A method for reducing the ash content of plant carbon black in fruit shells

Abstract

This disclosure relates to the field of carbon black technology, specifically a method for reducing the ash content of palm shell plant carbon black. The palm shell plant carbon black uses palm shells as raw material. The method includes the following steps: providing palm shells as raw material, carbonizing the palm shells to obtain palm shell plant carbon black; adding the palm shell plant carbon black to a first acidic solution and performing ultrasonic cleaning; then soaking it in a second acidic solution, followed by dry ball milling, and then soaking it in a third acidic solution; followed by wet ball milling; finally, after post-treatment, obtaining palm shell plant carbon black with reduced ash content. The method provided in this disclosure significantly reduces the ash content and other impurities in palm shell plant carbon black prepared from palm shells.

Description

Technical Field

[0001] This disclosure relates to the field of carbon black technology, specifically a method for reducing the ash content of nutshell plant carbon black. Background Technology

[0002] Palm is an important economic crop, cultivated in many countries in Southeast Asia, Africa, and South America, and mainly distributed in areas south of the Yangtze River in my country. Its fruit is used to produce palm oil, an important component of the global oilseed market. However, the production of 2.5 kg of palm oil generates 80 kg of palm shells, a large amount of which is not effectively utilized and is mostly burned or landfilled. Palm shells have the advantage of high carbon content, meeting the requirements for use as a raw material in the production of carbon black.

[0003] However, palm shells contain a high ash content for the following reasons: (1) Most oil palm plantations are located in lateritic soils formed by the weathering of granite, basalt, etc., which have a high SiO2 content. The palm roots are densely distributed in the soil surface, and a large number of SiO2 particles are carried into the plant's vascular bundles by transpiration, and finally deposited in the fruit stalk and shell fiber cell walls. The SiO2 content in the palm shell can reach 6%-7%. (2) In palm cultivation, a large amount of fungicides such as Bordeaux mixture and mancozeb are used, so Cu and Zn ions remain on the surface of the palm fruit. (3) Micronutrients such as potassium dihydrogen phosphate, zinc sulfate, and aluminum sulfate are applied to the roots with water-soluble fertilizer. After being absorbed by the roots, they are distributed to the fruit stalk and shell fiber by transpiration, so the palm fruit contains Zn and Al ions. (4) Weathered soils such as granite and basalt also contain primary minerals such as CuFeS2 and ZnS. After being absorbed by the roots, they are distributed to the fruit bunch stalk and shell fiber by the transpiration flow. Therefore, palm fruits contain Cu ions, Fe ions and Zn ions.

[0004] Therefore, it can be seen that the ash content in palm shells is very high, and there is an urgent need for a method to reduce the ash content of plant carbon black in the shells. Summary of the Invention

[0005] This disclosure provides a method for reducing the ash content of plant carbon black in fruit shells, thereby addressing the shortcomings of related technologies.

[0006] According to a first aspect of the present disclosure, a method for reducing the ash content of palm shell plant carbon black is provided, wherein the palm shell plant carbon black is made from palm shells, and the method includes the following steps:

[0007] Step 1: Provide raw material palm shells, and carbonize the palm shells to obtain fruit shell plant carbon black;

[0008] Step 2: Add the fruit shell plant carbon black to the first acidic solution and perform ultrasonic cleaning to obtain ultrasonically cleaned carbon black.

[0009] Step 3: Add the ultrasonically cleaned carbon black to the second acidic solution for soaking to obtain the product of Step 3;

[0010] Step 4: The product from Step 3 is obtained by dry ball milling;

[0011] Step 5: Add the product from Step 4 to the third acidic solution for soaking to obtain the product from Step 5;

[0012] Step 6: The product from Step 5 is obtained by wet ball milling.

[0013] Step 7: The product from step 6 is post-processed to obtain ash-reduced nutshell plant carbon black.

[0014] The first acidic solution contains acetic acid; the second acidic solution contains phosphoric acid; and the third acidic solution contains phytic acid.

