CN113563376B - Recovery method of waste silicone rubber - Google Patents
Recovery method of waste silicone rubber Download PDFInfo
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- CN113563376B CN113563376B CN202110776667.0A CN202110776667A CN113563376B CN 113563376 B CN113563376 B CN 113563376B CN 202110776667 A CN202110776667 A CN 202110776667A CN 113563376 B CN113563376 B CN 113563376B
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- silicone rubber
- waste silicone
- dmc
- waste
- sulfuric acid
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- 229920002379 silicone rubber Polymers 0.000 title claims abstract description 129
- 239000002699 waste material Substances 0.000 title claims abstract description 122
- 239000004945 silicone rubber Substances 0.000 title claims abstract description 120
- 238000000034 method Methods 0.000 title claims abstract description 36
- 238000011084 recovery Methods 0.000 title description 12
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims abstract description 86
- 239000000843 powder Substances 0.000 claims abstract description 40
- 150000008044 alkali metal hydroxides Chemical class 0.000 claims abstract description 14
- 238000004064 recycling Methods 0.000 claims abstract description 14
- 238000007873 sieving Methods 0.000 claims abstract description 12
- 238000006462 rearrangement reaction Methods 0.000 claims abstract description 11
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 10
- 238000002156 mixing Methods 0.000 claims abstract description 8
- 238000003756 stirring Methods 0.000 claims abstract description 7
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical group [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 30
- 239000002245 particle Substances 0.000 claims description 25
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 claims description 13
- 238000010298 pulverizing process Methods 0.000 claims description 5
- 238000004140 cleaning Methods 0.000 claims description 3
- 238000001035 drying Methods 0.000 claims description 3
- 239000002253 acid Substances 0.000 abstract description 14
- 238000000197 pyrolysis Methods 0.000 abstract description 11
- 238000007233 catalytic pyrolysis Methods 0.000 abstract description 9
- 230000003197 catalytic effect Effects 0.000 abstract description 7
- 230000000694 effects Effects 0.000 abstract description 7
- 230000008707 rearrangement Effects 0.000 abstract description 5
- 238000002352 steam pyrolysis Methods 0.000 abstract 1
- 238000005336 cracking Methods 0.000 description 13
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 8
- 238000004523 catalytic cracking Methods 0.000 description 8
- 239000000945 filler Substances 0.000 description 6
- 239000000126 substance Substances 0.000 description 5
- 238000006243 chemical reaction Methods 0.000 description 4
- 239000000377 silicon dioxide Substances 0.000 description 4
- 235000012239 silicon dioxide Nutrition 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 3
- 229920001971 elastomer Polymers 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000005060 rubber Substances 0.000 description 3
- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 238000003776 cleavage reaction Methods 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000012691 depolymerization reaction Methods 0.000 description 2
- 125000000118 dimethyl group Chemical group [H]C([H])([H])* 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 125000005375 organosiloxane group Chemical group 0.000 description 2
- 230000000737 periodic effect Effects 0.000 description 2
- 238000000053 physical method Methods 0.000 description 2
- 238000007781 pre-processing Methods 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 230000007017 scission Effects 0.000 description 2
- 238000004227 thermal cracking Methods 0.000 description 2
- 239000004944 Liquid Silicone Rubber Substances 0.000 description 1
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 230000008094 contradictory effect Effects 0.000 description 1
- KPUWHANPEXNPJT-UHFFFAOYSA-N disiloxane Chemical class [SiH3]O[SiH3] KPUWHANPEXNPJT-UHFFFAOYSA-N 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 230000036541 health Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 229920003051 synthetic elastomer Polymers 0.000 description 1
- 239000005061 synthetic rubber Substances 0.000 description 1
- 239000004753 textile Substances 0.000 description 1
- 238000004073 vulcanization Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
- C07F7/00—Compounds containing elements of Groups 4 or 14 of the Periodic System
- C07F7/02—Silicon compounds
- C07F7/21—Cyclic compounds having at least one ring containing silicon, but no carbon in the ring
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Separation, Recovery Or Treatment Of Waste Materials Containing Plastics (AREA)
Abstract
The invention discloses a method for recycling waste silicone rubber, which comprises the following steps: s10, crushing and sieving the waste silicone rubber to obtain waste silicone rubber powder; s20, mixing waste silicone rubber powder with alkali metal hydroxide, and reacting under the conditions of 120-160 ℃ of water vapor, inert atmosphere and 3-5 MPa of high pressure to obtain crude DMC; s30, stirring the crude DMC and dilute sulfuric acid at 140-150 ℃ to enable the crude DMC to undergo depolymerization rearrangement reaction to obtain an intermediate; s40, rectifying the intermediate to obtain the refined DMC. In this way, the dilute sulfuric acid is adopted to carry out catalytic pyrolysis on the waste silicon rubber, so that the corrosiveness on equipment is reduced, and meanwhile, the catalytic activity of the dilute sulfuric acid is improved by placing the dilute sulfuric acid at 140-150 ℃, so that the acid catalytic pyrolysis effect is ensured; in addition, the waste silicon rubber powder is firstly subjected to steam pyrolysis treatment to obtain crude DMC, then the crude DMC is subjected to acid catalytic depolymerization rearrangement, and the pyrolysis rate and the DMC yield are further improved through two-step pyrolysis.
