CN113618965A

CN113618965A - Purification and regeneration process and equipment for waste refrigerator plastic

Info

Publication number: CN113618965A
Application number: CN202110871639.7A
Authority: CN
Inventors: 秦玉飞; 牛远航; 吕怀兴; 高风翔; 秦晓辉; 陈龙; 刘玉清; 董李鹏
Original assignee: Jiangxi Green Recycling Industry Co ltd
Current assignee: Jiangxi Green Recycling Industry Co ltd
Priority date: 2021-07-30
Filing date: 2021-07-30
Publication date: 2021-11-09

Abstract

The invention relates to a purification and regeneration process of waste refrigerator plastics, which comprises the following steps: s1 crushing and sorting, S2 dry sorting, S3 wet sorting and S4 purification and granulation. The embodiment of the invention has the following beneficial effects: the purification and regeneration process of the waste refrigerator plastic adopts a dry grinding-winnowing method in S2 to pre-separate foam cotton, reduces the pollution of the foam cotton to a solution medium in subsequent wet separation, removes residual chloride ions (chloride) and foam cotton on the surface of the plastic through multiple times of flotation system treatment in S3, improves the regeneration quality of the plastic, and effectively solves the problem that the separation efficiency of the waste refrigerator plastic is low and the purification product potential difference is poor.

Description

Purification and regeneration process and equipment for waste refrigerator plastic

Technical Field

The invention relates to the technical field of refrigerator scrap treatment, in particular to a process and equipment for purifying and regenerating waste refrigerator plastics.

Background

With the rapid updating and upgrading of electric and electronic products, the quantity of electronic wastes in China is increased sharply, the scrappage in 2025 years is estimated to reach 1000 ten thousand tons/year, and the green treatment process is still to be developed. The maturity and popularization of any process do not leave the breakthrough of corresponding key technical problems, and the breakthrough of any key technical problem does not leave the identification and solution of the back key scientific problem. The complex structure and components of the electronic waste limit the popularization and application of the automatic disassembling equipment, and become a key problem commonly encountered in the electronic waste industry. Therefore, the key point of the environmental pollution control and the resource treatment of the electronic waste lies in the innovation and research of green treatment equipment, and the mechanical disassembly for realizing the automation, modularization and universalization of the environmental pollution control and the resource treatment of the electronic waste is the key research and development direction of the resource recycling of the electronic waste.

The waste refrigerator is used as an important part of electronic waste, the components of the waste refrigerator mainly comprise copper, aluminum, iron, polyurethane foam, ABS (terpolymer of three monomers of acrylonitrile (A), butadiene (B) and styrene (S)) plastics, and a small amount of PP (polypropylene) and PS (polystyrene) plastics, and the existing treatment process mainly comprises crushing and sorting. However, in practical production, a large amount of foam cotton dust is adhered to the surface of plastic particles after the waste refrigerator is crushed, and is difficult to remove, so that the recycling of plastics is limited. Therefore, a perfect purification and regeneration technology is needed to realize the recycling of plastic resources of the refrigerator.

The prior patents for treating the waste refrigerator mainly adopt crushing-magnetic separation-eddy current separation processes, such as a waste refrigerator box recycling treatment method and a waste refrigerator box treatment device (Renji, CN102274849B), a waste refrigerator crushing and separation resource recycling method (Linchuntao, CN102166580A) and a waste refrigerator dismantling and crushing recovery line (Zhang Ren, CN109174924A and CN110216133A), however, a large amount of foam cotton adheres to the surface of plastic particles after eddy current separation, and the problem of purification and regeneration of the plastic particles after the refrigerator crushing is ignored. Patent "a useless refrigerator upper cover plastics breaker" (Wang Dong sword, CN208788863U) discloses a crushing equipment, and the research object is only the useless refrigerator upper cover plastics alone, and the equipment range of application is little, relies on manual sorting.

Patent "a complete set recovery processing equipment of waste refrigerator plastics" (xu shi, CN209007766U) discloses a waste refrigerator plastics cleaning and recovery equipment, wherein the cleaning device includes a high-speed friction cleaning machine, a heat cleaning tank and a two-stage sink-and-float cleaning tank, the sink-and-float cleaning tank is used for separating plastics and non-plastic particles, and the electrostatic separation is used for separating resin, PP, PS and ABS, so as to solve the difficult problem that the waste refrigerator plastics are not easy to clean and classify. However, the above patent focuses on cleaning and separating plastics and non-plastics by using a two-stage sink-float cleaning tank, and only one electrostatic separation device is used to separate various particles of resin, PP, PS and ABS, resulting in poor separation and purification effects of different plastics. Further extrusion granulation reduces the grade and utility value of the plastic particles.