[0015] In one aspect of this disclosure, step 1 includes:

[0016] Step 1-1: Provide raw material palm shells, and process the palm shells using a shear crusher and an air classifier to obtain palm shell fragments;

[0017] Steps 1-2: Carbonize the palm shell fragments using a continuous carbonization furnace to obtain the fruit shell plant carbon black.

[0018] In one aspect of this disclosure, the carbonization atmosphere is primarily nitrogen with an oxygen content of less than 1%.

[0019] In one aspect of the embodiments of this disclosure, the carbonization process involves heating from room temperature to 600°C within 45 minutes and holding at that temperature for 3 hours; then heating to 800°C within 30 minutes and holding at that temperature for 1.5 hours; and then cooling to room temperature in the furnace to obtain nutshell plant carbon black.

[0020] In one aspect of this disclosure, step 2 includes:

[0021] Step 2-1: Prepare the first acidic solution; the first acidic solution contains 15-30 g / L acetic acid, 10-20 g / L H2O2 and 5-10 g / L KCl;

[0022] Step 2-2: Add the fruit shell plant carbon black to the first acidic solution prepared in step 2-1 and perform ultrasonic cleaning. The ultrasonic cleaning temperature is selected from 40℃-50℃; the ultrasonic cleaning time is selected from 1-2.5h.

[0023] Steps 2-3: After ultrasonic cleaning, the carbon black is obtained by draining and drying.

[0024] In one aspect of this disclosure, step 3 includes:

[0025] Step 3-1: Prepare a second acidic solution, which contains 120-250 g / L of phosphoric acid and 2-8 g / L of surfactant;

[0026] Step 3-2: Add the ultrasonically cleaned carbon black to the second acidic solution prepared in step 3-1, and soak it at room temperature for 3-8 hours. After soaking, wash and dry to obtain the product of step 3.

[0027] In one aspect of this disclosure, the surfactant is selected from alkyl polysaccharide glycosides or polyvinylpyrrolidone.

[0028] In one aspect of this disclosure, step 4 includes:

[0029] Step 4-1: After the product of step 3 is dried with hot air, it is added to a vertical ball mill or a horizontal ball mill for ball milling to obtain the product of step 4; wherein, the ball milling time is selected from 60-120 min, the ball milling media is zirconia beads, the particle size of the zirconia beads is selected from 5-20 mm, and the ball-to-material ratio is selected from (3-6):1.

[0030] In one aspect of this disclosure, step 4-1 involves ball milling using a horizontal ball mill.

[0031] In one aspect of the embodiments of this disclosure, zirconia beads of about 5.5-6.0 mm and zirconia beads of about 15.0-16.0 mm are used as the ball milling media, with a ball-to-material ratio of 5:1 and a mass ratio of about 5.5-6.0 mm zirconia beads to about 15.0-16.0 mm zirconia beads of 1:4.

[0032] In one aspect of this disclosure, step 5 includes:

[0033] Step 5-1: Prepare a third acidic solution; the third acidic solution contains 25-45 g / L of phytic acid, 2-8 g / L of aminotrimethylenephosphonic acid and 5-10 g / L of tetrasodium diacetate of glutamate;

[0034] Step 5-2: Add the product from step 4 to the third acidic solution prepared in step 5-1, heat the solution to 45℃-55℃ and stir for 30-60 min; then cool to room temperature and let stand for 4-12 h.

[0035] Step 5-3: After standing, the product from step 5 is obtained by washing and drying.

[0036] In one aspect of this disclosure, step 6 includes:

[0037] Step 6-1: Add the product from step 5 to a mixed solution of ethanol and water, then add a dispersant to obtain a mixture.

[0038] Step 6-2: Add the mixture obtained in step 6-1 to a drum ball mill, planetary ball mill or vibratory ball mill for wet ball milling to obtain the product of step 6; wherein, the ball milling time is selected from 2-5h, the ball milling media is zirconia beads, the particle size of the zirconia beads is selected from 2-5mm, and the ball-to-material ratio is selected from (8-10):1.

[0039] In one aspect of this disclosure, step 7 includes:

[0040] Step 7-1: After washing and drying the product from step 6, it is then depolymerized and demagnetized to obtain nutshell plant carbon black with reduced ash content.

