CN113605132A

CN113605132A - Production process of waste paper reconstituted corrugated medium paper for improving fiber recovery rate

Info

Publication number: CN113605132A
Application number: CN202110785834.8A
Authority: CN
Inventors: 刘伟锋; 易荣宗; 赖耀康
Original assignee: Dongguan Shunyu Paper Industry Co ltd
Current assignee: Dongguan Shunyu Paper Industry Co ltd
Priority date: 2021-07-12
Filing date: 2021-07-12
Publication date: 2021-11-05
Anticipated expiration: 2041-07-12
Also published as: CN113605132B

Abstract

The invention discloses a production process of waste paper reconstruction corrugated core paper for improving the recovery rate of fibers, which comprises a pulping step, a water injection sub-step, a soaking sub-step, a jolting sub-step and a pulping sub-step, wherein multiple lossless pulping machines are used for lossless pulping in the pulping step.

Description

Production process of waste paper reconstituted corrugated medium paper for improving fiber recovery rate

Technical Field

The invention relates to the technical field of waste paper papermaking processes, in particular to a production process of waste paper reconstituted corrugated medium paper for improving the fiber recovery rate.

Background

The pulping production line in the process of using the waste paper to reproduce the corrugated medium paper comprises various devices, including pulping devices, various impurity removing devices, multiple lossless refiners and various auxiliary devices for adding additives or auxiliary materials, at present, the multiple lossless refiners are refined by a millstone type refiner, the loss of the millstone is serious in the refining process, the maintenance frequency of the devices is high, and fiber blocks or fiber bundles in the pulp are pressed by high pressure, grinding and impacting in the refining process, so that the breakage rate of fibers of the pulp is high, the recovery rate of the fibers is low, and therefore improvement is necessary.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide the production process of the waste paper reconstruction corrugated medium paper for improving the fiber recovery rate, the fiber recovery rate is high in the pulping process, and the recovered fiber quality is high.

In order to achieve the purpose, the invention adopts the technical scheme that: a production process of waste paper reconstruction corrugated medium paper for improving the recovery rate of fiber, which comprises the following steps,

a waste paper conveying step, namely conveying the recycled waste paper to the upper part of the large-sized pulping barrel through a waste paper conveying belt, so that the waste paper can freely fall into the large-sized pulping barrel;

a pulping step, wherein a large pulping barrel is selected and used, a double D-shaped pulping barrel which can hit a pulping plane is respectively fixed at two opposite sides in the barrel, two pulping planes in the large pulping barrel are arranged in parallel, a pulping mechanism is rotationally installed in a pulping chamber of the large pulping barrel and comprises a suspension bracket fixed at the lower part of the pulping chamber, a pulping shaft rotationally installed above the middle part of the suspension bracket, a plurality of pulping rods and a plurality of pulping plates, the pulping chamber is internally provided with the plurality of pulping plates at intervals along the circumferential direction, the upper end parts of the pulping plates respectively extend to the upper part of the pulping chamber, the lower end parts of the pulping plates respectively extend to the lower part of the pulping chamber, the outer sides of the pulping plates are close to the inner wall of the pulping chamber, the inner sides of the pulping plates are longitudinally fixed with the plurality of transversely installed pulping rods at intervals, the inner ends of the pulping rods are respectively fixed on the pulping shaft, and the pulping shafts are driven to rotate by a pulping motor installed above the large pulping barrel, the pulping bars and the pulping plates are driven to rotate by a pulping shaft, the width of each pulping plate in the radial direction is set to be 5-20cm, the side edges of the pulping bars and the pulping plates are designed to be obtuse angles, the side edges of the pulping bars and the pulping plates break and disperse the waste paper and release fibers in a waste paper impacting mode, the fiber breakage rate is reduced, the outline shapes of the inner side edges and the outer side edges of the pulping plates are designed to be curve shapes, a pulp high-pressure impacting area is formed at the front side of the pulping plates and a pulp opposite impacting negative pressure area is formed at the rear side of the pulping plates in the pulping process along the advancing direction of the pulping plates, pulp which is impacted by the pulping plates and pushed to two sides in the pulping process bypasses the inner side edges and the outer side edges of the pulping plates and then respectively impacts the negative pressure area at the rear side of the pulping plates mutually, an asymmetrical opposite impacting pulp flow is formed in the negative pressure area at the rear side of the pulping plates, and then a disordered negative pressure flow is formed at the rear side of the pulping plates, until being impacted by the next beating plate again;

in the pulping process, a water injection sub-step, a soaking sub-step, a jolting sub-step and a pulping sub-step are sequentially carried out,

a water injection sub-step, wherein clear water and weak alkali liquor are injected into the beating chamber, the weight percentage of the weak alkali liquor relative to the waste paper put into the beating chamber is 0.01-0.3%, the weak alkali liquor is dissolved in a cationic starch adhesive layer attached to the surface of the waste paper in the surface sizing treatment process, the water injection is stopped after the water level in the beating chamber reaches 80% of the height of the beating chamber,

a soaking sub-step, namely soaking the waste paper in a pulping chamber for 10-20 minutes, driving a pulping plate to rotate at a low speed by a pulping motor in the soaking process, controlling the rotating speed of the pulping plate to be 60-100 revolutions per minute, and improving the wetting speed of the waste paper so that the waste paper is completely wetted and thorough in a shorter time;

in the jolting substep, the beating plate is driven by the pulping motor to circularly execute high-speed forward and reverse rotation jolting actions for 10-20 minutes, waste paper is physically cracked into blocky materials with different sizes through jolting, the forward rotation angle or the reverse rotation angle of the beating plate in one high-speed forward and reverse rotation jolting action is controlled to be 10-30 degrees, and the time period for finishing one high-speed forward and reverse rotation jolting action is controlled to be 1-3 seconds;

a pulping substep, namely continuously driving a pulping plate to rotate for pulping by a pulping motor, controlling the rotating speed of the pulping plate at 1000-3000 r/min, continuously pulping for 1-1.5 hours, and striking blocky materials in a pulping chamber or pulp formed by fibers dispersed from the blocky materials by rotating a pulping rod and the pulping plate to obtain papermaking raw pulp after pulping treatment is finished;

a hydraulic impurity removal step, namely pumping the paper-making raw pulp to a hydraulic impurity removal workshop for hydraulic impurity removal treatment;

a washing step, namely pumping the papermaking raw pulp subjected to the hydraulic impurity removal treatment to a pulp washing tank for washing treatment;

a deslagging step, namely pumping the washed paper-making raw pulp to a deslagging workshop, performing high-concentration deslagging treatment on the washed paper-making raw pulp through high-concentration deslagging equipment in the deslagging workshop, and performing low-concentration deslagging treatment on the washed paper-making raw pulp through low-concentration deslagging equipment;

a bleaching step, namely pumping the papermaking raw pulp subjected to the deslagging step to a first high-speed pulp washing unit, and bleaching the pulp by the first high-speed pulp washing unit;

a filter pressing step, namely pumping the bleached paper-making raw pulp into a filter pressing workshop, performing high-concentration filter pressing treatment on the paper-making raw pulp through high-concentration filter pressing equipment in the filter pressing workshop, and performing low-concentration filter pressing treatment on the paper-making raw pulp through low-concentration filter pressing equipment in the filter pressing workshop;

a flotation deinking step, namely pumping the paper making raw pulp subjected to the filter pressing step to a flotation deinking workshop, and performing flotation deinking treatment through a flotation deinking pool to obtain paper making raw pulp;