The prior patents on plastic sorting are directed to pure plastics, such as "dedicated production line for sorting plastic chips or particles of ABS, HIPS, PP, PE, GPPS" (li lixin, CN105108930B), "a method for separating multi-component waste plastics by flotation" (luyanpeng, CN 111873246A). The patent does not take the refrigerator broken plastic as a research object, neglects the practical problems of foam cotton adhered on the refrigerator broken plastic particles in the practical production and has limited application range. Patent Yuanyong, CN111251507A realizes fine separation of different waste plastics step by step in a gradient manner through five-stage brine flotation and electrostatic separation. However, if the method is applied to the separation of the broken plastics in the refrigerator, the adverse effect of the adhesive foam cotton on the purification of the plastics cannot be avoided, the foam cotton can be diffused and suspended in saline media at all levels, and the water treatment cost is increased. Meanwhile, a large amount of introduced chloride ions are enriched on the surface of the plastic and are not removed, so that the quality of the plastic is reduced.

Disclosure of Invention

In view of the above, it is necessary to provide a process and an apparatus for purifying and regenerating waste refrigerator plastics, so as to solve the technical problem in the prior art that the recovery effect of three plastics, i.e., ABS, PS and PP, in a waste refrigerator is not good.

The invention provides a purification and regeneration process of waste refrigerator plastics, which comprises the following steps: s1 crushing and sorting, S2 dry sorting, S3 wet sorting and S4 purification and granulation; s1, crushing and sorting, namely crushing the waste refrigerator, magnetically separating to remove iron, and performing vortex sorting to obtain copper, aluminum and an adhesive of an insulating plastic sheet and foam cotton; s2 dry sorting comprises S21 dry grinding and air separation treatment of the adhesive of the plastic sheet and the foam cotton to obtain plastic concentrate and foam cotton; s3 wet separation comprises the steps of carrying out multiple times of flotation system treatment on the plastic concentrate to respectively obtain concentrates of PP plastic, ABS and PS; s4, purifying and granulating, wherein the S41 is used for carrying out electrostatic separation and color separation on the ABS and PS concentrates to respectively obtain pure-color ABS plastics and PS plastics and variegated-color ABS plastics and PS plastics; s42, respectively selecting the colors of the PP plastics to obtain pure PP plastics and variegated PP plastics; s43, respectively carrying out hot melting extrusion and grain cutting on the plastics obtained in S41 and S42 to respectively obtain ABS, PS and PP plastic particles.

Further, the step of S1 crushing and sorting comprises the steps of S11 extracting the refrigerant of the waste refrigerator, and dismantling the compressor of the waste refrigerator; s12, crushing the waste refrigerator processed in the step S11, magnetically separating the crushed waste refrigerator to remove iron, and obtaining waste refrigerator fragments; s13, carrying out vortex sorting treatment on the waste refrigerator fragments to obtain copper, aluminum and an adhesive of the insulating plastic sheets and the foam cotton.

Further, the dry separation of S2 also comprises the step of magnetically separating again the plastic concentrate obtained in the step S21 again to remove iron impurities in the plastic concentrate by the step S22.

Further, S3 wet sorting includes S31 swirling and/or multi-media flotation of the plastic concentrate in water obtained in S21, wherein the soil and metals are removed by sinking and the plastic concentrate floats.

Further, the wet separation of S3 further comprises the step of S32 carrying out dehydration-crushing-wet friction-water flotation on the plastic concentrate obtained in the step S31, wherein PP plastic and residual foam cotton float upwards and are separated, and the ABS and PS concentrate sink.

Further, the wet separation of S3 further comprises the step of S33 carrying out hydrocyclone and/or multi-medium flotation-dehydration-wet friction-water flotation treatment on the ABS and PS concentrates obtained in the step S32 for multiple times to obtain pure ABS and PS concentrates.

Further, the wet sorting of S3 further comprises S34 of dehydrating, drying, dry grinding and air separation the mixture of the PP plastic obtained in S32 and the residual foam cotton to obtain pure PP plastic.

Further, in the purification and granulation of S4, white plastic is selected as a recognition target in color selection, and white pure-color plastic and variegated plastic mixed with other colors are obtained.

