Method for rapidly detecting pseudo-boehmite peptization index

Abstract

This invention discloses a method for rapidly detecting the gel solubility index of pseudoboehmite, comprising: weighing a weight of m 1 The pseudoboehmite was calcined in a high-temperature furnace, then transferred to a desiccator to cool to room temperature, and weighed. m 2 The mass fraction of Al2O3 is calculated according to... W The value of Al2O3 content was determined by weighing it on a balance. m 3 The pseudoboehmite was placed in a beaker, deionized water was added, and the mixture was mechanically stirred. Nitric acid solution was added dropwise, and stirring continued until a gel was formed. The gel was then transferred to a centrifuge tube and centrifuged. After centrifugation, the supernatant was discarded, the inner wall of the centrifuge tube was rinsed with water, and the washing liquid was discarded. The insoluble matter at the bottom of the centrifuge tube was removed and rinsed with water. The insoluble matter and washing water were poured into a weighing bottle, dried, and then transferred to a desiccator to cool to room temperature before weighing and recording the weight. m 4 The gel solubility index of boehmite is calculated. This invention has the advantages of short testing cycle, simple operation, high accuracy, economic practicality, and strong adaptability.

Description

Technical Field

[0001] This invention belongs to the technical field of the petroleum catalyst industry. Specifically, this invention relates to a method for rapidly detecting the gel solubility index of pseudoboehmite. Background Technology

[0002] Boehmite, also known as monohydrate alumina or pseudo-boehmite, has the molecular formula AlOOH·nH2O, where n = 0.08–0.62. It is non-toxic, tasteless, odorless, and a white colloidal (wet) or powder (dry) product. Boehmite belongs to the series of chemical alumina products. It possesses a spatial network structure, large porosity, a large specific surface area, and thixotropic properties, transforming into a viscous colloidal state under acidic conditions. It exhibits high crystalline purity, good colloidal properties, strong adhesion, and thixotropic gel characteristics, directly influenced by the boehmite's colloidal index.

[0003] In the enterprise standard Q / CHALCOA020-2012 of Aluminum Corporation of China Limited, the Al2O3 content in the sample during ignition is first determined, and then the amount of water and acid added is calculated. 20g of the sample (accurate to 0.1g) is weighed into a constant-weight porcelain crucible (50ml), transferred to a low-temperature high-temperature furnace, gradually heated to 550℃, held at that temperature for 2 hours, removed, cooled to room temperature, and weighed. The mass of Al2O3 in the sample is calculated, and the amount of nitric acid added is calculated (0.15-0.20g of nitric acid is added per gram of Al2O3). 20g of the sample (accurate to 0.1g) is weighed into a 500mL beaker, diluted with water to form a slurry containing 10% Al2O3, and nitric acid is added under stirring for gelation. Stirring continues for 10 minutes. A portion of the pectin slurry was placed in a 10mL test tube, weighed, and centrifuged. The supernatant was carefully extracted, evaporated, dried, and then ignited at 550℃ for 2 hours. After cooling to room temperature, it was weighed. Another portion of the pectin slurry of the same weight was placed in a constant-weight porcelain crucible, evaporated, dried, and then ignited at 550℃ for 2 hours. After cooling to room temperature, it was weighed. The pectin index was calculated by comparing the final weight of the centrifuged pectin with the final weight of the uncentrifuged pectin. While this method is simpler than the industry standard, the post-processing steps are cumbersome, and the testing time is relatively long.