a pulping step, pumping the papermaking coarse pulp to a multiple nondestructive pulping machine for nondestructive pulping, wherein the multiple nondestructive pulping machine comprises a pulping motor, a pulping outer cylinder, a pulping inner cylinder and a pulp collecting bin, the pulping outer cylinder is provided with a pulping cylinder cavity which vertically penetrates through the pulping outer cylinder, the pulping outer cylinder is vertically fixed above the pulp collecting bin, the pulping inner cylinder is movably sleeved in the pulping cylinder cavity of the pulping outer cylinder, the pulping inner cylinder is driven to rotate relative to the pulping outer cylinder by the pulping motor, a pulping gap is arranged between the outer circumferential wall surface of the pulping inner cylinder and the inner circumferential wall surface of the pulping outer cylinder, the upper end part of the pulping gap is provided with a pulp inlet, the lower end part of the pulping gap is provided with a pulp outlet, the upper part of the pulping outer cylinder is provided with a pulp inlet, and the lower part of the pulp inlet is communicated with the pulp inlet,

the inner circumferential wall surface of the pulping outer cylinder is respectively provided with grinding teeth or grinding grains which relatively protrude into the pulping clearance, the outer circumferential wall surface of the pulping inner cylinder is sequentially provided with a coarse grinding area, a middle grinding area and a fine grinding area from top to bottom, the area of the outer circumferential wall surface of the pulping inner cylinder, which corresponds to the coarse grinding area, is formed with a plurality of coarse pulp strip-shaped teeth which are arranged at intervals, the area of the outer circumferential wall surface of the pulping inner cylinder, which corresponds to the middle grinding area, is formed with a plurality of middle pulping strip-shaped teeth which are arranged at intervals, and the area of the outer circumferential wall surface of the pulping inner cylinder, which corresponds to the fine grinding area, is formed with a plurality of fine grinding strip-shaped teeth which are arranged at intervals;

pumping the papermaking coarse pulp to a pulp inlet, enabling the papermaking coarse pulp to enter a pulp grinding gap through a pulp inlet product, enabling the papermaking coarse pulp to sequentially pass through a coarse grinding area, a middle grinding area and a fine grinding area from top to bottom, enabling the papermaking coarse pulp to sequentially pass through coarse grinding treatment, middle grinding treatment and fine grinding treatment, finally discharging the coarse pulp through a pulp outlet, sequentially completing multiple pulp grinding treatment of the papermaking coarse pulp in the pulp grinding gap of a multiple lossless pulp grinder, and controlling the time for the papermaking coarse pulp to pass through the multiple lossless pulp grinder for 30-60 seconds;

a pulp washing step, namely pumping the primary pulp to a second high-speed pulp washing machine set, and carrying out pulp washing treatment through the second high-speed pulp washing machine set;

a pulp mixing step, namely pumping the primary pulp subjected to pulp washing treatment to a pulp mixing workshop for pulp mixing treatment to obtain papermaking pulp;

a papermaking forming step, namely pumping papermaking slurry to a papermaking forming workshop, continuously spraying the papermaking slurry to the mesh cloth through a spray gun, forming a layered slurry layer on the mesh cloth, and continuously outputting the layered slurry layer;

a squeezing and dewatering treatment step, wherein the layered pulp layer is continuously transferred to a squeezing unit through a first vacuum suction and moving roller, the layered pulp layer is continuously conveyed forwards, and the layered pulp layer is sequentially squeezed through a plurality of squeezing and dewatering rollers of the squeezing unit to dewater the layered pulp layer to obtain a wet paper layer;

a drying treatment step, transferring the wet paper layer to a drying unit through a second vacuum suction shifting roller, continuously conveying the wet paper layer forwards, and drying the wet paper layer to obtain dry paper through a plurality of drying rollers of the drying unit in sequence;

and a post-treatment step, namely performing rewinding treatment, press polishing treatment, surface sizing treatment, slitting treatment and packaging treatment on the dry paper in sequence to obtain the finished corrugated medium paper.

In a further technical scheme, the multiple nondestructive pulping machine comprises a hoisting mechanism, wherein the pulping inner cylinder is vertically arranged, the upper end of the pulping inner cylinder is enabled to protrude above the pulping outer cylinder, the upper end of the pulping inner cylinder is movably hoisted to the hoisting mechanism, the pulping inner cylinder is freely suspended in a cavity of the pulping cylinder, the widths of different positions of a pulping gap after the pulping gap is filled with pulp are in a dynamic change state, the lower part of the pulping inner cylinder and the upper part of the pulping outer cylinder freely and slightly shake under the action of internal pressure, so that the papermaking coarse pulp spirally flows downwards along the circumferential direction in the pulping gap, and blocky, blocky or bunched fiber blocks in the papermaking coarse pulp are scattered in the pulping process, so that the pulp is prevented from being excessively ground, and fibers in the fiber blocks are prevented from being broken.

In a further technical scheme, the width of the refining gap is set to be 3-8mm, the refining gap with large width enables the papermaking coarse pulp to smoothly pass through the refining gap while being fully ground, the height of the refining gap in the vertical direction is set to be 120-250cm, the outer diameter of the refining inner cylinder is set to be 50-150cm, the height of the refining inner cylinder is set to be 150-300cm, and after the refining gap between the refining outer cylinder and the refining inner cylinder is filled with pulp, the inner circumferential surface of the refining outer cylinder and the outer circumferential surface of the refining inner cylinder are both subjected to the hydraulic action of the papermaking coarse pulp; under the action of self gravity and the pressure from a pulp inlet, papermaking coarse pulp flows downwards, and under the action of providing the circumferential direction for the papermaking coarse pulp entering a pulping gap through a rotating pulping inner cylinder, the path of the papermaking coarse pulp passing through the pulping gap is converted into a spiral shape, the pulping path is designed into the spiral shape to increase the length of the pulping path of the papermaking coarse pulp, and the equivalent pulping area of the multiple nondestructive pulping machine is increased;

the width of the refining gap of the lower part of the refining inner cylinder along different directions of the circumferential direction is different, the pressure intensity of the lower part of the refining inner cylinder along different directions of the circumferential direction is different, the size of the refining gap between the lower part of the refining inner cylinder and the refining outer cylinder is inversely proportional to the pressure intensity of the position, the pressure intensity acting on the lower part of the refining inner cylinder is directly proportional to the pressure intensity acting on the lower part of the refining inner cylinder, and the lower part of the refining inner cylinder continuously and repeatedly moves from one side with high pressure intensity to one side with low pressure intensity in the refining process, so that the lower part of the refining inner cylinder continuously and randomly moves along any radial direction with small amplitude;

the width of the refining gap in different directions of the upper part of the refining outer cylinder along the circumferential direction is different, the pressure intensity in different directions of the upper part of the refining outer cylinder along the circumferential direction is different, the size of the refining gap between the upper part of the refining outer cylinder and the refining inner cylinder is inversely proportional to the pressure intensity at the position, the pressure intensity acting on the upper part of the refining outer cylinder is directly proportional to the pressure intensity acting on the upper part of the refining outer cylinder, and the upper part of the refining outer cylinder continuously and repeatedly moves from the side with high pressure intensity to the side with low pressure intensity in the refining process, so that the upper part of the refining outer cylinder continuously and randomly moves in any radial direction in a small range.

In a further technical scheme, a support frame is fixed at the upper part of the pulp collecting bin, the lower end part of the pulping outer cylinder is fixedly arranged on the support frame, so that the upper end part of the pulping outer cylinder is freely suspended, and the upper end part of the pulping outer cylinder has displacement along any radial direction;

the upper end of the pulping inner cylinder is fixed with a suspension post, the middle of the suspension post is fixed with a ball with a diameter larger than that of the suspension post, the middle of the hoisting mechanism is provided with a ball socket, the middle lower part of the suspension post movably penetrates through the ball socket, the ball freely supports against the upper side of the ball socket, the pulping motor is arranged above the hoisting mechanism, and the pulping motor is connected with the upper end of the suspension post through a universal coupling, so that the lower end of the pulping inner cylinder has displacement along any radial direction.