Description
Technical Field
The invention relates to the technical field of silicone rubber products, in particular to a method for recycling waste silicone rubber.
Background
The silicone rubber is a synthetic rubber taking a silicon-oxygen bond as a main chain, has excellent heat resistance, cold resistance, dielectric property, ozone resistance and ageing resistance, and is widely applied to the fields of aerospace, electronic and electric, light industry, chemical industry, textile, machinery, building, agriculture, transportation, medical treatment and health and the like. The silicone rubber products are mainly divided into three categories of high-temperature rubber, room-temperature rubber, liquid silicone rubber and the like, and the application fields are very wide. With the continuous rising of the consumption of silicone rubber products in the current society, the waste silicone rubber and leftover materials generated in vulcanization molding processing and waste silicone rubber formed after application are rapidly increasing, and if the waste silicone rubber is not recycled, the waste silicone rubber not only occupies space, but also wastes resources and pollutes the environment.
At present, the recovery methods of the silicon rubber leftover materials and the waste products mainly comprise two methods of physics and chemistry. The physical method is mainly to crush the waste silicone rubber and then use the crushed waste silicone rubber as the filler, the method is simple and easy to operate, but the dimethyl cyclosiloxane (DMC) and the filler silicon dioxide contained in the silicone rubber are high in price, the waste silicone rubber is directly used as the filler without recycling, the value of the waste silicone rubber is not fully utilized, and resources are wasted. The chemical method is mainly to recycle the raw material organosiloxane ring body and silicon dioxide of the synthetic silicone rubber through pyrolysis. And the chemical cracking method comprises thermal cracking, ultrasonic cracking, catalytic cracking and the like. At present, an acid catalytic cracking method is mainly adopted, but the acid catalytic cracking method has the problems of serious corrosion to equipment, periodic replacement and high cost.
Disclosure of Invention
The invention mainly aims to provide a recovery method of waste silicone rubber, and aims to solve the problem that the existing acid catalytic cracking method has higher corrosiveness to equipment.
In order to achieve the above purpose, the invention provides a recovery method of waste silicone rubber, which comprises the following steps:
s10, crushing and sieving the pretreated waste silicone rubber to obtain waste silicone rubber powder;
s20, mixing the waste silicone rubber powder with alkali metal hydroxide, and reacting under the conditions of 120-160 ℃ of water vapor, inert atmosphere and 3-5 MPa high pressure to obtain crude DMC;
s30, stirring the crude DMC and the dilute sulfuric acid solution at 140-150 ℃ to enable the crude DMC to undergo further depolymerization rearrangement reaction to obtain an intermediate;
and S40, rectifying the intermediate to obtain the refined DMC.
Optionally, in step S10, the preprocessing step includes:
and cleaning and drying the waste silicone rubber.
Optionally, step S10 includes:
preliminary crushing the pretreated waste silicone rubber to obtain waste silicone rubber particles;
finely pulverizing the waste silicone rubber particles, and sieving with a 50-100 mesh sieve to obtain waste silicone rubber powder.
Optionally, in step S20, the mass ratio of the alkali metal hydroxide to the waste silicone rubber powder is (0.2-2): 100.
optionally, in step S20, the alkali metal hydroxide is sodium hydroxide or potassium hydroxide.
Optionally, in step S30:
in the dilute sulfuric acid solution, the mass fraction of the sulfuric acid is 50-65%.
