Some standard content:
Record number: 2766-1999
HG/T 2968-1999
This standard adopts the American Society for Testing and Materials standard ASTMD595:1985 (confirmed in 1990) "Specifications for anhydrous sodium pyrophosphate" and is a revision of the chemical industry standard HG/T2968-1988 "Industrial sodium pyrophosphate". The main technical differences between this standard and the ASTM standard are as follows:
1ASTM standard is the specification of anhydrous sodium pyrophosphate; this standard is divided into two categories: anhydrous sodium pyrophosphate and sodium pyrophosphate decahydrate, among which anhydrous sodium pyrophosphate is divided into three grades: superior product, first-class product, and qualified product. 2ASTM standard sets two indicators: main content and water-insoluble matter; this standard adds pH value and orthophosphate indicators based on the actual production situation of my country's products.
3ASTM standard water-insoluble matter index is 0.20%; this standard sodium pyrophosphate decahydrate water-insoluble matter index is 0.10%. 4 In terms of analytical methods, the analytical method of the main content of this standard is equivalent to the American Society for Testing and Materials standard ASTMD501:1989 "Sampling and chemical analysis methods for alkaline detergents - determination method of sodium pyrophosphate", which is equivalent to the international standard IS2999 "Industrial sodium pyrophosphate - determination of pyrophosphate content - potentiometric method". The requirements and test methods of this standard are basically consistent with HG/T2968--1988, and appropriate modifications have been made in terms of scope and marking, packaging, transportation, storage, etc.
From the date of entry into force, this standard will replace Appendix A of HG/T2968-1988 as the appendix of the standard.
This standard was proposed by the Technical Supervision Department of the former Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of the inorganic salt product standardization technical unit of the Ministry of Chemical Industry. The drafting units of this standard are: Tianjin Chemical Research Institute of the Ministry of Chemical Industry, Lianyungang Hongqi Chemical Plant. The main drafters of this standard are: Liu Zhen, Shi Jie, and Pan Hangjun. This standard was first issued as a national standard in March 1988 and was adjusted from a national standard to a recommended chemical industry standard in 1992. The Ministry of Chemical Industry's inorganic salt product standardization technical unit is responsible for the interpretation of this standard. 932
1 Scope
Chemical Industry Standard of the People's Republic of China
Industrial Sodium Pyrophosphate
Sodiun Pyrophosphate for Industrial Use This standard specifies the requirements, test methods, marking, packaging, transportation and storage of industrial sodium pyrophosphate. HG/T 2968--1999
Replaces HG/T2968..1988
This standard applies to industrial sodium pyrophosphate, which is mainly used in detergents, auxiliaries for fine bleaching, water treatment agents, electroplating and oil drilling.
2 Referenced Standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard was published, the versions shown were all valid. All standards are subject to revision and parties using this standard should investigate the possibility of using the most recent versions of the following standards. GB191—90 Pictorial symbols for packaging, storage and transportation
GB/T 601--88 Preparation of standard solutions for titration analysis (volumetric analysis) of chemical reagents GB/T602--88 Preparation of standard solutions for determination of impurities of chemical reagents (neqISO6353-1:1982) GB/T603-—88 Preparation of preparations and products used in test methods for chemical reagents (neqISO6353-1:1982) GB/T6678—86 General rules for sampling of chemical products GB/T6679—86 General rules for sampling of solid chemical products GB/T6682--92 Specifications and test methods for water used in analytical laboratories (eqvISO3696:1987) GB/T 8946—88
3 Plastic woven bags
3 Classification
Industrial sodium pyrophosphate is divided into two categories: anhydrous sodium pyrophosphate and decahydrate sodium pyrophosphate. 3.1 Anhydrous sodium pyrophosphate
Molecular formula: NaP,O,
Relative molecular mass: 265.90 (according to the 1995 international relative atomic mass) 3.2 Sodium pyrophosphate decahydrate
Molecular formula: NaaP,O,·10H,0
Relative molecular mass: 446.05 (according to the 1995 international relative atomic mass) 4 Requirements
4.1 Appearance: This product is white powder or crystal. 4.2 Technical indicators should meet the requirements of Table 1.
