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Similar standardsGB/T 34709-2017: General test method for silica gel---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/GBT34709-2017NATIONAL STANDARD OF THE PEOPLE’S REPUBLIC OF CHINA ICS 71.060.01 G 10 General test method for silica gel ISSUED ON: NOVEMBER 01, 2017 IMPLEMENTED ON: MAY 01, 2018 Issued by: General Administration of Quality Supervision, Inspection and Quarantine of PRC; Standardization Administration of PRC. Table of ContentsForeword ... 3 1 Scope ... 4 2 Normative references ... 4 3 Test methods ... 5 3.1 General provisions ... 5 3.2 Determination of particle size ... 5 3.3 Determination of percent of pass of particle size ... 6 3.4 Determination of wear rate ... 8 3.5 Determination of compacted bulk density ... 12 3.6 Loose density ... 13 3.7 Determination of adsorption capacity ... 15 3.8 Identification of color change ... 18 3.9 Determination of pore volume ... 18 3.10 Determination of heating loss ... 21 3.11 Determination of ignition loss ... 22 3.12 Determination of the percent of pass of spherical particles ... 23 3.13 Determination of silica content ... 23 3.14 Determination of iron content ... 25 3.15 Determination of chloride content ... 27 3.16 Determination of pH ... 27 3.17 Determination of specific resistance ... 28 3.18 Determination of specific surface area ... 28 3.19 Determination of cobalt chloride content ... 28 3.20 Determination of carbon dioxide adsorption capacity ... 30 3.21 Determination of particle strength ... 30 3.22 Determination of the rate of non-burst in contact with water ... 31 Appendix A (Informative) Standard operating method for typical instruments for the determination of BET specific surface area ... 32 Appendix B (Informative) Standard operating method-1 for typical instruments for the determination of carbon dioxide adsorption ... 34 Appendix C (Informative) Standard operating method-2 for typical instruments for the determination of carbon dioxide adsorption ... 36 General test method for silica gel1 ScopeThis standard specifies the test methods for silica gel series products. This standard applies to the series product such as type-A silica gel, type-C silica gel, microsphere silica gel, color-changing silica gel, indicator silica gel, type-B silica gel, pressure-swing-adsorption silica gel, FNG water-resistant silica gel, cat-litter silica gel, additive silica gel, macro-porous silica gel.2 Normative referencesThe following documents are essential to the application of this document. For the dated documents, only the versions with the dates indicated are applicable to this document; for the undated documents, only the latest version (including all the amendments) are applicable to this standard. GB/T 3049-2006 Chemical products for industrial use - General method for determination of iron content - 1,10-Phenanthroline spectrophotometric method GB/T 6003.1-2012 Test sieves - Technical requirements and testing - Part 1: Test sieves of metal wire cloth GB/T 6003.2-2012 Test sieves - Technical requirements and testing - Part 2: Test sieves of metal wire cloth GB/T 6682-2008 Water for analytical laboratory use - Specification and test methods GB/T 13390-2008 Metallic powder - Determination of the specific surface area - Method of nitrogen adsorption HG/T 3696.2 Inorganic chemicals for industrial use - Preparations of standard and reagent solutions for chemical analysis - Part 2: Preparations of standard solutions for impurity HG/T 3696.3 Inorganic chemicals for industrial use - Preparations of standard and reagent solutions for chemical analysis - Part 3: Preparations of reagent solutions 3.3.2.2 Test sieve of metal perforated plate: The series of test sieves as specified in GB/T 6003.2-2012, which is equipped with a sealing cover and a receiving tray. It is used for the determination of spherical silica gel. 3.3.3 Analytical procedures Install two sieves which have mesh sizes respectively equivalent to the upper limit and lower limit of the particle size as agreed between both parties and receiving trays sequentially (the general range of particle size of the spherical silica gel is: 1 mm ~ 3 mm; 2 mm ~ 5 mm; 4 mm ~ 8 mm. The general range of particle size of the bulk silica gel is: 0.5 mm ~ 2 mm; 1 mm ~ 6 mm; 2 mm ~ 8 mm). According to the particle size of the product, select the following operations: a) For products which have a particle size of above 250 μm (60-mesh), weigh 50 g ~ 100 g of specimen, accurate