White carbon black preparation method based on rice husk resource utilization

Abstract

The invention discloses a white carbon black preparation method based on rice husk resource utilization, which comprises the following steps: carbonization: drying rice husks, carrying out anoxic carbonization at 550-600 DEG C for 3-4 hours, crushing and sieving; alkali dissolution: mixing the carbonized rice husks with a 2mol / L NaOH solution according to a mass ratio of 1: (5-7), reacting in a water bath at 95 DEG C for 3-4 hours, and filtering to obtain a sodium silicate solution; acid leaching: slowly adding a 9-10% H2SO4 solution into the filtrate, firstly adjusting the pH value to 11-12, aging for 1 hour, then adjusting the pH value to 9-10, and aging for 2-3 hours at 80 DEG C; post-treatment: washing to be neutral, and drying to obtain a white carbon black product. The specific surface area of the product is larger than or equal to 200 m < 2 > / g, the SiO2 purity is larger than or equal to 95%, efficient comprehensive utilization of rice hull resources is achieved, and the white carbon black production cost is reduced; a staged pH regulation and control process is developed, and the amorphous state purity of the white carbon black is improved; and a carbonization-alkali dissolution-acid leaching whole-flow process system is constructed, so that the environmental pollution is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of white carbon black preparation, and in particular to a method for preparing white carbon black based on resource utilization of rice husks. Background Art

[0002] White carbon black (precipitated silica) is an important inorganic chemical material, widely used in rubber, plastics, coatings, inks and other fields. It plays an irreplaceable role as a reinforcing agent in green tires. Traditional white carbon black production processes are mainly precipitation and vapor phase methods: Precipitation method: Using water glass (sodium silicate) as raw material, it is prepared by acidification with sulfuric acid, hydrochloric acid or carbon dioxide. The process is mature but has problems such as high energy consumption and high pollution (such as sulfate-containing wastewater). Vapor phase method: Using silicon tetrachloride as raw material, it is hydrolyzed at high temperature. The product has high purity but is expensive and the equipment is complex. It is only suitable for high-end fields.

[0003] With stricter environmental regulations and the need for resource recycling, the development of low-cost, green silica production technologies has become a research hotspot. Agricultural waste, such as rice husks, is an ideal alternative to traditional raw materials due to its high content of silica (approximately 15%-20%) and carbon resources.

[0004] Rice husk is a by-product of rice processing, with an annual global production of over 150 million tons, but traditional treatment methods (incineration, landfill) lead to resource waste and environmental pollution. The silica content in rice husk ash can reach 70%-90%, and it has a porous structure, making it a potential raw material for the preparation of white carbon black. Existing rice husk resource technology is mainly divided into two categories: one-step activation co-production method: the rice husk is directly carbonized at high temperature and then activated to simultaneously prepare white carbon black and activated carbon, but there are problems such as low silicon dissolution rate (<85%) and poor product dispersibility. Step-by-step alkali dissolution-acidification method: the sodium silicate solution is extracted by alkali dissolution and then acidified to precipitate white carbon black, but the traditional process requires multiple washings, high energy consumption, and difficult filtrate treatment.

[0005] For example, the prior art CN201710554604.4 discloses a method for efficiently utilizing rice husks to prepare white carbon black, comprising the following steps: (1) washing and removing impurities from the rice husks, drying them, grinding them into powder, adding dilute hydrochloric acid, an organic solvent, and a sodium bicarbonate solution, and boiling them. The alkaline substances in the rice husks are removed, the organic matter is hydrolyzed, and the metal ions form a metal organic complex with ethyl acetate. After boiling, the silica content and the whiteness of the white carbon black can be greatly improved; (2) cooling the cooked mixed system to 20-25°C, standing it for 4-6 hours, and filtering it. The obtained filtrate is put into an acetone solution, stirred and dispersed, and the hydrophobicity and affinity of the silicon compound can be improved; (3) adding a silica aerogel with a mass fraction of 0.3-0.5% to the obtained dried material, mixing and calcining them, and obtaining white carbon black with uniform particles and a high specific surface area.

[0006] Traditional silica production relies on quartz sand as raw material, which consumes a lot of energy and produces a large amount of carbon emissions; the incineration or landfill of rice husks causes resource waste and environmental pollution; the silicon extraction efficiency in the alkaline dissolution stage is low, affecting the purity of the final product.

