Some standard content:
Chemical Industry Standard of the People's Republic of China
HG/T2765.5—1996
Published on January 24, 1996
Test Methods
Implementation on January 1, 1997
Ministry of Chemical Industry of the People's Republic of China
WHG/T2765.5—1996
The test methods specified in this standard mainly adopt the relevant test methods in the Russian national standard rOCT3956—76 (91) and the corresponding test methods in the Japanese standard JIS Z0701—1977 (1992). Among them, the particle size qualification rate, bulk density, adsorption (static adsorption method), heating loss, silica, pH value, specific resistance are equivalent to JISZ0701-1977 (1992); the abrasion rate and adsorption (dynamic adsorption method) are equivalent to IOCT3956-76 (91); the color change is equivalent to rOCT8984-75 (91); the spherical particle qualification rate is the original national standard GB/T7823-87 method. The important technical content changes between this standard and GB/T7823-87 are: the upper and lower limit tests of particle size determination are cancelled, and the test methods of silica, pH value, specific resistance and specific surface area are added. HG/T2765 is divided into the following independent parts under the general title of "Silica Gel": HG/T2765.1 Silica Gel Fine Pore Silica Gel
HG/T2765.2
Silica Gel Coarse Pore Silica Gel
HG/T2765.3
HG/T2765.4
HG/T2765.5
Microsphere Silica Gel
Blue Glue Indicator and Color Changing Silica Gel
Test Method
This standard will be invalidated from the date of entry into force of GB/T7823-87. This standard is proposed by the Technical Supervision Department of the Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of Tianjin Chemical Research Institute of the Ministry of Chemical Industry. The drafting units of this standard are Qingdao Ocean Chemical Industry Group Co., Ltd., Chongqing Dongfeng Chemical Plant, and Tianjin Chemical Research Institute of the Ministry of Chemical Industry. The main drafters of this standard are Wang Ninghua, Hu Ximei, Fan Guoqiang, Jiang Junhua, and Du Jian. 1
W.bzsoso.coI1Scope
Chemical Industry Standard of the People's Republic of China
This standard specifies the test methods for silica gel. Test methods
HG/T2765.5—1996
This standard applies to the test methods required by HG/T2765.1 "Silica gel fine pore silica gel", HG/T2765.2 "Silica gel coarse pore silica gel", HG/T2765.3 "Silica gel microsphere silica gel", and HG/T2765.4 "Silica gel blue gel indicator and color-changing silica gel".
2Cited standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T2922-82 Determination of specific surface area of chromatographic carriers for chemical reagents GB/T6003-85 Test sieves
3 Determination of particle size qualification rate
3.1 Method summary
Place the sample in a test sieve with a certain mesh size, sieve it according to the specified conditions, and then weigh it. 3.2 Instruments and equipment
Test sieve: R40/3 series test sieves in accordance with the provisions of GB/T6003. 3.2.1 Metal wire mesh test sieve: equipped with a sealing cover and a receiving tray. Used for the determination of block silica gel and micro-spherical silica gel. 3.2.2 Metal perforated plate test sieve: equipped with a sealing cover and a receiving tray. Used for the determination of spherical silica gel. 3.3 Analysis steps
Install two sieves and receiving trays with mesh sizes equal to the upper and lower limits of the particle size specification in sequence. Weigh 50g of the sample (accurate to 0.1g) and place it in the upper sieve. Cover the sealing cover, hold it with your hands, and shake it in a horizontal circle for 1 minute (do not knock, shake 60 to 70 times, and the shaking amplitude is about 20 cm). Weigh the sample in the lower limit sieve (accurate to 0.1g). 3.4 Expression of analysis results
The particle size qualification rate (X) expressed as mass percentage is calculated according to formula (1): ml×100.
Where: m1——the mass of the sample in the lower limit sieve, g; m
——the mass of the sample, g.
3.5 Allowable difference
Take the arithmetic mean of the parallel determination results as the determination result, and the absolute difference of the parallel determination results shall not exceed 2.0%. Approved by the Ministry of Chemical Industry of the People's Republic of China on January 24, 1996 (1)
Implemented on January 1, 1997
W.bzsoso: Determination of abrasion rate of cOn4
4.1 Ball milling method
4.1.1 Summary of the method
HG/T2765.5—1996
Put a certain amount of sample in a ball mill and rotate it under specified conditions so that the sample rubs against the steel balls and the wall of the mill, then sieve and weigh. 4.1.2 Instruments and equipment
4.1.2.1 Metal wire mesh test sieve: R40/3 series test sieve specified in GB/T6003, mesh size 1mm, equipped with a sealing cover and a receiving tray.