to 0.1 g. Place it in the upper limit sieve. Cover the sealing cover. Use hand to hold it. Shake it horizontally and circumferentially for 1 min. The total number of shaking is 60 ~ 70. The amplitude of shaking is about 20 cm. Weigh the specimen amount in the lower limit sieve, accurate to 0.1 g. b) For products which have a particle size of 250 μm (60-mesh) and below, weigh approximately 20 g of specimen, accurate to 0.1 g. Place it in the upper limit sieve. Use a brush to gently brush the specimen. Brush it whilst sieving it. After about 30 min, weigh the specimen amount in the lower limit sieve, accurate to 0.1 g. 3.3.4 Calculation of results The percent of pass of particle size is expressed by mass fraction w1 and calculated by the formula (1): Where: m1 - The mass of the specimen in the lower limit sieve, in grams (g); m - The mass of the specimen, in grams (g). Take the arithmetic mean of the results of parallel determinations as the determination result. The absolute difference between the results of two parallel determination is not more than 2.0%. 3.4.2.3 Analytical procedures Take approximately 25 mL of the specimen. Use a 425 μm test sieve (for products of 300 μm ~ 850 μm) or a 250 μm test sieve (for products of 125 μm ~ 425 μm). Carry out sieving according to the method as specified in 3.3. Place about 10 mL of specimen which remains on the sieve into a 50 mL beaker. Uniformly pour the specimen from the beaker into a glass measuring device which is equipped with a glass funnel within about 1 min. Take about (10 ± 0.1) mL. Open the disc collision object 5 and the metal mesh 6 of the guiding fountain-bed. Pour the specimen into the guiding fountain-bed. Install it well. Turn on the air compressor, to allow the air to flow through the humidifier and flowmeter. At the airflow rate of (15 ± 0.5) L/min, blow-grind it for 30 min. Remove the nozzle 4. Take out the specimen. Use a 300 μm test sieve (for products of 300 μm ~ 850 μm) or a 125 μm test sieve (for products of 125 μm ~ 425 μm) to sieve it. Use the same method as above to measure the volume of the sieve residue, accurate to 0.1 mL. 3.4.2.4 Calculation of results The wear rate is expressed by mass fraction w3 and calculated by the formula (3): Where: V - The volume of the specimen, in milliliters (mL); V1 - The volume of the sieve residue after blow-grinding, in milliliters (mL). Take the arithmetic mean of the results of parallel determinations as the determination result. The absolute difference between the results of two parallel determinations is not more than 3%. 3.5 Determination of compacted bulk density 3.5.1 Summary of method Stack the weighed specimen into a container of a certain volume. Use the specified method to vibrate-compact it. Read the volume of the specimen. Make calculation. 3.5.2 Instruments and equipment Glass measuring cylinder: A measuring cylinder which has a capacity of 100 mL and an inner diameter of (25 ± 2) mm as well as a glass base. 3.7 Determination of adsorption capacity 3.7.1 Static adsorption method 3.7.1.1 Summary of method Place a certain amount of dried specimen in a closed container of a certain relative humidity. Make it achieve adsorption equilibrium. Then weigh the specimen. Calculate the amount of adsorption. 3.7.1.2 Reagents Sulfuric acid solution: Use sulfuric acid and water to prepare sulfuric acid solution of different concentrations according to Table 1, to air of different relative humidity. Table 1 3.7.1.3 Instruments and equipment 3.7.1.3.1 Electrothermal constant-temperature drying oven: The temperature can be controlled at 170 °C ~ 190 °C. 3.7.1.3.2 Closed containers: Glass dryers for general laboratory use. 3.7.1.4 Analytical procedures Heat and dry the specimen at 170 °C ~ 190 °C for 2 h. Weigh about 0.3 g ~ 0.5 g of specimen. Quickly place it in a weighing bottle which has been dried at 170 °C ~ 190 °C to a constant mass. Spread it flatly and uniformly as practical as possible. Immediately apply the stopper tightly. Place it in a desiccator. Cool it to room temperature. Accurately weigh it, accurate to 0.0002 g. Follow the Table 1 to prepare sulfuric acid solution of different concentrations (the amount of sulfuric acid solution used is more than 100 mL per specimen). Respectively place it in a series of closed containers. Keep the relative humidity in the closed container at 20%, 50%, 90% (or other relative humidity as required by the standard). Place the weighing bottle which has the weighed