the waste rubber, that is, to add alkali solution to the waste rubber so that the alkali content in the waste rubber is 6-8%. The diluted waste rubber can solve the problems of KKF filter difficulty, low filtration efficiency and low waste rubber recovery rate in the waste rubber recovery process. However, it is obviously not applicable in the filament multi-slurry production system, because the addition of alkali solution during the pretreatment of the waste rubber cannot effectively stabilize the relevant quality indicators of the waste rubber (acetone content, viscosity, degree of esterification, surface tension, maturity, alkali content, etc.), and reuse in large-scale production will impact normal viscose and cause quality fluctuations.

[0008] A Chinese patent document discloses a waste rubber recycling system (patent announcement number: CN206232870U), which uses different processing methods for different waste rubbers, mixes them after processing, and directly adds the waste rubber to normal viscose after filtering, and enters the viscose production system for the production of viscose filaments to solve the problem of the impact of recycled waste rubber on spinning properties. However, when it is necessary to purify impurities with large diameters and hard textures, impurities with smaller diameters, and elastic gel particles in filaments, these impurities with different components and diameters cannot be treated separately by different treatment methods and then mixed. Summary of the invention

[0009] In view of the problems in the prior art that the amount of waste rubber generated is large, and contains a high number of particles, ash content, unswollen fibers and large particles of chemical fiber dust, it is difficult to purify it by simple filtering, the recycling value is low, regular discharge is required, and there is environmental pressure, the utility model provides a waste rubber recycling system in a viscose filament production system. The utility model can not only better cooperate with the waste rubber recycling process in the viscose filament production, that is, to realize the collection, filtration and purification of various waste rubbers formed in the viscose filament production, and then reuse them in the filament production; but also can ensure the orderliness and systematization of the waste rubber recycling process, and at the same time, ensure that after the waste rubber is reused, the stability of the quality of the viscose filament product can be improved.

[0010] In order to solve the above technical problems, the utility model adopts the following technical solutions: a waste rubber recovery system in a viscose filament production system, comprising a waste rubber collection tank A for collecting and temporarily storing waste rubber, a pre-filtering unit and a step filtering unit, the waste rubber collection tank A being arranged at the rear side of the station of a viscose filtering section in the viscose filament production system; the waste rubber collection tank A being connected to a feed inlet of the pre-filtering unit through a conveying pipe I, the pre-filtering unit being arranged at the rear side of the station of the waste rubber collection tank A; the pre-filtering unit being connected to a feed inlet of the step filtering unit through a conveying pipe II, the step filtering unit being arranged at the rear side of the station of the pre-filtering unit; the step filtering unit being connected to a degassing section in the viscose filament production system, and a continuous passage for waste rubber generation, treatment and recycling being formed between the viscose filtering section, the waste rubber collection tank A, the pre-filtering unit, the step filtering unit and the degassing section.

[0011] Furthermore, at least two pre-filtration units are provided, and the pre-filtration units are connected in parallel. The pre-filtration unit includes at least two KKF filters, and the KKF filters are connected in parallel. The parallel-connected KKF filters and pre-filtration units are collected and connected to the feed port of the cascade filtration unit through a conveying pipe II.

[0012] Furthermore, a waste rubber buffer tank A is provided on the conveying pipe II, the upper feed port of the waste rubber buffer tank A is connected to the pre-filtration unit through the conveying pipe II, and the bottom discharge port of the waste rubber buffer tank A is connected to the cascade filtration unit through the conveying pipe II.

[0013] Furthermore, at least two of the step filter units are provided, and the step filter units are connected in series. The step filter unit includes at least two plate-and-frame filters, and the plate-and-frame filters are connected in parallel.

[0014] Furthermore, there are three step filter units, including a step filter unit BI, a step filter unit BII and a step filter unit BIII which are sequentially connected in series.

[0015] Furthermore, the filter cloth structure of the step filter unit BI includes a layer of polypropylene and a layer of plain cloth, the filter cloth structure of the step filter unit BII includes a layer of polypropylene, a layer of double velvet, a layer of plain cloth and a layer of poplin, and the filter cloth structure of the step filter unit BIII includes a layer of polypropylene, a layer of double velvet, a layer of plain cloth and two layers of poplin.

