Silica ash / thermal cracking carbon black compound carbon black as well as preparation method and application thereof

Abstract

The invention discloses a preparation method and an application method of silica ash / thermal cracking carbon black compounded carbon black. Biomass ash is finely crushed and cleaned to remove soluble salt, and hydrogen peroxide is added for activation after dehydration; adding alkali for dissolving, washing the rice hull ash residue subjected to alkali washing with hot water or hot alkaline water, and carrying out solid-liquid separation to obtain silica ash residue; drying, crushing and sieving the silicon ash slag; adding a surface treating agent, and carrying out activating treatment such as high-temperature stirring; and mixing the silica ash / thermal cracking carbon black compound carbon black with the thermal cracking carbon black in proportion to obtain the silica ash / thermal cracking carbon black compound carbon black which completely meets the performance of tire rubber. According to the method, the residue obtained after water glass is extracted from the rice hull ash is recycled, so that waste is reduced, and the rice hull utilization industry chain is extended; and the thermal cracking carbon black from the waste tires is compounded and combined for use, so that the wastes are doubly utilized, and the environmental burden is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of composite materials, and particularly relates to a rubber reinforcing material. Background Art

[0002] As a natural product, rubber has a wide range of applications. However, raw rubber is usually composed of linear macromolecular chains and has poor mechanical properties. To obtain rubber products that meet various use properties, reinforcing agents are usually required. As a common rubber reinforcing agent, carbon black can significantly improve the wear resistance, elasticity, strength, and dynamic properties of rubber.

[0003] In the prior art, there has been a technical solution that uses waste tires to carry out pyrolysis reactions to prepare pyrolytic carbon black for resource recycling. However, the carbon black produced by the pyrolysis of waste tires often has problems such as low surface activity and poor wear resistance, and when it is repeatedly used as a reinforcing material for tire rubber, problems such as low hardness and poor wear resistance often occur.

[0004] Biomass ash such as rice husk ash and other silica ash residues after extracting water glass (sodium silicate) contain residual alkali (pH>10) and low-activity silicon components, and are usually landfilled as waste, which not only occupies land but also easily causes soil alkalization pollution. Silica ash residues are rich in silicon dioxide (SiO2), which can provide a rigid structure and wear resistance. Therefore, the silica ash residues of biomass ash have considerable application prospects in the application of tire rubber reinforcing aids. By modifying and compounding silica ash residues with pyrolytic carbon black, a recycled carbon black with both environmental protection and high performance can be developed, which can promote resource recycling and cost reduction and efficiency improvement in the rubber industry. Summary of the Invention

[0005] The purpose of the present invention is to provide a preparation method and an application method of silica ash residue / pyrolytic carbon black compounded carbon black to solve the above technical problems.

[0006] To solve the above technical problems, the present invention discloses the following technical solutions:

[0007] In a first aspect, the present invention discloses a preparation method of silica ash residue / pyrolytic carbon black compounded carbon black, which comprises the following steps:

[0008] S1. After crushing biomass ash and washing it with water to remove soluble salts, an activator is added for activation;

[0009] S2. An alkali solution is added to the activated biomass ash for a dissolution reaction;

[0010] S3. The residue of the biomass ash solution after the dissolution reaction is subjected to solid-liquid filtration and separation to obtain a silica ash residue filter cake;

[0011] S4. The silica ash residue filter cake is subjected to preliminary crushing and drying to obtain silica ash residue;

[0012] S5. Re-crush the dried silica fume residue, and add a surface treatment agent during crushing for modification treatment to obtain modified silica fume residue;

[0013] S6. Mix the modified silica fume residue and pyrolytic carbon black in a mass ratio of 5% - 30%: 95% - 70% to obtain silica fume residue / pyrolytic carbon black composite carbon black.

[0014] Further, the biomass ash is one or a mixture of rice husk ash, rice straw ash, corn straw ash, wheat straw ash, bamboo ash or bagasse ash.

