Process for the preparation of rubber bitumen

Abstract

The application discloses a preparation method of rubber asphalt. The acid treatment montmorillonite is modified by a quaternary ammonium salt, so that the montmorillonite forms a microporous and mesoporous multi-dimensional void structure, and the adsorption capacity is improved. Under the action of isocyanate, the montmorillonite is combined with the tire rubber powder. When the asphalt is constructed at high temperature, the hydrogen sulfide scattered by the rubber powder is adsorbed by the montmorillonite and removed by zinc oxide. The modified montmorillonite is designed and pre-combined with the rubber powder. When the asphalt is constructed, the hydrogen sulfide gas scattered by the rubber powder can be effectively removed, the environmental protection requirement is met, and the harm to human bodies is reduced.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of asphalt, in particular to a preparation method of rubber asphalt. BACKGROUND

[0002] Common treatment methods of waste tires, such as making rubber powder, adding the rubber powder into asphalt to improve high and low temperature resistance, fatigue resistance and the like, easily lead to limited flow of the asphalt, and the temperature requirement during construction is high, thereby easily leading to release of smoke gas, such as hydrogen sulfide gas, which has toxicity and odor and the like, and influences the environment and human health.

[0003] In this regard, some enterprises add zinc oxide and the like for removing hydrogen sulfide into the asphalt, but there are problems such as small removal amount, and improvement is needed. SUMMARY

[0004] To solve at least one of the above technical defects, the application provides the following technical scheme:

[0005] The application discloses a preparation method of rubber asphalt, comprising the following steps:

[0006] Firstly, the montmorillonite is treated with an acid, the montmorillonite treated with the acid is compounded with zinc oxide, and the montmorillonite compounded with the zinc oxide is modified with a quaternary ammonium salt;

[0007] Secondly, the quaternary ammonium salt modified montmorillonite and a diisocyanate type modifier are added into a solvent, and the isocyanate modified montmorillonite is prepared through heating reaction;

[0008] Thirdly, the tire rubber powder pre-depleted of sulfur and activated is placed in the solvent together with the isocyanate modified montmorillonite, and the montmorillonite compounded tire rubber powder is prepared through heating reaction;

[0009] Fourthly, the montmorillonite compounded tire rubber powder is mixed with base asphalt and an additive to prepare rubber asphalt.

[0010] Through acid treatment of the montmorillonite and modification with the quaternary ammonium salt, the montmorillonite can form a micro-porous and mesoporous multi-dimensional void structure, which helps to improve the adsorption capacity, and the montmorillonite is combined with the tire rubber powder under the action of the isocyanate, and the hydrogen sulfide released from the rubber powder during high-temperature construction of the asphalt is adsorbed by the montmorillonite and removed by the zinc oxide.

[0011] Further, the montmorillonite treated with the acid is mixed with a zinc salt and a carbonate solution, and after stirring reaction, pyrolysis, grinding and crushing, the montmorillonite compounded with the zinc oxide is formed, the zinc oxide is combined with the montmorillonite as a whole through co-precipitation and pyrolysis, and the reaction is easy to operate.

[0012] Further, the montmorillonite is treated with acetic acid, the zinc salt is zinc sulfate, and the carbonate is sodium carbonate, and the pyrolysis temperature is 320-360 DEG C.

[0013] Further, the tire rubber powder is subjected to plasma activation, and the activation parameters are: a treatment power of 200-400 W, a treatment time of 260-340 s, and a vacuum degree of 10-30 Pa, so that the surface roughness of the rubber powder is improved through plasma activation, and the surface contains active groups such as hydroxyl groups, thereby combining with isocyanate to stably compound the montmorillonite and the rubber powder, and better absorbing hydrogen sulfide gas emitted by the rubber powder in the asphalt, and higher adsorption removal efficiency.

[0014] Further, the diisocyanate modifier is isophorone diisocyanate, the diisocyanate modifier and the quaternary ammonium salt modified montmorillonite are added into a solvent DMAC, the mass ratio of the diisocyanate modifier and the quaternary ammonium salt modified montmorillonite is 1:8-12, the temperature is increased to 70-90 DEG C and reacted for 4-8 h, and then the diisocyanate modified montmorillonite is obtained through solid-liquid separation, drying and grinding, so that the modification effect of the montmorillonite is improved under the limited parameters.