[0016] Furthermore, it also includes a secondary waste rubber recovery unit, which includes a waste rubber collection tray A arranged at the bottom of the pre-filtration unit, a waste rubber collection tray B arranged at the bottom of the step filtration unit and a secondary filtration unit, the outlet end of the waste rubber collection tray A is connected to the waste rubber collection tank B through the delivery pipe III, and the outlet end of the waste rubber collection tray B is connected to the waste rubber collection tank B through the delivery pipe III.

[0017] Furthermore, the outlet end of the waste rubber collection tank B is connected to the secondary filtration unit through a delivery pipe III, and the discharge port of the secondary filtration unit and the discharge port of the cascade filtration unit are connected to the degassing section through a pipeline.

[0018] Furthermore, the outlet ends of the step filtration units are connected to waste rubber buffer tanks B, the upper feed port of the waste rubber buffer tanks B is connected in series to the previous step filtration unit through a pipeline, and the bottom discharge port of the waste rubber buffer tanks B is connected in series to the next step filtration unit through a pipeline; the outlet end of the secondary filtration unit is connected to the waste rubber buffer tank C through a conveying pipe III, and the waste rubber buffer tank B is connected in series to the waste rubber buffer tank C and then connected to the degassing section.

[0019] Furthermore, at least two waste rubber collection tanks A are provided, and the waste rubber collection tanks A are connected in parallel.

[0020] In summary, the beneficial effects brought by the utility model are:

[0021] 1. Collect the waste rubber generated in viscose production, and reuse the filtered and purified waste rubber in the viscose filament production system. Compared with using waste rubber for staple fiber production, it has higher economic benefits;

[0022] 2. Use KKF fully automatic backwash filter for pre-filtration treatment, with metal sintered filter as the filter medium, to achieve large-flux waste rubber filtration. This process does not require manual intervention during operation except for manual replacement of the filter according to production needs. It can intercept impurities with larger diameter and harder texture in the waste rubber, reduce the frequency of filter cleaning in the post-filtration process, save production costs, and intercept a larger proportion of impurities in pre-filtration, reduce impurities entering the post-process, and reduce the number of plate and frame filter dismantling, thereby reducing the labor intensity of employees;

[0023] 3. Through the combination of various filters, the impurities in the waste rubber can be intercepted multiple times in a graded manner, which can effectively ensure the stability of the spinning process and the quality of the product;

[0024] 4. It solves the problem of purifying and recycling waste rubber during the production of multiple filament pulps. The secondary waste rubber in the waste rubber recycling process can also be recycled and reused. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a structural diagram of the waste rubber recovery system.

[0026] Figure 2 Another structural schematic diagram of the waste rubber recovery system.

[0027] The accompanying drawings are described as follows:

[0028] 1. Waste rubber collection tank A; 11. Delivery pipe I; 12. Delivery pipe II; 2. Pre-filtration unit; 21. KKF ​​filter; 22. Waste rubber buffer tank A; 23. Waste rubber collection tray A; 3. Step filtration unit; 31. Step filtration unit BI; 32. Step filtration unit BII; 33. Step filtration unit BIII; 310. Plate and frame filter; 311. Waste rubber buffer tank B; 34. Waste rubber collection tray B; 4. Secondary waste rubber recovery unit; 40. Delivery pipe III; 41. Waste rubber collection tank B; 42. Secondary filtration unit; 43. Waste rubber buffer tank C; 5. Viscose filtration section; 6. Degassing section. DETAILED DESCRIPTION

[0029] The utility model is further described in detail below in conjunction with the embodiments.

