Method for improving performance of waste paper pulp

Abstract

The invention relates to the technical field of waste paper pulp treatment, and discloses a method for improving the performance of waste paper pulp, which comprises the following steps: S1, paper pulp pretreatment: S2, paper pulp impurity removal: putting to-be-treated pulp into screening equipment, and collecting to obtain undersize pulp; s3, extruding and dispersing: putting the undersize material into an extruding machine; s4, ultrasonic treatment: readjusting the concentration of the extruded slurry, and then putting the slurry into an ultrasonic processor to obtain pretreated slurry; s5, preparing a compound liquid: mixing alkaline amino acid, acidic amino acid and neutral amino acid according to a mass ratio, adding ionized water, and stirring to obtain the amino acid compound liquid; s6, modification treatment: mixing and stirring the pretreated slurry subjected to ultrasonic treatment and the amino acid compound liquid in S5; and S7, washing and drying: washing the mixed pulp after the reaction in the step S6 with deionized water to obtain the high-performance paper pulp. The method has the following advantages and effects: through physical and chemical combination and compounding treatment of multiple amino acids, synchronous optimization of whiteness and strength is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of waste paper pulp processing, and particularly relates to a method for improving the performance of waste paper pulp. BACKGROUND

[0002] Utilization of waste paper pulp (i.e. waste paper recycled pulp) is one of the core paths for the paper industry to realize "circular economy", and its significance covers multiple dimensions such as resource protection, environmental protection, and economic efficiency; the paper industry has traditionally relied on wood (virgin fiber), and the utilization of waste paper pulp reduces the consumption of forest resources from the source; virgin wood pulp papermaking needs to go through a complex process such as "logging-pulping-bleaching", which has high energy consumption and heavy pollution; the waste paper pulp processing flow is more concise, and the environmental load is significantly reduced, in addition, it can also reduce the cost of enterprises and drive the recycling industry chain.

[0003] However, the fiber damage and fiber hornification in the waste paper pulp are more prominent, and the current mainstream methods include physical methods, chemical methods, and biological methods; when a single method is used, the performance improvement of the waste paper pulp product is limited, and therefore a method for improving the performance of waste paper pulp in combination is needed. SUMMARY

[0004] The purpose of the present application is to provide a method for improving the performance of waste paper pulp, which has the effect.

[0005] The above technical purpose of the present application is achieved by the following technical scheme: comprising the following steps:

[0006] S1, pulp pretreatment: mixing waste paper pulp with water, adjusting the pulp concentration, stirring at 30-40 DEG C, and making the fibers fully swell to obtain a treated pulp;

[0007] S2, pulp impurity removal: putting the treated pulp into a screening device to collect the undersize pulp;

[0008] S3, extrusion dispersion: putting the undersize material into an extruder to rub and twist the fibers to obtain dispersed fiber pulp;

[0009] S4, ultrasonic treatment: re-adjusting the concentration of the extruded pulp, and then putting it into an ultrasonic processor to strip the ink particles on the limiting surface to obtain pretreated pulp;

[0010] S5, preparation of a compounded liquid: mixing alkaline amino acids, acidic amino acids, and neutral amino acids according to the mass ratio, adding ionized water and stirring until completely dissolved to obtain an amino acid compounded liquid;

[0011] S6, modification treatment: mixing the pretreated pulp after ultrasonic treatment with the amino acid compounded liquid in S5, adding a pH adjuster to adjust the pH to 7-8, and then stirring at 50-60 DEG C for 20-40 mins.

[0012] S7, washing and drying: the mixed slurry after the reaction in S6 is washed with deionized water, and after the pH of the slurry reaches 6.5-7.5, it is dried to obtain high-performance pulp.

[0013] Further provided in the application is that the basic amino acid, the acidic amino acid and the neutral amino acid in S5 are preferably lysine, glutamic acid and glycine.

[0014] Further provided in the application is that the mass ratio of the lysine, the glutamic acid and the glycine is 3-5:2-3:1-2.

[0015] Further provided in the application is that the concentration of the amino acid compound solution in S5 is 2-4 wt%.

[0016] Further provided in the application is that the mass ratio of the pretreated slurry to the amino acid compound solution in S6 is 1:0.8-1.2.

[0017] Further provided in the application is that the pH regulator in S6 is preferably a sodium carbonate solution.

[0018] Further provided in the application is that the slurry concentration in S1 is 8-12 wt%, and the stirring time is 15-20 mins.

[0019] The application has the following beneficial effects:

[0020] 1. The impurities in the pulp are removed, and large-size impurities such as coarse fiber bundles and ink particles can be removed. In addition, when the pulp is extruded, the excess water is removed, and the fibers can be slightly rubbed and dispersed by the extrusion roller with rhombic convex points on the roller surface. After ultrasonic treatment, the micro-ink particles remaining on the surface of the fibers are further stripped by the cavitation effect of the ultrasonic waves, and the fiber cutting rate is reduced, so that the whiteness and strength of the physically treated pulp are improved.