[0004] According to the enterprise standard Q / SY KG07542-2025 of China National Petroleum Corporation, after the sample is ignited in a muffle furnace at 550℃ for 2 hours, X grams of wet sample are weighed and (50-X) grams of distilled water are accurately added using a burette to prepare a 10m% alumina slurry. Add 7.0 mL of 10 v / v% nitric acid dropwise using a burette while stirring. Dissolve the slurry under electromagnetic stirring for approximately 15 minutes. Shake well and pour into a dry centrifuge tube. Centrifuge for 10 minutes. Immediately pipette 1 mL of the upper gel layer into a 100 mL beaker, add a small amount of water and 4 mL of 1:1 sulfuric acid, and heat until the gel is completely dissolved and the solution is clear. After cooling, transfer the entire solution to a 100 mL volumetric flask, dilute to the mark with distilled water, and shake well. Pipette 10 mL of the treated analytical solution into an Erlenmeyer flask, add 30 mL of EDTA standard solution using a burette, add approximately 0.1 g of xylenol orange indicator, and adjust with 1:1 ammonia until the purple color just appears. Heat to boiling for 1 minute, remove from heat, cool to room temperature, and adjust to lemon yellow with 1:1 hydrochloric acid. Add 1.5 g of solid hexamethylenetetramine and titrate with zinc chloride standard solution until a wine-red endpoint is reached. Record the volume of zinc chloride solution consumed and calculate the gel solubility index. This method uses EDTA complexometric titration for detection, which is complicated, involves a wide variety of reagents, requires high operational skills, takes a long time, and demands high professional skills from the testing personnel. Furthermore, the total volume of products from different manufacturers after adding acid to form a gel varies, resulting in an error of approximately 0-5% in the aluminum content when 1 mL of gel is transferred for testing, which affects the test results.

[0005] Therefore, it is necessary to provide a more convenient and reliable detection method, which will help promote the development and application of pseudoboehmite-related technologies. Summary of the Invention

[0006] One object of the present invention is to solve at least the above-mentioned problems and / or defects, and to provide at least the advantages described below.

[0007] To achieve these objectives and other advantages of the present invention, a method for rapidly detecting the gel solubility index of pseudoboehmite is provided, comprising the following steps: Step 1: Weigh out the following weight: m 1 The pseudoboehmite was placed in a high-temperature furnace for calcination. After calcination, it was transferred to a desiccator to cool to room temperature. The calcined pseudoboehmite was weighed and recorded as follows: m 2 mass fraction of Al2O3 W Calculate according to formula (1): (1) Step Two, according to W The value of Al2O3 content was determined by weighing it on a balance. m 3The pseudoboehmite was placed in a beaker, deionized water was added and mechanically stirred, and nitric acid aqueous solution was added drop by drop. After the addition was completed, stirring was continued to form a gel. The gelled liquid was transferred to a centrifuge tube and centrifuged. Step 3: After centrifugation, slowly pour off the supernatant. Rinse the inner wall of the centrifuge tube with clean water to remove any remaining gel. Slowly pour off the wash water. Remove the insoluble matter from the bottom of the centrifuge tube. Wash the insoluble matter with clean water, and pour the insoluble matter and wash water together into a weighing bottle to dry. After drying, transfer the bottle to a desiccator to cool to room temperature before weighing. Record the remaining net weight as follows: m 4 The gel solubility index of pseudoboehmite Ig Calculate according to formula (2): (2).

[0008] Preferably, in step one, the temperature of the high-temperature furnace is 500-600℃, and the roasting time is 2-3 hours.

[0009] Preferably, in step two, the balance accuracy is 0.0001g, and the volume of deionized water is 30-60mL.

[0010] Preferably, in step two, the mechanical stirring time is 3 to 10 minutes and the mechanical stirring speed is 200 to 300 r / min.

[0011] Preferably, in step two, the volume ratio of concentrated nitric acid to water in the nitric acid aqueous solution is 1:1.95 to 2.05, the molar ratio of the added nitric acid aqueous solution to boehmite is n(H):n(Al) = 1:9 to 11, the dropwise addition rate is 1 to 2 drops per second, and the stirring time is 10 to 30 minutes.

[0012] Preferably, in step two, the centrifugation speed is 4000-6000 r / min and the centrifugation time is 5-15 min.

[0013] Preferably, in step three, the drying temperature is 100–110°C and the drying time is 2–3 hours.