Promulgated by the State Administration of Petroleum and Chemical Industry on April 20, 1999 and implemented on April 1, 2000
Main content/%
Water-insoluble matter content/%
pH value (10g/L solution)
Orthophosphate
5Test method
Superior product
HG/T2968--1999
Table 1 Requirements
Anhydrous sodium pyrophosphate (NaP.O,)
First-class product
Qualified product
Pass the test
+Hydrated sodium pyrophosphate (NaP ()·10HzO) 98.0
The reagents and water used in this standard, unless otherwise specified, refer to analytical pure reagents and grade 3 water specified in GB/T6682. The standard titration solutions, impurity standard solutions, preparations and products used in the test, unless otherwise specified, are prepared in accordance with the provisions of (GB/T601, GB/T602, GB/T603.
Safety Tips: Be careful when using strong acids and alkalis in the test. 5.1 Determination of Sodium Pyrophosphate Content
5.1.1 Method Summary
Sodium pyrophosphate reacts with hydrochloric acid to form disodium dihydrogen pyrophosphate. Zinc sulfate is added to the solution to form zinc pyrophosphate precipitation and sulfuric acid. The generated sulfuric acid is titrated with sodium hydroxide standard titration solution. This method is only used to determine sodium pyrophosphate. When polyphosphate is present, this method is not Accurate. 5.1.2 Reagents and materials
5.1.2.1 Hydrochloric acid solution: 1+20 and 1+100. 5.1.2.2 Sulfuric acid solution: 1+500.
5.1.2.3 Zinc sulfate solution: 125g/1 (adjust to pH 3.8). Preparation: Dissolve 125g zinc sulfate (ZnSO·7H2O) in water, dilute to 1L, and adjust the pH value to 3.8 on a pH meter using sulfuric acid solution or sodium hydroxide solution.
5.1.2.4 Anhydrous sodium pyrophosphate: Recrystallize sodium pyrophosphate from water three times [preparation method see Appendix A (Standard Appendix)] and place in a platinum crucible. Incubate at 400℃ to constant weight.
5.1.2.5 Standard sodium hydroxide titration solution: c(NaOH) is about 0.1mol/L. Calibration: Weigh about 0.5g of anhydrous sodium pyrophosphate (5.1.2.4) (accurate to 0.0002g), place in a 250mL beaker, add 90ml of water to dissolve, add hydrochloric acid solution while stirring to adjust the solution pH to 3.8, and then calibrate according to the steps described in 5.1.4, starting from "add 50mL of zinc sulfate solution".
The number of grams of sodium pyrophosphate (T) equivalent to each milliliter of sodium hydroxide standard titration solution is calculated according to formula (1): T=m
where: m.--the mass of anhydrous sodium pyrophosphate (5.1.2.4), g; V,--the volume of sodium hydroxide standard titration solution consumed in calibration, mL. 5.1.3 Instruments and equipment
5.1.3.1 Potentiometric titrator or pH meter: the graduation value is 0.01mV or 0.1pH unit. 5.1.3.2 Magnetic stirrer.
5.1.4 Analysis steps
Weigh about 5g of sample (accurate to 0.0002g), dissolve the sample in water, transfer to a 500ml volumetric flask, dilute to the scale and shake, filter if necessary.