[0015] Further, the pre-desulfurized and activated tire rubber powder and the diisocyanate modified montmorillonite are added into a solvent DMAC according to a mass ratio of 100:1-4, the temperature is increased to 70-90 DEG C and reacted for 4-8 h, and then the montmorillonite composite tire rubber powder is obtained through solid-liquid separation, drying and grinding, so that the montmorillonite and the rubber powder are better combined under the limited parameters.

[0016] Further, the mass ratio of the base asphalt and the tire rubber powder is 5:0.8-1.2, and the additives include one or more of a softening agent, a modifier and a crosslinking agent.

[0017] Further, in the fourth step, the rubber asphalt is formed after high-speed stirring, shearing and development after material mixing.

[0018] Further, the quaternary ammonium salt includes cetyltrimethylammonium bromide and tetradecyl dimethyl benzyl ammonium chloride, and the mass ratio of the two is 2:1-3, and the multi-quaternary ammonium salt is treated with acid to form a multi-dimensional void structure of the montmorillonite, and the adsorption force is obviously improved.

[0019] Compared with the prior art, the beneficial effects of the present application are:

[0020] 1. The present application designs modified montmorillonite and pre-composites the modified montmorillonite and the rubber powder, so that hydrogen sulfide gas emitted by the rubber powder can be effectively removed during asphalt construction, the environmental protection requirement is better met, and the harm to human body is reduced. DETAILED DESCRIPTION

[0021] The present application is further described below in combination with specific embodiments.

[0022] Embodiment 1

[0023] The preparation method of the rubber asphalt comprises the following steps:

[0024] First, the sodium-based montmorillonite is dispersed in 0.8 mol / L acetic acid solution, the mass fraction is 15%, stirring at 85°C for 3.5h, suction filtration and washing with distilled water, drying and grinding, after grinding, the acid-treated montmorillonite is obtained.

[0025] The acid-treated montmorillonite and zinc sulfate are added to the solution, the mass fraction of montmorillonite and zinc sulfate is 10% and 4% respectively, sodium carbonate solution is added to the above montmorillonite and zinc sulfate solution, the mass fraction of sodium carbonate and zinc sulfate is consistent, stirring for 1.5h, after filtration, the solid is heated to 350°C and decomposed for 40min, the product after thermal decomposition is crushed to obtain montmorillonite composite with zinc oxide.

[0026] The montmorillonite composite with zinc oxide is added to deionized water, and hexadecyl trimethyl ammonium bromide and tetradecyl dimethyl benzyl ammonium chloride are added, the mass ratio of the two is 2:1, the mass fraction of montmorillonite composite with zinc oxide and quaternary ammonium salt in the solution is 6% and 3% respectively, stirring and ultrasonic dispersion, heating to 38°C for 12h, suction filtration and washing, the obtained solid product is dried and ground to obtain quaternary ammonium salt modified montmorillonite.

[0027] Second, the quaternary ammonium salt modified montmorillonite and isophorone diisocyanate are added to the solvent DMAC (N, N-dimethylacetamide), the mass ratio of isophorone diisocyanate and quaternary ammonium salt modified montmorillonite is 1:8, the mass fraction of quaternary ammonium salt modified montmorillonite in the solution is 5%, heating to 85°C for 7h, suction filtration and washing, the obtained solid product is dried and ground to obtain isocyanate modified montmorillonite (about 200 mesh).

[0028] Third, the pre-desulfurized and activated tire rubber powder is treated by a plasma treatment device, the desulfurization degree of the rubber powder (about 60 mesh) is 30-40%, the parameters are: treatment power 300W, treatment time 320s, vacuum degree 15Pa, under air atmosphere, the pre-desulfurized and activated tire rubber powder and isocyanate modified montmorillonite are placed in the solvent DMAC according to the mass ratio of 100:1, stirring and heating to 80°C for 8h, suction filtration and washing, the obtained solid product is dried and ground to obtain montmorillonite composite tire rubber powder.