[0021] 2. The amino group of the basic amino acid can enhance the positive charge on the fiber surface and promote fiber combination. The carboxyl group of the acidic amino acid can improve the hydrophilicity of the fiber and assist dispersion. The neutral amino acid can act as a cross-linking bridge to strengthen the action between active groups. Through the treatment of multiple amino acid compounds, the simultaneous optimization of whiteness and strength is realized.

[0022] 3. The amino acid used is a natural bio-based material, which is biodegradable and has no toxic and harmful substance emission in the treatment process, and is friendly to the environment. DETAILED DESCRIPTION

[0023] The technical solutions of the present application will be clearly and completely described below in combination with specific embodiments. Apparently, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0024] Embodiment 1

[0025] S1, pulp pretreatment: waste paper pulp is mixed with water, the pulp concentration is adjusted to 10wt%, and the fiber is fully swollen by stirring at 30℃ for 20mins to obtain the treated pulp;

[0026] S2, pulp impurity removal: the treated pulp is put into a screening device to collect the undersize pulp;

[0027] S3, extrusion dispersion: the undersize material is put into an extruder to rub and twist the fiber to obtain a dispersed fiber pulp;

[0028] S4, ultrasonic treatment: the extruded pulp is re-adjusted in concentration and then put into an ultrasonic processor to strip the ink particles on the limiting surface to obtain a pretreated pulp;

[0029] S5, preparation of a compounded liquid: basic amino acids, acidic amino acids and neutral amino acids are mixed according to a mass ratio of 3:2:1, ionized water is added and stirred until completely dissolved to obtain an amino acid compounded liquid, and the concentration of the obtained amino acid compounded liquid is 4wt%;

[0030] S6, modification treatment: the pretreated pulp after ultrasonic treatment is mixed with the amino acid compounded liquid in S5, the mass ratio of the pretreated pulp to the amino acid compounded liquid is 1:0.8, a pH adjuster sodium carbonate solution is added, the pH is adjusted to 7.5, and the temperature is raised to 50℃ for stirring for 30mins;

[0031] S7, washing and drying: the mixed slurry after reaction in S6 is washed with deionized water, and the slurry is dried after the pH reaches 7 to obtain a high-performance pulp.

[0032] Embodiment 2

[0033] S1, pulp pretreatment: waste paper pulp is mixed with water, the pulp concentration is adjusted to 10wt%, and the fiber is fully swollen by stirring at 30℃ for 20mins to obtain the treated pulp;

[0034] S2, pulp impurity removal: the treated pulp is put into a screening device to collect the undersize pulp;

[0035] S3, extrusion dispersion: the undersize material is put into an extruder to rub and twist the fiber to obtain a dispersed fiber pulp;

[0036] S4, ultrasonic treatment: the concentration of the extruded pulp is adjusted again, and then the pulp is put into an ultrasonic processor to strip the ink particles on the limiting surface, to obtain pretreated pulp;

[0037] S5, preparation of a complex solution: alkaline amino acids, acidic amino acids, and neutral amino acids are mixed in a mass ratio of 3:2:1, ionized water is added, and stirring is performed until complete dissolution, to obtain an amino acid complex solution, the concentration of the obtained amino acid complex solution being 4wt%;

[0038] S6, modification treatment: the pretreated pulp after ultrasonic treatment is mixed with the amino acid complex solution in S5, the mass ratio of the pretreated pulp to the amino acid complex solution being 1:1, a pH adjuster sodium carbonate solution is added, the pH is adjusted to 7.5, and after being warmed to 50℃, stirring is performed for 30 mins;

[0039] S7, washing and drying: the mixed slurry after the reaction in S6 is washed with deionized water, and after the pH of the slurry reaches 7, drying is performed, to obtain high-performance pulp.

[0040] Example 3:

[0041] S1, pulp pretreatment: waste paper pulp is mixed with water, the concentration of the pulp is adjusted to 10wt%, and stirring is performed at 30℃ for 20 mins, to make the fibers fully swell, to obtain a to-be-treated pulp;

[0042] S2, pulp impurity removal: the to-be-treated pulp is put into a screening device, and undersize pulp is collected;

[0043] S3, extrusion dispersion: the undersize material is put into an extruder, to rub and twist the fibers, to obtain dispersed fiber pulp;

[0044] S4, ultrasonic treatment: the concentration of the extruded pulp is adjusted again, and then the pulp is put into an ultrasonic processor to strip the ink particles on the limiting surface, to obtain pretreated pulp;