[0007] Therefore, in response to the above problems, the present invention discloses a method for preparing silica based on the resource utilization of rice husks, so as to achieve efficient and comprehensive utilization of rice husk resources and reduce the production cost of silica; develop a staged pH control process to improve the purity of the amorphous phase of silica; and construct a "carbonization-alkali dissolution-acid leaching" full-process process system to reduce environmental pollution. Summary of the Invention

[0008] The purpose of the present invention is to provide a method for preparing white carbon black based on the resource utilization of rice husks, so as to achieve efficient and comprehensive utilization of rice husk resources and reduce the production cost of white carbon black.

[0009] The purpose of the present invention is achieved through the following technical solutions:

[0010] A method for preparing white carbon black based on rice husk resource utilization comprises the following steps:

[0011] (1) Carbonization: The rice husks are dried and then placed in a muffle furnace for carbonization. The temperature in the muffle furnace is raised and kept warm. After carbonization, the rice husks are crushed and sieved.

[0012] (2) Alkali dissolution: immerse the sample after carbonization and sieving in step (1) in a NaOH solution, heat it in a water bath and stir it, then filter it with suction and take the filtrate (sodium silicate solution);

[0013] (3) acid leaching: adding H2SO4 solution to the filtrate obtained in step (2), adjusting the pH value, and allowing to stand for aging;

[0014] (4) Post-treatment: The acid-leached mixture is washed to neutrality, filtered and dried to obtain the silica product, and then the product performance indicators are tested.

[0015] Preferably, the concentration of the NaOH solution is 2 mol / L, and the mass ratio of the carbonized and sieved sample to the NaOH solution is 1:5-7.

[0016] Preferably, in step (1), the rice husk is dried at 100-110°C, the temperature in the muffle furnace is raised to 550-600°C and kept warm for 3-4 hours, and the heating rate is 3-5°C / min.

[0017] Preferably, in step (2), the water bath heating temperature is 90-95° C., and the water bath heating and stirring time is 3-4 h.

[0018] Preferably, in step (3), the acid leaching adopts a gradient acidification method: first, H2SO4 solution is added to adjust the pH value to 11-12 and the mixture is allowed to stand for 1 hour, and then H2SO4 solution is added to adjust the pH value to 9-10 and the mixture is allowed to stand for 2-3 hours.

[0019] Preferably, in step (3), the concentration of the H2SO4 solution used in the acid leaching is 8-10%, and the static aging temperature is 75-80°C.

[0020] Preferably, in step (4), the washing adopts centrifugal-ultrasonic alternating washing, and the drying temperature is 105-120°C.

[0021] Due to the application of the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0022] 1. The silicon dissolution rate of the present invention is significantly improved. The carbonization stage adopts 550-600°C and is kept warm for 3-4 hours to ensure that the organic matter in the rice husk is fully decomposed, the carbon skeleton structure is loosened, and the loss of silicon wrapped by carbon is reduced. The alkaline dissolution step uses 2mol / LNaOH solution and a material-liquid ratio of 1:5-7 to fully dissolve the sodium silicate at 95°C. Compared with the existing one-step activation co-production method (silicon dissolution rate of 80%-85%), the silicon dissolution rate of the present invention is increased to >90%, and the utilization rate of rice husk resources is improved.

[0023] 2. The process of the present invention is simplified and energy consumption is reduced. The acidification stage adopts step-by-step control (first adjust the pH to acidify and let it stand for aging, and then wash to neutrality), avoiding the formation of silicone gel caused by the sudden drop in pH in the traditional process and reducing the number of washing times (only 3-4 times are needed to reach neutrality);

[0024] 3. The product of the present invention has superior performance, wide application range, high purity and high specific surface area. Through gradient acidification and aging control, the obtained white carbon black SiO2 purity is ≥95% and the specific surface area is ≥200m 2 / g (better than the national standard GB / T32678-2016); strong controllability, by adjusting parameters such as carbonization temperature and acidification pH, products with different particle sizes and surface activities can be customized;

[0025] 4. The present invention utilizes agricultural waste as a resource, reducing environmental pollution; it efficiently utilizes rice husks. Traditional rice husk treatment methods (such as incineration and landfill) cause environmental pollution, while this method converts them into high-value-added white carbon black, realizing the "waste-to-treasure" transformation; it also reduces silicon ore mining. Traditional white carbon black relies on mineral raw materials such as quartz sand, while this method utilizes biomass silicon in rice husks, reducing dependence on non-renewable resources;