[0015] Further, the activator is hydrogen peroxide, and the addition amount of the activator is 0.1 - 30% of the mass of the biomass ash. Since the main component of rice husk ash is amorphous silica (SiO₂), hydrogen peroxide may increase its surface hydroxyl groups through oxidation, making it hydrophilic and facilitating the leaching of alkali solution.

[0016] Further, the alkali solution is one or a mixture of caustic soda solution, soda ash solution, potassium hydroxide solution or potassium carbonate solution; the addition amount of the alkali solution is 2 - 5 times the mass of the biomass ash.

[0017] Further, the temperature of the dissolution reaction is 50 - 200 °C, the reaction pressure is 0.05 - 0.6 MPa, and the reaction time is 0.5 - 5 h.

[0018] Further, in the solid-liquid filtration process of step S3, use a weak alkali solution or clear water above 75 °C to wash repeatedly until the pH of the silica fume residue filter cake is 7 - 9.5. The silica fume residue filter cake is washed with a hot weak alkali solution or clear water, the purpose of which is to reduce the pH value in the filter cake and activate the silica, so as to modify the silica fume residue subsequently.

[0019] Further, the weak alkali solution in step S3 is one or a mixture of sodium carbonate or sodium bicarbonate.

[0020] Further, the moisture content of the silica fume residue obtained by drying in step S4 is controlled below 2%.

[0021] Further, the surface treatment agent is one or a mixture of bis-[γ-(triethoxysilyl)propyl]tetrasulfide, bis-[γ-(triethoxysilyl)propyl]disulfide, γ-aminopropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, paraffin or stearic acid; the addition amount of the surface treatment agent is 1 - 3% of the mass of the biomass ash.

[0022] In the second aspect, the present invention discloses the silica fume residue / pyrolytic carbon black composite carbon black prepared by the above preparation method.

[0023] Thirdly, the present invention discloses the application of the silica fume residue / pyrolytic carbon black composite carbon black prepared by the above preparation method in rubber composites, such as being used as a reinforcing agent in tire rubber.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] (1) By compounding the pyrolytic carbon black from waste tires with the silica fume residue from rice husk ash and reasonably controlling the compounding process, the prepared ash residue / pyrolytic carbon black composite carbon black can solve the drawback of poor mechanical properties when using a single raw material as a rubber reinforcing agent.

[0026] (2) The silica fume residue obtained in the process route of the present invention is rich in silicon dioxide (SiO), which can provide a rigid structure and wear resistance. Combining with pyrolytic carbon black can promote the positive synergistic effect of chemical structure and mechanical properties, and can meet the performance requirements of tire rubber.

[0027] (3) The process steps of the present invention are simple, reducing the types and amounts of agents added in the preparation process, lowering the production cost; no complex equipment is required during the production process, which is suitable for industrial production.

[0028] (4) The present invention reuses the residue after extracting sodium silicate from rice husk ash, reducing waste and extending the industrial chain of rice husk utilization; and compounding and using the pyrolytic carbon black from waste tires, double-utilizing waste and reducing the environmental burden; it not only conforms to the concept of circular economy but also improves economic benefits. Specific Embodiments

[0029] The present invention will be further described below through the description of specific embodiments. However, this is not a limitation to the present invention. Those skilled in the art can make various modifications or improvements according to the basic idea of the present invention, but as long as they do not depart from the basic idea of the present invention, they are within the protection scope of the present invention.

[0030] Among them, the reagents used in the present invention are all common reagents, which can be purchased from regular reagent production and sales companies.

