This standard specifies the determination method of the pH value of acetylene carbon black. This standard is applicable to the determination of the pH value of acetylene carbon black. GB/T 3781.4-1993 Determination of the pH value of acetylene carbon black GB/T3781.4-1993 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Determination of pH value of acetylene black
Acetylene black-Determinatlon of pH value1 Subject content and scope of application
This standard specifies the determination method of pH value of acetylene black. This standard is applicable to the determination of pH value of acetylene black. 2 Reference standards
Chemical reagents 95% ethanol
GH 679
GB 1263
Chemical reagents disodium hydrogen phosphate
Chemical reagents
GB 1274
Chemical reagents
GB1291
Potassium monohydrogen phosphate
Potassium hydrogen phthalatebzxz.net
GB 6682
Laboratory water specifications
3 Instruments
3. 1 Industrial balance; accurate to 0. 1 g. 3.2 Analytical balance: accurate to 0.1 mg. 3.3 Acidity meter; accuracy is 0.1 pH. 3.4 Beaker: 250 mL or more,
3.5 Surface blood; diameter 100 mm.
3.6 Electric heating plate or electric heating furnace.
3.7 Electric centrifuge: can be controlled at more than 1 000 r/min. 4 Reagents
4.1 95% ethanol (GB 679): analytical grade.
4.2 Disodium nitrogen phosphate (Na,HPO4, GB1263): analytical grade. 4.3 Potassium diammonium phosphate (KH,PO., GB1274): analytical grade. 4.4 Potassium hydrogen phthalate (KHC,H,O., GB1291): analytical grade. GB/T3781.4-93
Recommended GR3781.183
4.5, in line with the requirements of GB 6682 Grade III water. Before use, it should be placed in a chemically resistant glass container and boiled for 5~[0 min, and then covered and cooled. The storage time should not exceed 30 min. 5 Steps
5.1 The test room should be free of acid and alkali gases. The temperature of the sample to be measured should be consistent with that of the buffer solution. 5.2 Weigh 5 μl of the sample to an accuracy of 0.2 μl and transfer it to a 250 mL beaker (3.4). Add 150 mL of freshly boiled and cooled distilled water. If the sample is not wetted by water, add 3 to 5 mL of ethanol and boil it on a hot stove or hot plate for 5 minutes. Note that it is not allowed to boil until dry. Approved by the State Administration of Technical Supervision on March 3, 1993 and implemented on December 1, 1993
GB/T3781.4--93
5.3 Remove the beaker, cover with a watch glass, and cool to room temperature. 5.4 Pour off the supernatant and transfer the carbon black slurry to a centrifuge bottle and centrifuge it on an electric centrifuge (3.7) for 2 minutes. 5.5 Remove the centrifuge bottle, pour off the supernatant, and leave the carbon black slurry. 5.6 At the test temperature, calibrate the instrument with a standard buffer solution (see Appendix A) with a pH value close to that of carbon black according to the instrument operating procedures. 5.7 Transfer the carbon black slurry into a small beaker, stir it thoroughly with a glass rod, insert the clean calomel electrode and the entire ball of the glass electrode into the carbon black slurry, and allow the carbon black slurry to adhere well to the electrode circumference. Measure according to the instrument operating procedures. 5.8 Stir the carbon black slurry thoroughly with a stirring rod again and measure. Repeat this operation until the change in the measured values ​​for three consecutive times does not exceed 0.1 pH value, and take the average value.
6 Result Expression
6.1 The pH value of the sample is expressed as the number displayed by the pH meter. The difference between the two measurement results shall not exceed 0.3pH6.2The test results are rounded to the integer
7Test report
The test report should include the following items:
The national standard number on which this test is based:
The type and mark of the sample,
The average of the two test results;
Indicate the differences from the prescribed test steps; e. Test date.
Reagent Name
Potassium Hydrogen Phosphate
KHC,H,O,
Potassium Dihydrogen Phosphate
Disodium Chlorophosphate
Potassium Dihydrogen Phosphate
Disodium Hydrogen Phosphate
PFI Value
GB/T 3781.4—93
Appendix A
Standard Buffer Solution
(Supplement)
Standard Buffer Solution
Solution Concentration/1.
Reagent Treatment
Dry at 110℃ for 1h
Dry at 110℃ for 1h h
Dry at 110℃ for 1h
Dry at 110℃ for 1h
Dry at 110℃ for 1h
Table A2 pH value of standard buffer solution
Temperature,
10.12 g/L Potassium dihydrogen phthalate
3. 388 g/L Potassium dihydrogen phosphate+
3.533 g/L Sodium chloride phosphate
1.179 g/L Potassium dihydrogen phosphate-
4. 302 g/L Sodium hydrogen phosphate
Additional remarks:
This standard was proposed by the Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of the Carbon Black Industry Research and Design Institute of the Ministry of Chemical Industry. This standard was drafted by the Carbon Black Industry Research and Design Institute of the Ministry of Chemical Industry. The main drafters of this standard are Yu Lian and Meng Chuanying. 6. 881
Requirements for water quality of distilled water
It is not necessary to remove dissolved
Carbon dichloride
It is not necessary to remove dissolved
Carbon dioxide
It is not necessary to remove dissolved
Carbon dioxide
It is not necessary to remove dissolved
Carbon dioxide
It is not necessary to remove dissolved
Carbon dioxide
Reagent grade
Analytical pure
Analytical pure
Analytical pure
Analytical pure
This standard adopts the industrial standard JIS K1469-84 (89) (method for determination of pH value in acetylene black) equivalently.
Tip: This standard content only shows part of the intercepted content of the complete standard. If you need the complete standard, please go to the top to download the complete standard document for free.