4.1.2.2 Ball mill: The device is shown in Figure 1. The ball mill cylinder is made of aluminum, with an inner diameter of 80 mm and a length of 125 mm. It contains 5 steel balls with a diameter of 22 ± 0.5 mm and a rotation speed of 50 ± 2 r/min.
Motor
4.1.3 Analysis steps
Coupling
Sliding bearing
Figure 1 Ball mill apparatus
Ball mill cylinder
Bake the sample at 150 ± 5°C to constant weight. Use the test sieve (4.1.2.1) to sieve according to the method specified in 3.3. Take 50 mL of the sieve residue and weigh it (accurate to 0.01 g). Put all of them in the ball mill cylinder, arrange the steel balls in a straight line in the cylinder, tighten the cylinder cover, and start the ball mill. After running for 15 minutes, remove the ball mill cylinder, open the cylinder cover, and take out the steel balls with tweezers. Pour all the sample in the cylinder into the test sieve (4.1.2.1) and sieve according to the method specified in 3.3. Weigh the sample in the receiving tray (accurate to 0.01g). 4.1.4 Expression of analysis results
The wear rate (x2) expressed as mass percentage is calculated according to formula (2): 2
.bzsoso:comWhere: m1-
-mass of sample in the receiving tray, g;
mass of sample, g.
4.1.5 Allowable difference
HG/T2765.5—1996
Take the arithmetic mean of the parallel determination results as the determination result. The absolute difference of the parallel determination results shall not exceed 0.5% for spherical silica gel; for block silica gel, when the determination result is less than 5%, it shall not exceed 1.0%; when the determination result is 5-10%, it shall not exceed 1.5%; when the determination result is greater than 10%, it shall not exceed 2.0%.
4.2 Guided spouting bed method
4.2.1 Method summary
A certain volume of sample is placed in the guided spouting bed, and the silica gel particles are driven by the airflow to impact and rub under specified conditions, and then screened and the volume is measured.
4.2.2 Instruments and equipment
4.2.2.1 Guided spouting bed device: as shown in Figure 2. Flow meter
Humidifier
Guided fountain bed
Figure 2 Guided fountain bed measurement device
4.2.2.1.1 Humidifier: diameter 120mm, height 500mm, with ceramic ring inside, water replacement at the bottom. 4.2.2.1.2 Flow meter: range 0～30L/min. Separator
Collection bottle
4.2.2.1.3 Guided fountain bed: structure and dimensions as shown in Figure 3. The guide fountain pipe (1) is made of glass, and the other parts are made of stainless steel. 3
W.bzsoso.coHG/T2765.5—1996
1—Guide fountain pipe, 2—Drop-shaped collision body; 3—Positioning ring; 4—Nozzle; 5—Disc collision body; 6—Metal mesh, pore size 125μm Figure 3 Guide fountain bed
4.2.2.1.4 Separator and absorption bottle;
4.2.2.2 Glass measuring device: Graduation value 0.1mL. 4.2.2.3 Metal wire mesh test sieve: R40/3 series test sieve specified in GB/T6003, with sieves with mesh sizes of 125μm, 250μm, 300μm and 425μm, each equipped with a sealing cover and a receiving tray. 4.2.3 Analysis steps
Take about 25 mL of sample and use a 425 μm test sieve (for products with specifications of 300 to 850 μm) or a 250 μm test sieve (for products with specifications of 125 to 425 μm) according to 3.3. Sieve in the prescribed method. Place about 10 mL of the sieve residue in a 50 mL beaker, then pour the sample in the beaker evenly into a glass measuring vessel (4.2.2.2) equipped with a glass funnel in about 1 minute, and measure 10 ± 0.1 mL. Open the disc collision body (5) and metal mesh (6) of the guiding fountain bed, pour the sample into the guiding fountain bed, and install it. 4
W.bzsoso.coIHG/T2765.5—1996