Optionally, in step S30:
the mass ratio of the crude DMC to the dilute sulfuric acid is 10: (0.1-0.5).
Optionally, in step S30:
the stirring time is 120-180 min.
Optionally, in step S40:
the temperature of the rectification treatment is 150-250 ℃.
According to the technical scheme provided by the invention, the dilute sulfuric acid is adopted to carry out catalytic pyrolysis on the waste silicone rubber, so that the corrosiveness of an acid catalytic pyrolysis method on equipment is reduced, and meanwhile, the catalytic activity of the dilute sulfuric acid is improved by placing the dilute sulfuric acid at 140-150 ℃, so that the acid catalytic depolymerization rearrangement effect is ensured; in addition, the waste silicon rubber powder is firstly subjected to pyrolysis treatment by using steam to obtain crude DMC, and then the crude DMC is subjected to further acid catalytic pyrolysis rearrangement, so that the pyrolysis rate and the yield of DMC are further improved through two-step pyrolysis.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below. The specific conditions are not noted in the examples and are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention.
The specific conditions were not specified in the examples, and the examples were conducted under the conventional conditions or the conditions recommended by the manufacturer. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention. In addition, the meaning of "and/or" as it appears throughout includes three parallel schemes, for example "A and/or B", including the A scheme, or the B scheme, or the scheme where A and B are satisfied simultaneously. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be regarded as not exist and not within the protection scope of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The recovery method of the silicon rubber leftover materials and the waste products mainly comprises two methods of physics and chemistry. The physical method is mainly to crush the waste silicone rubber and then use the crushed waste silicone rubber as the filler, the method is simple and easy to operate, but the dimethyl cyclosiloxane (DMC) and the filler silicon dioxide contained in the silicone rubber are high in price, the waste silicone rubber is directly used as the filler without recycling, the value of the waste silicone rubber is not fully utilized, and resources are wasted. The chemical method is mainly to recycle the raw material organosiloxane ring body and silicon dioxide of the synthetic silicone rubber through pyrolysis. And the chemical cracking method comprises thermal cracking, ultrasonic cracking, catalytic cracking and the like. At present, an acid catalytic cracking method is mainly adopted, but the acid catalytic cracking method has the problems of serious corrosion to equipment, periodic replacement and high cost.
In view of the above, the invention provides a method for recycling waste silicone rubber, and aims to provide a method for recycling waste silicone rubber which is less in equipment corrosiveness and higher in DMC yield. In one embodiment, the recycling method comprises the steps of:
and S10, crushing and sieving the pretreated waste silicone rubber to obtain waste silicone rubber powder.
Wherein the preprocessing step comprises the following steps: and cleaning and drying the waste silicone rubber. Therefore, dust, dirt and the like on the surface of the waste silicone rubber can be removed, so that other impurities are prevented from being brought in the recovery process, and the recovery effect is prevented from being influenced. The invention is not limited to the source of the waste silicone rubber, and the waste silicone rubber product is only required.
Further, in order to make the crushing effect of the waste silicone rubber better, so that the waste silicone rubber can better react with water vapor or dilute sulfuric acid, so that the cracking effect is better, in one embodiment, the step S10 includes:
and S11, performing preliminary crushing treatment on the pretreated waste silicone rubber to obtain waste silicone rubber particles.
Wherein, the preliminary crushing can be carried out by any one of a crusher, a ball mill and an open mill so as to obtain granular waste silicone rubber.
And S12, finely crushing the waste silicone rubber particles, and sieving the crushed waste silicone rubber particles with a 50-100-mesh sieve to obtain waste silicone rubber powder.
The present invention is not limited to the specific step of the fine pulverization, and the waste silicone rubber particles may be repeatedly pulverized by a crusher, a ball mill, or an open mill to achieve fine pulverization, and in an embodiment, the fine pulverization may be performed by an ultra-fine pulverizer. And then, the finely crushed waste silicone rubber particles are sieved by a sieve with 50-100 meshes to obtain waste silicone rubber powder with the particle size of 0.15-0.3 mm, so that the contact area of the waste silicone rubber powder with water vapor and dilute sulfuric acid is larger, and the cracking reaction is more complete.
And step S20, mixing the waste silicone rubber powder with alkali metal hydroxide, and reacting under the conditions of 120-160 ℃ of water vapor, inert atmosphere and 3-5 MPa high pressure to obtain crude DMC by preliminary cracking of the waste silicone rubber powder.