HG/T 2968—-1999
Use a pipette to transfer 50 ml of the test solution into a 250 ml beaker, add 40 ml of water, and slowly add hydrochloric acid solution while stirring to adjust the solution pH to 3.8. Add 50 ml of zinc sulfate solution and stir for 5 min. Titrate with sodium hydroxide standard titration solution while stirring until the solution pH is close to 3.6, stop titration, stir for 2 min to allow the solution to reach equilibrium, and continue titrating until the pH is 3.8. At this time, stir for 30 seconds after adding each drop. 5.1.5 Expression of analysis results
The content of sodium pyrophosphate (NaP,O,) expressed as mass percentage (X) is calculated according to formula (2): × 100 = 1 000 V
X =
m × 500
The content of sodium pyrophosphate decahydrate X, (calculated as NaP,O,·10H,O) expressed as mass percentage (X,) is calculated according to formula (3): X,
TV. X1.678 × 100 = 1.678 TV50
m×500
Number of grams of anhydrous sodium pyrophosphate equivalent to each milliliter of sodium hydroxide standard titration solution, g/mL; where.T-—
Volume of sodium hydroxide standard titration solution consumed by the titration test solution, ml; mass of the test sample, g;
Coefficient for converting anhydrous sodium pyrophosphate into sodium pyrophosphate decahydrate. 5.1.6 Allowable difference
The arithmetic mean of the parallel determination results is taken as the determination result. The absolute difference of the parallel determination results shall not exceed 0.3%. 5.2 Determination of water-insoluble matter content
5.2.1 Summary of the method
After the sample is dissolved in water, it is filtered, washed, dried and weighed. 5.2.2 Instruments and equipment
5.2.2.1 Glass crucible: filter plate pore size 5μm~15um; 5.2.2.2 Electric oven: control temperature (105±2)℃. 5.2.3 Analysis steps
·(2))
(3)
Weigh 20.0g sample (accurate to 0.1g), place it in a 400ml beaker, add 200ml water and heat to dissolve, filter with a glass crucible that has been kept constant at (105±2)℃, wash with hot water until the filtrate is not alkaline, and test with a wide range pH test paper. Place the glass crucible in a (105±2)℃ oven and dry until constant weight. 5.2.4 Expression and calculation of analysis results
The water-insoluble content (X2) expressed as a mass percentage is calculated according to formula (4): Xz = m = m × 100
Wherein: m1—mass of glass crucible, g;
mass of residue and glass crucible, g;
mass of sample, g.
5.2.5 Allowable difference
The arithmetic mean of the parallel determination results is taken as the determination result. The absolute difference of the parallel determination results shall not exceed 0.02%. 5.3 Determination of pH value
5.3.1 Summary of method
The glass electrode and the reference electrode are immersed in the test solution to form a primary cell, whose potential is related to the pH value of the solution. The pH value of the solution can be obtained by measuring the potential of the primary cell. 5.3.2 Reagents and materials
Water without carbon dioxide.
5.3.3 Instruments and equipment
pH meter: the graduation value is 0.1pH unit.
5.3.4 Analysis steps
HG/T 2968—1999
Connect the reference electrode and the measuring electrode to the acidometer, preheat, zero and position. Weigh about 1g of the sample (accurate to 0.01g), place it in a 100ml beaker, dissolve it in water without carbon dioxide, transfer it to a 100mL volumetric flask, dilute to the scale, and shake it well. Pour it into a 100ml dry beaker and use a pH meter to determine the pH value of the test solution. 5.3.5 Allowable difference
Take the arithmetic mean of the parallel determination results as the determination result. The absolute difference of the parallel determination results shall not exceed 0.1pH unit. . 5.4 Inspection of orthophosphate
5.4.1 Reagents and materials
Silver nitrate solution: 50g/L.
5.4.2 Analysis steps
Weigh 1.0g of the sample ground into powder, add 2~~3 drops of silver nitrate solution, and no obvious yellow color should be produced. 6 Inspection rules
6.1 All four indicators specified in the requirements of this standard are type inspection items, among which the main content, pH value and orthophosphate are routine inspection items and should be inspected batch by batch. Under normal circumstances, type inspection shall be carried out at least once every three months. 6.2 Each batch of products shall not exceed 10t.