Turn on the air compressor, pass the air flow through the humidifier and flow meter, and blow the air flow at a flow rate of 15 ± 0.5 L/min for 30 minutes. Remove the nozzle (4) and take out the sample. Sieve with a 300μm test sieve (products with specifications of 300~850μm) or a 125μm test sieve (products with specifications of 125~425μm). Measure the volume of the sieve residue in the same way as above, and measure to 0.1 mL. 4.2.4 Expression of analysis results
The wear rate (X:) expressed as a mass percentage is calculated according to formula (3): V-Vi
Wherein, V is the volume of the sample, mL, and
V1 is the volume of the sample after grinding, mL. 4.2.5 Allowable difference
The arithmetic mean of the parallel determination results is taken as the determination result, and the absolute difference of the parallel determination results shall not exceed 3%. 5 Determination of bulk density
5.1 Summary of the method
According to the prescribed method, the sample is piled in a container of a certain volume and weighed. 5.2 Instruments and equipment
Glass measuring cylinder: a measuring cylinder with a capacity of 100mL and an inner diameter of 25±2mm and a glass base. 5.3 Analysis steps
Pour the sample into the weighed glass measuring cylinder and vibrate for half a minute after pouring 20mL. During vibration, the measuring cylinder forms an angle of about 80° with the operating table (covered with a rubber sheet about 3 mm thick) and rotates around the axis, with an amplitude of about 2 cm and an amplitude frequency of about 130 times/min. After filling 100 mL, weigh (accurate to 0.1 g).
5.4 Expression of analytical results
The bulk density (X,) expressed in g/L is calculated according to formula (4): X=100
Where: m——mass of 100 mL sample, g. 5.5 Allowable difference
The arithmetic mean of the parallel determination results is taken as the determination result, and the absolute difference of the parallel determination results shall not exceed 10 g/L. 6 Determination of adsorption amount
6.1 Static adsorption method (arbitration method)
6.1.1 Summary of the method
Place a certain amount of sample in a closed container with a certain relative humidity to allow it to reach adsorption equilibrium, and then weigh it. 6.1.2 Reagents and solutions
Sulfuric acid: analytical grade.
6.1.3 Analytical steps
(4)
Crush the sample, sieve it with a 850μm test sieve (3.2.1), mix it evenly, and heat it at 170~190℃ for 2h. Take about 0.3~0.5g and quickly put it in a weighing bottle, and spread it as evenly as possible, immediately cover the bottle stopper, put it in a desiccator, cool it to room temperature, and weigh it accurately. Prepare sulfuric acid aqueous solutions of different concentrations according to Table 1, and keep the relative humidity in the sealed container at RH20%, RH50%, and RH90%. Put the weighed sample into a sealed container and keep it at 25±2.5℃ for 48h, then take it out, immediately cover the bottle stopper and weigh it. 6.1.4 Expression of analysis results
HG/T2765.5—1996
The adsorption amount (Xs) expressed as mass percentage is calculated according to formula (5): Xg-
Wherein: m1
-mass of the sample after adsorption equilibrium, g;
-mass of the sample, g.
6.1.5 Allowable difference
The arithmetic mean of the parallel determination results is taken as the determination result, and the absolute difference of the parallel determination results shall not exceed 1.0%. 6.2 Dynamic adsorption method
6.2.1 Method summary
Let air with a certain relative humidity pass through a certain amount of sample to achieve adsorption equilibrium, and then weigh it. 6.2.2 Instruments and equipment
Dynamic adsorption device: as shown in Figure 4. The dynamic adsorption tube is made of glass, and its shape and size are shown in Figure 5. The ambient temperature of the measurement device is maintained at 25±2.5℃.