[0031] The present invention relates to a method for preparing recycled carbon black by compounding silica fume residue and pyrolytic carbon black. The biomass ash is finely pulverized, washed to remove soluble salts, dehydrated, then activated with hydrogen peroxide, dissolved with alkali to produce sodium silicate by the alkali solution. The residue of rice husk ash after alkali washing is washed with hot water or hot alkali water, and solid-liquid separation is carried out to obtain silica fume residue. The pH value is controlled during the washing process. The silica fume residue is dried, pulverized, and sieved. A surface treatment agent is added for activation treatment such as high temperature and stirring, and then mixed with pyrolytic carbon black in a certain proportion to obtain recycled carbon black that fully meets the performance requirements of tire rubber.

[0032] A method for preparing recycled carbon black by compounding silica fume slag and pyrolytic carbon black provided by the present invention mainly comprises the following steps:

[0033] S1. Biomass ash with a particle size of 0.1 - 10 mm is finely pulverized to a particle size of 3 - 50 μm, washed with water to remove soluble salts, and after dehydration, 0.1 - 30% of hydrogen peroxide based on the mass of the biomass ash is added for activation;

[0034] S2. 2 - 5 times the mass of the biomass ash of an alkali solution is added for dissolution, the dissolution temperature is 50 - 200 °C, the reaction pressure is 0.05 - 0.6 MPa, and the reaction time is 0.5 - 5 h.

[0035] S3. The solution residue with sufficient chemical reaction is subjected to solid - liquid filtration and separation with a plate - and - frame filter. During the filtration process, a weak alkali solution or clear water at a temperature above 75 °C is used for repeated washing to obtain a silica fume slag filter cake with a pH of 7 - 9.5.

[0036] S4. The silica fume slag filter cake is initially pulverized and dried using a pulverizer to make the moisture content less than 2%.

[0037] S5. The dried silica fume slag is pulverized so that the residue on a 325 - mesh sieve is less than 0.5%, and during pulverization, a silane or alkane is added for modification treatment;

[0038] S6. The modified silica fume slag and pyrolytic carbon black are mixed at a mass ratio of 5% - 30%: 95% - 70% to obtain the silica fume slag / pyrolytic carbon black compounded carbon black.

[0039] The biomass ash in step S1 is one or a mixture of rice husk ash, rice straw ash, corn straw ash, wheat straw ash, bamboo ash, and bagasse ash.

[0040] The pulverization equipment selected in steps S1, S4, and S5 is pulverization equipment such as ring - roll mills, jet mills, impact mills, and Raymond mills.

[0041] The alkali solution in step S2 is one or a mixture of caustic soda solution, soda ash solution, potassium hydroxide solution, potassium carbonate solution, etc.

[0042] The weak alkali solution in step S3 is one or a mixture of sodium carbonate, sodium bicarbonate, etc.

[0043] The surface treatment agent is one or a mixture of Si69, Si75, KH - 550, KH - 570, paraffin, or stearic acid; the addition amount of the surface treatment agent is 1 - 3% of the mass of the biomass ash. Among them:

[0044] Si69: bis - [γ - (triethoxysilyl)propyl]tetrasulfide;

[0045] Si75: Bis-[γ-(triethoxysilyl)propyl] disulfide;

[0046] KH-550: γ-aminopropyltriethoxysilane;

[0047] KH-570: γ-methacryloxypropyltrimethoxysilane.

[0048] The S3 filtration and impurity removal equipment selects one or more of dehydration equipment such as plate and frame, horizontal scroll, and centrifuge.

[0049] The drying, modification, and mixing equipment for steps S4, S5, and S6 are large ovens, dynamic calcination furnaces, rotary kilns, etc.

[0050] The mixing in step S6 is to proportionally put the modified silica fume residue and pyrolytic carbon black into a rotary kiln for mixing. The temperature of the rotary kiln is 60 - 120 °C, and the mixing time is 10 - 60 minutes.

[0051] The pyrolytic carbon black in step S6 is the carbon black that meets GB / T3780 - 2015 after the pyrolysis of waste tires.

[0052] The silica fume residue in the present invention is rich in silicon dioxide (SiO2), which can provide a rigid structure and wear resistance. Combining with the synergistic effect of pyrolytic carbon black, it has significant potential in the field of recycled materials and can meet the performance requirements of tire rubber.