6.3 Determine the number of sampling units in accordance with 6.6 of GB/T6678-1986. Each bag is a packaging unit. When sampling, insert the sampler obliquely from the top of the packaging bag to 3/4 of the material layer for sampling. After mixing the collected samples, reduce them to about 500g by quartering method, and immediately put them into two clean and dry wide-mouth bottles with ground stoppers and seal them. Paste labels on the bottles, indicating the manufacturer's name, product name, grade, batch number, sampling date and name of the sampler. One bottle is used as a laboratory sample, and the other bottle is kept for three months for reference. 6.4 Industrial sodium pyrophosphate should be inspected by the quality supervision and inspection department of the manufacturer in accordance with the provisions of this standard. The manufacturer should ensure that each batch of products shipped from the factory meets the requirements of this standard. If one indicator of the test results does not meet the requirements of this standard, re-samples should be taken from twice the amount of packaging for re-testing. Even if only one indicator of the re-test results does not meet the requirements of this standard, the entire batch of products will be unqualified. 6.5 Determine whether the test results meet the standards according to the rounded value comparison method specified in 5.2 of GB/T1250--1989. 7 Marking, packaging, transportation, storage
7.1 The packaging bags of industrial sodium pyrophosphate should have firm and clear markings, including the manufacturer's name, address, product name, trademark, category, grade, net content, batch number or production date, shelf life, this standard number, and the "wet-afraid" mark in GB191. 7.2 Each batch of industrial sodium pyrophosphate shipped out of the factory should be accompanied by a quality certificate. The content includes the manufacturer's name, address, product name, trademark, grade, net content, proof that the product quality meets this standard and this standard number. 7.3 Industrial sodium pyrophosphate is double-layered. The inner packaging is a polyethylene film bag with a thickness of not less than 0.07mm; the outer packaging is a plastic woven bag, and its performance and inspection methods should comply with the provisions of GB/T8946B. The net content of each bag is 25kg or 50kg. 7.4 For the packaging of industrial sodium pyrophosphate, the film bag should be tied with vinyl rope or rope of equivalent quality, or sealed with other equivalent methods; the outer bag should be folded at a distance of not less than 30mm from the bag edge, and the opening should be sewed with vinyl thread or other thread of equivalent quality at a distance of not less than 15mm from the bag edge. The stitches should be neat and the stitch length should be uniform. There should be no leakage or skipping. 7.5 Industrial sodium pyrophosphate should be covered during transportation to prevent it from being exposed to the sun, rain, and moisture. It should not be transported together with toxic and hazardous items. Prevent pollution. wwW.bzxz.Net
7.6 Industrial sodium pyrophosphate should be stored in a cool and dry place to prevent it from being exposed to rain, moisture, and sunlight. 936
HG/T2968—1999
Appendix A
(Appendix to the standard)
Preparation method of thrice-crystallized sodium pyrophosphate
First crystallization: weigh 30g of industrial anhydrous sodium pyrophosphate, place it in a 400mL beaker, add 100ml of water, heat to dissolve, and filter with medium-speed quantitative filter paper. Cool the filtrate in a cold water bath, precipitate crystals, pour out the solution, and wash the crystals twice with a small amount of water. Second crystallization: Heat and dissolve the first crystals with a small amount of water, cool in a cold water bath, precipitate crystals, and pour out the solution. Third crystallization: Recrystallize the second crystals once according to the second crystallization method. If the reagent sodium pyrophosphate decahydrate is used, weigh 80g and operate according to the first and second crystallization methods. 9374 Analysis steps
HG/T 2968—1999
Connect the reference electrode and the measuring electrode to the acidometer, preheat, zero and position. Weigh about 1g of the sample (accurate to 0.01g), place it in a 100ml beaker, dissolve it in water without carbon dioxide, transfer it to a 100mL volumetric flask, dilute to the scale, and shake it well. Pour it into a 100ml dry beaker and use a pH meter to determine the pH value of the test solution. 5.3.5 Allowable difference
Take the arithmetic mean of the parallel determination results as the determination result. The absolute difference of the parallel determination results shall not exceed 0.1pH unit. . 5.4 Test for orthophosphate
5.4.1 Reagents and materials
Silver nitrate solution: 50g/L.
5.4.2 Analysis steps
Weigh 1.0g of the sample ground into powder, add 2~~3 drops of silver nitrate solution, and no obvious yellow color should be produced. 6 Inspection rules
6.1 All four indicators specified in the requirements of this standard are type inspection items, among which the main content, pH value and orthophosphate are routine inspection items and should be inspected batch by batch. Under normal circumstances, type inspection shall be carried out at least once every three months. 6.2 Each batch of products shall not exceed 10t.