In a further technical scheme, the middle of the refining inner cylinder is cylindrical, an inner cavity of the refining inner cylinder is sealed, a plurality of support plates are arranged in the inner cavity of the refining inner cylinder at intervals from top to bottom, each support plate is hermetically connected with the inner wall surface of the refining inner cylinder, the inner cavity of the refining inner cylinder is divided into a plurality of sealing chambers through the support plates, damping liquid accounting for 50-70% of the volume of the sealing chamber is stored in the sealing chamber below the refining inner cylinder, the inertia of the lower end part of the refining inner cylinder is increased through the damping liquid, the refining inner cylinder has flexible refining force, the refining force of the refining inner cylinder is increased, the shaking amplitude and the moving speed of the refining inner cylinder are reduced through the damping effect of the damping liquid stored in the refining inner cylinder in the back-and-forth shaking process, and the refining inner cylinder and the refining outer cylinder are prevented from colliding with each other.

In a further technical scheme, the upper end part of the refining inner cylinder extends into the pulp inlet hopper, an annular feeding chamber with an upper opening and a large upper part and a small lower part is formed between the refining inner cylinder and the pulp inlet hopper, a plurality of arc-shaped shifting plates are fixed on the outer side of the refining inner cylinder at intervals along the circumferential direction, each shifting plate is arranged at the lower part of the feeding chamber, the outer side edge of each shifting plate abuts against the inner wall surface of the pulp inlet hopper, the lower side of each shifting plate is adjacent to or extends into the refining gap, the papermaking coarse pulp entering the feeding chamber is pushed by the shifting plates and pushed into the refining gap, and the papermaking coarse pulp entering the refining gap has periodic impact surge.

In a further technical scheme, a plurality of strip-shaped grinding grains which are arranged at intervals are formed on the inner circumferential wall surface of the pulping outer cylinder;

a plurality of rough grinding pulp strip-shaped teeth arranged at intervals along the circumferential direction and a plurality of rough grinding pulp strip-shaped teeth arranged at intervals along the vertical direction are arranged in the rough grinding area, the thickness of the rough grinding pulp strip-shaped teeth is set to be 0.1-1mm, the width of the rough grinding pulp strip-shaped teeth is set to be 5-20mm, and rough grinding treatment is completed through grinding cooperation of the rough grinding pulp strip-shaped teeth and grinding patterns;

the middle grinding area is provided with a plurality of middle grinding strip-shaped teeth arranged at intervals along the circumferential direction and a plurality of middle grinding strip-shaped teeth arranged at intervals along the vertical direction, and middle grinding processing is completed through grinding cooperation of the middle grinding strip-shaped teeth and the grinding grains;

the fine grinding area is provided with a plurality of fine grinding pulp strip-shaped teeth arranged at intervals along the circumferential direction and a plurality of fine grinding pulp strip-shaped teeth arranged at intervals along the vertical direction, the thickness of the fine grinding pulp strip-shaped teeth is set to be 1-3mm, the width of the fine grinding pulp strip-shaped teeth is set to be 1-10mm, and fine grinding processing is completed through grinding matching of the fine grinding pulp strip-shaped teeth and grinding grains;

the width of the profile tooth of the rough grinding pulp is larger than that of the profile tooth of the middle grinding pulp, and the width of the profile tooth of the middle grinding pulp is larger than that of the profile tooth of the fine grinding pulp;

the distance between two adjacent rough grinding strip-shaped teeth is larger than that between two adjacent middle grinding strip-shaped teeth, and the distance between two adjacent middle grinding strip-shaped teeth is larger than that between two adjacent fine grinding strip-shaped teeth;

the thickness of the profile teeth of the rough grinding pulp is less than that of the profile teeth of the middle grinding pulp, the thickness of the profile teeth of the middle grinding pulp is less than that of the profile teeth of the fine grinding pulp,

the profile teeth of the rough grinding pulp strip, the profile teeth of the middle grinding pulp strip and the profile teeth of the fine grinding pulp strip are respectively arranged in an inclined way relative to the vertical direction.

In a further technical scheme, in the step of grinding, the lower end part of the grinding inner cylinder is protruded below the grinding outer cylinder, a flow guide cone part with a large upper part and a small lower part is arranged at the lower end part of the grinding inner cylinder, the lower end part of the grinding outer cylinder, the lower end part of the grinding inner cylinder and the lower end part of the flow guide cone part are all positioned in the pulp collecting bin, primary pulp is guided into the pulp collecting bin through the flow guide cone part, a pulp discharging port is arranged at one side of the pulp collecting bin, and the primary pulp is discharged through the pulp discharging port;

the grinding grains formed on the inner circumferential wall surface of the refining outer cylinder relatively protrude in the refining gap, the thickness of the grinding grains is set to be 0.1-1mm, and the width of the grinding grains is set to be 5-20 mm;

the grinding grains are obliquely arranged relative to the vertical direction, the oblique direction of the grinding grains is opposite to that of the rough grinding pulp strip-shaped teeth, and the oblique directions of the rough grinding pulp strip-shaped teeth, the middle grinding pulp strip-shaped teeth and the fine grinding pulp are the same;

the damping liquid comprises water and/or oil.

In a further technical scheme, the beating plate is provided with a beating plate surface with the width of 6-10cm along the rotation direction of the beating plate, the beating plate surface is obliquely arranged relative to the vertical surface, the widths of different positions of the beating plate surface are different, the distances between the different positions of the beating plate surface and the inner wall of the beating chamber are different, and the distances between the different positions of the beating plate surface and a beating shaft are different.

Compared with the prior art, the invention has the advantages that: the method has the advantages of simple process, low equipment cost, low operation cost, energy conservation and environmental protection, high recovery rate of the fiber in the waste paper of more than 95 percent, high recovery rate of the long fiber, low breakage rate of the long fiber in the waste paper in the pulping and pulping processes of less than 10 percent, great reduction of the breakage rate of the fiber, and high quality of the recovered fiber, so that the finally produced corrugated core paper or corrugated paper has the structural strength and toughness.

Drawings

The invention is further illustrated with reference to the following figures and examples.

FIG. 1 is a schematic process flow diagram of the present invention.

Fig. 2 is a schematic structural view of a large size crushed pulp bucket of the present invention.

Fig. 3 is a schematic view of the structure of the multiple lossless refiner of the present invention.

Fig. 4 is a schematic view of the internal structure of the multiple lossless refiner of the present invention.

The labels in the figure are:

1 a refining outer cylinder 11 and a refining gap of a refining hopper 12.

2 guiding conical part 22 of refining inner cylinder 21, supporting plate 23, material shifting plate 24, coarse grinding area 26, fine grinding area 27 and hanging post 28 in coarse grinding area 25, driving flange 29 with damping liquid.

3 pulp collecting bin 31 supporting frame 32 discharge port.

Detailed Description

The following are merely preferred embodiments of the present invention, and do not limit the scope of the present invention.

A production process of waste paper reconstruction corrugated medium paper for improving the recovery rate of fiber, which is shown in figures 1 to 4 and comprises the following steps,

and a waste paper conveying step of conveying the recovered waste paper to the upper part of the large pulp crushing barrel 4 through a waste paper conveying belt 5 so that the waste paper can freely fall into the large pulp crushing barrel 4.