[0030] In one embodiment, if Figure 1 to Figure 2 As shown, a waste rubber recovery system in a viscose filament production system comprises a waste rubber collection tank A1 for collecting and temporarily storing waste rubber, a pre-filtering unit 2 and a step filtering unit 3, wherein the waste rubber collection tank A1 is arranged at the rear side of the station of a viscose filtering section 5 in the viscose filament production system; the waste rubber collection tank A1 is connected to the feed port of the pre-filtering unit 2 through a conveying pipe I11, and the pre-filtering unit 2 is arranged at the rear side of the station of the waste rubber collection tank A1; the pre-filtering unit 2 is connected to the feed port of the step filtering unit 3 through a conveying pipe II12, and the step filtering unit 3 is arranged at the rear side of the station of the pre-filtering unit 2; the step filtering unit 3 is connected to the degassing section 6 in the viscose filament production system, and a continuous passage for waste rubber generation, treatment and recycling is formed between the viscose filtering section 5, the waste rubber collection tank A1, the pre-filtering unit 2, the step filtering unit 3 and the degassing section 6. The waste rubber collection tank A1 is used to store the waste rubber collected in the production of multiple filament pulps. The waste rubber collected in the waste rubber collection tank A1 is filtered and purified in turn by the pre-filtration unit 2 and the step filtration unit 3; after the pre-filtration unit 2 intercepts the impurities with larger diameter and hard texture in the waste rubber, the step filtration unit 3 further filters the waste rubber, and the waste rubber filtered by the step filtration unit 3 can be reused in the production of viscose filaments.

[0031] The combined use of multiple pulps will bring about the problem of poor uniformity of yellowing reaction. The direct reaction in the later process is the increase of filtered waste rubber. The waste rubber collection tank A is used to connect the waste rubber conveying pipeline to uniformly convey the waste rubber in production to the pre-filtration unit 2. The preliminary pre-filtration unit 2 first intercepts the inorganic insoluble impurities, resin particles, incompletely yellowed cellulose particles and other large-diameter impurities in the waste rubber, and intercepts a large number of impurities in the pre-filtration stage. The pre-filtration equipment uses an online automatic backwashing filter to improve production efficiency, extend the cleaning and replacement cycle of the filter cloth in the subsequent filtration process, and reduce production costs; the waste rubber after pre-filtration cannot be used directly. When it is conveyed to the cascade treatment unit, according to the filtration situation of the waste rubber, specifically refer to the quality parameters of the filtered waste rubber, set a multi-stage plate and frame filter, and further filter and purify the waste rubber. In summary, the waste rubber in the filtration system is purified in multiple stages and finally recycled, overcoming the problems of large amount of filtered waste rubber, high production cost and high wastewater discharge caused by the inherent differences in pulp when multiple pulp types are used.

[0032] In one embodiment, the waste rubber recycling system includes a waste rubber collection tank A1, a pre-filtration unit 2 and a step filtration unit 3, and a continuous passage for waste rubber generation, processing and recycling is formed among the viscose filtration section 5, the waste rubber collection tank A1, the pre-filtration unit 2, the step filtration unit 3 and the degassing section 6.

[0033] In this embodiment, at least two pre-filtering units 2 are provided, and the pre-filtering units 2 are connected in parallel. The pre-filtering units 2 include at least two KKF filters 21, and the KKF filters 21 are connected in parallel. The parallel-connected KKF filters 21 and the pre-filtering units 2 are collected and connected to the feed port of the cascade filtering unit 3 through the conveying pipe II12.

[0034] The pre-filtration equipment uses a fully automatic online backwash filter (KKF filter) because: if the plate-and-frame filter is used directly to filter the waste rubber, more secondary waste rubber will be generated, resulting in waste. Because the waste rubber has many impurities and poor filtering performance, the filter cloth of the plate-and-frame filter is blocked quickly, the filtering flux decays seriously in a short time, and it is difficult to balance the amount of rubber passing and the filtering quality. The filtering capacity can only be restored by manually disassembling and washing the filter, which has high labor intensity and high equipment occupancy rate. In addition, the disassembly and assembly of the filter and the washing process of the filter cloth will also cause secondary waste rubber, reducing the overall recovery efficiency of the waste rubber. A KKF filter pre-filtration system is set in front of the plate-and-frame filter of the waste rubber cascade purification system, and a metal sintered filter with a filtering accuracy of 15 to 40 μm is selected to effectively reduce the impurities entering the plate-and-frame filter. The backwash waste rubber outlet of the KKF filter is connected to the secondary waste rubber collection tank, and the secondary waste rubber recovery efficiency is high.

[0035] The number of pre-filtering units 2 is arranged according to the amount of waste rubber. Multiple KKF filters 21 are arranged in parallel in each pre-filtering unit 2. The purpose is that after the KKF filter 21 has filtered for a period of time, the flow rate is reduced due to blockage, so backwashing is required. The backwashing usually takes 20 minutes. Therefore, multiple KKF filters 21 and pre-filtering units 2 are arranged to ensure the filtration flow rate, as well as to ensure the sustainability and continuity of the waste rubber recovery process.