[0041] In one aspect of the embodiments of this disclosure, in step 7-1, deagglomeration is performed using a flat air jet mill or a fluidized bed air jet mill; and demagnetization is performed using a grid-type iron separator.

[0042] Compared with the prior art, the beneficial effects of this disclosure are:

[0043] The method provided in this disclosure significantly reduces the ash and other impurities in podaceous plant black prepared from palm shells. Detailed Implementation

[0044] Exemplary embodiments will now be described in detail. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0045] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with embodiments. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. The embodiments described herein are illustrative in nature and are used to provide a basic understanding of this application. The embodiments of this application should not be construed as limiting this application.

[0046] For the sake of brevity, this article only discloses a few specific numerical ranges. However, any lower limit can be combined with any upper limit to form an unspecified range; and any lower limit can be combined with other lower limits to form an unspecified range, just as any upper limit can be combined with any other upper limit to form an unspecified range. Furthermore, each individually disclosed point or single value can itself serve as a lower or upper limit and be combined with any other point or single value or with other lower or upper limits to form an unspecified range.

[0047] The present invention will be further described below by way of specific embodiments. Unless otherwise specified, all chemical reagents used in the embodiments of the present invention were obtained through conventional commercial means. Unless otherwise specified, all contents mentioned below are mass contents. Unless otherwise specified, it is understood that the process was carried out at room temperature.

[0048] Examples and Comparative Examples

[0049] Preparation Example

[0050] 5000 parts by weight of raw palm shells were weighed, and the palm shells were crushed and air-separated using a shear crusher and an air classifier to obtain palm shell fragments. The palm shell fragments were carbonized using a continuous carbonization furnace. The carbonization atmosphere was mainly nitrogen with an oxygen content of less than 1%. The carbonization process was to raise the temperature from room temperature to 600°C within 45 minutes and hold it for 3 hours. Then, the temperature was raised to 800°C within 30 minutes and held for 1.5 hours. The carbon was then cooled to room temperature with the furnace to obtain fruit shell plant carbon black. The following examples and comparative examples all used the fruit shell plant carbon black obtained in the preparation example.

[0051] Example 1

[0052] Example 1 includes the following steps:

[0053] Prepare a first acidic solution; the first acidic solution contains 25 g / L acetic acid, 12 g / L H2O2 and 10 g / L KCl; weigh 150 parts by weight of fruit shell plant carbon black and add it to 350 parts by weight of the first acidic solution, and perform ultrasonic cleaning at a temperature of 42℃ for 1.5 hours; after ultrasonic cleaning, drain and dry.

[0054] Prepare a second acidic solution containing 220 g / L of phosphoric acid and 5 g / L of the surfactant polyvinylpyrrolidone. Add the ultrasonically cleaned carbon black to 400 parts by weight of the second acidic solution and soak it at room temperature for 4 hours. After soaking, wash and dry it.

[0055] After drying, the product is further dried with hot air and then fed into a horizontal ball mill for ball milling to obtain an intermediate product. The ball milling time is 90 minutes, and the ball milling media is zirconia beads. Zirconia beads of approximately 5.5-6.0 mm and approximately 15.0-16.0 mm in size are used as the ball milling media, with a ball-to-material ratio of 5:1 and a mass ratio of approximately 5.5-6.0 mm zirconia beads to approximately 15.0-16.0 mm zirconia beads of 1:4.

[0056] A third acidic solution was prepared, containing 35 g / L phytic acid, 6 g / L aminotrimethylenephosphonic acid, and 8 g / L tetrasodium glutamate diacetate. The intermediate product was added to the third acidic solution, and the solution was heated to 50°C and stirred for 45 min. It was then cooled to room temperature and allowed to stand for 8 h. After standing, the intermediate product was washed and dried to obtain the final intermediate product. The intermediate product was added to a mixed solution of ethanol and water (ethanol to water volume ratio 2:1), and then magnesium stearate was added as a dispersant to obtain a mixture. The mixture was then subjected to wet ball milling in a planetary ball mill to obtain a crude product. The milling time was 4 h, the milling media were zirconia beads with a particle size of approximately 2.6-2.8 mm, and the ball-to-material ratio was 8:1. The crude product was washed, dried, and then depolymerized and demagnetized to obtain the ash-reduced nutshell plant carbon black of this embodiment.