A pulping step, wherein the large pulping barrel 4 is selected from a double-D type pulping barrel, two pulping planes in the large pulping barrel 4 are arranged in parallel, a pulping mechanism is rotatably arranged in a pulping chamber 45 of the large pulping barrel 4 and comprises a suspension bracket 41 fixed at the lower part of the pulping chamber 45, a pulping shaft 42 rotatably arranged above the middle part of the suspension bracket 41, a plurality of pulping rods 43 and a plurality of pulping plates 44, the plurality of pulping plates 44 are arranged in the pulping chamber 45 at intervals along the circumferential direction, the upper end part of each pulping plate 44 respectively extends to the upper part of the pulping chamber 45, the lower end part of each pulping plate 44 respectively extends to the lower part of the pulping chamber 45, the inner wall of the pulping chamber 45 at the outer side of the pulping plate 44 is longitudinally fixed with the plurality of transversely arranged pulping rods 43 at intervals at the inner side of the pulping plate 44, the inner ends of the pulping rods 43 are respectively fixed on the pulping shaft 42, the pulping shaft 42 is driven to rotate by a pulping motor 46 arranged above the large pulping barrel 4, each pulping rod 43 and each pulping plate 44 are driven to rotate by the pulping shaft 42, the width of each pulping plate 44 along the radial direction is set to be 5-20cm, preferably, the pulping plates 44 along the rotating direction of the pulping plates 44 are provided with pulping plate surfaces with the width of 6-10cm, the pulping plate surfaces are obliquely arranged relative to a vertical plane, the widths of different positions of the pulping plate surfaces are different, the distances between different positions of the pulping plate surfaces and the inner wall of the pulping chamber 45 are different, the distances between different positions of the pulping plate surfaces and the pulping shaft 42 are different, the side edges of the pulping rods 43 and the side edges of the pulping plates 44 are designed to be obtuse angles, the side edges of the pulping rods 43 and the pulping plates 44 break and disperse waste paper by impacting the waste paper and release fibers, meanwhile, the fiber breakage rate is reduced, the outline shapes of the inner side edges and the outer side edges of the pulping plates 44 are designed to be curved shapes, a pulp high-pressure impact area and a pulp opposite-impact negative pressure area are formed on the front side and the rear side of the beating plate 44 in the pulp crushing process along the advancing direction of the beating plate 44, two kinds of pulp which are impacted by the beating plate 44 and pushed to the two sides in the pulp crushing process are respectively impacted into the negative pressure area on the rear side of the beating plate 44 after bypassing the inner side and the outer side of the beating plate 44 and are impacted with each other, an asymmetrical opposite-impact pulp flow is formed in the negative pressure area on the rear side of the beating plate 44, and then a disordered pulp flow of a disordered type is formed until the pulp is impacted by the next beating plate 44 again;

a water injection sub-step, wherein clear water and weak alkali liquor are injected into the beating chamber 45, the weight percentage of the weak alkali liquor relative to the waste paper put into the beating chamber 45 is 0.01-0.3 percent, the cationic starch glue layer attached to the surface of the waste paper in the surface sizing treatment process is dissolved by weak alkali liquor, stopping injecting water when the water level in the beating chamber 45 reaches 80% of the height of the beating chamber 45, wherein the weak alkali solution can be various weak alkali liquids capable of dissolving starch, in particular to alkalescent liquid capable of quickly dissolving cationic starch, can quickly dissolve the cationic starch glue layer on the surface of the waste paper, the fiber in the waste paper is not damaged, so that the wetting speed of the waste paper can be accelerated, the waste paper without the cationic starch glue layer is more easily decomposed into fiber blocks or fiber bundles in the subsequent shock treatment and pulping treatment, and the fiber in the waste paper is more easily decomposed in a physical mode;

a soaking sub-step, in which the waste paper is soaked in the pulping chamber 45 for 10-20 minutes, the pulping plate 44 is driven to rotate at a low speed by the pulping motor 46 in the soaking process, the rotating speed of the pulping plate 44 is controlled at 60-100 revolutions per minute, the wetting speed of the waste paper is improved, and the waste paper is fully wetted thoroughly in a shorter time;

a jolting substep, driving a beating plate 44 to circularly execute high-speed forward and reverse rotation jolting actions for 10-20 minutes by a pulping motor 46, physically cracking the waste paper into blocky materials with different sizes by jolting, controlling the forward rotation angle or the reverse rotation angle of the beating plate 44 to be 10-30 degrees in one high-speed forward and reverse rotation jolting action, controlling the time period of finishing one high-speed forward and reverse rotation jolting action to be 1-3 seconds, rapidly switching forward rotation and reverse rotation by the beating plate 44, immediately stopping and rapidly reversing the beating plate 44 after the beating plate 44 impacts wetted and thorough waste paper at high speed, starting to move at high speed in reverse direction and impacting the waste paper on the other side, continuously and repeatedly impacting the waste paper in the beating chamber 45 by the beating plate 44 to form jolting effect on the waste paper, so as to realize that the waste paper (containing no water) weighing 10-30 tons in the beating chamber 45 is completely shaken apart and is physically decomposed into small blocky materials in the shortest time, and the acting force generated during beating and countershocking can penetrate into the waste paper, so that all the fibers in the blocky materials formed after shocking are relatively separated, the fibers in the blocky materials are in a loose combination state, and part of the fibers in the waste paper are dispersed out in the process of shocking;

a pulping substep, wherein a pulping motor 46 continuously drives a pulping plate 44 to rotate for pulping, the rotating speed of the pulping plate 44 is controlled at 1000-;

for the large size pulping barrel 4 with the effective capacity of 10-20 tons, the operation time for completing primary pulping and pulping is shortened to 0.5-1 hour, and for the large size pulping barrel 4 with the effective capacity of 20-50 tons, the operation time for completing primary pulping and pulping is shortened to 1-1.5 hours, so that the pulping time is greatly shortened, compared with the traditional pulping equipment, the pulping time is shortened by more than 50 percent, and the energy consumption is reduced by more than 50 percent.

a pulping step, pumping papermaking coarse pulp to a multiple nondestructive pulping machine for nondestructive pulping, wherein the multiple nondestructive pulping machine comprises a pulping motor, a pulping outer cylinder 1, a pulping inner cylinder 2 and a pulp collecting bin 3, the pulping outer cylinder 1 is provided with a pulping cylinder cavity which vertically penetrates through the pulping outer cylinder 1, the pulping outer cylinder 1 is vertically fixed above the pulp collecting bin 3, the pulping inner cylinder 2 is movably sleeved in the pulping cylinder cavity of the pulping outer cylinder 1, the pulping inner cylinder 2 is driven by the pulping motor to rotate relative to the pulping outer cylinder 1, a pulping gap 12 is arranged between the outer circumferential wall surface of the pulping inner cylinder 2 and the inner circumferential wall surface of the pulping outer cylinder 1, the upper end part of the pulping gap 12 is provided with a pulp inlet, the lower end part of the pulping gap 12 is provided with a pulp outlet, the upper part of the pulping outer cylinder 1 is provided with a pulp inlet hopper 11, and the lower part of the pulp inlet hopper 11 is communicated with the pulp inlet,

the inner circumferential wall surface of the pulping outer cylinder 1 is respectively provided with grinding teeth or grinding grains which are relatively protruded in the pulping clearance 12, the outer circumferential wall surface of the pulping inner cylinder 2 is sequentially provided with a rough grinding area 24, a middle grinding area 25 and a fine grinding area 26 from top to bottom, the area of the outer circumferential wall surface of the pulping inner cylinder 2, which corresponds to the rough grinding area 24, is formed with a plurality of rough grinding strip-shaped teeth which are arranged at intervals, the area of the outer circumferential wall surface of the pulping inner cylinder 2, which corresponds to the middle grinding area 25, is formed with a plurality of middle pulping strip-shaped teeth which are arranged at intervals, and the area of the outer circumferential wall surface of the pulping inner cylinder 2, which corresponds to the fine grinding area 26, is formed with a plurality of fine grinding strip-shaped teeth which are arranged at intervals;