[0036] In one embodiment, the waste rubber recycling system includes a waste rubber collection tank A1, a pre-filtration unit 2 and a cascade filtration unit 3, and a continuous passage for waste rubber generation, treatment and recycling is formed between the viscose filtration section 5, the waste rubber collection tank A1, the pre-filtration unit 2, the cascade filtration unit 3 and the degassing section 6. At least two pre-filtration units 2 are provided, and the pre-filtration units 2 are connected in parallel. The pre-filtration unit 2 includes at least two KKF filters 21, and the KKF filters 21 are connected in parallel. The parallel KKF filters 21 and the pre-filtration unit 2 are connected to the feed port of the cascade filtration unit 3 through the conveying pipe II12 after being collected.

[0037] In this embodiment, at least two step filter units 3 are provided, and two adjacent step filter units 3 are connected in series. The step filter unit 3 includes at least two plate-frame filters 310, and the plate-frame filters 310 are connected in parallel. The step filter unit 3 can be set to include 2-4 levels or more, and combined with the filter cloth accuracy, the purpose of step filtering can be achieved.

[0038] Preferably, three cascade filtration units 3 are provided, including cascade filtration unit BI31, cascade filtration unit BII32 and cascade filtration unit BIII33 connected in series. The cascade filtration unit 3 needs to be provided with a multi-stage plate and frame filter. In the waste rubber after pre-filtration treatment, there are still impurities with smaller diameters and some elastic gel particles.

[0039] A metal sintered filter with a filter screen accuracy of 15 to 40 μm is used as the filter medium to achieve large-flux waste rubber filtration. In addition to manually changing the filter screen according to production needs, this process does not require manual intervention during operation, intercepting impurities with larger diameters and harder textures in the waste rubber, reducing the frequency of filter machine cleaning in the post-filtration process, and saving production costs. Then set up a first-level plate and frame filtration, a second-level plate and frame filtration, and a third-level plate and frame filtration. Each level of plate and frame filtration uses multiple parallel plate and frame filters, with specific filter cloth tissues. The filter cloth tissues include polypropylene felt, flat cloth, double velvet, poplin, etc. According to actual needs, the filter cloth tissue can be set to multiple layers, and the filter material in the filter cloth tissue can be flexibly adjusted. The filtration accuracy is gradually improved, meeting the filtration flux while balancing the filter load of the filter machine, which is used to intercept impurities with smaller diameters in the waste rubber and some elastic gel particles.

[0040] Optionally, the filter cloth structure of the step filter unit BI31 includes a layer of polypropylene and a layer of plain cloth, the filter cloth structure of the step filter unit BII32 includes a layer of polypropylene, a layer of double velvet, a layer of plain cloth and a layer of poplin, and the filter cloth structure of the step filter unit BIII33 includes a layer of polypropylene, a layer of double velvet, a layer of plain cloth and two layers of poplin. Through the combination of the three-stage plate and frame filter, the impurities in the waste rubber are intercepted multiple times in stages to ensure the stability of the spinning process and the product quality.

[0041] Among them, the first-level filtration accuracy is 30-45μm, the second-level filtration accuracy is 15-30μm, and the third-level filtration accuracy is 8-15μm; the post-filtration index parameters are mainly judged by the number of viscose particles (pieces / ml), microscopic value (roots / gram) and filtration value (ml / min). In the process of pre-filtration and cascade filtration, the post-filtration indexes are as follows:

[0042]

[0043] As an embodiment, it includes a waste rubber collection tank A1, a pre-filter unit 2 and a step filter unit 3, and a continuous passage for waste rubber generation, treatment and reuse is formed between the viscose filtration section 5, the waste rubber collection tank A1, the pre-filter unit 2, the step filter unit 3 and the degassing section 6. At least two pre-filter units 2 are provided, and the pre-filter units 2 are connected in parallel. The pre-filter unit 2 includes at least two KKF filters 21, and the KKF filters 21 are connected in parallel. The parallel KKF filters 21 and the pre-filter unit 2 are connected to the feed port of the step filter unit 3 through a conveying pipe I11 after being collected. At least two step filter units 3 are provided, and two adjacent step filter units 3 are connected in series. The step filter unit 3 includes at least two plate-frame filters 310, and the plate-frame filters 310 are connected in parallel.