[0026] 5. The process of the present invention is green and environmentally friendly, meeting the requirements of sustainable development; low energy consumption carbonization, adopting medium temperature carbonization at 550-600℃ (traditional methods require above 800℃), reducing energy consumption; no pollution discharge: the alkali dissolution-acid leaching process is closed-loop treatment, waste liquid can be recycled (such as Na2SO4 by-product), and no strong acid and strong alkali waste liquid is directly discharged; no toxic reagents are used, and no hazardous chemicals such as chlorosilane are used in the whole process (compared with the fumed silica process);

[0027] 6. The present invention has low production cost and significant economic benefits; the raw material cost is low, and rice husk is an agricultural by-product, and its price is much lower than quartz sand or silane raw materials; the process is simplified, and compared with the gas phase method (high equipment investment) or precipitation method (large acid consumption), this method has low equipment requirements and is suitable for industrial scale-up; the by-product value is increased, and the rice husk ash produced in the carbonization stage can be further used to extract activated carbon or potash fertilizer, thereby improving the overall benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific embodiments or the description of the prior art. Obviously, some of the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be made based on these drawings without paying any creative work.

[0029] Figure 1 This is a process flow chart of Example 1 of the present invention;

[0030] Figure 2 This is the XRD pattern of white carbon black in Example 1 of the present invention. DETAILED DESCRIPTION

[0031] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, a specific implementation scheme is now described in detail.

[0032] The present invention is further described below with reference to the following examples, but the present invention is not limited to the following examples. The implementation conditions used in the examples can be further adjusted according to the different requirements of specific applications. The implementation conditions not specified are conventional conditions in the industry. The technical features involved in the various embodiments of the present invention may be combined with each other as long as they do not conflict with each other.

[0033] Example 1

[0034] See attached Figure 1 And attached Figure 2 This embodiment provides a method for preparing white carbon black based on the resource utilization of rice husks, comprising the following steps:

[0035] (1) Carbonization: The rice husks were dried at 105°C and then carbonized in a muffle furnace. The temperature in the muffle furnace was raised to 580°C and kept at this temperature for 4 h at a heating rate of 5°C / min. After carbonization, the husks were crushed and passed through a 100-mesh sieve.

[0036] (2) Alkali dissolution: immerse the carbonized and sieved sample in step (1) in a 2 mol / L NaOH solution, wherein the mass ratio of the carbonized and sieved sample to the NaOH solution is 1:6, heat in a 95°C water bath and stir for 4 h, then filter and take the filtrate (sodium silicate solution);

[0037] (3) Acid leaching: first add 9% H2SO4 solution to the filtrate obtained in step (2) to adjust the pH value to 11, and then let it stand at 80°C for 1 hour. Then add 9% H2SO4 solution to adjust the pH value to 9, and let it stand at 80°C for 3 hours.

[0038] (4) Post-treatment: The mixture after acid leaching is washed alternately by centrifugation and ultrasound until it becomes neutral, filtered and dried at a drying temperature of 110° C. to obtain the white carbon black product, and then the product performance indicators are tested.

[0039] Example 2

[0040] This embodiment provides a method for preparing white carbon black based on the resource utilization of rice husks, comprising the following steps:

[0041] (1) Carbonization: The rice husks were dried at 105°C and then carbonized in a muffle furnace. The temperature in the muffle furnace was raised to 580°C and kept at this temperature for 4 h at a heating rate of 5°C / min. After carbonization, the husks were crushed and passed through a 100-mesh sieve.

[0042] (2) Alkali dissolution: immerse the carbonized and sieved sample in step (1) in a 2 mol / L NaOH solution, wherein the mass ratio of the carbonized and sieved sample to the NaOH solution is 1:6, heat in a 95°C water bath and stir for 4 h, then filter and take the filtrate (sodium silicate solution);

[0043] (3) Acid leaching: first add 10% H2SO4 solution to the filtrate obtained in step (2) to adjust the pH value to 11, and then let it stand at 80°C for 1 hour. Then add 10% H2SO4 solution to adjust the pH value to 9, and let it stand at 80°C for 3 hours.

[0044] (4) Post-treatment: The mixture after acid leaching is washed alternately by centrifugation and ultrasound until it becomes neutral, filtered and dried at a drying temperature of 110° C. to obtain the white carbon black product, and then the product performance indicators are tested.