[0014] Preferably, in step one, the desiccant in the dryer should be replaced regularly to ensure its drying effect and prevent the sample from absorbing moisture and affecting the weighing results.

[0015] Preferably, in step two, when preparing the nitric acid aqueous solution, concentrated nitric acid should be slowly poured into the water while continuously stirring to prevent the solution from overheating and splashing out.

[0016] Preferably, in step two, the centrifuge speed is controlled at 4000 r / min as the minimum speed, and the speed can be increased to 5000-6000 r / min for better centrifugation effect; if the speed is increased, the centrifugation time can be appropriately shortened, but it shall not be less than 5 min.

[0017] Preferably, step two can be replaced by: according to W The value of Al2O3 content was determined by weighing it on a balance. m 3 The pseudoboehmite was placed in a flask, and 30-60 mL of deionized water and a nitric acid aqueous solution with a ratio of n(H):n(Al) = 1:9-11 were added. A stir bar was added, and the flask was placed on a heated magnetic stirrer. The mixture was stirred and refluxed at 70-90°C for 10-20 min to form a gel at a stirring speed of 300-500 rpm. The gelled liquid was transferred to a centrifuge tube, and the stir bar and flask were rinsed with deionized water. The washings were also transferred to a centrifuge tube and centrifuged at 4000-6000 rpm for 5-15 min.

[0018] The present invention has at least the following beneficial effects: I. Short testing cycle: The post-processing steps of this invention are simpler than those of the China Aluminum Corporation's enterprise standard Q / CHALCO A020-2012, shortening the testing cycle by 2 to 3 hours, enabling faster testing results, improving testing efficiency, and meeting the needs of enterprises for rapid production and decision-making.

[0019] II. Simple Operation: Compared with the enterprise standard Q / SY KG07542-2025 of China National Petroleum Corporation and the industry standard YS / T 1161.1-2016, this invention does not use EDTA complexometric titration, requires fewer types of reagents, and has relatively simple operation steps, reducing the professional skills required for testing personnel. Ordinary operators can start operating after simple training.

[0020] III. High Accuracy: This invention reduces the impact of operational errors and environmental factors on the test results by precisely controlling parameters such as the preparation ratio of the nitric acid aqueous solution, stirring speed, centrifugation speed, and drying temperature, thereby improving the accuracy and reliability of the test results. Simultaneously, it avoids errors in aluminum content detection caused by differences in the total volume after acidification and gelation of products from different manufacturers.

[0021] IV. Economic and Practical: The experimental equipment and reagents required for this invention are common and relatively inexpensive, reducing testing costs. Furthermore, the energy consumption during the testing process is relatively low, meeting the requirements of enterprises for energy conservation, emission reduction, and cost reduction.

[0022] V. High adaptability: The detection method of the present invention is applicable to boehmite of various sources and qualities, and has wide applicability and versatility, which can meet the detection needs of different enterprises and different application scenarios.

[0023] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Detailed Implementation

[0024] The present invention will now be described in further detail so that those skilled in the art can implement it based on the description.

