This standard specifies the method for determining the pH value of carbon black. This standard is applicable to the determination of pH value of S212, S315, N472, natural gas semi-reinforced and natural gas tank carbon black, mixed gas carbon black and other varieties in rubber carbon black. GB/T 3780.7-1996 Determination of pH value of carbon black GB/T3780.7-1996 Standard download decompression password: www.bzxz.net

GB/T 3780. 7-1996
This standard is equivalent to the American Society for Testing and Materials standard ASTMD1512-93 "Determination of pH value of carbon black". The main technical differences between this standard and ASTMD1512-93 are: this standard only stipulates a method of boiling carbon black slurry to determine the pH value of carbon black, while ASTM D1512 stipulates two methods, namely boiling carbon black slurry method and ultrasonic slurry method. According to the domestic actual situation, only one boiling carbon black slurry method is formulated, which can fully meet the requirements of the carbon black industry.
The reagents used in the process of determining the pH value of carbon black are fully in line with the national standard analytical reagents. After years of practice, domestic reagents have reached the level of international similar reagents.
This standard stipulates that distilled water should be boiled in a flask, while ASTMD1512 uses stainless steel or copper containers. After practice, the use of flasks to boil distilled water meets the requirements.
The differences between this standard and the original GB/T3780.7-83 in terms of technical content: a) The scope and content have been changed, and the corresponding content of ASTMD1512-93 has been adopted equivalently: b) The results are expressed according to the actual situation in China, and the repeatability of 0.72 pH units specified in the original GB/T3780.7--83 is changed to the allowable difference of 0.5 pH units:
c) Appendix A of the original GB/T3780.7-83 is a supplement. According to the provisions of GB/T1.1-1993, Appendix A of this standard is revised to the appendix of the standard.
This standard was first issued in June 1983. This revision is a revision of the first edition. This standard replaces GB/T 3780.7-83 from the date of entry into force.
Appendix A of this standard is the appendix of the standard.
This standard is 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: Carbon Black Industry Research and Design Institute, Ministry of Chemical Industry. The main drafter of this standard: Yu Lian.
1 Scope
National Standard of the People's Republic of China
Determination of pH value of carbon black
Carbon black -- Determination of pH value1.1 This standard specifies the method for determining the pH value of carbon black. GB/T 3780.7—1996
Replaces GB/T 3780. 7—83
1.2 This standard is applicable to the determination of pH value of S212, S315, N472, natural gas semi-reinforced and natural gas tank carbon black, mixed gas carbon black and other varieties in rubber carbon black.
2 Referenced standards
The provisions contained in the following standards constitute the provisions of the standards through reference in this standard. At the time of publication of the standard, the versions shown are valid. All standards will be revised. All parties using this standard should explore the possibility of using the latest version of the following standards. GB 3778—94 Carbon black for rubber
GB/T6682—92 Specifications and test methods for water used in analytical laboratories 3 Instruments
3. 1 pH meter: accuracy ±0. 11.
3.2 Flask, capacity 500cm or 1000cm.
3.3 Electric furnace or hot plate.
3. 4 High-speed grinder, mixer or mortar and mortar.
3.5 Glass beaker, capacity 100cm.
3.6 Industrial balance: accurate to 0.1 mg.
3.7 Analytical balance: accurate to 0.1 mg.
3.8 Surface blood: for covering beaker (3.5).
4 Reagents
4.1 Sodium carbonate (Na:CO,); analytical grade.
Sodium bicarbonate (NaHCO.): analytical grade.
4.395% ethanol (C,H,OH), analytical grade.
4.4 Propane (CH,COCHa): analytical grade.
4.5 Disodium hydrogen phosphate (Na,HPO,): analytical grade. 4.6 Potassium dihydrogen phosphate (KH,FO,): analytical grade. 4.7 Potassium hydrogen phthalate (KHCH,O,): analytical grade. Instructions for use:
1I The sugar content of the pH meter used in ASTM D1512 is ±0.05. 2] ASTM D1512 stipulates the use of non-inductive or copper flasks, National Inspection and Technical Supervision Period 1996-10-28 Approved 1997-06-01 Yi Shi
GB/T 37B0.7—1996
4.8 Distilled water: Meet the requirements of GB/T6682 Grade 3 water. - Before use, it should be placed in a chemically resistant glass container (3.2) and boiled for 5 to 10 minutes and then covered and cooled. The tube should not be placed for more than 30 minutes. 4.9 Standard buffer solution: PH 4.00, 7.00; 10.00 (see Appendix A). 5 Sampling
5.1 Follow Section 6.2 of GB377894. 6 Steps
6.1 Grind the granular or block carbon black into powder using a high-speed grinder, mixer or grinder and grinder. 6.2 Weigh 5g of carbon black to 0.1g and transfer it to a 100cm* beaker. 6.3 Add 10cm of boiled and cooled distilled water (4.8) for every gram of carbon black, add 50cm of distilled water, and then add 2 to 3 drops of acetone or 95% ethanol to facilitate wetting the sample.
6.4 Cover the surface III on the glass beaker and boil it on the electric stove or hot plate for 15 minutes. Note that it is not allowed to boil to dryness. 6.5 Remove the beaker, cover the surface blood and cool to room temperature in an environment not contaminated by chemical gases. 6.6 At the test temperature, calibrate the instrument (pH meter) with a standard buffer solution (see Appendix A) with a pH value close to that of the carbon monoxide according to the instrument operation procedure, rinse the electrode with distilled water, and clean the electrode after each test. 6.7 Pour off the upper clear liquid of the beaker (6.5), put the electrode in the slurry, and gently rotate the beaker in different directions until a stable pH value is obtained, and record the pH value, reading to 0:1pH. 6.8 Rinse the electrode with distilled water and clean it. When the test is completed, the glass electrode should be soaked in distilled water. 7 Results display
7.1 The pH value of the black sample is indicated by the number displayed on the pH meter. 7.2 Allowable difference: The difference between two measurement results shall not exceed 0.5pH. 8 Test report
B.1 The test report shall include the following items.
B.1.1 National standard number on which this test is based; 8.1.2 Type and mark of sample,
8. 1.3 Test results, accurate to 0.1 pH. Instructions for use:
1] ASTM D1512 does not specify the boiling time of distilled soil water. Al
Preparation of standard blasting solution
GB/T3780.71996
Appendix A
(Appendix of the standard)
Standard buffer solution
The preparation method of standard buffer solution is shown in Table A1, and its pH value at different temperatures is shown in Table A2. Table A1 Standard buffer solution
Reagent name
Potassium hydrogen phthalate
Potassium dihydrogen phosphate
KH,PO,
Disodium hydrogen phosphate
Potassium dihydrogen phosphate
Disodium hydrogen phosphate
Na2HPO
Sodium ammonium carbonatewwW.bzxz.Net
Sodium carbonate
Temperature, °C
10.12 g/L Potassium hydrogen phthalate
3. 388 g/L Dihydrogen phosphate
Potassium + 3.533 g/L Phosphoric acid
1. 179 g/L Dihydrogen phosphate
Potassium + 4.302 g/L Phosphate gel
Disodium nitrogen
2. 092 g/L sodium bicarbonate
+2.640g/L sodium carbonate
Solution liquid
Reagent treatment
Dry at 110 for 1h
Burn at 270℃ for 1h
Water quality requirements for distilled water
No need to remove dissolved
Carbon dioxide
Boil for 15min
Table A2 Standard buffer solution pH value and temperature correspondence table 0
4, 015
Reagent grade
Analytical grade
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