6.3 Determine the number of sampling units in accordance with 6.6 of GB/T6678-1986. Each bag is a packaging unit. When sampling, insert the sampler obliquely from the top of the packaging bag to 3/4 of the material layer for sampling. After mixing the collected samples, reduce them to about 500g according to the quartering method, and immediately put them into two clean and dry wide-mouth bottles with ground stoppers and seal them. A label is attached to the bottle, indicating the manufacturer's name, product name, grade, batch number, sampling date and the name of the sampler. One bottle is used as a laboratory sample, and the other is kept for three months for reference. 6.4 Industrial sodium pyrophosphate should be inspected by the quality supervision and inspection department of the manufacturer in accordance with the provisions of this standard. The manufacturer should ensure that each batch of products shipped out of the factory meets the requirements of this standard. If one of the indicators in the inspection results does not meet the requirements of this standard, the sample should be re-tested from twice the amount of packaging. Even if only one indicator does not meet the requirements of this standard in the re-test results, the entire batch of products is unqualified. 6.5 Determine whether the test results meet the standards according to the rounded value comparison method specified in 5.2 of GB/T1250--1989. 7 Marking, packaging, transportation, storage
7.1 The packaging bag of industrial sodium pyrophosphate should have firm and clear markings, including the manufacturer's name, address, product name, trademark, category, grade, net content, batch number or production date, shelf life, this standard number, and the "wet-afraid" mark in GB191. 7.2 Each batch of industrial sodium pyrophosphate shipped out of the factory should be accompanied by a quality certificate. The content includes the manufacturer's name, address, product name, trademark, grade, net content, proof that the product quality complies with this standard and the number of this standard. 7.3 Industrial sodium pyrophosphate is double-packed. The inner packaging is a polyethylene film bag with a thickness of not less than 0.07mm; the outer packaging is a plastic woven bag, and its performance and inspection methods should comply with the provisions of GB/T8946B. The net content of each bag is 25kg or 50kg. 7.4 For the packaging of industrial sodium pyrophosphate, the film bag is tied with vinyl rope or a rope of equivalent quality, or sealed with other equivalent methods; the outer bag is folded at a distance of not less than 30mm from the edge of the bag, and the edge is sewn with vinyl thread or other thread of equivalent quality at a distance of not less than 15mm from the edge of the bag. The stitches are neat and the stitch length is uniform. There is no leakage or skipping. 7.5 Industrial sodium pyrophosphate should be covered during transportation to prevent sun exposure, rain and moisture. It must not be transported together with toxic and hazardous items. Prevent pollution.
7.6 Industrial sodium pyrophosphate should be stored in a cool, dry place to prevent rain, moisture and sunlight. 936
HG/T2968—1999
Appendix A
(Appendix to the standard)
Preparation method of three-crystallized sodium pyrophosphate
First crystallization: weigh 30g of industrial anhydrous sodium pyrophosphate, place it in a 400mL beaker, add 100ml of water, heat to dissolve, and filter with medium-speed quantitative filter paper. Cool the filtrate in a cold water bath, precipitate crystals, pour out the solution, and wash the crystals twice with a small amount of water. Second crystallization: Heat and dissolve the first crystals with a small amount of water, cool in a cold water bath, precipitate crystals, and pour out the solution. Third crystallization: Recrystallize the second crystals once according to the second crystallization method. If the reagent sodium pyrophosphate decahydrate is used, weigh 80g and operate according to the first and second crystallization methods. 9374 Analysis steps
HG/T 2968—1999
Connect the reference electrode and the measuring electrode to the acidometer, preheat, zero and position. Weigh about 1g of the sample (accurate to 0.01g), place it in a 100ml beaker, dissolve it in water without carbon dioxide, transfer it to a 100mL volumetric flask, dilute to the scale, and shake it well. Pour it into a 100ml dry beaker and use a pH meter to determine the pH value of the test solution. 5.3.5 Allowable difference
Take the arithmetic mean of the parallel determination results as the determination result. The absolute difference of the parallel determination results shall not exceed 0.1pH unit. . 5.4 Test for orthophosphate
5.4.1 Reagents and materials
Silver nitrate solution: 50g/L.