[0045] Example 3

[0046] This embodiment provides a method for preparing white carbon black based on the resource utilization of rice husks, comprising the following steps:

[0047] (1) Carbonization: The rice husks were dried at 105°C and then carbonized in a muffle furnace. The temperature in the muffle furnace was raised to 580°C and kept at this temperature for 4 h at a heating rate of 5°C / min. After carbonization, the husks were crushed and passed through a 100-mesh sieve.

[0048] (2) Alkali dissolution: immerse the carbonized and sieved sample in step (1) in a 2 mol / L NaOH solution, wherein the mass ratio of the carbonized and sieved sample to the NaOH solution is 1:6, heat in a 95°C water bath and stir for 4 h, then filter and take the filtrate (sodium silicate solution);

[0049] (3) Acid leaching: first add 10% H2SO4 solution to the filtrate obtained in step (2) to adjust the pH value to 11, and then let it stand at 80°C for 1 hour. Then add 10% H2SO4 solution to adjust the pH value to 10, and let it stand at 80°C for 3 hours.

[0050] (4) Post-treatment: The mixture after acid leaching is washed alternately by centrifugation and ultrasound until it becomes neutral, filtered and dried at a drying temperature of 110° C. to obtain the white carbon black product, and then the product performance indicators are tested.

[0051] Example 4

[0052] This embodiment provides a method for preparing white carbon black based on the resource utilization of rice husks, comprising the following steps:

[0053] (1) Carbonization: The rice husks were dried at 105°C and then carbonized in a muffle furnace. The temperature in the muffle furnace was raised to 580°C and kept at this temperature for 4 h at a heating rate of 5°C / min. After carbonization, the husks were crushed and passed through a 100-mesh sieve.

[0054] (2) Alkali dissolution: immerse the carbonized and sieved sample in step (1) in a 2 mol / L NaOH solution, wherein the mass ratio of the carbonized and sieved sample to the NaOH solution is 1:5, heat in a 95°C water bath and stir for 4 h, then filter and take the filtrate (sodium silicate solution);

[0055] (3) Acid leaching: first add 9% H2SO4 solution to the filtrate obtained in step (2) to adjust the pH value to 11, and then let it stand at 80°C for 1 hour. Then add 9% H2SO4 solution to adjust the pH value to 9, and let it stand at 80°C for 3 hours.

[0056] (4) Post-treatment: The mixture after acid leaching is washed alternately by centrifugation and ultrasound until it becomes neutral, filtered and dried at a drying temperature of 110° C. to obtain the white carbon black product, and then the product performance indicators are tested.

[0057] Example 5

[0058] This embodiment provides a method for preparing white carbon black based on the resource utilization of rice husks, comprising the following steps:

[0059] (1) Carbonization: The rice husks were dried at 105°C and then carbonized in a muffle furnace. The temperature in the muffle furnace was raised to 580°C and kept at this temperature for 4 h at a heating rate of 5°C / min. After carbonization, the husks were crushed and passed through a 100-mesh sieve.

[0060] (2) Alkali dissolution: immerse the carbonized and sieved sample in step (1) in a 2 mol / L NaOH solution, wherein the mass ratio of the carbonized and sieved sample to the NaOH solution is 1:7, heat in a 95°C water bath and stir for 4 h, then filter and take the filtrate (sodium silicate solution);

[0061] (3) Acid leaching: first add 9% H2SO4 solution to the filtrate obtained in step (2) to adjust the pH value to 11, and then let it stand at 80°C for 1 hour. Then add 9% H2SO4 solution to adjust the pH value to 9, and let it stand at 80°C for 3 hours.

[0062] (4) Post-treatment: The mixture after acid leaching is washed alternately by centrifugation and ultrasound until it becomes neutral, filtered and dried at a drying temperature of 110° C. to obtain the white carbon black product, and then the product performance indicators are tested.

[0063] Comparative Example 1

[0064] This comparative example provides a method for preparing white carbon black based on the resource utilization of rice husks, comprising the following steps:

[0065] (1) Carbonization: The rice husks were dried at 105°C and then carbonized in a muffle furnace. The temperature in the muffle furnace was raised to 580°C and kept at this temperature for 4 h at a heating rate of 5°C / min. After carbonization, the husks were crushed and passed through a 100-mesh sieve.