[0057] Example 2

[0058] Example 2 includes the following steps:

[0059] Prepare a first acidic solution; the first acidic solution contains 25 g / L acetic acid, 12 g / L H2O2 and 10 g / L KCl; weigh 150 parts by weight of fruit shell plant carbon black and add it to 350 parts by weight of the first acidic solution, and perform ultrasonic cleaning at a temperature of 42℃ for 1.5 hours; after ultrasonic cleaning, drain and dry.

[0060] Prepare a second acidic solution containing 220 g / L of phosphoric acid and 5 g / L of the surfactant polyvinylpyrrolidone. Add the ultrasonically cleaned carbon black to 400 parts by weight of the second acidic solution and soak it at room temperature for 4 hours. After soaking, wash and dry it.

[0061] After drying, the product is further dried with hot air and then fed into a horizontal ball mill for ball milling to obtain an intermediate product. The ball milling time is 90 minutes, and the ball milling media is zirconia beads. Zirconia beads of approximately 5.5-6.0 mm and approximately 15.0-16.0 mm in size are used as the ball milling media, with a ball-to-material ratio of 5:1 and a mass ratio of approximately 5.5-6.0 mm zirconia beads to approximately 15.0-16.0 mm zirconia beads of 1:4.

[0062] A third acidic solution was prepared, containing 35 g / L phytic acid and 8 g / L tetrasodium glutamate diacetate. The intermediate product was added to the third acidic solution, and the solution was heated to 50°C and stirred for 45 min. It was then cooled to room temperature and allowed to stand for 8 h. After standing, the intermediate product was washed and dried to obtain the final intermediate product. The intermediate product was added to a mixed solution of ethanol and water (ethanol to water volume ratio 2:1), and then magnesium stearate was added as a dispersant to obtain a mixture. The mixture was then fed into a planetary ball mill for wet ball milling to obtain a crude product. The ball milling time was 4 h, the milling media were zirconia beads with a particle size of approximately 2.6-2.8 mm, and the ball-to-material ratio was 8:1. The crude product was washed, dried, and then subjected to depolymerization using a flat air jet mill and demagnetization using a grid-type iron separator to obtain the ash-reduced nutshell plant carbon black of this embodiment.

[0063] The main difference between Example 2 and Example 1 is that Example 2 does not contain aminotrimethylenephosphonic acid.

[0064] Example 3

[0065] Example 3 includes the following steps:

[0066] Prepare a first acidic solution; the first acidic solution contains 25 g / L acetic acid, 12 g / L H2O2 and 10 g / L KCl; weigh 150 parts by weight of fruit shell plant carbon black and add it to 350 parts by weight of the first acidic solution, and perform ultrasonic cleaning at a temperature of 42℃ for 1.5 hours; after ultrasonic cleaning, drain and dry.

[0067] Prepare a second acidic solution containing 220 g / L of phosphoric acid and 5 g / L of the surfactant polyvinylpyrrolidone. Add the ultrasonically cleaned carbon black to 400 parts by weight of the second acidic solution and soak it at room temperature for 4 hours. After soaking, wash and dry it.

[0068] After drying, the product is further dried with hot air and then fed into a horizontal ball mill for ball milling to obtain an intermediate product. The ball milling time is 90 minutes, and the ball milling media is zirconia beads. Zirconia beads of approximately 5.5-6.0 mm and approximately 15.0-16.0 mm in size are used as the ball milling media, with a ball-to-material ratio of 5:1 and a mass ratio of approximately 5.5-6.0 mm zirconia beads to approximately 15.0-16.0 mm zirconia beads of 1:4.