[0045] S5, preparation of a complex solution: alkaline amino acids, acidic amino acids, and neutral amino acids are mixed in a mass ratio of 4:2:1, ionized water is added, and stirring is performed until complete dissolution, to obtain an amino acid complex solution, the concentration of the obtained amino acid complex solution being 4wt%;

[0046] S6, modification treatment: the pretreated pulp after ultrasonic treatment is mixed with the amino acid complex solution in S5, the mass ratio of the pretreated pulp to the amino acid complex solution being 1:0.8, a pH adjuster sodium carbonate solution is added, the pH is adjusted to 7.5, and after being warmed to 50℃, stirring is performed for 30 mins;

[0047] S7, washing and drying: the mixed slurry after the reaction in S6 is washed with deionized water, and after the pH of the slurry reaches 7, drying is performed, to obtain high-performance pulp.

[0048] Example 4:

[0049] S1, pulp pretreatment: waste paper pulp is mixed with water, the pulp concentration is adjusted to 10wt%, and the fiber is fully swollen by stirring at 30℃ for 20mins to obtain the treated pulp;

[0050] S2, pulp impurity removal: the treated pulp is put into a screening device to collect the undersize pulp;

[0051] S3, extrusion dispersion: the undersize material is put into an extruder to rub and twist the fiber to obtain a dispersed fiber pulp;

[0052] S4, ultrasonic treatment: the extruded pulp is re-adjusted in concentration and then put into an ultrasonic processor to strip the ink particles on the limiting surface to obtain a pretreated pulp;

[0053] S5, preparation of complex solution: basic amino acid, acidic amino acid and neutral amino acid are mixed in a mass ratio of 4:2:1, ionized water is added and stirred until completely dissolved to obtain an amino acid complex solution, and the concentration of the obtained amino acid complex solution is 4wt%;

[0054] S6, modification treatment: the pretreated pulp after ultrasonic treatment is mixed with the amino acid complex solution in S5, the mass ratio of the pretreated pulp to the amino acid complex solution is 1:1, a pH adjuster sodium carbonate solution is added, the pH is adjusted to 7.5, and the temperature is raised to 50℃ and stirred for 30mins;

[0055] S7, washing and drying: the mixed slurry after reaction in S6 is washed with deionized water, and the slurry is dried after the pH reaches 7 to obtain a high-performance pulp.

[0056] Example 5:

[0057] S1, pulp pretreatment: waste paper pulp is mixed with water, the pulp concentration is adjusted to 10wt%, and the fiber is fully swollen by stirring at 30℃ for 20mins to obtain the treated pulp;

[0058] S2, pulp impurity removal: the treated pulp is put into a screening device to collect the undersize pulp;

[0059] S3, extrusion dispersion: the undersize material is put into an extruder to rub and twist the fiber to obtain a dispersed fiber pulp;

[0060] S4, ultrasonic treatment: the extruded pulp is re-adjusted in concentration and then put into an ultrasonic processor to strip the ink particles on the limiting surface to obtain a pretreated pulp;

[0061] S5, preparation of a complex solution: mixing the basic amino acid, the acidic amino acid and the neutral amino acid according to a mass ratio of 5:3:2, adding ionized water and stirring until completely dissolved to obtain an amino acid complex solution, the concentration of the obtained amino acid complex solution being 4wt%;

[0062] S6, modification treatment: mixing the pretreated pulp after ultrasonic treatment with the amino acid complex solution in S5, the mass ratio of the pretreated pulp to the amino acid complex solution being 1:0.8, adding a pH regulator sodium carbonate solution, adjusting the pH to 7.5, and stirring for 30 mins after heating to 50℃;

[0063] S7, washing and drying: washing the mixed slurry after the reaction in S6 with deionized water, drying after the pH of the slurry reaches 7, and obtaining a high-performance pulp.

[0064] Example 6:

[0065] S1, pulp pretreatment: mixing waste paper pulp with water, adjusting the pulp concentration to 10wt%, and stirring at 30℃ for 20 mins to make the fibers fully swell, and obtaining a treated pulp;

[0066] S2, pulp impurity removal: putting the treated pulp into a screening device, and collecting the undersize pulp;

[0067] S3, extrusion dispersion: putting the undersize material into an extruder, rubbing and rubbing the fibers to obtain a dispersed fiber slurry;

[0068] S4, ultrasonic treatment: re-adjusting the concentration of the extruded pulp, and putting it into an ultrasonic processor to strip the ink particles on the limiting surface, and obtaining a pretreated pulp;

[0069] S5, preparation of a complex solution: mixing the basic amino acid, the acidic amino acid and the neutral amino acid according to a mass ratio of 5:3:2, adding ionized water and stirring until completely dissolved to obtain an amino acid complex solution, the concentration of the obtained amino acid complex solution being 4wt%;

[0070] S6, modification treatment: mixing the pretreated pulp after ultrasonic treatment with the amino acid complex solution in S5, the mass ratio of the pretreated pulp to the amino acid complex solution being 1:1, adding a pH regulator sodium carbonate solution, adjusting the pH to 7.5, and stirring for 30 mins after heating to 50℃;

[0071] S7, washing and drying: washing the mixed slurry after the reaction in S6 with deionized water, drying after the pH of the slurry reaches 7, and obtaining a high-performance pulp.