specimen into the compartment of closed container. Open the weighing bottle’s stopper. Hold it at (25 ± 2.5) °C for 48 hours. Remove and immediately tighten the stopper. Weigh it, accurate to 0.0002 g. 3.7.1.5 Calculation of results Relative humidity / % Concentration of sulfuric acid / % Relative density of water solution ~ 2 h, until the weight gain does not exceed 0.001 g. 3.7.2.5 Calculation of results The adsorption capacity is expressed by mass fraction w7 and calculated by the formula (7): Where: m1 - The mass of specimen after adsorption equilibrium, in grams (g); m - The mass of specimen, in grams (g). Take the arithmetic mean of the results of parallel determinations as the determination result. When the relative humidity of the air is 20%, the difference between the results of two parallel determinations is not more than 1.0%. When the relative humidity of the air is 35% ~ 50%, the difference between the results of two parallel determinations is not more than 1.5%. When the relative humidity of the air is 80%, the difference between the results of two parallel determinations is not more than 2.0%. 3.8 Identification of color change 3.8.1 Summary of method The color of specimen as displayed after reaching the adsorption equilibrium at different relative humidity of the air is compared with the indicated chromatogram. 3.8.2 Determination procedures Compare the specimen as measured according to 3.7 or the specimen which reaches adsorption equilibrium at the corresponding relative humidity with the specified indicator chromatogram. The color of the specimen shall meet the requirements of the corresponding color scale or expression. 3.9 Determination of pore volume 3.9.1 Water titration method 3.9.1.1 Summary of method Take a specimen of a certain particle size. Add water dropwise. When the The pore volume w8 is expressed in mL/g and calculated according to formula (8): Where: V - The volume of water consumed, in milliliters (mL); m - The mass of specimen, in grams (g). Take the arithmetic mean of the results of parallel determinations as the determination result. The absolute difference between the results of two parallel determinations is not more than 0.02 mL/g. 3.9.2 Nitrogen adsorption method 3.9.2.1 Summary of method Use the specific surface porosity meter to measure the adsorption isotherm at relative pressure (P/P0) of the sample at the liquid nitrogen temperature, that is, use the BET method to determine the specific surface process. According to Kelvin's theory, when P/P0 > 0.35, pore coagulation will begin to appear; when P/P0 > 0.99, the pores of silica gel are basically full. According to the adsorption capacity, it may calculate the pore volume of sample. 3.9.2.2 Instruments and equipment Specific surface porosity tester: It is equipped with high-purity nitrogen. 3.9.2.3 Analytical procedures Weigh 0.2 g ~ 0.3 g of specimen which has been dried to a constant mass, accurate to 0.0002 g. Put it into the measuring tube. At 150 °C ~ 200 °C, vacuum-degas it for 2 h, to make the vacuum degree drop below 1 Pa. Start measuring the adsorption isotherm. For the initial determination, it requires starting the dead volume correction. When the pore volume is specially determined, the setting points of relative pressure (P/P0) may be concentrated between 0.35 and 0.995. It may also continue the BET method to determine the specific surface process, to continue the relative pressure (P/P0) to 0.995. Then end the measurement. According to the measured adsorption isotherm, use the volume of liquid nitrogen as adsorbed corresponding to the relative pressure (P/P0) of 0.995 to calculate the total pore volume. Use the value of the pore volume per unit mass as the pore volume, in the unit of mL/g. For the typical instrument operation, see Appendix A. The instrument uses a program-controlled halogen lamp/infrared lamp for temperature-rise to heat the sample. Make continuous automatic weighing, until the mass is constant. Report the results. 3.10.2.2 Instruments and equipment Rapid moisture analyzer: Halogen/infrared heating type, which has a weighing accuracy of 0.001 g. 3.10.2.3 Analytical procedures Spread approximately 2 g ~ 10 g of specimen in the drying tray of the rapid moisture analyzer. Set the drying temperature, to control it at (150 ± 5) °C (120 °C ± 5 °C for blue silica gel indicator and color-changing silica gel); 170 °C ~ 190 °C for fine-pored silica gel). Enter the mass of specimen. Start the determination program. At the end of determination, the instrument automatically reports the results. Take the arithmetic mean of the results of parallel determinations as the determination result. The absolute difference between the results of two parallel determinations is not more than 0.5%. 