[0066] (2) Alkali dissolution: immerse the carbonized and sieved sample in step (1) in a 2 mol / L NaOH solution, wherein the mass ratio of the carbonized and sieved sample to the NaOH solution is 1:6, heat in a 95°C water bath and stir for 4 h, then filter and take the filtrate (sodium silicate solution);

[0067] (3) Acid leaching: first add 9% H2SO4 solution to the filtrate obtained in step (2) to adjust the pH value to 11, and then let it stand at 80°C for 1 hour. Then add 9% H2SO4 solution to adjust the pH value to 8, and let it stand at 80°C for 3 hours.

[0068] (4) Post-treatment: The mixture after acid leaching is washed alternately by centrifugation and ultrasound until it becomes neutral, filtered and dried at a drying temperature of 110° C. to obtain the white carbon black product, and then the product performance indicators are tested.

[0069] Comparative Example 2

[0070] This comparative example provides a method for preparing white carbon black based on the resource utilization of rice husks, comprising the following steps:

[0071] (1) Carbonization: The rice husks were dried at 105°C and then carbonized in a muffle furnace. The temperature in the muffle furnace was raised to 580°C and kept at this temperature for 4 h at a heating rate of 5°C / min. After carbonization, the husks were crushed and passed through a 100-mesh sieve.

[0072] (2) Alkali dissolution: immerse the carbonized and sieved sample in step (1) in a 2 mol / L NaOH solution, wherein the mass ratio of the carbonized and sieved sample to the NaOH solution is 1:4, heat in a 95°C water bath and stir for 4 h, then filter and take the filtrate (sodium silicate solution);

[0073] (3) Acid leaching: first add 9% H2SO4 solution to the filtrate obtained in step (2) to adjust the pH value to 11, and then let it stand at 80°C for 1 hour. Then add 9% H2SO4 solution to adjust the pH value to 9, and let it stand at 80°C for 3 hours.

[0074] (4) Post-treatment: The mixture after acid leaching is washed alternately by centrifugation and ultrasound until it becomes neutral, filtered and dried at a drying temperature of 110° C. to obtain the white carbon black product, and then the product performance indicators are tested.

[0075] Comparative Example 3

[0076] This comparative example provides a method for preparing white carbon black based on the resource utilization of rice husks, comprising the following steps:

[0077] (1) Carbonization: The rice husks were dried at 105°C and then carbonized in a muffle furnace. The temperature in the muffle furnace was raised to 580°C and kept at this temperature for 4 h at a heating rate of 5°C / min. After carbonization, the husks were crushed and passed through a 100-mesh sieve.

[0078] (2) Alkali dissolution: immerse the carbonized and sieved sample in step (1) in a 2 mol / L NaOH solution, wherein the mass ratio of the carbonized and sieved sample to the NaOH solution is 1:8, heat in a 95°C water bath and stir for 4 h, then filter and take the filtrate (sodium silicate solution);

[0079] (3) Acid leaching: first add 9% H2SO4 solution to the filtrate obtained in step (2) to adjust the pH value to 11, and then let it stand at 80°C for 1 hour. Then add 9% H2SO4 solution to adjust the pH value to 9, and let it stand at 80°C for 3 hours.

[0080] (4) Post-treatment: The mixture after acid leaching is washed alternately by centrifugation and ultrasound until it becomes neutral, filtered and dried at a drying temperature of 110° C. to obtain the white carbon black product, and then the product performance indicators are tested.

[0081] The white carbon black products obtained in the above examples and comparative examples were tested, and the test results are shown in Table 1.

[0082] Table 1

[0083]

[0084] According to Table 1, it can be seen that the purity and yield of the white carbon black prepared in Example 5 are the highest.