Further, in S21, the adhesive product of the plastic sheet and the foam cotton is subjected to dry polishing treatment using a dry polishing apparatus including an outer cylinder and a polishing blade built in the outer cylinder, the outer cylinder and the polishing blade being rotated in opposite directions.

The invention provides equipment for a purification and regeneration process of waste refrigerator plastics, which comprises a crushing device, a first magnetic separation device, an eddy current separation device, a dry grinding device, a second magnetic separation device, a multi-medium flotation device, an electrostatic separation device, a photoelectric color separation device and a plastic granulation and regeneration device which are sequentially arranged.

Compared with the prior art, the purification and regeneration process of the waste refrigerator plastics comprises four major steps of S1 crushing and sorting, S2 dry sorting, S3 wet sorting and S4 purification and granulation, wherein a dry grinding-winnowing method is adopted in S2 to pre-separate foam cotton, so that the pollution of the foam cotton to a solution medium in the subsequent wet sorting is reduced, residual chloride ions (chloride) and foam cotton on the surface of the plastics are removed through multiple times of treatment of a flotation system in S3, the regeneration quality of the plastics is improved, and the problem of low separation efficiency and poor purification level of the waste refrigerator plastics is effectively solved.

The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical solutions of the present invention more clearly understood and to be implemented according to the content of the description, the following detailed description is given with reference to the accompanying drawings. The detailed description of the present invention is given in detail by the following examples and the accompanying drawings.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention. In the drawings:

FIG. 1 is a flow chart of the purification and regeneration process of waste refrigerator plastics provided by the invention;

FIG. 2 is a schematic view of the vortex sorting apparatus of FIG. 1;

FIG. 3 is a schematic view of the dry grinding apparatus of FIG. 1;

FIG. 4 is a schematic view of the structure of the water swirling device in FIG. 1;

FIG. 5 is a schematic diagram of the construction of the multi-media flotation device of FIG. 1;

FIG. 6 is a schematic structural diagram of the electrochromic device shown in FIG. 1;

FIG. 7 is a block diagram of the apparatus for purifying and recycling waste refrigerator plastics according to the present invention.

Detailed Description

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate preferred embodiments of the invention and together with the description, serve to explain the principles of the invention and not to limit the scope of the invention.

Referring to fig. 1, the process for purifying and recycling waste refrigerator plastics comprises four major steps of S1 crushing and sorting, S2 dry sorting, S3 wet sorting and S4 purifying and granulating.

Wherein, in step S1, 3 small steps are included again: s11, extracting the refrigerant of the waste refrigerator, and removing the compressor of the waste refrigerator, wherein the step is to recover the refrigerant in the waste refrigerator, so as to avoid environmental pollution caused by refrigerant leakage. In addition, the compressor is taken as a high-value part, is generally disassembled and uniformly treated, and is not crushed along with the waste refrigerator.

S12, crushing the waste refrigerator processed in the step S11, magnetically separating the crushed waste refrigerator to remove iron, and obtaining waste refrigerator fragments. Since the refrigerator contains a large amount of foam for heat preservation, a negative pressure device can be arranged to extract the foam in the step. And because the foam cotton is extruded and is easy to flash explosion, when the waste refrigerator is crushed, protective gas such as nitrogen can be introduced into the waste refrigerator, so that the oxygen content during crushing is reduced, and the flash explosion probability of the foam cotton is reduced.

S13, carrying out vortex sorting treatment on the waste refrigerator fragments to obtain copper, aluminum and an adhesive of the insulating plastic sheets and the foam cotton. The vortex sorting device is constructed as shown in fig. 2, wherein the belt 11 has an adjustable inclination angle, and two baffles 12 are provided for separating copper a, aluminum B and insulating plastic C, which often has foam cotton adhered thereon and needs further separation treatment.

The inclined throw motion tracks of different nonferrous metals (copper and aluminum) in the vortex separator are different, the horizontal moving distance of the aluminum inclined throw motion is larger than that of copper, and the horizontal moving distance of the copper inclined throw motion is larger than that of plastic. Therefore, in order to separate the plastic and the metal to the maximum extent, the applicant obtains the maximum difference between the horizontal movement distance of the copper and the plastic when the ejection angle of the ejection motion is 42-48 degrees through a plurality of experiments, and the best separation effect can be obtained.