3.11 Determination of ignition loss 3.11.1 Instruments and equipment 3.11.1.1 High-temperature furnace: The controllable temperature is 1000 °C ± 50 °C. 3.11.1.2 Porcelain crucible: 50 mL. 3.11.2 Analytical procedures Weigh 1 g ~ 2 g of specimen which has been subjected to the test of heating loss, accurate to 0.0002 g. Place it in a porcelain crucible which was previously burned at 1000 °C ± 50 °C to a constant mass. Burn it at 1000 °C ± 50 °C for 2 h. Remove it. Cool it in a desiccator. Weigh it. 3.11.3 Calculation of results The ignition loss is expressed in mass fraction w10 and is calculated according to formula (10): Where: 3.13.2.3 Perchloric acid. 3.13.3 Instruments and equipment 3.13.3.1 High-temperature furnace: Controllable temperature (1000 ± 50) °C. 3.13.3.2 Electrothermal constant-temperature drying oven: The temperature can be controlled at 170 °C ~ 190 °C. 3.13.3.3 Platinum crucible: 50 mL. 3.13.4 Analytical procedures Weigh about 2 g of the specimen which has been pulverized to smaller than 125 μm. Place it in a weighing bottle. Put it in a drying oven at 170 °C ~ 190 °C to dry it. After 2 hours, remove and put it in a desiccator to cool it to room temperature. Weigh 1.0 g ~ 1.1 g of the cooled specimen, accurate to 0.0001 g. Place it in a platinum crucible which has been burnt to a constant mass at (1000 ± 50) °C. Use water to wet the specimen. Add 10 drops of sulfuric acid and 20 mL of hydrofluoric acid. Place the platinum crucible on a sand bath to heat it dry. Then add 20 mL of hydrofluoric acid (if necessary, add 2 mL of perchloric acid). Evaporate it until white smoke disappears. Put the platinum crucible in a high-temperature furnace at (1000 ± 50) °C to burn it to a constant mass. 3.13.5 Calculation of results The silica content is expressed in mass fraction w12 and calculated by the formula (12): Where: m1 - The mass of platinum crucible, in grams (g); m2 - The mass of platinum crucible and specimen, in grams (g); m3 - The mass of platinum crucible and residue, in grams (g). Take the arithmetic mean of the results of parallel determinations as the determination result. The absolute difference between the results of two parallel determinations is not more than 0.5%. Weigh about 1 g of the specimen, accurate to 0.0001 g. Place it in 50 mL platinum crucible. Use water to wet it. Add 5 drops ~ 6 drops of sulfuric acid, 10 mL of hydrofluoric acid. Evaporate it on the electric stove until white smoke starts to appear. Cool it. Add 10 mL of hydrofluoric acid, 2 mL of perchloric acid. Evaporate it dry. Add 2 mL of hydrochloric acid solution (see 3.14.2.5). Heat to dissolve it. Transfer it into a 100 mL volumetric flask. Make its volume reach to the mark. Shake it uniformly. This solution is the solution B. Meanwhile carry out a blank test. 3.14.4.3 Determination Respectively, pipette 10 mL of test solution A or test solution B as well as 10 mL of corresponding blank test solution in 100 mL beaker. Start operation from “if necessary, add water to 60 mL ...” in clause 6.4 of GB/T 3049-2006. From the working curve, find the corresponding iron mass. 3.14.5 Calculation of results The iron content is expressed in mass fraction w13 of iron (Fe) and calculated by the formula (13): Where: m1 - The mass of iron in the test solution as found from the working curve, in milligrams (mg); m2 - The mass of iron in the blank test solution as found from the working curve, in milligrams (mg); V1 - The volume of the specimen after treatment and reaching to the mark, in milliliters (mL); V2 - The volume of the test solution as pipetted during the determination, in milliliters (mL); m - The mass of specimen, in grams (g). Take the arithmetic mean of the results of parallel determinations as the determination result. The absolute difference between the results of two parallel determinations is not more than 0.002%. Weigh (10.0 ± 0.1) g of specimen. Place it a 250 mL beaker. Add 200 mL of water. Cover the watch glass. Place it on a water bath at (80 ± 3) °C to heat it for 30 min. Cool it to room temperature. Take the supernatant. Use an acidity meter to determine the pH of the solution. Take the arithmetic mean of the results of parallel determinations as the determination result. The absolute difference of the results of parallel determinations is not more than 0.5. 