[0025] Example 1 A method for rapid detection of the gel solubility index of pseudoboehmite includes the following steps: Step 1: Weigh 5.0003g of boehmite and calcine it in a high-temperature furnace at 550℃ for 2 hours. After calcination, quickly transfer it to a desiccator to cool to room temperature. Weigh the calcined boehmite to 3.5525g. The mass fraction of Al2O3 is... ; Step Two, according to W The value was determined by weighing 7.0373g of pseudoboehmite (5.0000g / L) with an Al2O3 content of 5.0000g using a balance. W Place the sample in a 100mL beaker, and weigh two 7.0373g portions of boehmite as parallel samples. Add 45.0mL of deionized water to each sample and mechanically stir at 200r / min for 5min. Then, add nitric acid aqueous solution (concentrated nitric acid to water volume ratio of 1:2) dropwise at a ratio of n(H):n(Al)=1:10, at a drop rate of 2 drops per second. After the addition is complete, continue stirring for 15min to allow the sample to fully gel. Transfer the gelled liquid to a centrifuge tube and centrifuge at 4000r / min for 10min. Step 3: After centrifugation, slowly pour off the supernatant. Rinse the inner wall of the centrifuge tube with clean water to remove any remaining gel. Slowly pour off the wash water. Use a sampling spoon to remove the insoluble matter from the bottom of the centrifuge tube. Wash the insoluble matter with clean water. Pour the insoluble matter and wash water together into a weighing bottle and dry it in an oven at 105℃ for 3 hours. After drying, transfer it to a desiccator to cool to room temperature and weigh it. The remaining net weight is 0.1525g. The remaining net weight of parallel sample 1 is 0.1534g, and the remaining net weight of parallel sample 2 is 0.1540g. The gel solubility index of boehmite is... , , ,average value =96.93%, relative standard deviation RSD=0.016%.

[0026] Example 2 A method for rapid detection of the gel solubility index of pseudoboehmite includes the following steps: Step 1: Weigh 5.0005 g of boehmite and calcine it in a high-temperature furnace at 550℃ for 2 hours. After calcination, quickly transfer it to a desiccator to cool to room temperature. Weigh the calcined boehmite to find it weighs 3.4348 g. The mass fraction of Al2O3 is... ; Step Two, according to W The value was determined by weighing 7.2791g of pseudoboehmite (5.0000g / L) with an Al2O3 content of 5.0000g using a balance. W Place the sample in a 100mL beaker, and weigh two 7.2791g portions of boehmite as parallel samples. Add 45.0mL of deionized water to each sample and mechanically stir at 200r / min for 5min. Then, add nitric acid aqueous solution (concentrated nitric acid to water volume ratio of 1:2) dropwise at a ratio of n(H):n(Al)=1:10, at a drop rate of 2 drops per second. After the addition is complete, continue stirring for 15min to allow the sample to fully gel. Transfer the gelled liquid to a centrifuge tube and centrifuge at 4000r / min for 10min. Step 3: After centrifugation, slowly pour off the supernatant. Rinse the inner wall of the centrifuge tube with clean water to remove any remaining gel. Slowly pour off the wash water. Use a sampling spoon to remove the insoluble matter from the bottom of the centrifuge tube. Wash the insoluble matter with clean water. Pour the insoluble matter and wash water together into a weighing bottle and dry it in an oven at 105℃ for 3 hours. After drying, transfer it to a desiccator to cool to room temperature and weigh it. The remaining net weight is 0.1832g, the remaining net weight of parallel sample 1 is 0.1861g, and the remaining net weight of parallel sample 2 is 0.1856g. The gel solubility index of boehmite is... , , ,average value =96.30%, relative standard deviation RSD=0.033%.

[0027] Example 3 A method for rapid detection of the gel solubility index of pseudoboehmite includes the following steps: Step 1: Weigh 4.9997g of boehmite and calcine it in a high-temperature furnace at 550℃ for 2 hours. After calcination, quickly transfer it to a desiccator to cool to room temperature. Weigh the calcined boehmite to find it weighs 3.6082g. The mass fraction of Al2O3 is... ; Step Two, according to W The value was determined by weighing 6.9281g (5.0000g / ) of pseudoboehmite with an Al2O3 content of 5.0000g using a balance.W Place the sample in a 100mL beaker, and weigh two 6.9281g portions of boehmite as parallel samples. Add 45.0mL of deionized water to each sample and mechanically stir at 200r / min for 5min. Then, add nitric acid aqueous solution (concentrated nitric acid to water volume ratio of 1:2) dropwise at a ratio of n(H):n(Al)=1:10, at a drop rate of 2 drops per second. After the addition is complete, continue stirring for 15min to allow the sample to fully gel. Transfer the gelled liquid to a centrifuge tube and centrifuge at 4000r / min for 10min. Step 3: After centrifugation, slowly pour off the supernatant. Rinse the inner wall of the centrifuge tube with clean water to remove any remaining gel. Slowly pour off the wash water. Use a sampling spoon to remove the insoluble matter from the bottom of the centrifuge tube. Wash the insoluble matter with clean water. Pour the insoluble matter and wash water together into a weighing bottle and dry it in an oven at 105℃ for 3 hours. After drying, transfer it to a desiccator to cool to room temperature and weigh it. The remaining net weight is 0.1716g. The remaining net weight of parallel sample 1 is 0.1742g, and the remaining net weight of parallel sample 2 is 0.1727g. The gel solubility index of boehmite is... , , ,average value =96.55%, relative standard deviation RSD=0.026%.