[0044] KKF filter and plate and frame filter are commonly used filtering equipment. They remove solid particles or impurities in waste rubber by filtering to ensure the quality of waste rubber. After multiple filtrations of the yellowed and dissolved viscose, although the impurity content in the viscose can be reduced to meet the requirements of the subsequent spinning production process, the filtration process will inevitably cause the generation of waste rubber, so it needs to be collected and processed. The secondary waste rubber generated by KKF filter and plate and frame filter can be recovered and processed by the following methods.

[0045] A secondary waste rubber recovery unit 4 is provided, and the secondary waste rubber recovery unit 4 includes a waste rubber collection tray A23 provided at the bottom of the pre-filtering unit 2 and a waste rubber collection tray B34 provided at the bottom of the step filtering unit 3, and the outlet end of the waste rubber collection tray A23 is connected to the waste rubber collection tank B41 through a conveying pipe III40, and the outlet ends of the waste rubber collection tray A23 and the waste rubber collection tray B34 are connected to the waste rubber collection tank B41 through a conveying pipe III40.

[0046] During implementation, the outlet end of the waste rubber collection tank B41 is connected to the secondary filtration unit 42 through the delivery pipe III40, and the discharge port of the secondary filtration unit 42 and the discharge port of the cascade filtration unit 3 are connected to the degassing section 6 through a pipeline.

[0047] In one embodiment, a waste rubber collection tank A1, a pre-filtering unit 2 and a cascade filtering unit 3 are included, and a continuous passage for waste rubber generation, treatment and recycling is formed between the viscose filtering section 5, the waste rubber collection tank A1, the pre-filtering unit 2, the cascade filtering unit 3 and the degassing section 6. At least two pre-filtering units 2 are provided, and the pre-filtering unit 2 includes at least two KKF filters 21. At least two cascade filtering units 3 are provided, and the cascade filtering unit 3 includes at least two plate and frame filters 310.

[0048] The present embodiment also includes a secondary waste rubber recovery unit 4, which includes a waste rubber collection tray A23 arranged at the bottom of the pre-filtering unit 2 and a waste rubber collection tray B34 arranged at the bottom of the step filtering unit 3, the outlet end of the waste rubber collection tray A23 is connected to the waste rubber collection tank B41 through a conveying pipe III40, and the outlet end of the waste rubber collection tray B34 is connected to the waste rubber collection tank B41 through a conveying pipe III40.

[0049] The difference between this embodiment and the above embodiment is that the outlet ends of the step filter units 3 are connected to the waste rubber buffer tank B311, the upper feed port of the waste rubber buffer tank B311 is connected in series with the previous step filter unit 3 through a pipeline, and the bottom discharge port of the waste rubber buffer tank B311 is connected in series with the next step filter unit 3 through a pipeline; the outlet end of the secondary filter unit 42 is connected to the waste rubber buffer tank C through a delivery pipe III40, and the waste rubber buffer tank B311 is connected in series with the waste rubber buffer tank C43 and then connected to the degassing section 6. Through the above method, the secondary waste rubber generated by the KKF filter and the plate and frame filter can be effectively treated to protect the environment and resources.

[0050] In one or more embodiments, at least two waste rubber collection tanks A1 are provided, and the waste rubber collection tanks A1 are connected in parallel. Multiple waste rubber collection tanks A can be provided in parallel to prevent overflow during waste rubber collection, and multiple waste rubber collection tanks A can be externally connected for backup, and valves can be provided.

[0051] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A waste rubber recovery system in a viscose filament production system, characterized in that: The invention comprises a waste rubber collection tank A (1) for collecting and temporarily storing waste rubber, a pre-filtering unit (2) and a step-filtering unit (3), wherein the waste rubber collection tank A (1) is arranged at the rear side of a workstation of a viscose filtering section (5) in a viscose filament production system; the waste rubber collection tank A (1) is connected to a feed inlet of the pre-filtering unit (2) via a conveying pipe I (11), and the pre-filtering unit (2) is arranged at the rear side of the workstation of the waste rubber collection tank A (1); the pre-filtering unit (2) is connected to a feed inlet of the step-filtering unit (3) via a conveying pipe II (12), and the step-filtering unit (3) is arranged at the rear side of the workstation of the pre-filtering unit (2); the step-filtering unit (3) is connected to a degassing section (6) in the viscose filament production system, and a continuous passage for waste rubber generation, treatment and recycling is formed between the viscose filament production section (5), the waste rubber collection tank A (1), the pre-filtering unit (2), the step-filtering unit (3) and the degassing section (6).