The S2 dry sorting comprises the step of S21 dry grinding and air separation treatment of the plastic sheet and foam cotton adhesive to obtain plastic concentrate and foam cotton. The dry grinding apparatus is constructed as shown in fig. 3, and includes a rotatable outer cylinder 21 and a grinding blade 22 disposed in the outer cylinder 21, the outer cylinder 21 and the grinding blade 22 being rotated in opposite directions. The plastic concentrate is obtained by cutting off foam cotton and other substances adhered to the plastic sheet, separating the foam cotton from the plastic sheet, and separating by means of negative pressure and the like.

S22 magnetic separating again the plastic concentrate obtained in S21 to remove the iron impurities, which may be adhered to the foam cotton before being removed, so that the iron impurities are removed again by magnetic separation.

The wet separation of S3 is to perform multiple times of flotation system treatment on the plastic concentrate to respectively obtain concentrates of PP plastic, ABS and PS.

The method specifically comprises S31 cyclone and/or multi-medium flotation of the plastic concentrate in water, wherein mud and metal sink and are removed, and the plastic concentrate floats upwards. The underwater swirling device is shown in fig. 4, and is generally arranged in multiple stages, wherein an overflow pipe 31 is arranged above each stage, and a sinking port 32 is arranged at the bottom. Where the lighter material floats upwards and flows away from the overflow pipe 31 and the heavier material sinks to the bottom and is discharged from the sinking spout 32.

Multi-media flotation device as shown in fig. 5, the multi-media flotation device is provided with an upper discharge pipe 41 at the top, a lower discharge pipe 42 at the bottom, and a rotating stick 43 at the water surface. Under the push of the rotating roller 43, the lighter materials float on the upper part and are discharged from the upper discharging pipe 41, and the heavier materials sink on the bottom part and are discharged from the lower discharging pipe 42.

The underwater cyclone device and the multi-medium flotation device separate materials with different densities by utilizing buoyancy, and can obtain better separation precision by changing the density of the solution for multiple separation.

Similarly, the S32 carries out dehydration-crushing-wet friction-water flotation system treatment on the plastic concentrate obtained in the S31, the size of plastic particles is reduced to 15-25 mm under the crushing action, and residual foam cotton and chloride ions are further dissociated under the crushing-wet friction action. And then carrying out water flotation treatment, floating and separating foam cotton and PP plastics to obtain ABS and PS plastic concentrates. The density of the solution used is generally 1.1 to 1.3 g/mL.

S33, carrying out the hydrocyclone and/or multi-medium flotation-dehydration-wet friction-water flotation system on the ABS and PS concentrates obtained in the S32 for multiple times (at least 2 times) to obtain pure ABS and PS concentrates.

S34, dehydrating, drying, dry-grinding and winnowing the mixture of the PP plastic obtained in S32 and the residual foam cotton to obtain pure PP plastic.

S4 purifying and granulating, including S41 carrying out electrostatic separation on the ABS and PS concentrates to obtain ABS plastics and PS plastics, then carrying out color separation, and arranging a sensor in the color separation to obtain pure-color ABS plastics and PS plastics and impure-color ABS plastics and PS plastics by taking white plastics as an identification target. The structure of the photoelectric color selection device is shown in fig. 6, and the photoelectric color selection device can also adopt a multi-stage structure, and each stage of structure comprises a set of oppositely arranged light source 51, air gun 52, sensor 53 and background plate 54. The sensor 54 recognizes that the plastic is not white and activates the air gun 52 to blow the plastic sheet away, so that only pure white plastic and mottled plastic are obtained.

Similarly, S42 color sorting the PP plastic to obtain pure color PP plastic and variegated color PP plastic respectively. Step S41 is not sequential to step S42 and may be performed simultaneously. S43, respectively carrying out hot melting extrusion and grain cutting on the plastics obtained in S41 and S42 to respectively obtain ABS, PS and PP plastic particles.

The properties of the ABS plastic particles after granulation and regeneration are shown in the table.

Referring to fig. 7, the equipment for the purification and regeneration process of the waste refrigerator plastics comprises a crushing device 1, a first magnetic separation device 2, a vortex separation device 3, a dry grinding device 4, a second magnetic separation device 5, a multi-medium flotation device 6, an electrostatic separation device 7, a photoelectric color separation device 8 and a plastic granulation and regeneration device 9 which are sequentially arranged. These means are respectively used to implement the respective steps described above.