1—500mL Monteggia gas washing bottle; 2—2500mL glass bottle; 3, 4—screw clamp; 5—drying tube, filled with glass wool; 6—dynamic adsorption tube; 7—gas flowmeter; 8—connected to air compressor Figure 4 Dynamic adsorption device
W.bzsoso.coI6.2.3 Reagents and solutions
6.2.3.1 Sulfuric acid: analytical grade.
HG/T2765.5—1996
1—sieve plate; 2—glass fiber; 3—ground mouth Figure 5 Dynamic adsorption tube
6.2.3.2 Prepare aqueous sulfuric acid solutions of different concentrations according to Table 1 to prepare air with different relative humidity. Table 1
Relative temperature (RH), %
Concentration of sulfuric acid solution (m/m), %
Relative density of solution (25/4℃)
6.2.4 Analysis steps
Add sulfuric acid solution of the same concentration to four Monte Carlo gas washing bottles (1). The concentration is determined according to the relative humidity of the air required for the test according to Table 1. The height of the added solution is about 6 to 8 cm. Connect the instrument according to Figure 4. Weigh 1.01.5g (accurate to 0.0002g) of the sample that has been dried to constant weight according to 8.2 and place it in the dynamic adsorption tube (6). Close the stopper of the water glass bottle (2), fully open the screw clamp (4), start the air compressor, and open the screw clamp (3). Use spiral clamp 7
W.HG/T2765.5—1996
（4）to control the air flow rate at 2～2.5L/min, and adsorb for 5h at 25±2.5℃ and normal pressure. Fully open spiral clamp (4), close spiral clamp (3), remove dynamic adsorption tube and weigh (accurate to 0.0002g). Repeat the above operation and weigh every 1.5～2h until the weight gain does not exceed 0.001g.
6.2.5 Expression of analysis results
The adsorption amount (X) expressed as mass percentage is calculated according to formula (6): Xg=mlm×100www.bzxz.net
Where: m1——mass of sample after adsorption equilibrium, g; m——mass of sample, g.
6.2.6 Allowable difference
The arithmetic mean of the parallel determination results is taken as the determination result, and the absolute difference of the parallel determination results shall not exceed 1.0%. (6)
When the relative humidity of the air is 20%, the difference between the two parallel determination results shall not exceed 1.0%; when the relative humidity of the air is 35%-50%, the difference between the two parallel determination results shall not exceed 1.5%; when the relative humidity of the air is 80%, the difference between the two parallel determination results shall not exceed 2.0%. 7 Determination of pore volume
7.1 Summary of the method
Take a sample of a certain particle size and drip distilled water into it. When the sample absorbs water to saturation, a slight excess of water will cause adhesion between the sample particles, thereby specifying the titration end point. 7.2 Instruments and equipment
Wire mesh test sieve: R40/3 series test sieve specified in GB/T6003, sieves with mesh sizes of 250μm and 850μm, and a sealing cover and a receiving tray. 7.3 Analysis steps
7.3.1 Sample preparation
For coarse-pore microspherical silica gel, use the original specification sample directly. For coarse-pore large-particle silica gel, first crush the sample, and then use the test sieve to select particles of 250-850μm for determination. 7.3.2 Determination
Weigh about 10g (accurate to 0.01g) of the sample (7.3.1) dried to constant weight at 150±5℃. Place it in a dry 250mL conical flask with a ground stopper, add about 7mL of distilled water at a time with a 25mL burette, cover the stopper, and leave it for 15min. Then shake the conical flask until the sample becomes loose. Open the bottle stopper and add water drop by drop, and shake the conical flask after each addition of water. If the sample is still loose after shaking, continue to add water drop by drop; if the sample particles stick to each other and adhere to the bottle wall and continue shaking for 1 minute and it still does not disappear, it is the titration end point. Record the volume of distilled water consumed.
7.4 Expression of analysis results
The pore volume (X) expressed in mL/g is calculated according to formula (7): X7
Where: V is the volume of distilled water consumed, mLm--the mass of the sample, g.
7.5 Allowable difference
Take the arithmetic mean of the parallel determination results as the determination result, and the absolute difference of the parallel determination results shall not exceed 0.02mL/g. (7)
W8 Determination of heating loss
8.1 Summary of method
Bake the sample to constant weight at the specified temperature. 8.2 Analysis steps
HG/T2765.5—1996
Use a flat weighing bottle that has been dried to constant weight at the specified temperature to weigh 2 to 3 g of sample (accurate to 0.0002g), placed in an electric oven controlled at 150±5℃ (120±5℃ for blue gel indicator and color-changing silica gel, 170～190℃ for fine-pore silica gel) to constant weight (accurate to 0.0002g).
8.3 Expression of analysis results
Heating loss (X:) expressed as mass percentage is calculated according to formula (8): Xg-
-mass of sample, 8;
Where: m-
-mass of sample after drying, g.