[0028] Example 4 A method for rapid detection of the gel solubility index of pseudoboehmite includes the following steps: Step 1: Weigh 5.0003g of boehmite and calcine it in a high-temperature furnace at 550℃ for 2 hours. After calcination, quickly transfer it to a desiccator to cool to room temperature. Weigh the calcined boehmite to 3.5525g. The mass fraction of Al2O3 is... ; Step Two, according to W The value was determined by weighing 7.0373g of pseudoboehmite (5.0000g / L) with an Al2O3 content of 5.0000g using a balance. W Place the sample in a 250 mL flask, and weigh two 7.0373 g samples of boehmite as parallel samples. Add 45.0 mL of deionized water and a nitric acid aqueous solution with a ratio of n(H):n(Al) = 1:10 (the volume ratio of concentrated nitric acid to water is 1:2) to each sample. Place the flask on a heated magnetic stirrer and stir and reflux at 80 °C for 10 min to form a gel. The stirring speed is 300 rpm. Transfer the gelled liquid to a centrifuge tube. Wash the stirrer and flask with deionized water and transfer the washings to the centrifuge tube. Centrifuge at 4000 r / min for 10 min. Step 3: After centrifugation, slowly pour off the supernatant. Rinse the inner wall of the centrifuge tube with clean water to remove any remaining gel. Slowly pour off the wash water. Use a sampling spoon to remove the insoluble matter from the bottom of the centrifuge tube. Wash the insoluble matter with clean water. Pour the insoluble matter and wash water together into a weighing bottle and dry it in an oven at 105℃ for 3 hours. After drying, transfer it to a desiccator to cool to room temperature and weigh it. The remaining net weight is 0.1528g. The remaining net weight of parallel sample 1 is 0.1518g, and the remaining net weight of parallel sample 2 is 0.1506g. The gel solubility index of boehmite is... , , average =96.96%, relative standard deviation RSD=0.026%.

[0029] The boehmite samples from Examples 1 to 4 were tested using the industry standard YS / T 1161.1-2016 "Analytical Methods for Boehmite Part 1: Determination of Peptizability Index by EDTA Volumetric Method". Two parallel samples were prepared for each sample, and the average value of the results was taken. The comparison between the test results and the test results of the method of this invention is shown in Table 1.

[0030] Table 1 As shown in Table 1, the difference between the detection results obtained by the methods used in Examples 1 to 4 of this invention and the industry standard EDTA volumetric method is less than 0.05%, indicating high accuracy. In Example 4, reflux heating at 70–90°C is used to fully gel the Al2O3 in boehmite. Compared with Examples 1 to 3, this shortens the gelation time and avoids the dissolution of the non-gelatinizable stable phase at excessively high temperatures, ensuring the accuracy of the results. Furthermore, compared with the industry standard EDTA volumetric method, the average operation time for detecting a single sample using the method of this invention is 1.5–2 hours, while the average operation time for detecting a single sample using the industry standard EDTA volumetric method is approximately 3 hours, resulting in an average reduction of 1–1.5 hours in operation time. If multiple samples are tested or parallel samples are prepared, since individual titration is not required, the method of this invention can significantly shorten the time for complete detection of the boehmite gel solubility index. This invention greatly improves detection efficiency through common reagents, a simplified operation process, and a simple calculation method. Meanwhile, this method has relatively low requirements for the testing environment and can be completed under general laboratory conditions. Its test results have a small error range and high precision, providing a reliable basis for the detection of the pseudoboehmite solubility index in related industries.