[0069] A third acidic solution was prepared, containing 35 g / L phytic acid and 6 g / L aminotrimethylenephosphonic acid. The intermediate product was added to the third acidic solution, and the solution was heated to 50°C and stirred for 45 min. It was then cooled to room temperature and allowed to stand for 8 h. After standing, the intermediate product was washed and dried to obtain the final intermediate product. The intermediate product was added to a mixed solution of ethanol and water (ethanol to water volume ratio 2:1), and then magnesium stearate was added as a dispersant to obtain a mixture. The mixture was then fed into a planetary ball mill for wet ball milling to obtain a crude product. The ball milling time was 4 h, the milling media were zirconia beads with a particle size of approximately 2.6-2.8 mm, and the ball-to-material ratio was 8:1. The crude product was washed, dried, and then subjected to depolymerization using a flat air jet mill and demagnetization using a grid-type iron separator to obtain the ash-reduced nutshell plant carbon black of this embodiment.

[0070] The main difference between Example 3 and Example 1 is that Example 3 does not contain tetrasodium diglutamate.

[0071] Comparative Example 1

[0072] Comparative Example 1 includes the following steps:

[0073] Prepare a first acidic solution; the first acidic solution contains 25 g / L acetic acid, 12 g / L H2O2 and 10 g / L KCl; weigh 150 parts by weight of fruit shell plant carbon black and add it to 350 parts by weight of the first acidic solution, and perform ultrasonic cleaning at a temperature of 42℃ for 1.5 hours; after ultrasonic cleaning, drain and dry.

[0074] Prepare a second acidic solution containing 220 g / L of phosphoric acid and 5 g / L of the surfactant polyvinylpyrrolidone. Add the ultrasonically cleaned carbon black to 400 parts by weight of the second acidic solution and soak it at room temperature for 4 hours. After soaking, wash and dry it.

[0075] After drying, the product is further dried with hot air and then fed into a horizontal ball mill for ball milling to obtain an intermediate product. The ball milling time is 90 minutes, and the ball milling media is zirconia beads. Zirconia beads of approximately 5.5-6.0 mm and approximately 15.0-16.0 mm in size are used as the ball milling media, with a ball-to-material ratio of 5:1 and a mass ratio of approximately 5.5-6.0 mm zirconia beads to approximately 15.0-16.0 mm zirconia beads of 1:4.

[0076] The intermediate product was added to a mixed solution of ethanol and water (volume ratio of ethanol to water: 2:1), and then magnesium stearate was added as a dispersant to obtain a mixture. The mixture was then fed into a planetary ball mill for wet ball milling to obtain a crude product. The ball milling time was 4 hours, the ball milling media were zirconia beads with a particle size of approximately 2.6-2.8 mm, and the ball-to-material ratio was 8:1. After washing and drying, the crude product was further subjected to depolymerization and demagnetization to obtain the ash-reduced nutshell plant carbon black of this comparative example.

[0077] The main difference between Comparative Example 1 and Example 1 is that Comparative Example 1 does not include the process of soaking with a third acidic solution, but instead directly performs wet ball milling on the product after dry ball milling.

[0078] Comparative Example 2

[0079] Comparative Example 2 includes the following steps:

[0080] Prepare a first acidic solution; the first acidic solution contains 25 g / L acetic acid, 12 g / L H2O2 and 10 g / L KCl; weigh 150 parts by weight of fruit shell plant carbon black and add it to 350 parts by weight of the first acidic solution, and perform ultrasonic cleaning at a temperature of 42℃ for 1.5 hours; after ultrasonic cleaning, drain and dry.

[0081] Prepare a second acidic solution containing 220 g / L of phosphoric acid and 5 g / L of the surfactant polyvinylpyrrolidone. Add the ultrasonically cleaned carbon black to 400 parts by weight of the second acidic solution and soak it at room temperature for 4 hours. After soaking, wash and dry it.

[0082] A third acidic solution was prepared, containing 35 g / L phytic acid, 6 g / L aminotrimethylenephosphonic acid, and 8 g / L tetrasodium glutamate diacetate. The dried product was added to the third acidic solution, and the solution was heated to 50°C and stirred for 45 min. It was then cooled to room temperature and allowed to stand for 8 h. After standing, the product was washed and dried to obtain an intermediate product. The intermediate product was added to a mixed solution of ethanol and water (ethanol to water volume ratio 2:1), and then magnesium stearate was added as a dispersant to obtain a mixture. The mixture was then wet-milled in a planetary ball mill to obtain a crude product. The milling time was 4 h, the milling media were zirconia beads with a particle size of approximately 2.6-2.8 mm, and the ball-to-material ratio was 8:1. The crude product was washed, dried, and then depolymerized and demagnetized to obtain the ash-reduced nutshell plant carbon black of this comparative example.