3.17 Determination of specific resistance 3.17.1 Instruments and equipment Conductivity meter: It is equipped with platinum conductivity cell. 3.17.2 Analytical procedures Calibrate the conductivity meter according to its operation manual. Weigh (10.0 ± 0.1) g of specimen. Place it in a 250 mL beaker. Add 200 mL of water (specific resistance is more than 105 Ω • cm). Cover the watch glass. Heat it on a water bath at (80 ± 3) °C for 30 min. Cool it to room temperature. Take the supernatant. Insert it into a platinum conductivity cell. Use the conductivity meter to determine its specific resistance. Take the arithmetic mean of the results of parallel determinations as the determination result. The absolute difference of the results of parallel determinations is not more than 300 Ω • cm. 3.18 Determination of specific surface area The specimen which has been dried to a constant mass is desorbed at 150 °C for 2 h. It is measured according to the volumetric method as specified in GB/T 13390-2008. For the typical instrument operation, see Appendix A. 3.19 Determination of cobalt chloride content 3.19.1 Reagents 3.19.1.1 Sulfuric acid. 3.19.1.2 Hydrofluoric acid. 3.19.1.3 Nitric acid solution: 1 mol/L. 3.19.1.4 Barium nitrate solution: 50 g/L. m1 - The milligrams of cobalt in the solution to be tested, in milligrams (mg); m - The mass of specimen, in grams (g); m1 - The relative atomic mass of cobalt (Co) (58.93); m2 - The relative molecular mass of cobalt chloride (CoCl2) (129.9). Take the arithmetic mean of the results of parallel determinations as the determination result. The absolute difference between the results of two parallel determinations is not more than 0.02%. 3.20 Determination of carbon dioxide adsorption capacity 3.20.1 Summary of method Use a specific surface porosity meter. At a constant-temperature of 25 °C of the sample, measure the gas adsorption isotherms of carbon dioxide at a series of absolute pressure (mmHg). 3.20.2 Instruments and equipment Specific surface porosity meter: It is equipped with high-purity carbon dioxide (purity of 99.99% and above). 3.20.3 Analytical procedures Weigh 0.2 g ~ 0.3 g of specimen, accurate to 0.0002 g. Put it into the measuring tube. Vacuum to degas it at (180 ± 2) °C for 2 h, to bring the degree of vacuum to be less than 1 Pa. The water bath’s temperature is 25 °C. Use carbon dioxide gas as the adsorption gas, start to measure the adsorption isotherm. At the initial determination, it needs starting a dead volume correction. Select the absolute pressure (mmHg). Generally the setting points may be concentrated near the low-pressure (50 mmHg) and normal pressure (760 mmHg). After the measurement is completed, it may follow the requirements to read the adsorption capacity at the corresponding pressure. For the typical instrument operation, see the Appendix B, Appendix C. 3.21 Determination of particle strength 3.21.1 Summary of method Select a certain amount of intact silica gel particles. Use a particle strength meter to determine the force as undertaken by each sample when it breaks. 3.21.2 Instruments and equipmentAppendix A(Informative) Standard operating method for typical instruments for the determination of BET specific surface area A.1 Instrument A.1.1 Adsorption analysis workstation: It is equipped with high-purity nitrogen (purity 99.99%); high-purity helium (purity 99.99%). A.1.2 Dewar flask: It is equipped with liquid nitrogen. A.2 Analytical procedures A.2.1 Initializing instrument Install and initialize the instrument according to the instrument’s operating manual. A.2.2 Determination of mass of sample tube Install the clean empty sample tube (if necessary, together with the packing rod) in the degassing station of the instrument. Vacuum to degas it for 5 min. It does not require heating the sample tube. At the end of degassing, backfill helium. Remove the sample tube. Immediately cover the rubber stopper. Weigh it, accurate to 0.0001 g. Record the mass of the helium filled sample tube, stopper and packing rod. A.2.3 Pretreatment of samples Load the sample in a weighed sample tube. The mass of the sample is different depending the specific surface area of the sample material. The recommended mass of sample shall ensure that the total surface area of the sample in the tube is within 20 m2 ~ 50 m2. Put the sample tube into the heating