5.4.2 Analysis steps
Weigh 1.0g of the sample ground into powder, add 2~~3 drops of silver nitrate solution, and no obvious yellow color should be produced. 6 Inspection rules
6.1 All four indicators specified in the requirements of this standard are type inspection items, among which the main content, pH value and orthophosphate are routine inspection items and should be inspected batch by batch. Under normal circumstances, type inspection shall be carried out at least once every three months. 6.2 Each batch of products shall not exceed 10t.
6.3 Determine the number of sampling units in accordance with 6.6 of GB/T6678-1986. Each bag is a packaging unit. When sampling, insert the sampler obliquely from the top of the packaging bag to 3/4 of the material layer for sampling. After mixing the collected samples, reduce them to about 500g according to the quartering method, and immediately put them into two clean and dry wide-mouth bottles with ground stoppers and seal them. A label is attached to the bottle, indicating the manufacturer's name, product name, grade, batch number, sampling date and the name of the sampler. One bottle is used as a laboratory sample, and the other is kept for three months for reference. 6.4 Industrial sodium pyrophosphate should be inspected by the quality supervision and inspection department of the manufacturer in accordance with the provisions of this standard. The manufacturer should ensure that each batch of products shipped out of the factory meets the requirements of this standard. If one of the indicators in the inspection results does not meet the requirements of this standard, the sample should be re-tested from twice the amount of packaging. Even if only one indicator does not meet the requirements of this standard in the re-test results, the entire batch of products is unqualified. 6.5 Determine whether the test results meet the standards according to the rounded value comparison method specified in 5.2 of GB/T1250--1989. 7 Marking, packaging, transportation, storage
7.1 The packaging bag of industrial sodium pyrophosphate should have firm and clear markings, including the manufacturer's name, address, product name, trademark, category, grade, net content, batch number or production date, shelf life, this standard number, and the "wet-afraid" mark in GB191. 7.2 Each batch of industrial sodium pyrophosphate shipped out of the factory should be accompanied by a quality certificate. The content includes the manufacturer's name, address, product name, trademark, grade, net content, proof that the product quality complies with this standard and the number of this standard. 7.3 Industrial sodium pyrophosphate is double-packed. The inner packaging is a polyethylene film bag with a thickness of not less than 0.07mm; the outer packaging is a plastic woven bag, and its performance and inspection methods should comply with the provisions of GB/T8946B. The net content of each bag is 25kg or 50kg. 7.4 For the packaging of industrial sodium pyrophosphate, the film bag is tied with vinyl rope or a rope of equivalent quality, or sealed with other equivalent methods; the outer bag is folded at a distance of not less than 30mm from the edge of the bag, and the edge is sewn with vinyl thread or other thread of equivalent quality at a distance of not less than 15mm from the edge of the bag. The stitches are neat and the stitch length is uniform. There is no leakage or skipping. 7.5 Industrial sodium pyrophosphate should be covered during transportation to prevent sun exposure, rain and moisture. It must not be transported together with toxic and hazardous items. Prevent pollution.
7.6 Industrial sodium pyrophosphate should be stored in a cool, dry place to prevent rain, moisture and sunlight. 936
HG/T2968—1999
Appendix A
(Appendix to the standard)
Preparation method of three-crystallized sodium pyrophosphate
First crystallization: weigh 30g of industrial anhydrous sodium pyrophosphate, place it in a 400mL beaker, add 100ml of water, heat to dissolve, and filter with medium-speed quantitative filter paper. Cool the filtrate in a cold water bath, precipitate crystals, pour out the solution, and wash the crystals twice with a small amount of water. Second crystallization: Heat and dissolve the first crystals with a small amount of water, cool in a cold water bath, precipitate crystals, and pour out the solution. Third crystallization: Recrystallize the second crystals once according to the second crystallization method. If the reagent sodium pyrophosphate decahydrate is used, weigh 80g and operate according to the first and second crystallization methods. 937
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