In high pressure steam, the silicon-oxygen bond of the waste silicone rubber can be broken, and depolymerized into siloxane oligomer, in this embodiment, the depolymerization reaction is more likely to occur by the addition of alkali metal hydroxide.
The invention is not limited to the specific type of alkali metal hydroxide, and in one embodiment, the alkali metal hydroxide is sodium hydroxide (NaOH) or potassium hydroxide (KOH), which is readily available and at a low cost.
Further, in this embodiment, the mass ratio of the alkali metal hydroxide to the waste silicone rubber powder is (0.2 to 2): 100, so, the depolymerization effect of the waste silicone rubber powder is good by adding a small amount of alkali metal hydroxide, and meanwhile, the small amount of alkali metal hydroxide is not easy to cause potential safety hazard, so that the operation safety is high.
And step S30, stirring the crude DMC and the dilute sulfuric acid solution at 140-150 ℃ to enable the crude DMC to undergo further depolymerization rearrangement reaction, so as to obtain an intermediate.
In order to reduce the corrosiveness of acid catalytic cracking to equipment, in the embodiment, dilute sulfuric acid solution is adopted to carry out cracking rearrangement reaction on the crude DMC, and the catalytic activity of the dilute sulfuric acid is improved through high temperature of 140-150 ℃. Further, in this embodiment, the mass fraction of the sulfuric acid in the dilute sulfuric acid solution is 50-65% for the comprehensive consideration of ensuring the catalytic activity of the cleavage rearrangement reaction and reducing the corrosiveness to the equipment, and the dilute sulfuric acid can further catalyze the macromolecular chains in the crude DMC to depolymerize and undergo molecular rearrangement, so that more DMC can be recovered.
Wherein the stirring time is 120-180 min, so that the depolymerization rearrangement reaction is sufficient. Furthermore, in one embodiment, to ensure the effectiveness of the cleavage rearrangement reaction, and to save costs, the ratio of the crude DMC to the dilute sulfuric acid mass is 10: (0.1-0.5).
And step S40, rectifying the intermediate to obtain the refined DMC.
The rectification is a separation process for separating the components by utilizing the difference in volatility of the components in the mixture, and common equipment comprises a plate type rectification tower and a packed rectification tower. In this example, to separate the DMC in the intermediate, it was subjected to a rectification treatment under reduced pressure to separate a refined DMC. Wherein the temperature of the rectification treatment is 150-250 ℃.
According to the technical scheme provided by the invention, the dilute sulfuric acid is adopted to carry out catalytic pyrolysis on the waste silicon rubber, so that the corrosiveness of an acid catalytic pyrolysis method on equipment is reduced, and meanwhile, the catalytic activity of the dilute sulfuric acid is improved by placing the dilute sulfuric acid under the heating condition of 140-150 ℃, so that the acid catalytic pyrolysis effect is ensured; in addition, the waste silicon rubber powder is firstly subjected to pyrolysis treatment by using steam, then the crude DMC obtained after preliminary pyrolysis is subjected to further acid catalytic pyrolysis rearrangement, and the recovery rate of DMC can reach more than 92% by two-step pyrolysis, so that the reaction condition of each step of pyrolysis is mild, and the time and the cost are saved.
The following description of the embodiments of the present invention will be presented in further detail with reference to the examples, which should be understood as being merely illustrative of the present invention and not limiting.
Example 1
(1) And (3) carrying out preliminary crushing treatment on the washed and dried waste silicone rubber by adopting a crusher to obtain waste silicone rubber particles, finely crushing the waste silicone rubber particles by adopting an ultrafine crusher, and sieving the crushed waste silicone rubber particles with a 80-mesh sieve to obtain waste silicone rubber powder.
(2) Mixing the waste silicone rubber powder with NaOH (wherein the mass ratio of the waste silicone rubber powder to the NaOH is 1:100), and reacting under the conditions of water vapor at 140 ℃, inert atmosphere and high pressure of 3.5MPa to make the waste silicone rubber powder undergo preliminary cracking to obtain crude DMC.
(3) The crude DMC and a dilute sulfuric acid solution (in the dilute sulfuric acid solution, the mass fraction of sulfuric acid is 50 percent, and the mass ratio of the crude DMC to the dilute sulfuric acid solution is 10:0.3) are stirred for 150min at 150 ℃, so that the crude DMC undergoes further depolymerization rearrangement reaction to obtain an intermediate.