The embodiment of the invention has the following beneficial effects: the purification and regeneration process of the waste refrigerator plastics comprises four major steps of S1 crushing and sorting, S2 dry sorting, S3 wet sorting and S4 purification and granulation, wherein a dry grinding-winnowing method is adopted in S2 to pre-separate foam cotton, so that the pollution of the foam cotton to a solution medium in the subsequent wet sorting is reduced, and residual chloride ions (chloride) and foam cotton on the surface of the plastics are removed through multiple flotation system treatment in S3, so that the regeneration quality of the plastics is improved, and the problem that the separation efficiency of the waste refrigerator plastics is low and the purification product potential difference is poor is effectively solved.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.

Claims

1. The purification and regeneration process of the waste refrigerator plastic is characterized by comprising the following steps: s1 crushing and sorting, S2 dry sorting, S3 wet sorting and S4 purification and granulation;

the S1 crushing and sorting, namely crushing the waste refrigerator, magnetically separating to remove iron, and performing vortex sorting to obtain copper, aluminum and an adhesive of an insulating plastic sheet and foam cotton;

the S2 dry sorting comprises the steps of S21, carrying out dry grinding and air separation on the adhesive of the plastic sheet and the foam cotton to obtain plastic concentrate and the foam cotton;

the S3 wet separation comprises the steps of carrying out multiple times of flotation system treatment on the plastic concentrate to respectively obtain concentrates of PP plastic, ABS and PS;

the S4 purification and granulation comprises S41 of electrostatic separation and color separation of the ABS and PS concentrates to respectively obtain pure-color ABS plastics and PS plastics and variegated-color ABS plastics and PS plastics; s42, respectively selecting the colors of the PP plastics to obtain pure PP plastics and variegated PP plastics; s43, respectively carrying out hot melting extrusion and grain cutting on the plastics obtained in S41 and S42 to respectively obtain ABS, PS and PP plastic particles.

2. The process of purifying and recycling waste refrigerator plastics as claimed in claim 1, wherein the S1 crushing and sorting comprises S11 extracting refrigerant of the waste refrigerator, and removing a compressor of the waste refrigerator; s12, crushing the waste refrigerator processed in the step S11, magnetically separating the crushed waste refrigerator to remove iron, and obtaining waste refrigerator fragments; s13, carrying out vortex sorting treatment on the waste refrigerator fragments to obtain copper, aluminum and an adhesive of an insulating plastic sheet and foam cotton.

3. The process of purifying and recycling waste refrigerator plastics as claimed in claim 1, wherein the S2 dry separation further comprises S22 magnetic separation treatment of the plastic concentrate obtained in S21 again to remove iron impurities therein.

4. The process of purifying and recycling waste refrigerator plastics as claimed in claim 1, wherein the S3 wet separation comprises S31 cyclone and/or multi-media flotation of the plastic concentrate water obtained in S21, wherein the soil and metal are removed by sinking and the plastic concentrate floats.

5. The process of purifying and recycling waste refrigerator plastics as claimed in claim 4, wherein the wet sorting of S3 further comprises S32 subjecting the plastic concentrate obtained in S31 to dehydration-crushing-wet friction-water flotation system, separating PP plastics and residual foam cotton in a floating manner, and settling ABS and PS concentrates.

6. The process of claim 5, wherein the wet separation of S3 further comprises a process of S33 performing hydrocyclone and/or multi-media flotation-dehydration-wet friction-water flotation on the ABS and PS concentrate obtained in S32 for multiple times to obtain pure ABS and PS concentrate.

7. The process of claim 6, wherein the wet separation of S3 further comprises S34 dehydrating, drying, dry grinding and air separation the mixture of PP plastics and residual foam cotton obtained in S32 to obtain pure PP plastics.

8. The process for purifying and recycling waste refrigerator plastics as claimed in claim 1, wherein the purification and granulation of S4 is performed by using white plastics as identification targets to obtain white pure-color plastics and other mixed-color plastics.

9. The process of claim 1, wherein in step S21, the adhesive of the plastic sheet and the foam cotton is ground in a dry manner by a dry grinding device, the dry grinding device includes an outer cylinder and a grinding blade disposed in the outer cylinder, and the outer cylinder and the grinding blade rotate in opposite directions.

10. The equipment for the purification and regeneration process of the waste refrigerator plastic is characterized by comprising a crushing device, a first magnetic separation device, a vortex separation device, a dry grinding device, a second magnetic separation device, a multi-medium flotation device, an electrostatic separation device, a photoelectric color separation device and a plastic granulation and regeneration device which are sequentially arranged.