pumping the papermaking coarse pulp to a pulp inlet, enabling the papermaking coarse pulp to enter a pulp grinding gap 12 through a pulp inlet product, enabling the papermaking coarse pulp to sequentially pass through a coarse grinding area 24, a middle grinding area 25 and a fine grinding area 26 from top to bottom, enabling the papermaking coarse pulp to sequentially undergo coarse grinding treatment, middle grinding treatment and fine grinding treatment, finally discharging the primary pulp through a pulp outlet, sequentially completing multiple pulp grinding treatment of the papermaking coarse pulp in the pulp grinding gap 12 of a multiple lossless pulp grinder, controlling the time of the papermaking coarse pulp passing through the multiple lossless pulp grinder for 30-60 seconds, and not needing to use various different types of pulp grinders for combined pulp grinding;

the lower end part of the refining inner cylinder 2 is protruded below the refining outer cylinder 1, the lower end part of the refining inner cylinder 2 is provided with a diversion pyramid part 21 with a big top and a small bottom, the lower end part of the refining outer cylinder 1, the lower end part of the refining inner cylinder 2 and the lower end part of the diversion pyramid part 21 are all positioned in the pulp collecting bin 3, the primary pulp is guided into the pulp collecting bin 3 through the diversion pyramid part 21, one side of the pulp collecting bin 3 is provided with a pulp discharging port 32, and the primary pulp is discharged through the pulp discharging port 32.

The multi-nondestructive pulping machine comprises a hoisting mechanism, wherein the pulping inner cylinder 2 is vertically arranged, the upper end part of the pulping inner cylinder 2 protrudes above the pulping outer cylinder 1, the upper end part of the pulping inner cylinder 2 is movably hoisted to the hoisting mechanism, the pulping inner cylinder 2 is freely suspended in a cavity of the pulping outer cylinder, the widths of different positions of the pulping gap 12 are in a dynamic change state after the pulping gap 12 is filled with pulp, the lower part of the pulping inner cylinder 2 and the upper part of the pulping outer cylinder 1 freely and slightly shake under the action of internal pressure, coarse pulp flows downwards in the pulping gap 12 in a spiral mode along the circumferential direction, and fiber blocks in the coarse pulp are scattered in the pulping process, so that excessive grinding of the pulp and fiber breakage in the fiber blocks are avoided.

The width of the refining gap 12 is set to be 3-8mm, the refining gap 12 with large width enables coarse pulp to smoothly pass through the refining gap 12 while being fully ground, the height of the refining gap 12 in the vertical direction is set to be 250cm in the range of 120 plus one, the outer diameter of the refining inner cylinder 2 is set to be 50-150cm in the range of 50 plus one, the height of the refining inner cylinder 2 is set to be 300cm in the range of 150 plus one, and after the refining gap 12 between the refining outer cylinder 1 and the refining inner cylinder 2 is filled with pulp, the inner circumferential surface of the refining outer cylinder 1 and the outer circumferential surface of the refining inner cylinder 2 are both subjected to the hydraulic action of the coarse pulp; under the action of self gravity and the pressure from a pulp inlet, the coarse pulp flows downwards, under the action of the circumferential direction of the coarse pulp entering the pulping clearance 12 provided by the rotary pulping inner cylinder 2, the path of the coarse pulp passing the pulping clearance 12 is changed into a spiral shape, the pulping path is designed into the spiral shape to increase the length of the pulping path of the coarse pulp, and the equivalent pulping area of the multiple nondestructive pulping machine is increased; the spread area of the outer circumferential wall surface of the refining inner cylinder 2 is the minimum equivalent refining area of the multiple lossless refining machines, the spread area of the inner circumferential wall surface of the refining outer cylinder 1 is the maximum equivalent refining area of the multiple lossless refining machines, the equivalent refining area is about 3.14 multiplied by radius multiplied by height, the refining gap 12 between the oversized refining outer cylinder 1 and the refining inner cylinder 2 is designed into a refining surface, so that the multiple lossless refining machines have the refining surface with the oversized area, and the coarse pulp can rapidly pass through the refining gap 12 along the spiral refining path in 30-60 seconds by matching with various designs of the multiple lossless refining machines.

The equipment used by the invention has simple structure, low equipment cost, low comprehensive operation cost of the equipment, extremely small abrasion, low maintenance frequency, high fiber recovery rate of more than 95 percent of fiber in the waste paper, high fiber recovery rate and low production cost, and does not need to use various chemical preparations for assisting pulping and jordaning in the pulping and jordaning processes, so that the fiber in the waste paper can be damaged by various chemical preparations for assisting pulping and jordaning in the conventional waste paper making enterprises, the performances of structural strength, toughness and the like of the finished paper can be reduced, and the process difficulty of recycling the recycled paper making can be increased.

The invention has the advantages of high pulping speed and pulping speed, no need of long-time pulping and long-time pulping, greatly reduced fiber breakage rate, controlled fiber breakage rate of short-length fibers below 5 percent and long-fiber breakage rate between 5 and 10 percent in the pulping and pulping processes, greatly improved fiber recovery rate and utilization rate, and high pulping quality, so that the finally produced corrugated core paper has more proportion of long fibers, longer fibers and higher quality of the corrugated core paper with the proportion of the long fibers, therefore, the invention ensures that the finally produced corrugated core paper has higher bending strength and higher tensile strength.

The recycling rate of long fibers in the waste paper is high, so that the structural strength and the toughness of the finally produced corrugated core paper or corrugated paper are reduced by 10% by using the waste paper raw materials in unit capacity, the pulping energy consumption is reduced to 1 kilowatt hour/ton, the electric energy required in the pulping process is reduced by more than 45%, the pulping speed of one multi-lossless pulping machine is 1-2 tons/hour, the pulping efficiency is extremely high, one multi-lossless pulping machine can complete the pulping operation of 24-48 tons of coarse pulp every day, continuous and efficient large-batch pulping can be realized through one device, and common waste paper enterprises only need to configure 1-3 multi-lossless pulping machines to meet the pulping requirement of the full-line operation.

The widths of the refining gaps 12 of the lower part of the refining inner cylinder 2 in different directions along the circumferential direction are different, the pressures of the lower part of the refining inner cylinder 2 in different directions along the circumferential direction are different, the size of the refining gap 12 between the lower part of the refining inner cylinder 2 and the refining outer cylinder 1 is inversely proportional to the pressure at the position, the pressure acting on the lower part of the refining inner cylinder 2 is proportional to the pressure acting on the lower part of the refining inner cylinder 2, and the lower part of the refining inner cylinder 2 continuously and repeatedly moves from the side with high pressure to the side with low pressure automatically in the refining process, so that the lower part of the refining inner cylinder 2 continuously and randomly moves in small amplitude along any radial direction;

the widths of the refining gaps 12 of the upper part of the refining outer cylinder 1 in different directions along the circumferential direction are different, the pressures of the upper part of the refining outer cylinder 1 in different directions along the circumferential direction are different, the size of the refining gap 12 between the upper part of the refining outer cylinder 1 and the refining inner cylinder 2 is inversely proportional to the pressure at the position, the pressure acting on the upper part of the refining outer cylinder 1 is proportional to the pressure acting on the upper part of the refining outer cylinder 1, and the upper part of the refining outer cylinder 1 continuously and repeatedly moves from the side with high pressure to the side with low pressure automatically in the refining process, so that the upper part of the refining outer cylinder 1 continuously and randomly moves along any radial direction in a small range.