8.4 Allowable difference
Take the arithmetic mean of the parallel determination results as the determination result, and the absolute difference of the parallel determination results shall not exceed 0.5%. 9 Determination of qualified rate of spherical particles
9.1 Analysis steps
Weigh about 20g of sample (accurate to 0.1g) and place it in a porcelain dish. Use tweezers to select the hemisphere and the fragments smaller than the hemisphere, and weigh the remaining particles (accurate to 0.1g).
9.2 Expression of analysis results
The qualified rate of spherical particles (X9) expressed as mass percentage is calculated according to formula (9): mlx100
wherein m1-
-mass of remaining particles, g;
-mass of sample, g.
9.3 Allowable difference
The arithmetic mean of the parallel determination results is taken as the determination result, and the absolute difference of the parallel determination results shall not exceed 4.0%. 10 Determination of silicon dioxide content
10.1 Summary of the method
After drying the adsorbed water at 170-190℃, the sample is heated with excess hydrofluoric acid to decompose silicon dioxide and weighed after burning. 10.2 Reagents and solutions
10.2.1 Hydrogen fluoride solution: analytical grade;
10.2.2 Sulfuric acid: analytical grade.
10.3 Instruments and equipment
Platinum crucible: 50mL.
10.4 Analysis steps
Weigh about 2g of the sample crushed to less than 125μm, place it in a weighing bottle and dry it in an electric oven at 170-190℃ for 2h. After taking it out, cool it to room temperature in a desiccator. Weigh 1.0-1.1g of the cooled sample and place it in a platinum crucible, moisten the sample with distilled water, add 9 drops of sulfuric acid and 20mL of hydrofluoric acid, place the platinum in a sand bath, heat and evaporate it to dryness, and then burn it at 1000±50℃ to constant weight. 10.5 Expression of analysis results
The silicon dioxide content (X1) expressed as mass percentage is calculated according to formula (10): m-ml×100
Wherein: m1——mass of residue after cooling, g; m——mass of sample after drying at 170~190℃, g. 10.6 Allowable difference
The arithmetic mean of the parallel determination results is taken as the determination result, and the absolute difference of the parallel determination results shall not exceed 0.5%. 11 Determination of pH value
11.1 Summary of method
The soluble components in the sample are leached with hot water, and the pH value of the leaching solution is determined by an acidometer. 11.2 Instruments and equipment
Acidometer: the graduation value is 0.1.
11.3 Analysis steps
(10)
Weigh 10.0±0.1g of sample and put it into a 300mL beaker. Add 200mL of distilled water, cover the surface III, heat at 80±3℃ for 30min, cool to room temperature, take the supernatant and use an acidometer to measure the pH value of the solution. 12 Determination of specific resistance
12.1 Instruments and equipment
Conductivity meter.
12.2 Analysis steps
Weigh 10.0±0.1g of sample and put it into a 300mL beaker. Add 200mL of distilled water (specific resistance greater than 10°Q·cm), cover the surface blood, heat at 80±3℃ for 30min, cool to room temperature, take the supernatant and use a conductivity meter to measure its specific resistance at 25℃.
12.3 Allowable difference
Take the arithmetic mean of the parallel determination results as the determination result, and the absolute difference of the parallel determination results shall not exceed 300Q·cm. 13 Determination of specific surface area
The sample is desorbed at 150℃ for 2h and measured according to GB/T2922. 14 Identification of color change
14.1 Summary of method
Compare the color displayed by the sample after reaching adsorption equilibrium at different relative air humidity with the indicator chromatogram. 14.2 Determination steps
Compare the sample measured in accordance with the provisions of Chapter 6 with the indicator chromatogram of the blue gel indicator (Figure 6). The color of the sample should meet the requirements of the corresponding color scale or description.2 Determination steps
Compare the sample determined in accordance with Chapter 6 with the indicator chromatogram of the blue gel indicator (Figure 6). The color of the sample should conform to the requirements of the corresponding color scale or description.2 Determination steps
Compare the sample determined in accordance with Chapter 6 with the indicator chromatogram of the blue gel indicator (Figure 6). The color of the sample should conform to the requirements of the corresponding color scale or description.
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