[0053] Example 1

[0054] A preparation method of silica fume residue / pyrolytic carbon black compound carbon black, the specific steps are as follows:

[0055] S1. 100 kg of rice husk ash with a particle size of 0.1 mm is finely pulverized by a ring-roll mill to a particle size of 3 μm, washed with water to remove soluble salts, and after dehydration, 0.1 kg of hydrogen peroxide is added for activation;

[0056] S2. 300 kg of alkali solution is added for dissolution. The dissolution temperature is 160 °C, the reaction pressure is 0.5 MPa, and the reaction time is 3 h.

[0057] S3. The solution residue with sufficient chemical reaction is subjected to solid-liquid filtration and separation with a plate and frame. During the filtration process, it is repeatedly washed with sodium bicarbonate above 75 °C to obtain a silica fume residue filter cake with a pH of 8.

[0058] S4. The silica fume residue filter cake is preliminarily pulverized and dried by a pulverizer so that the water content is less than 2%.

[0059] S5. Re-crush the dried silica fume slag with a ring-roll mill until the residue on a 325-mesh sieve is less than 0.5%. During the crushing process, add 1.5% of bis-[γ-(triethoxysilyl)propyl]tetrasulfide silane coupling agent based on the mass of the biomass ash for modification treatment.

[0060] S6. Put the modified silica fume slag (20%) and pyrolytic carbon black (80%) into a rotary kiln for mixing. The temperature of the rotary kiln is 100 °C, and the mixing time is 30 minutes to obtain the silica fume slag / pyrolytic carbon black composite carbon black.

[0061] Apply the prepared silica fume slag / pyrolytic carbon black composite carbon black to the rubber test according to the following test formula, and use a three-stage mixing process for mixing to finally obtain the well-mixed rubber compound. Test and compare the reinforcement performance of the mixed rubber compound, and the test results are shown in Table 1.

[0062] Test formula (by mass): NR (Hainan rubber) 100; composite carbon black 50; zinc oxide 5; stearic acid 2; aromatic oil 5; antioxidant 4010NA 1.5; antioxidant RD 1; sulfur 2.5; vulcanization accelerator TBBS 1.2; accelerator TMTD 0.3.

[0063] Comparative Example 1

[0064] A preparation method of silica fume slag / pyrolytic carbon black composite carbon black:

[0065] Steps S1 - S5 are the same as those in Example 1. Only in step S6, mix the activated silica fume slag (50%) and pyrolytic carbon black (50%) to obtain the silica fume slag / pyrolytic carbon black composite carbon black.

[0066] Apply the prepared silica fume slag / pyrolytic carbon black composite carbon black to the rubber test according to the test formula in the example, and use a three-stage mixing process for mixing to finally obtain the well-mixed rubber compound. Test and compare the reinforcement performance of the mixed rubber compound, and the test results are shown in Table 1.

[0067] Comparative Example 2

[0068] Replace the composite carbon black in the test formula of Example 1 with the modified silica fume slag prepared according to the steps of Example 1 for the rubber test. Test and compare the reinforcement performance of the mixed rubber compound, and the test results are shown in Table 1.

[0069] Comparative Example 3

[0070] The one purchased from Qucheng Silicon Chemical Co., Ltd. model After mixing 175 parts of precipitated silica (20%) and pyrolytic carbon black (80%), it was applied to the rubber test according to the test formula in Example 1, and a three-stage mixing process was used for mixing, and finally the well-mixed rubber compound was obtained. The reinforcement performance of the mixed rubber compound was tested and compared, and the test results are shown in Table 1.