A support frame 31 is fixed at the upper part of the pulp collection bin 3, the lower end part of the pulping outer cylinder 1 is fixedly arranged on the support frame 31, the upper end part of the pulping outer cylinder 1 is freely suspended, and the upper end part of the pulping outer cylinder 1 has displacement along any radial direction;

a suspension post 27 is fixed at the upper end of the refining inner cylinder 2, a ball 28 with a diameter larger than that of the suspension post 27 is fixed at the middle of the suspension post 27, a ball socket is arranged at the middle of the hoisting mechanism, the middle lower part of the suspension post 27 is movably arranged in the ball socket in a penetrating way, the ball 28 freely props against the upper side of the ball socket, a motor is arranged above the hoisting mechanism, and the motor is connected with the upper end of the suspension post 27 through a universal coupling, so that the lower end of the refining inner cylinder 2 has displacement along any radial direction.

The middle part of the refining inner cylinder 2 is in a cylindrical shape, the inner cavity of the refining inner cylinder 2 is arranged in a sealing mode, a plurality of supporting plates 22 are arranged in the inner cavity of the refining inner cylinder 2 at intervals from top to bottom, and each supporting plate 22 is respectively connected with the inner wall surface of the refining inner cylinder 2 in a sealing mode, so that the refining inner cylinder 2 has stronger structural strength, the deformation of the refining inner cylinder 2 is avoided, and meanwhile the stability of the refining inner cylinder 2 in the refining process is improved. In addition, the inner cavity of the refining inner cylinder 2 is divided into a plurality of sealing chambers by the supporting plate 22, the damping liquid 29 accounting for 50-70% of the volume of the sealing chamber positioned below is stored in the sealing chamber positioned below, the damping liquid 29 comprises water or oil and can also be mixed liquid containing a plurality of different components, the inertia of the lower end part of the refining inner cylinder 2 is increased by the damping liquid 29, so that the refining inner cylinder 2 has flexible refining force and the refining force is increased, the shaking amplitude and the moving speed of the refining inner cylinder 2 are reduced by the damping effect of the damping liquid 29 stored in the refining inner cylinder 2 in the process of shaking back and forth, the mutual impact between the refining inner cylinder 2 and the refining outer cylinder 1 is avoided, and the refining inner cylinder 2 and the refining outer cylinder 1 are ensured to have larger refining force.

The upper end of the refining inner cylinder 2 extends into the pulp inlet hopper 11, an annular feeding chamber with an upper opening and a large upper part and a small lower part is formed between the refining inner cylinder 2 and the pulp inlet hopper 11, a plurality of arc-shaped kicking plates 23 are fixed on the outer side of the refining inner cylinder 2 at intervals along the circumferential direction, each kicking plate 23 is arranged at the lower part of the feeding chamber, the outer side edges of each kicking plate 23 respectively prop against the inner wall surface of the pulp inlet hopper 11, the lower side of each kicking plate 23 is adjacent to or extends into the refining gap 12, the coarse pulp entering the feeding chamber is pushed by the kicking plates 23 and enters the refining gap 12, downward acting force is provided for the coarse pulp by the kicking plates 23, and the coarse pulp entering the refining gap 12 has periodic impact surge.

A plurality of strip-shaped grinding lines which are arranged at intervals are formed on the inner circumferential wall surface of the pulping outer cylinder 1;

a plurality of coarse grinding pulp strip-shaped teeth arranged at intervals along the circumferential direction and a plurality of coarse grinding pulp strip-shaped teeth arranged at intervals along the vertical direction are arranged in the coarse grinding area 24, the thickness of the coarse grinding pulp strip-shaped teeth is set to be 0.1-1mm, the width of the coarse grinding pulp strip-shaped teeth is set to be 5-20mm, coarse grinding treatment is completed through grinding cooperation of the coarse grinding pulp strip-shaped teeth and grinding patterns, coarse grinding processing of pulp is completed in the coarse grinding area 24, large-particle fiber blocks are scattered, and loose fibers on the surfaces of the fiber blocks are separated out;

the middle grinding area 25 is provided with a plurality of middle grinding strip-shaped teeth arranged at intervals along the circumferential direction and a plurality of middle grinding strip-shaped teeth arranged at intervals along the vertical direction, middle grinding processing is completed through grinding cooperation of the middle grinding strip-shaped teeth and grinding grains, and fiber blocks in the pulp are further scattered and fibers are further separated in the middle grinding area 25;

the fine grinding zone 26 is provided with a plurality of fine grinding pulp strip-shaped teeth which are arranged at intervals along the circumferential direction and a plurality of fine grinding pulp strip-shaped teeth which are arranged at intervals along the vertical direction, the thickness of the fine grinding pulp strip-shaped teeth is set to be 1-3mm, the width of the fine grinding pulp strip-shaped teeth is set to be 1-10mm, fine grinding processing is completed through grinding matching of the fine grinding pulp strip-shaped teeth and grinding grains, fine grinding processing is completed in the fine grinding zone 26, all fiber blocks in the pulp are scattered, and all fibers are scattered;

The grinding lines formed on the inner circumferential wall surface of the pulping outer cylinder 1 relatively protrude in the pulping clearance 12, the thickness of the grinding lines is set to be 0.1-1mm, and the width is set to be 5-20 mm;

the grinding grains are obliquely arranged relative to the vertical direction, the oblique direction of the grinding grains is opposite to that of the rough grinding pulp strip-shaped teeth, and the oblique directions of the rough grinding pulp strip-shaped teeth, the middle grinding pulp strip-shaped teeth and the fine grinding pulp are the same.

The above description is only a preferred embodiment of the present invention, and for those skilled in the art, the present invention should not be limited by the description of the present invention, which should be interpreted as a limitation.

Claims

1. The production process of the waste paper reconstruction corrugated medium paper for improving the fiber recovery rate is characterized by comprising the following steps of: comprises the following steps of (a) carrying out,

a waste paper conveying step, namely conveying the recycled waste paper to the upper part of the large pulp crushing barrel (4) through a waste paper conveying belt (5) so that the waste paper can freely fall into the large pulp crushing barrel (4);

a pulping step, wherein a large pulping barrel (4) is a double-D type pulping barrel, two pulping planes in the large pulping barrel (4) are arranged in parallel, a pulping mechanism is rotationally arranged in a pulping chamber (45) of the large pulping barrel (4), the pulping mechanism comprises a suspension bracket (41) fixed at the lower part of the pulping chamber (45), a pulping shaft (42) rotationally arranged above the middle part of the suspension bracket (41), a plurality of pulping rods (43) and a plurality of pulping plates (44), a plurality of pulping plates (44) are arranged in the pulping chamber (45) at intervals along the circumferential direction, the upper end part of each pulping plate (44) respectively extends to the upper part of the pulping chamber (45), the lower end part of each pulping plate respectively extends to the lower part of the pulping chamber (45), the outer side of each pulping plate (44) is close to the inner wall of the pulping chamber (45), and a plurality of pulping rods (43) transversely arranged are longitudinally fixed at intervals at the inner side of each pulping plate (44), the inner ends of the pulping rods (43) are respectively fixed on a pulping shaft (42), the pulping shaft (42) is driven to rotate by a pulping motor (46) arranged above the large pulping barrel (4), the pulping rods (43) and the pulping plates (44) are driven to rotate by the pulping shaft (42), the width of each pulping plate (44) along the radial direction is set to be 5-20cm, the side edges of the pulping rods (43) and the pulping plates (44) are designed to be obtuse angles, the side edges of the pulping rods (43) and the pulping plates (44) break and disperse waste paper and release fibers in a mode of impacting the waste paper, meanwhile, the fiber breakage rate is reduced, the outline shapes of the inner side edge and the outer side edge of the pulping plates (44) are designed to be curved shapes, a pulp high-pressure impact area is formed on the front side of the pulping plates (44) in the pulping process along the advancing direction of the pulping plates (44), and a pulp opposite-pressure impact area is formed on the rear side of the pulping plates (44), the two streams of pulp which are impacted by the beating plate (44) and pushed to two sides in the pulping process are respectively impacted into the negative pressure area at the rear side of the beating plate (44) after bypassing the inner side edge and the outer side edge of the beating plate (44) and are impacted with each other, firstly an asymmetric opposite impact pulp flow is formed in the negative pressure area at the rear side of the beating plate (44), and then a disordered pulp flow is formed until the pulp is impacted by the next beating plate (44) again;