2. The waste rubber recovery system in the viscose filament production system according to claim 1, characterized in that: At least two pre-filtering units (2) are provided, and the pre-filtering units (2) are connected in parallel. The pre-filtering units (2) include at least two KKF filters (21), and the KKF filters (21) are connected in parallel. The parallel-connected KKF filters (21) and the pre-filtering units (2) are connected to the feed port of the cascade filtering unit (3) through a conveying pipe II (12) after being collected.

3. The waste rubber recovery system in the viscose filament production system according to claim 2, characterized in that: A waste rubber buffer tank A (22) is provided on the conveying pipe II (12), an upper feed port of the waste rubber buffer tank A (22) is connected to the pre-filtering unit (2) via the conveying pipe II (12), and a bottom discharge port of the waste rubber buffer tank A (22) is connected to the cascade filtering unit (3) via the conveying pipe II (12).

4. The waste rubber recovery system in the viscose filament production system according to claim 2, characterized in that: At least two of the step filter units (3) are provided, and the step filter units (3) are connected in series. The step filter units (3) include at least two plate-and-frame filters (310), and the plate-and-frame filters (310) are connected in parallel.

5. The waste rubber recovery system in the viscose filament production system according to claim 4, characterized in that: The step filter units (3) are provided in three numbers, including a step filter unit BI (31), a step filter unit BII (32) and a step filter unit BIII (33) which are sequentially connected in series.

6. The waste rubber recovery system in the viscose filament production system according to claim 5, characterized in that: The filter cloth structure of the step filter unit BI (31) includes a layer of polypropylene and a layer of plain cloth, the filter cloth structure of the step filter unit BII (32) includes a layer of polypropylene, a layer of double velvet, a layer of plain cloth and a layer of poplin, and the filter cloth structure of the step filter unit BIII (33) includes a layer of polypropylene, a layer of double velvet, a layer of plain cloth and two layers of poplin.

7. The waste rubber recovery system in the viscose filament production system according to claim 4, characterized in that: The invention also comprises a secondary waste rubber recovery unit (4), wherein the secondary waste rubber recovery unit (4) comprises a waste rubber collection tray A (23) arranged at the bottom of the pre-filtering unit (2), a waste rubber collection tray B (34) arranged at the bottom of the step filter unit (3), and a secondary filter unit (42), wherein the outlet end of the waste rubber collection tray A (23) is connected to a waste rubber collection tank B (41) via a delivery pipe III (40), and the outlet end of the waste rubber collection tray B (34) is connected to a waste rubber collection tank B (41) via a delivery pipe III (40).

8. The waste rubber recovery system in the viscose filament production system according to claim 7, characterized in that: The outlet end of the waste rubber collection tank B (41) is connected to the secondary filtration unit (42) via a delivery pipe III (40), and the outlet of the secondary filtration unit (42) and the outlet of the cascade filtration unit (3) are connected to the degassing section (6) via a pipeline.

9. The waste rubber recovery system in the viscose filament production system according to claim 8, characterized in that: The outlet ends of the step filtration units (3) are connected to a waste rubber buffer tank B (311); the upper feed port of the waste rubber buffer tank B (311) is connected in series to the previous step filtration unit (3) via a pipeline; the bottom discharge port of the waste rubber buffer tank B (311) is connected in series to the next step filtration unit (3) via a pipeline; the outlet end of the secondary filtration unit (42) is connected to the waste rubber buffer tank C (43) via a conveying pipe III (40); the waste rubber buffer tank B (311) is connected in series to the waste rubber buffer tank C (43) and then connected to the degassing section (6).

10. The waste rubber recovery system in the viscose filament production system according to claim 1, characterized in that: At least two waste rubber collection tanks A (1) are provided, and the waste rubber collection tanks A (1) are connected in parallel.

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