(4) The intermediate was subjected to rectification under reduced pressure at 200℃to give purified DMC with a DMC yield of 93%.
Example 2
(1) And (3) carrying out preliminary crushing treatment on the washed and dried waste silicone rubber by adopting a ball mill to obtain waste silicone rubber particles, finely crushing the waste silicone rubber particles by adopting an ultrafine crusher, and sieving the crushed waste silicone rubber particles with a 50-mesh sieve to obtain waste silicone rubber powder.
(2) Mixing the waste silicone rubber powder with NaOH (wherein the mass ratio of the waste silicone rubber powder to the NaOH is 2:100), and reacting under the conditions of 120 ℃ water vapor, inert atmosphere and high pressure of 3MPa to ensure that the waste silicone rubber powder is subjected to preliminary cracking, so as to obtain crude DMC.
(3) The crude DMC and a dilute sulfuric acid solution (in the dilute sulfuric acid solution, the mass fraction of sulfuric acid is 60 percent, and the mass ratio of the crude DMC to the dilute sulfuric acid solution is 10:0.1) are stirred for 180 minutes at 140 ℃, so that the crude DMC undergoes further depolymerization rearrangement reaction to obtain an intermediate.
(4) The intermediate was subjected to rectification under reduced pressure at 150℃to give purified DMC with a DMC yield of 92%.
Example 3
(1) And (3) carrying out preliminary crushing treatment on the cleaned and dried waste silicone rubber by adopting an open mill to obtain waste silicone rubber particles, finely crushing the waste silicone rubber particles by adopting an ultrafine crusher, and sieving the crushed waste silicone rubber particles with a 100-mesh sieve to obtain waste silicone rubber powder.
(2) Mixing the waste silicone rubber powder with KOH (wherein the mass ratio of the waste silicone rubber powder to the NaOH is 0.2:100), and reacting under the conditions of 160 ℃ water vapor, inert atmosphere and 5MPa high pressure to cause the waste silicone rubber powder to be subjected to preliminary cracking, so as to obtain crude DMC.
(3) The crude DMC and a dilute sulfuric acid solution (the mass fraction of sulfuric acid in the dilute sulfuric acid solution is 65 percent; the mass ratio of the crude DMC to the dilute sulfuric acid solution is 10:0.5) are stirred for 120min at 145 ℃, and the crude DMC is subjected to further depolymerization rearrangement reaction to obtain an intermediate.
(4) The intermediate is subjected to rectification treatment under reduced pressure at 250 ℃ to obtain refined DMC, and the yield of DMC is 95%.
Comparative example 1
(1) And (3) carrying out preliminary crushing treatment on the cleaned and dried waste silicone rubber by adopting an open mill to obtain waste silicone rubber particles, finely crushing the waste silicone rubber particles by adopting an ultrafine crusher, and sieving the crushed waste silicone rubber particles with a 100-mesh sieve to obtain waste silicone rubber powder.
(2) Mixing the waste silicone rubber powder with KOH (wherein the mass ratio of the waste silicone rubber powder to the NaOH is 0.2:100), and reacting under the conditions of 160 ℃ water vapor, inert atmosphere and 5MPa high pressure to cause the waste silicone rubber powder to undergo a cracking reaction to obtain crude DMC.
(3) And (3) rectifying the crude DMC under the condition of reduced pressure at 250 ℃ to obtain refined DMC, wherein the yield of DMC is 40%.
Comparative example 2
(1) And (3) carrying out preliminary crushing treatment on the washed and dried waste silicone rubber by adopting a crusher to obtain waste silicone rubber particles, finely crushing the waste silicone rubber particles by adopting an ultrafine crusher, and sieving the crushed waste silicone rubber particles with a 80-mesh sieve to obtain waste silicone rubber powder.
(2) The waste silicon rubber powder and a dilute sulfuric acid solution (in the dilute sulfuric acid solution, the mass fraction of sulfuric acid is 50 percent, and the mass ratio of the crude DMC to the dilute sulfuric acid solution is 10:0.3) are stirred for 150 minutes at 150 ℃ to carry out depolymerization reaction on the waste rubber powder, so as to obtain the crude DMC.
(3) And (3) rectifying the crude DMC under the condition of reduced pressure at 200 ℃ to obtain refined DMC, wherein the yield of DMC is 50%.