[0071] Comparative Example 4

[0072] The pyrolytic carbon black G685 purchased from Anhui Gurit New Materials Technology Co., Ltd. was applied to the rubber test according to the test formula in Example 1, and a three-stage mixing process was used for mixing, and finally the well-mixed rubber compound was obtained. The reinforcement performance of the mixed rubber compound was tested and compared, and the test results are shown in Table 1.

[0073] Table 1:

[0074]

[0075] As can be seen from Table 1, the physical properties of Example 1 are significantly better than those of Comparative Examples 1 and 2. That is, the activated silica ash residue cannot be directly used in the production of rubber tires, and when the proportion of the activated silica ash residue is large, its performance will be insufficient. The silica (SiO2) in Example 1 can provide a rigid structure and wear resistance, and combined with the positive synergistic effect of pyrolytic carbon black on chemical structure and mechanical properties, it can meet the performance requirements of tire rubber.

[0076] From Example 1 and Comparative Examples 3 and 4, it can be seen that some physical property parameters of Example 1 are slightly worse than those of Comparative Examples 3 and 4, but basically meet the production requirements of rubber tires. However, the present invention reuses the residue after extracting water glass from rice husk ash, reduces waste, extends the industrial chain of rice husk utilization, and reduces the production cost of rubber tires.

[0077] The above embodiments are only illustrative of the principles and effects of the present invention, and are not used to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A preparation method of silica fume slag / pyrolytic carbon black compound carbon black, characterized in that, It includes the following steps: S1. After crushing the biomass ash, washing it with water to remove soluble salts, add an activator for activation; S2. Add an alkali solution to the activated biomass ash for a dissolution reaction; S3. Filter and separate the solid and liquid of the biomass ash solution residue with sufficient dissolution reaction to obtain a silica ash residue filter cake; S4. Primarily crush and dry the silica ash residue filter cake to obtain silica ash residue; S5. Re-crush the dried silica ash residue, and add a surface treatment agent during crushing for modification treatment to obtain modified silica ash residue; S6. Mix the modified silica ash residue with pyrolytic carbon black at a mass ratio of 5% - 30% : 95% - 70%. Then the silica ash residue / pyrolytic carbon black composite carbon black is obtained.

2. The preparation method according to claim 1, characterized in that, The biomass ash is one or a mixture of more than one of rice husk ash, rice straw ash, corn straw ash, wheat straw ash, bamboo ash or bagasse ash.

3. The preparation method according to claim 1, characterized in that, The activator is hydrogen peroxide, and the addition amount of the activator is 0.1 - 30% of the mass of the biomass ash.

4. The preparation method according to claim 1, characterized in that, The alkali solution is one or a mixture of more than one of caustic soda solution, soda ash solution, potassium hydroxide solution or potassium carbonate solution; the addition amount of the alkali solution is 2 - 5 times the mass of the biomass ash.

5. The preparation method according to claim 4, characterized in that, The temperature of the dissolution reaction is 50 - 200 °C, the reaction pressure is 0.05 - 0.6 MPa, and the reaction time is 0.5 - 5 h.

6. The preparation method according to claim 1, characterized in that, In the solid-liquid filtration process in step S3, use a weak alkali solution or clear water above 75 °C to wash repeatedly until the pH of the silica ash residue filter cake is 7 - 9.

5.

7. The preparation method according to claim 1, characterized in that, In step S4, the moisture content of the silica ash residue obtained by drying is controlled below 2%.

8. The preparation method according to claim 1, characterized in that, The surface treatment agent is one or a mixture of more than one of bis-[γ-(triethoxysilyl)propyl]tetrasulfide, bis-[γ-(triethoxysilyl)propyl]disulfide, γ-aminopropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, paraffin or stearic acid; the addition amount of the surface treatment agent is 1 - 3% of the mass of the biomass ash.

9. The silica ash residue / pyrolytic carbon black composite carbon black prepared by the preparation method according to any one of claims 1 - 8.

10. An application of the silica ash residue / pyrolytic carbon black composite carbon black as claimed in claim 8 in a rubber composite material.

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