[0083] The main difference between Comparative Example 2 and Example 1 is that Comparative Example 2 does not include the process of dry ball milling before soaking in the third acidic solution.

[0084] Comparative Example 3

[0085] Comparative Example 3 includes the following steps:

[0086] Prepare a first acidic solution; the first acidic solution contains 25 g / L acetic acid, 12 g / L H2O2 and 10 g / L KCl; weigh 150 parts by weight of fruit shell plant carbon black and add it to 350 parts by weight of the first acidic solution, and perform ultrasonic cleaning at a temperature of 42℃ for 1.5 hours; after ultrasonic cleaning, drain and dry.

[0087] After drying, the product is further dried with hot air and then fed into a horizontal ball mill for ball milling to obtain an intermediate product. The ball milling time is 90 minutes, and the ball milling media is zirconia beads. Zirconia beads of approximately 5.5-6.0 mm and approximately 15.0-16.0 mm in size are used as the ball milling media, with a ball-to-material ratio of 5:1 and a mass ratio of approximately 5.5-6.0 mm zirconia beads to approximately 15.0-16.0 mm zirconia beads of 1:4.

[0088] A third acidic solution was prepared, containing 35 g / L phytic acid, 6 g / L aminotrimethylenephosphonic acid, and 8 g / L tetrasodium glutamate diacetate. The intermediate product was added to the third acidic solution, and the solution was heated to 50°C and stirred for 45 min. It was then cooled to room temperature and allowed to stand for 8 h. After standing, the intermediate product was washed and dried to obtain the final intermediate product. The intermediate product was added to a mixed solution of ethanol and water (ethanol to water volume ratio 2:1), and then magnesium stearate was added as a dispersant to obtain a mixture. The mixture was then wet-milled in a planetary ball mill to obtain a crude product. The milling time was 4 h, the milling media were zirconia beads with a particle size of approximately 2.6-2.8 mm, and the ball-to-material ratio was 8:1. The crude product was washed, dried, and then depolymerized and demagnetized to obtain the ash-reduced nutshell plant carbon black of this comparative example.

[0089] The main difference between Comparative Example 3 and Example 1 is that Comparative Example 3 does not include the process of soaking in a second acidic solution.

[0090] Comparative Example 4

[0091] Comparative Example 4 includes the following steps:

[0092] Prepare a first acidic solution; the first acidic solution contains 25 g / L acetic acid, 12 g / L H2O2 and 10 g / L KCl; weigh 150 parts by weight of fruit shell plant carbon black and add it to 350 parts by weight of the first acidic solution, and perform ultrasonic cleaning at a temperature of 42℃ for 1.5 hours; after ultrasonic cleaning, drain and dry.

[0093] Prepare a second acidic solution containing 220 g / L of phosphoric acid and 5 g / L of the surfactant polyvinylpyrrolidone. Add the ultrasonically cleaned carbon black to 400 parts by weight of the second acidic solution and soak it at room temperature for 4 hours. After soaking, wash and dry it.

[0094] After drying, the product is further dried with hot air and then fed into a horizontal ball mill for ball milling to obtain an intermediate product. The ball milling time is 90 minutes, and the ball milling media is zirconia beads. Zirconia beads of approximately 5.5-6.0 mm and approximately 15.0-16.0 mm in size are used as the ball milling media, with a ball-to-material ratio of 5:1 and a mass ratio of approximately 5.5-6.0 mm zirconia beads to approximately 15.0-16.0 mm zirconia beads of 1:4.