From the above, it can be seen that, in the recovery method provided by the embodiment, the yield of DMC is 92% or more, while in the recovery method provided by the comparative example, the yield of DMC is lower than 50%, that is, the recovery method of waste silicone rubber provided by the invention, through the combination of two-step cracking reaction, can better recover DMC in waste silicone rubber, thereby fully utilizing resources in waste silicone rubber.
The foregoing is merely a preferred embodiment of the present invention and is not intended to limit the scope of the present invention, but various modifications and variations will be apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (7)
1. The method for recycling the waste silicone rubber is characterized by comprising the following steps of:
s10, crushing and sieving the pretreated waste silicone rubber to obtain waste silicone rubber powder;
s20, mixing the waste silicone rubber powder with alkali metal hydroxide, and reacting under the conditions of 120-160 ℃ of water vapor, inert atmosphere and 3-5 MPa high pressure to obtain crude DMC;
s30, stirring the crude DMC and the dilute sulfuric acid solution at 140-150 ℃ to enable the crude DMC to undergo further depolymerization rearrangement reaction to obtain an intermediate;
s40, rectifying the intermediate to obtain refined DMC;
wherein, in the dilute sulfuric acid solution, the mass fraction of the sulfuric acid is 50-65%;
the mass ratio of the crude DMC to the dilute sulfuric acid is 10: (0.1-0.5).
2. The method for recycling waste silicone rubber according to claim 1, wherein in step S10, the pretreatment step comprises:
and cleaning and drying the waste silicone rubber.
3. The method for recycling waste silicone rubber according to claim 1, wherein step S10 comprises:
preliminary crushing the pretreated waste silicone rubber to obtain waste silicone rubber particles;
finely pulverizing the waste silicone rubber particles, and sieving with a 50-100 mesh sieve to obtain waste silicone rubber powder.
4. The method for recycling waste silicone rubber according to claim 1, wherein in step S20, the mass ratio of the alkali metal hydroxide to the waste silicone rubber powder is (0.2-2): 100.
5. the method for recycling waste silicone rubber according to claim 1, wherein in step S20, the alkali metal hydroxide is sodium hydroxide or potassium hydroxide.
6. The method for recycling waste silicone rubber according to claim 1, wherein in step S30: the stirring time is 120-180 min.
7. The method for recycling waste silicone rubber according to claim 1, wherein in step S40:
the temperature of the rectification treatment is 150-250 ℃.
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| CN114031636A (en) * | 2021-11-12 | 2022-02-11 | 福建师范大学 | Mechanical force chemical grinding assisted waste silicon rubber thermal cracking recovery method |
| CN114516977B (en) * | 2022-03-07 | 2023-11-24 | 广东省科学院资源利用与稀土开发研究所 | Method for recycling cyclosiloxane monomer by cracking waste silicone rubber under catalysis of rare earth |
| CN115156239B (en) * | 2022-07-15 | 2023-06-09 | 山东邦凯新材料有限公司 | Device and processing technology for preparing high-purity silicon dioxide by continuous type hazardous waste silica gel recovery treatment |
| CN115368400A (en) * | 2022-09-20 | 2022-11-22 | 湖北鑫金鹏新材料有限公司 | Process for recovering organic silicon ring body from silicon rubber series substances |
| CN116284990B (en) * | 2023-03-30 | 2023-09-19 | 江门市江业豪硅材料有限公司 | Method and device for recycling silicone rubber |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU939445A1 (en) * | 1980-12-12 | 1982-06-30 | Предприятие П/Я Г-4236 | Process for producing organocyclosiloxanes |
| CN102134331A (en) * | 2011-01-21 | 2011-07-27 | 合肥工业大学 | Recycling method of waste silicone rubber |
| CN103626797A (en) * | 2012-08-28 | 2014-03-12 | 杨晓林 | Steam cracking recovery method of silicone rubber |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU939445A1 (en) * | 1980-12-12 | 1982-06-30 | Предприятие П/Я Г-4236 | Process for producing organocyclosiloxanes |
| CN102134331A (en) * | 2011-01-21 | 2011-07-27 | 合肥工业大学 | Recycling method of waste silicone rubber |
| CN103626797A (en) * | 2012-08-28 | 2014-03-12 | 杨晓林 | Steam cracking recovery method of silicone rubber |
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