[0031] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and embodiments shown and described herein.

Claims

1. A method for rapid detection of the gel solubility index of pseudoboehmite, characterized in that, Includes the following steps: Step 1: Weigh out the following weight: m 1 The pseudoboehmite was placed in a high-temperature furnace for calcination. After calcination, it was transferred to a desiccator to cool to room temperature. The calcined pseudoboehmite was weighed and recorded as follows: m 2 mass fraction of Al2O3 W Calculate according to formula (1): （1） Step Two, according to W The value of Al2O3 content was determined by weighing it on a balance. m 3 The pseudoboehmite was placed in a beaker, deionized water was added and mechanically stirred, and nitric acid aqueous solution was added drop by drop. After the addition was completed, stirring was continued to form a gel. The gelled liquid was transferred to a centrifuge tube and centrifuged. Step 3: After centrifugation, slowly pour off the supernatant. Rinse the inner wall of the centrifuge tube with clean water to remove any remaining gel. Slowly pour off the wash water. Remove the insoluble matter from the bottom of the centrifuge tube. Wash the insoluble matter with clean water, and pour the insoluble matter and wash water together into a weighing bottle to dry. After drying, transfer the bottle to a desiccator to cool to room temperature before weighing. Record the remaining net weight as follows: m 4 The gel solubility index of pseudoboehmite Ig Calculate according to formula (2): （2）。 2. The method for rapid detection of the gel solubility index of pseudoboehmite as described in claim 1, characterized in that, In step one, the temperature of the high-temperature furnace is 500-600℃, and the roasting time is 2-3 hours.

3. The method for rapid detection of the gel solubility index of pseudoboehmite as described in claim 1, characterized in that, In step two, the balance accuracy is 0.0001g, and the volume of deionized water is 30-60mL.

4. The method for rapid detection of the gel solubility index of pseudoboehmite as described in claim 1, characterized in that, In step two, the mechanical stirring time is 3 to 10 minutes, and the mechanical stirring speed is 200 to 300 r / min.

5. The method for rapid detection of the gel solubility index of pseudoboehmite as described in claim 1, characterized in that, In step two, the volume ratio of concentrated nitric acid to water in the nitric acid aqueous solution is 1:1.95 to 2.05, the molar ratio of the added nitric acid aqueous solution to boehmite is n(H):n(Al) = 1:9 to 11, the dropwise addition rate is 1 to 2 drops per second, and the stirring time is 10 to 30 minutes.

6. The method for rapid detection of the gel solubility index of pseudoboehmite as described in claim 1, characterized in that, In step two, the centrifugation speed is 4000-6000 r / min and the centrifugation time is 5-15 min.

7. The method for rapid detection of the gel solubility index of pseudoboehmite as described in claim 1, characterized in that, In step three, the drying temperature is 100-110℃ and the drying time is 2-3 hours.

8. The method for rapid detection of the gel solubility index of pseudoboehmite as described in claim 1, characterized in that, Step two can be replaced by: according to W The value of Al2O3 content was determined by weighing it on a balance. m 3 The pseudoboehmite was placed in a flask, and deionized water and nitric acid solution were added. A stir bar was placed in the flask, and the flask was placed on a heated magnetic stirrer. The mixture was stirred and refluxed at 70-90°C for 10-20 minutes to form a gel. The gelled liquid was transferred to a centrifuge tube. The stir bar and flask were washed with deionized water, and the washings were transferred to the centrifuge tube and centrifuged.

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