bag. Use a metal heating bag clamp to fix it. Then mount the sample tube onto the degassing station. After all the samples which require degassing are mounted to the opening of the degassing station, start degassing. At this time, the indicator lamp of the selected degassing station lights up. From the digital thermostat of the corresponding degassing station, set the pretreatment temperature at 150 °C. It shall clearly record the degassing temperature in the printed report. The computer will automatically control the pressure inside the sample tube to gradually decrease and heat to degas.Appendix B(Informative) Standard operating method-1 for typical instruments for the determination of carbon dioxide adsorption B.1 Instrument B.1.1 Adsorption degassing station. B.1.2 Adsorption analysis workstation: It is equipped with high-purity carbon dioxide (purity 99.99%); high-purity helium (purity 99.99%); high-purity nitrogen (purity 99.99%). B.1.3 Dewar flask. B.2 Analytical procedures B.2.1 Initializing the instrument Install and initialize the instrument according to the instrument’s operating manual. B.2.2 Weighing sample tube Cover a rubber stopper to a clean empty sample tube (if necessary, together with the packing rod). Weigh it, accurate to 0.0001 g. Record the mass of the sample tube, stopper, packing rod. B.2.3 Pretreatment of samples Contain the sample which has been previously dried into a weighed sample tube. Accurately weigh the total mass of the sample tube and the sample, accurate to 0.0001 g. Record the data. From the digital thermostat of the degassing station, set the pretreatment temperature at 180 °C and raise the temperature to 180 °C. Place the sample tube in the heating bag of the degassing station. Use metal heating bag clamp to fix it. Then mount the sample tube onto the degassing station. When all samples which require degassing are installed onto the opening of degassing station, open the high-purity hydrogen switch to start degassing. The duration of degassing is 2 h. At the end of degassing, place the sample tube at the cooling port of the degassing station, to let it cool naturally to room temperature. B.2.4 Sample analysis B.2.4.1 PreparationAppendix C(Informative) Standard operating method-2 for typical instruments for the determination of carbon dioxide adsorption C.1 Instruments C.1.1 Specific surface area and pore size analyzer: It is equipped with high- purity carbon dioxide (purity 99.99%); high-purity helium (purity 99.99%). C.1.2 Dewar flask. C.2 Analytical procedures C.2.1 Initialization of instrument Install and initialize the instrument according to the instrument’s operating manual. C.2.2 Weighing sample Put it into the beaker. Return to zero. Weigh the clean empty sample tube, accurate to 0.0001 g. Record the mass of the sample tube. After adding the sample, weigh it again. Record the value and then pre-treat the sample. After degassing is completed, weigh the sample tube again. The difference between this weighed value and the gross mass of the sample tube is the mass of sample. C.2.3 Pretreatment of samples Install the sample to the sample pretreatment position on the left side of the instrument. Turn on the software. Perform “sample setup”, which is carried out in two stages, the first stage is to set the heating temperature-rise, the second stage is to set the heating-vacuuming. The temperature is set to 180 °C. The vacuum-degassing time is 120 min. After the setting is completed and saved, click “sample pretreatment”, the sample will be automatically heated, vacuumed, degassed. After completion, it will be automatically cooled to room temperature and perform the backfill gas. Remove and weigh it. Prepare for sample test. C.2.4 Sample analysis C.2.4.1 Determination of adsorption isotherms Enter the Chinese test interface. Click “Parameter setting”. From the “Parameter selection”, select the “BET specific surface area test”. From the ......Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al. Tips & Frequently Asked Questions:Question 1: How long will the true-PDF of English version of GB/T 34709-2017 be delivered?Answer: The full copy PDF of English version of GB/T 34709-2017 can be downloaded in 9 seconds, and it will also be emailed to you in 9 seconds (double mechanisms to ensure the delivery reliably), with PDF-invoice.Question 2: Can I share the purchased PDF of GB/T 34709-2017_English with my colleagues?Answer: Yes. 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