a water injection sub-step, wherein clear water and weak alkali liquor are injected into the beating chamber (45), the weight percentage of the weak alkali liquor relative to the waste paper put into the beating chamber (45) is 0.01-0.3%, the weak alkali liquor is dissolved in a cationic starch glue layer attached to the surface of the waste paper in the surface sizing treatment process, the water injection is stopped after the water level in the beating chamber (45) reaches 80% of the height of the beating chamber (45),

a soaking sub-step, in which the waste paper is soaked in a pulping chamber (45) for 10-20 minutes, a pulping motor (46) drives a pulping plate (44) to rotate at a low speed in the soaking process, the rotating speed of the pulping plate (44) is controlled at 60-100 revolutions per minute, the wetting speed of the waste paper is improved, and the waste paper is completely wetted in a shorter time;

in the jolting substep, the beating plate (44) is driven by the pulping motor (46) to circularly execute high-speed forward and reverse rotation jolting actions for 10 to 20 minutes, waste paper is physically cracked into block materials with different sizes through jolting, the forward rotation angle or the reverse rotation angle of the beating plate (44) in one high-speed forward and reverse rotation jolting action is controlled to be 10 to 30 degrees, and the time period for finishing one high-speed forward and reverse rotation jolting action is controlled to be 1 to 3 seconds;

a pulping substep, wherein a pulping motor (46) continuously drives a pulping plate (44) to rotate for pulping, the rotating speed of the pulping plate (44) is controlled at 1000-3000 r/min, the pulping is continuously carried out for 1-1.5 hours, and a rotary pulping rod (43) and the pulping plate (44) rotationally strike block materials in a pulping chamber (45) or pulp formed by fibers dispersed from the block materials, so that papermaking raw pulp is obtained after pulping treatment is finished;

a pulping step, pumping papermaking coarse pulp to a multiple nondestructive pulping machine for nondestructive pulping, wherein the multiple nondestructive pulping machine comprises a pulping motor, a pulping outer cylinder (1), a pulping inner cylinder (2) and a pulp collecting bin (3), the pulping outer cylinder (1) is provided with a pulping cylinder cavity which vertically penetrates through the pulping outer cylinder (1), the pulping outer cylinder (1) is vertically fixed above the pulp collecting bin (3), the pulping inner cylinder (2) is movably sleeved in the pulping cylinder cavity of the pulping outer cylinder (1), the pulping inner cylinder (2) is driven to rotate relative to the pulping outer cylinder (1) through the pulping motor, a pulping gap (12) is arranged between the outer circumferential wall surface of the pulping inner cylinder (2) and the inner circumferential wall surface of the pulping outer cylinder (1), the upper end part of the pulping gap (12) is provided with a pulp inlet, the lower end part of the pulping gap is provided with a pulp outlet, the upper part of the pulping outer cylinder (1) is provided with a pulp inlet hopper (11), the lower part of the pulp inlet hopper (11) is communicated with a pulp inlet,

the inner circumferential wall surface of the pulping outer cylinder (1) is respectively provided with grinding teeth or grinding grains which are relatively protruded in the pulping clearance (12), the outer circumferential wall surface of the pulping inner cylinder (2) is sequentially provided with a rough grinding area (24), a middle grinding area (25) and a fine grinding area (26) from top to bottom, a plurality of rough grinding pulp strip-shaped teeth which are arranged at intervals are formed in the area of the outer circumferential wall surface of the pulping inner cylinder (2) corresponding to the rough grinding area (24), a plurality of middle pulping strip-shaped teeth which are arranged at intervals are formed in the area of the outer circumferential wall surface of the pulping inner cylinder (2) corresponding to the middle grinding area (25), and a plurality of fine grinding pulp strip-shaped teeth which are arranged at intervals are formed in the area of the outer circumferential wall surface of the pulping inner cylinder (2) corresponding to the fine grinding area (26);

pumping the papermaking coarse pulp to a pulp inlet, enabling the papermaking coarse pulp to enter a pulp grinding gap (12) through a pulp inlet product, enabling the papermaking coarse pulp to sequentially pass through a coarse grinding area (24), a middle grinding area (25) and a fine grinding area (26) from top to bottom, enabling the papermaking coarse pulp to sequentially undergo coarse grinding treatment, middle grinding treatment and fine grinding treatment, finally discharging the primary pulp through a pulp outlet, sequentially completing multiple pulp grinding treatment of the papermaking coarse pulp in the pulp grinding gap (12) of a multiple lossless pulp grinder, and controlling the time of the papermaking coarse pulp passing through the multiple lossless pulp grinder for 30-60 seconds;

2. The process for producing the waste paper-reconstituted corrugated medium paper with improved fiber recovery rate according to claim 1, which is characterized in that: the multi-nondestructive pulping machine comprises a hoisting mechanism, the pulping inner cylinder (2) is vertically arranged, the upper end part of the pulping inner cylinder (2) is protruded above the pulping outer cylinder (1), the upper end part of the pulping inner cylinder (2) is movably hoisted on the hoisting mechanism, the pulping inner cylinder (2) is freely suspended in a cavity of the pulping cylinder, after the refining gap (12) is filled with pulp, the widths of different positions of the refining gap (12) are in a dynamic change state, the lower part of the refining inner cylinder (2) and the upper part of the refining outer cylinder (1) freely and slightly shake under the action of internal pressure, so that the papermaking coarse pulp spirally flows downwards along the circumferential direction in the refining gap (12), the lumpy, lump or bundle-shaped fiber blocks in the papermaking coarse pulp are scattered in the pulp refining process, so that the pulp is prevented from being excessively ground, and the fibers in the fiber blocks are prevented from being broken.

3. The process for producing the waste paper-reconstituted corrugated medium paper with improved fiber recovery rate according to claim 2, characterized in that: the width of the refining gap (12) is set to be 3-8mm, the refining gap (12) with large width enables the papermaking coarse pulp to smoothly pass through the refining gap (12) while being fully ground, the height of the refining gap (12) in the vertical direction is set to be 250cm, the outer diameter of the refining inner cylinder (2) is set to be 50-150cm, the height of the refining inner cylinder (2) is set to be 300cm, and after the refining gap (12) between the refining outer cylinder (1) and the refining inner cylinder (2) is filled with pulp, the inner circumferential surface of the refining outer cylinder (1) and the outer circumferential surface of the refining inner cylinder (2) are both subjected to the hydraulic action of the papermaking coarse pulp; under the action of self gravity and the pressure from a pulp inlet, papermaking coarse pulp flows downwards, under the action of the circumferential direction of the papermaking coarse pulp entering a refining gap (12) provided by a rotating refining inner cylinder (2), the path of the papermaking coarse pulp passing through the refining gap (12) is changed into a spiral shape, the refining path is designed into the spiral shape to increase the length of the refining path of the papermaking coarse pulp, and the equivalent refining area of a multiple lossless refiner is increased;