[0029] Fourth, the montmorillonite composite tire rubber powder and base asphalt (70#), coal tar, SBS modifier are mixed, the mass ratio of base asphalt and tire rubber powder is 5:1, coal tar is used as softener, the mass fraction of softener is 1.5%, the mass fraction of SBS modifier is 1%, the mixture is stirred at high speed for 10 minutes at 180 DEG C, then the mixture is added into a high-speed shearing machine, the mixture is refined for 35 minutes at 185 DEG C with a rotation speed of 3000 r / min, at the same time, a crosslinking agent is added, the crosslinking agent is sulfur and accelerator TMTD, the mass ratio of the two is 2:1, the mass fraction of the crosslinking agent is 0.1%, the mixture after shearing is moved into a high-speed stirring machine, and the mixture is stirred at high speed (1000 r / min) for 2.5 hours at 175 DEG C, and the rubber asphalt is obtained.

[0030] Example 2

[0031] The preparation method of the rubber asphalt comprises the following steps:

[0032] First, sodium-based montmorillonite is dispersed in 1 mol / L acetic acid solution, the mass fraction is 10%, stirring at 80 DEG C for 3 hours, suction filtration and washing with distilled water, drying and grinding, and the acid-treated montmorillonite is obtained after grinding.

[0033] The acid-treated montmorillonite and zinc sulfate are added into a solution, the mass fractions of the montmorillonite and zinc sulfate are 9% and 3% respectively, sodium carbonate solution is added into the above montmorillonite and zinc sulfate solution, the mass fraction of sodium carbonate and zinc sulfate is consistent, stirring and reacting for 2 hours, after filtration, the solid is heated to 350 DEG C and thermally decomposed for 30 minutes, the product after thermal decomposition is crushed to obtain montmorillonite with zinc oxide.

[0034] The montmorillonite with zinc oxide is added into deionized water, and cetyltrimethylammonium bromide and tetradecyl dimethyl benzyl ammonium chloride are added, the mass ratio of the two is 2:1.5, the mass fractions of the montmorillonite with zinc oxide and quaternary ammonium salt in the solution are 3% and 5% respectively, stirring and ultrasonic dispersion, heating to 35 DEG C and reacting for 12 hours, suction filtration and washing, the obtained solid product is dried and ground to obtain quaternary ammonium salt modified montmorillonite.

[0035] Second, the quaternary ammonium salt modified montmorillonite and isophorone diisocyanate are added into solvent DMAC (N, N-dimethylacetamide), the mass ratio of isophorone diisocyanate and quaternary ammonium salt modified montmorillonite is 1:10, the mass fraction of quaternary ammonium salt modified montmorillonite in the solution is 6%, heating to 80 DEG C and reacting for 8 hours, suction filtration and washing, the obtained solid product is dried and ground to obtain isocyanate modified montmorillonite (about 200 mesh).

[0036] Third, the pre-desulfurized and activated tire rubber powder is treated by a plasma treatment device, and the desulfurization degree of the rubber powder (about 60 mesh) is 30-40%. The parameters are: treatment power 320 W, treatment time 290 s, vacuum degree 15 Pa, and air atmosphere. The pre-desulfurized and activated tire rubber powder and the isocyanate modified montmorillonite are placed in a solvent DMAC at a mass ratio of 100:1.5, stirred and heated to 80°C for 7h, filtered and washed, and the obtained solid product is dried and ground to obtain a montmorillonite composite tire rubber powder.

[0037] Fourth, the montmorillonite composite tire rubber powder is mixed with base asphalt (70#), coal tar, and SBS modifier. The mass ratio of base asphalt to tire rubber powder is 5:0.9. The mass ratio of softener to tire rubber powder is 1.5%. The mass ratio of SBS modifier to tire rubber powder is 1%. The mixture is stirred at high speed at 180°C for 10 min, then added to a high-speed shearing machine, refined at 185°C for 35 min at a speed of 3000 r / min, and a crosslinking agent is added at the same time. The crosslinking agent is a composite of sulfur and accelerator TMTD, and the mass ratio of the two is 2:1. The mass ratio of the crosslinking agent to the mixture is 0.1%. The sheared mixture is moved to a high-speed stirring machine and stirred at 175°C at a high speed (1000 r / min) for 2.5h to obtain the required rubber asphalt.