[0085] In summary, the silicon dissolution rate of the present invention is significantly improved. The carbonization stage adopts 550-600℃ and is kept warm for 3-4h to ensure that the organic matter in the rice husk is fully decomposed, the carbon skeleton structure is loosened, and the loss of silicon wrapped by carbon is reduced; the alkaline dissolution step uses 2mol / LNaOH solution and a material-liquid ratio of 1:5-7 to fully dissolve sodium silicate at 95℃; compared with the existing one-step activation co-production method (silicon dissolution rate 80%-85%), the silicon dissolution rate of the present invention is increased to >90%, and the utilization rate of rice husk resources is improved; the process of the present invention is simplified and energy consumption is reduced, and the acidification stage adopts step-by-step control (first adjust the pH to acidify and let it stand for aging, and then wash to neutrality) to avoid the formation of silica gel caused by the sudden drop of pH in the traditional process and reduce the number of washing times (only 3-4 times are needed to reach neutrality); the product of the present invention has superior performance, a wide range of applications, high purity and high specific surface area, and through gradient acidification and aging control, the obtained white carbon black SiO2 has a purity of ≥95% and a specific surface area of ≥200m 2 / g (better than the national standard GB / T32678-2016); strong controllability, by adjusting parameters such as carbonization temperature and acidification pH, products with different particle sizes and surface activities can be customized; the present invention utilizes agricultural waste as a resource to reduce environmental pollution; efficient utilization of rice husks, traditional rice husk treatment methods (such as incineration and landfill) will cause environmental pollution, while this method converts them into high-value-added white carbon black, realizing "turning waste into treasure"; reducing silicon ore mining, traditional white carbon black relies on mineral raw materials such as quartz sand, this method utilizes biomass silicon in rice husks, reducing dependence on non-renewable resources; the process of the present invention is green and environmentally friendly, in line with the requirements of sustainable development; low energy consumption carbonization, using 550-600 ° C medium temperature Carbonization (traditional methods require temperatures above 800°C) reduces energy consumption; no pollution emissions: the alkali dissolution-acid leaching process is closed-loop treatment, waste liquid can be recycled (such as Na2SO4 by-products), and no strong acid or strong alkali waste liquid is directly discharged; there are no toxic reagents, and no hazardous chemicals such as chlorosilane are used throughout the process (compared to the fumed silica process); the present invention has low production costs and significant economic benefits; low raw material costs, rice husks are an agricultural by-product, and their prices are much lower than quartz sand or silane raw materials; the process is simplified, and compared with the gas phase method (high equipment investment) or precipitation method (large acid consumption), this method has low equipment requirements and is suitable for industrial scale-up; by-product value-added, the rice husk ash produced in the carbonization stage can be further used to extract activated carbon or potash fertilizer, thereby improving comprehensive benefits.

[0086] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A method for preparing white carbon black based on rice husk resource utilization, characterized in that: The steps include: (1) Carbonization: The rice husks are dried and then placed in a muffle furnace for carbonization. The temperature in the muffle furnace is raised and kept warm. After carbonization, the rice husks are crushed and sieved. (2) Alkali dissolution: immerse the sample after carbonization and screening in step (1) in a NaOH solution, heat it in a water bath and stir it, then filter it with suction and take the filtrate; (3) acid leaching: adding H2SO4 solution to the filtrate obtained in step (2), adjusting the pH value, and allowing to stand for aging; (4) Post-treatment: The acid-leached mixture is washed to neutrality, filtered and dried to obtain the silica product, and then the product performance indicators are tested.

2. The method for preparing white carbon black based on rice husk resource utilization according to claim 1, characterized in that: The concentration of the NaOH solution is 2 mol / L, and the mass ratio of the carbonized and sieved sample to the NaOH solution is 1:5-7.

3. The method for preparing white carbon black based on rice husk resource utilization according to claim 1, characterized in that: In step (1), the rice husk is dried at 100-110° C., and the temperature in the muffle furnace is raised to 550-600° C. and kept warm for 3-4 hours at a heating rate of 3-5° C. / min.

4. The method for preparing white carbon black based on rice husk resource utilization according to claim 1, wherein: In step (2), the water bath heating temperature is 90-95° C., and the water bath heating and stirring time is 3-4 h.

5. The method for preparing white carbon black based on rice husk resource utilization according to claim 1, wherein: In step (3), the acid leaching adopts a gradient acidification method: first, H2SO4 solution is added to adjust the pH value to 11-12 and the mixture is allowed to stand for 1 hour, and then H2SO4 solution is added to adjust the pH value to 9-10 and the mixture is allowed to stand for 2-3 hours.

6. The method for preparing white carbon black based on rice husk resource utilization according to claim 1, characterized in that: In step (3), the concentration of the H2SO4 solution used in the acid leaching is 8-10%, and the static aging temperature is 75-80°C.

7. The method for preparing white carbon black based on rice husk resource utilization according to claim 1, characterized in that: In step (4), the washing adopts centrifugal-ultrasonic alternating washing, and the drying temperature is 105-120°C.

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