the width of a refining gap (12) at the lower part of the refining inner cylinder (2) along different directions of the circumferential direction is different, the pressure intensity at the lower part of the refining inner cylinder (2) along different directions of the circumferential direction is different, the size of the refining gap (12) between the lower part of the refining inner cylinder (2) and the refining outer cylinder (1) is inversely proportional to the pressure intensity at the position, the pressure intensity acting on the lower part of the refining inner cylinder (2) is proportional to the pressure intensity acting on the lower part of the refining inner cylinder (2), and the lower part of the refining inner cylinder (2) is continuously and repeatedly and automatically moved from the side with high pressure intensity to the side with low pressure intensity in the refining process, so that the lower part of the refining inner cylinder (2) continuously and randomly moves along any radial direction with small amplitude;

the width of a refining gap (12) of the upper part of a refining outer cylinder (1) along different directions of the circumferential direction is different, the pressure intensity of the upper part of the refining outer cylinder (1) along different directions of the circumferential direction is different, the size of the refining gap (12) between the upper part of the refining outer cylinder (1) and a refining inner cylinder (2) is inversely proportional to the pressure intensity of the position, the pressure intensity acting on the upper part of the refining outer cylinder (1) is proportional to the pressure intensity acting on the upper part of the refining outer cylinder (1), the upper part of the refining outer cylinder (1) is enabled to continuously and repeatedly and automatically move from the side with high pressure intensity to the side with low pressure intensity in the refining process, and the upper part of the refining outer cylinder (1) is enabled to continuously and randomly move along any radial direction in a small amplitude.

4. The process for producing the waste paper-reconstituted corrugated medium paper with improved fiber recovery rate according to claim 3, which is characterized in that: a support frame (31) is fixed at the upper part of the pulp collecting bin (3), the lower end part of the pulping outer cylinder (1) is fixedly arranged on the support frame (31), the upper end part of the pulping outer cylinder (1) is freely suspended, and the upper end part of the pulping outer cylinder (1) has displacement along any radial direction;

the upper end of the refining inner cylinder (2) is fixed with a suspension post (27), the middle of the suspension post (27) is fixed with a ball (28) with a diameter larger than that of the suspension post (27), the middle of the hoisting mechanism is provided with a ball socket, the middle lower part of the suspension post (27) is movably arranged in the ball socket in a penetrating way, the ball (28) freely abuts against the upper side of the ball socket, the refining motor is arranged above the hoisting mechanism and is connected with the upper end of the suspension post (27) through a universal coupling, and the lower end of the refining inner cylinder (2) is enabled to have displacement along any radial direction.

5. The process for producing the waste paper-reconstituted corrugated medium paper with improved fiber recovery rate according to claim 4, which is characterized in that: the middle part of the refining inner cylinder (2) is in a cylindrical shape, the inner cavity of the refining inner cylinder (2) is arranged in a sealing way, a plurality of support plates (22) are arranged in the inner cavity of the refining inner cylinder (2) at intervals from top to bottom, each support plate (22) is respectively connected with the inner wall surface of the refining inner cylinder (2) in a sealing way, the inner cavity of the refining inner cylinder (2) is divided into a plurality of sealing chambers through the support plates (22), damping liquid (29) accounting for 50-70% of the volume of the sealing chamber positioned below is stored in the sealing chamber, the inertia of the lower end part of the refining inner cylinder (2) is increased through the damping liquid (29), so that the refining inner cylinder (2) has flexible refining force and the refining force, the shaking amplitude and the moving speed of the refining inner cylinder (2) are reduced through the damping effect of the damping liquid (29) stored in the refining inner cylinder (2) in the back and forth shaking process, the mutual impact between the pulping inner cylinder (2) and the pulping outer cylinder (1) is avoided.

6. The process for producing the waste paper-reconstituted corrugated medium paper with improved fiber recovery rate according to claim 5, which is characterized in that: the upper end part of the refining inner cylinder (2) extends into the pulp inlet hopper (11), an annular feeding chamber with an upper opening and a large upper part and a small lower part is formed between the refining inner cylinder (2) and the pulp inlet hopper (11), a plurality of arc-shaped kicking plates (23) are fixed on the outer side of the refining inner cylinder (2) at intervals along the circumferential direction, each kicking plate (23) is arranged at the lower part of the feeding chamber, the outer side edge of each kicking plate (23) respectively butts against the inner wall surface of the pulp inlet hopper (11), the lower side of each kicking plate (23) is adjacent to or extends into the refining gap (12), the papermaking coarse pulp entering the feeding chamber is kicked and pushed into the refining gap (12) through the kicking plates (23), and the papermaking coarse pulp entering the refining gap (12) has periodic impact surge.

7. The process for producing the waste paper-reconstituted corrugated medium paper with improved fiber recovery rate according to claim 6, which is characterized in that: a plurality of strip-shaped grinding lines which are arranged at intervals are formed on the inner circumferential wall surface of the pulping outer cylinder (1);

a plurality of rough grinding pulp strip-shaped teeth arranged at intervals along the circumferential direction and a plurality of rough grinding pulp strip-shaped teeth arranged at intervals along the vertical direction are arranged in the rough grinding area (24), the thickness of the rough grinding pulp strip-shaped teeth is set to be 0.1-1mm, the width of the rough grinding pulp strip-shaped teeth is set to be 5-20mm, and rough grinding treatment is completed through grinding cooperation of the rough grinding pulp strip-shaped teeth and grinding patterns;

the middle grinding area (25) is provided with a plurality of middle grinding strip-shaped teeth arranged at intervals along the circumferential direction and a plurality of middle grinding strip-shaped teeth arranged at intervals along the vertical direction, and middle grinding processing is completed through the grinding cooperation of the middle grinding strip-shaped teeth and grinding grains;

the fine grinding area (26) is provided with a plurality of fine grinding pulp strip-shaped teeth arranged at intervals along the circumferential direction and a plurality of fine grinding pulp strip-shaped teeth arranged at intervals along the vertical direction, the thickness of the fine grinding pulp strip-shaped teeth is set to be 1-3mm, the width of the fine grinding pulp strip-shaped teeth is set to be 1-10mm, and fine grinding pulp is completed through grinding matching of the fine grinding pulp strip-shaped teeth and grinding grains;

8. The process for producing the waste paper-reconstituted corrugated medium paper with improved fiber recovery rate according to claim 7, characterized in that: in the pulping step, the lower end part of the pulping inner cylinder (2) is protruded below the pulping outer cylinder (1), a diversion pyramid part (21) with a large upper part and a small lower part is arranged at the lower end part of the pulping inner cylinder (2), the lower end part of the pulping outer cylinder (1), the lower end part of the pulping inner cylinder (2) and the lower end part of the diversion pyramid part (21) are all positioned in the pulp collecting bin (3), the primary pulp is guided into the pulp collecting bin (3) through the diversion pyramid part (21), a pulp discharging port (32) is arranged at one side of the pulp collecting bin (3), and the primary pulp is discharged through the pulp discharging port (32);

the grinding grains formed on the inner circumferential wall surface of the refining outer cylinder (1) relatively protrude in the refining gap (12), the thickness of the grinding grains is set to be 0.1-1mm, and the width of the grinding grains is set to be 5-20 mm;

the damping liquid (29) comprises water and/or oil.

9. The process for producing a used paper-reconstituted corrugated medium paper with improved fiber recovery according to any one of claims 1 to 8, characterized in that: the beating plate (44) is provided with a beating plate surface with the width of 6-10cm along the rotating direction of the beating plate (44), the beating plate surface is obliquely arranged relative to the vertical surface, the widths of different positions of the beating plate surface are different, the distances between the different positions of the beating plate surface and the inner wall of the beating chamber (45) are different, and the distances between the different positions of the beating plate surface and the beating shaft (42) are different.