[0038] Comparative Example 1

[0039] In this example, there is no composite of tire rubber powder and montmorillonite, and the two are independently added to the base asphalt.

[0040] Comparative Example 2

[0041] In this example, there is no acid treatment of montmorillonite.

[0042] The rubber asphalt prepared in the examples and comparative examples is subjected to smoke detection. Specifically, the rubber asphalt is moved to a container and heated, and the amount of smoke released is detected. The performance of the rubber asphalt prepared in the examples and comparative examples is tested, and the results are shown in Table 1.

[0043] Table 1

[0044] Flue gas release (g / kg) Average hydrogen sulfide concentration / ppm 5 °C ductility (cm) Example 1 1.2 1.12 7.6 Example 2 1.0 0.86 7.6 Comparative Example 1 1.7 1.68 7.5 Comparative Example 2 1.6 1.54 7.6

[0045] It can be seen that by compounding the rubber powder with montmorillonite by the process, the adsorption and removal capacity of hydrogen sulfide in the smoke is greatly improved, the environmental protection is improved, and the other performances of the rubber asphalt are not greatly affected.

[0046] The above are only preferred embodiments of the present application, and the protection scope of the present application is not limited to the above-mentioned embodiments. Any technical scheme falling within the concept of the present application shall fall within the protection scope of the present application. It should be noted that, for ordinary skilled persons in the art, some improvements and refinements without departing from the principles of the present application shall also be considered as falling within the protection scope of the present application.

Claims

1. A method for preparing rubber asphalt, characterized in that: The following steps are involved: First, the montmorillonite is treated with acid, the acid-treated montmorillonite is compounded with zinc oxide, and the zinc oxide-compounded montmorillonite is modified with a quaternary ammonium salt; Second, adding the quaternary ammonium salt modified montmorillonite and the diisocyanate type modifier into the solvent and heating the reaction to prepare the isocyanate modified montmorillonite; Third, the pre-desulfurized and activated tire rubber powder and isocyanate-modified montmorillonite are placed in a solvent and heated to react to prepare a montmorillonite composite tire rubber powder; Fourth, the montmorillonite composite tire rubber powder is mixed with the base asphalt and the additive to prepare rubber asphalt; The diisocyanate modifier is isophorone diisocyanate. The diisocyanate modifier and quaternary ammonium salt-modified montmorillonite are added to the solvent DMAC in a mass ratio of 1:8-12. The mixture is heated to 70-90°C for reaction for 4-8 hours. After solid-liquid separation, the mixture is dried and ground to obtain the isocyanate-modified montmorillonite. The pre-desulfurized and activated tire rubber powder and isocyanate-modified montmorillonite are added to the solvent DMAC at a mass ratio of 100:1-4, and the mixture is heated to 70-90°C for reaction for 4-8 hours. After solid-liquid separation, the mixture is dried and ground to obtain a montmorillonite composite tire rubber powder. The mass ratio of the matrix asphalt to tire rubber powder is 5:0.8-1.2, and the additives include one or more of a softener, a modifier, and a cross-linking agent; The quaternary ammonium salt includes hexadecyltrimethylammonium bromide and tetradecyldimethylbenzylammonium chloride, and the mass ratio of the two is 2:1-3.

2. The method for preparing rubber asphalt according to claim 1, wherein: The acid-treated montmorillonite is mixed with zinc salt and a carbonate solution is added, and the mixture is stirred for reaction, pyrolyzed, ground and crushed to form montmorillonite composited with zinc oxide.

3. The method for preparing rubber asphalt according to claim 2, wherein: The montmorillonite is treated with acetic acid, the zinc salt is zinc sulfate, the carbonate is sodium carbonate, and the pyrolysis temperature is 320-360℃.

4. The method for preparing rubber asphalt according to claim 1, wherein: The tire rubber powder is plasma activated, and the activation parameters are: processing power 200-400W, processing time 260-340s, vacuum degree 10-30Pa, and air atmosphere.

5. The method for preparing rubber asphalt according to claim 1, wherein: In the fourth step, after the materials are mixed, they are stirred, sheared, and developed at high speed to form rubber asphalt.