[0095] A third acidic solution was prepared, containing 35 g / L phosphoric acid, 6 g / L aminotrimethylenephosphonic acid, and 8 g / L tetrasodium glutamate diacetate. The intermediate product was added to the third acidic solution, and the solution was heated to 50°C and stirred for 45 min. It was then cooled to room temperature and allowed to stand for 8 h. After standing, the intermediate product was washed and dried to obtain the final intermediate product. The intermediate product was added to a mixed solution of ethanol and water (ethanol to water volume ratio 2:1), and then magnesium stearate was added as a dispersant to obtain a mixture. The mixture was then wet-milled in a planetary ball mill to obtain a crude product. The milling time was 4 h, the milling media were zirconia beads with a particle size of approximately 2.6-2.8 mm, and the ball-to-material ratio was 8:1. The crude product was washed, dried, and then depolymerized and demagnetized to obtain the ash-reduced nutshell plant carbon black of this comparative example.

[0096] The difference between Comparative Example 4 and Example 1 is that phytic acid in the third acidic solution of Comparative Example 4 was replaced with phosphoric acid.

[0097] Ash content testing and metal ion testing:

[0098] The determination of ash content in the prepared examples, embodiments, and comparative examples of nutshell plant carbon black was mainly carried out according to the method specified in the national standard GB / T3780.10-2009, "Determination of Ash Content in Carbon Black". First, the crucible was heated to constant weight and then placed in a muffle furnace (825±25℃) for 1 hour. The crucible was then removed and cooled to room temperature in a desiccator before weighing. A difference of no more than 0.3 mg between two weighings was considered sufficient to indicate that the crucible had reached constant weight. Next, 2 mg of biomass sample carbon was weighed and dried in a 125℃ forced-air drying oven for 1 hour. The sample was then removed and cooled to room temperature in a desiccator. The crucible containing the biomass carbon black was then placed in a muffle furnace (825±25℃) and heated to constant weight. It was then covered and cooled in a desiccator, and the ash content was calculated by weighing.

[0099] The metal ion residue test in the prepared examples, embodiments, and comparative examples of nutshell plant carbon black was performed to determine the content of Cu, Fe, Ca, and Al impurity elements. The instrument used was a fully automated elemental analyzer (FlashEA1112) manufactured by Thermo Scientific, USA. The nutshell plant carbon black was pre-dried in a forced-air drying oven at 85°C for 12 hours. 5 mg of the dried sample was weighed and elemental analysis was performed using the Flash EA1112 fully automated elemental analyzer.

[0100] The test results are shown in Table 1 below.

[0101] Table 1

[0102] Example Ash content (%) Cu(%) Fe(%) Ca (%) Al(%) Preparation Example 7.05 0.0027 0.0428 0.280 0.323 Example 1 0.23 Not detected 0.0012 0.0043 0.0184 Example 2 0.27 Not detected 0.0015 0.0932 0.139 Example 3 0.25 0.0007 0.0173 0.0051 0.0192 Comparative Example 1 2.75 0.0022 0.0372 0.1772 0.218 Comparative Example 2 3.62 0.0016 0.0249 0.1530 0.187 Comparative Example 3 5.17 0.0005 0.0201 0.0945 0.134 Comparative Example 4 0.59 0.0003 0.0080 0.0183 0.0329

[0103] Palm shells are rich in fibrous structure, and after carbonization, they retain the original plant fiber skeleton (mainly carbon skeleton fibers from the pyrolysis of cellulose and lignin). Phosphoric acid washing first dissolves CaCO3, CaSiO3, and Fe2O3, while removing SiO2 from the carbon skeleton fibers. Then, ball milling exposes the internal interface. Finally, phytic acid, aminotrimethylenephosphonic acid, and tetrasodium glutamate diacetate react with the new interface and its micropores. Aminotrimethylenephosphonic acid chelates with metal ions such as Ca and Al, while tetrasodium glutamate diacetate chelates with metal ions such as Cu and Fe. Phytic acid further reduces the content of the already finely broken SiO2, achieving a significant reduction in impurities.

[0104] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This disclosure is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein.