[0072] Comparative Example 1:

[0073] S1, pulp pretreatment: mix waste paper pulp with water, adjust the pulp concentration to 10wt%, stir at 30℃ for 20 mins to make the fibers fully swollen, and obtain the treated pulp;

[0074] S2, pulp impurity removal: put the treated pulp into a screening device to collect the undersize pulp;

[0075] S3, extrusion dispersion: put the undersize material into an extruder to rub and twist the fibers, and obtain the dispersed fiber pulp;

[0076] S4, ultrasonic treatment: adjust the concentration of the extruded pulp again, and put it into an ultrasonic processor to strip the ink particles on the limiting surface, and obtain the treated pulp.

[0077] The whiteness, tensile strength and tear index of the final pulp obtained in Examples 1-6 and Comparative Example 1 were detected, wherein the whiteness of the waste paper pulp was detected according to the diffuse reflection method (according to GB / T7974-2013 / ISO2470:2009), the tensile strength of the waste paper pulp was detected according to the tensile fracture method (according to GB / T12914-2018 / ISO 1924-3:2005), and the tear index of the waste paper pulp was detected according to the Elmendorf method (according to GB / T455-2002 / ISO1974:2012).

[0078] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Whiteness 86% ISO 88% ISO 89% ISO 90% ISO 88% ISO 89% ISO 70% ISO Tensile strength 55 N-m / g 56 N-m / g 56 N-m / g 60 N-m / g 58 N-m / g 58 N-m / g 43 N-m / g Tear index 11.9 mN-m2 / g 12.1 mN-m2 / g 12.7 mN-m2 / g 13.8 mN-m2 / g 13.4 mN-m2 / g 13 mN-m2 / g 10.2 mN-m2 / g

[0079] As can be seen from the above table, by using multiple amino acid complex treatment, the whiteness of the waste paper pulp is increased to 86-90% ISO, the tensile strength is increased to 55-60N·m / g, and the tear index is increased to 12-14mN·m² / g, realizing the synchronous optimization of whiteness and strength.

Claims

1. A method of improving the properties of waste paper pulp, characterized by: The method comprises the following steps S1, pulp pretreatment: mix waste paper pulp with water, adjust the pulp concentration, stir at 30-40℃, and make the fibers fully swell to obtain the treated pulp; S2, pulp impurity removal: put the treated pulp into a screening device to collect the undersize pulp; S3, extrusion dispersion: put the undersize material into an extruder to rub and twist the fibers to obtain dispersed fiber pulp; S4, ultrasonic treatment: adjust the concentration of the extruded pulp again, and then put it into an ultrasonic processor to strip the ink particles on the limiting surface to obtain pretreated pulp; S5, prepare a complex liquid: mix alkaline amino acids, acidic amino acids, and neutral amino acids according to the mass ratio, add ionized water and stir until completely dissolved to obtain an amino acid complex liquid; S6, modification treatment: mix the ultrasonic treated pretreated pulp with the amino acid complex liquid in S5, add a pH adjuster, adjust the pH to 7-8, heat to 50-60℃, and stir for 20-40 mins; S7, washing and drying: wash the mixed slurry after the reaction in S6 with deionized water, dry after the pH of the slurry reaches 6.5-7.5 to obtain high-performance pulp.

2. A method of improving the properties of waste paper pulp according to claim 1, characterized in that: The alkaline amino acids, acidic amino acids, and neutral amino acids in S5 are preferably lysine, glutamic acid, and glycine.

3. A method of improving the properties of waste paper pulp according to claim 2, characterized in that: The mass ratio of lysine, glutamic acid, and glycine is 3-5:2-3:1-2.

4. A method of improving the properties of waste paper pulp according to claim 3, characterized in that: The concentration of the amino acid complex liquid in S5 is 2-4wt%.

5. A method of improving the properties of waste paper pulp according to claim 1, characterized in that: The mass ratio of the pretreated pulp to the amino acid complex liquid in S6 is 1:0.8-1.

2.

6. The method of improving the properties of waste paper pulp according to claim 1, characterized in that: The pH adjuster in S6 is preferably a sodium carbonate solution.

7. The method of improving the properties of waste paper pulp according to claim 1, characterized in that: The pulp concentration in step S1 is 8-12wt%, and the stirring time is 15-20 mins.