Claims

1. A method for reducing the ash content of a fruit shell plant carbon black, said fruit shell plant carbon black using palm shell as a raw material; characterized by, The method includes the following steps: Step 1: Provide raw material palm shells, and carbonize the palm shells to obtain fruit shell plant carbon black; Step 2: Add the fruit shell plant carbon black to the first acidic solution and perform ultrasonic cleaning to obtain ultrasonically cleaned carbon black. Step 3: Add the ultrasonically cleaned carbon black to the second acidic solution for soaking to obtain the product of Step 3; Step 4: The product from Step 3 is obtained by dry ball milling; Step 5: Add the product from Step 4 to the third acidic solution for soaking to obtain the product from Step 5; Step 6: The product from Step 5 is obtained by wet ball milling. Step 7: The product from step 6 is post-processed to obtain ash-reduced nutshell plant carbon black. The first acidic solution contains acetic acid; the second acidic solution contains phosphoric acid; and the third acidic solution contains phytic acid. Step 2 includes: Step 2-1: Prepare the first acidic solution; the first acidic solution contains 15-30 g / L acetic acid, 10-20 g / L H2O2 and 5-10 g / L KCl; Step 2-2: Add the fruit shell plant carbon black to the first acidic solution prepared in step 2-1 and perform ultrasonic cleaning. The ultrasonic cleaning temperature is selected from 40℃-50℃; the ultrasonic cleaning time is selected from 1-2.5h. Steps 2-3: After ultrasonic cleaning, the carbon black is obtained by draining and drying. Step 3 includes: Step 3-1: Prepare a second acidic solution, which contains 120-250 g / L of phosphoric acid and 2-8 g / L of surfactant; Step 3-2: Add the ultrasonically cleaned carbon black to the second acidic solution prepared in step 3-1, soak at room temperature for 3-8 hours, and after soaking, wash and dry to obtain the product of step 3; Step 5 includes: Step 5-1: Prepare a third acidic solution; the third acidic solution contains 25-45 g / L of phytic acid, 2-8 g / L of aminotrimethylenephosphonic acid and 5-10 g / L of tetrasodium diacetate of glutamate; Step 5-2: Add the product from step 4 to the third acidic solution prepared in step 5-1, heat the solution to 45℃-55℃ and stir for 30-60 min; then cool to room temperature and let stand for 4-12 h. Step 5-3: After standing, the product from step 5 is obtained by washing and drying.

2. The method for reducing the ash content of plant carbon black in fruit shells according to claim 1, characterized in that, Step 1 includes: Step 1-1: Provide raw material palm shells, and process the palm shells using a shear crusher and an air classifier to obtain palm shell fragments; Steps 1-2: Carbonize the palm shell fragments using a continuous carbonization furnace to obtain the fruit shell plant carbon black.

3. The method for reducing the ash content of plant carbon black in fruit shells according to claim 1, characterized in that, Step 4 includes: Step 4-1: After the product of step 3 is dried with hot air, it is added to a vertical ball mill or a horizontal ball mill for ball milling to obtain the product of step 4; wherein, the ball milling time is selected from 60-120 min, the ball milling media is zirconia beads, the particle size of the zirconia beads is selected from 5-20 mm, and the ball-to-material ratio is selected from (3-6):

1.

4. The method for reducing the ash content of plant carbon black in fruit shells according to claim 1, characterized in that, Step 6 includes: Step 6-1: Add the product from step 5 to a mixed solution of ethanol and water, then add a dispersant to obtain a mixture. Step 6-2: Add the mixture obtained in step 6-1 to a drum ball mill, planetary ball mill or vibratory ball mill for wet ball milling to obtain the product of step 6; wherein, the ball milling time is selected from 2-5h, the ball milling media is zirconia beads, the particle size of the zirconia beads is selected from 2-5mm, and the ball-to-material ratio is selected from (8-10):

1.

5. The method for reducing the ash content of plant carbon black in fruit shells according to claim 1, characterized in that, Step 7 includes: Step 7-1: After washing and drying the product from step 6, it is then depolymerized and demagnetized to obtain nutshell plant carbon black with reduced ash content.

6. The method for reducing the ash content of plant carbon black in fruit shells according to claim 5, characterized in that, In step 7-1, deagglomeration is performed using a flat air jet mill or a fluidized bed air jet mill; demagnetization is performed using a grid-type iron separator.