Some standard content:
Registration No.: 7249-2000
HG/T 2965--2000
This standard is a text conversion of the chemical industry standard HG/T2965--1985 (1997) "Disodium Hydrogen Phosphate". The main differences between this standard and HG/T2965--1985 are: - "Disodium Hydrogen Phosphate" is changed to "Industrial Disodium Hydrogen Phosphate". - The determination of chloride content adopts GB/T3050--2000. From the date of implementation, this standard will replace HG/T2965--1985. This standard is proposed by the Policy and Regulations Department of the State Administration of Petroleum and Chemical Industry. This standard is under the jurisdiction of the Inorganic Chemical Branch of the National Chemical Standardization Technical Committee. The responsible drafting units of this standard are: Tianjin Chemical Research and Design Institute and Jiangsu Chengxing Phosphorus Chemical Group. The main drafter of this standard is: Li Guangming.
This standard was first issued in 1970, revised and changed to a national standard in 1985, adjusted to a chemical industry standard in 1992, and converted to HG/T2965-1985 in 1997.
This standard is interpreted by the Inorganic Chemical Branch of the National Technical Committee for Chemical Standardization. 911
Chemical Industry Standard of the People's Republic of China
Industrial disodium hydrogen phosphate
Disodium hydrogen phosphate for industrial useHG/T 2965-2000
Replaces HG/T2965--1985
This standard specifies the requirements, test methods, inspection rules, and marking, labeling, packaging, transportation, and storage of industrial disodium hydrogen phosphate. This standard applies to industrial disodium hydrogen phosphate, which is mainly used as industrial raw materials for chemicals, papermaking, leather, water treatment, etc. Molecular formula: NazHPO4·12H2O
Relative molecular mass: 357.96 (according to the 1997 International Relative Atomic Mass) Reference 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 are subject to revision. Parties using this standard should explore the possibility of using the latest versions of the following standards: GB/T 601
GB/T 602-
GB/T 603
Chemical reagents
Preparation of standard solutions for titration analysis (volume analysis) Chemical reagents
Preparation of standard solutions for impurity determination (neqISO6353-1:1982) Preparation of preparations and products used in chemical reagent test methods (neqISO6353-1:1982) GB/T 610. 1—1988
GB/T 1250
GB/T 3050--2000
GB/T 6678-1986
GB/T 6682-1992
3 Requirements
Chemical reagents General method for determination of arsenic (arsenic spot method) Method for expressing and determining limit values General method for determination of nitride content in inorganic chemical products Potentiometric titration (neqISO6227:1982) General rules for sampling of chemical products
Specifications and test methods for water used in analytical laboratories (neqISO3696:1987) Appearance: White uniform quicksand-like crystals.
3.2 Industrial disodium hydrogen phosphate shall meet the requirements of Table 1. Table 1 Requirements
Content of disodium hydrogen phosphate (as Na2HPO4-12Hz0)/%Content of sulfate (as SO4)/%
Content of chloride (as CI)/%
Content of arsenic (As)/%
Content of fluoride (as F)/%
Content of water-insoluble matter/%
pH value (1% aqueous solution)
Approved by the State Administration of Petroleum and Chemical Industry on May 23, 2000912
First-class product
Qualified product
Implemented on December 1, 2000
4 Test method
HG/T 2965—2000
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, shall be prepared in accordance with the provisions of GB/T601, GB/T602 and GB/T603.
4.1 Determination of disodium hydrogen phosphate content
4.1.1 Summary of the method
In an acidic medium, all phosphates in the test solution form a precipitate with the added quinomolybdate, which is filtered, dried and weighed to calculate the disodium hydrogen phosphate content.
4.1.2 Reagents and materials
4.1.2.1 Sodium molybdate.
4.1.2.2 Citric acid.
4.1.2.3 Hydrochloric acid solution: 1+1.
4.1.2.4 Nitric acid solution: 1+1.
4.1.2.5 Quinomolybdate solution.
Preparation:
a) Weigh 70g sodium molybdate and dissolve it in 100mL water, this solution is I; b) Weigh 60g citric acid and dissolve it in 150mL water and 85mL nitric acid, this solution is II; c) Pour solution I into solution II under stirring, this solution is III; d) Add 35mL nitric acid and 5mL quinoline to 100mL water, this solution is IV; e) Pour solution IV into solution II, let it stand for 12h, filter it with a glass crucible, add 280mL acetone, dilute it with water to 1000ml, mix well, and store it in a polyethylene bottle. 4.1.3 Instruments and equipment
4.1.3.1 Glass crucible: pore size is 5μm~15μm. 4.1.3.2 Electric oven: temperature can be controlled at (180±5)℃. 4.1.4 Analysis steps
4.1.4.1 Preparation of test solution
Weigh about 2.5g of sample (accurate to 0.0002g). Place in a 100mL beaker, add .50mL of water to dissolve, transfer to a 500mL volumetric flask, dilute to scale with water, and shake well. 4.1.4.2 Preparation of blank solution
Except for not adding sample, the amount of other reagents added is exactly the same as that of the test solution, and the same treatment is performed at the same time as the sample. 4.1.4.3 Determination bzxz.net
Use a pipette to transfer 20 mL of the test solution and blank solution into a 250 mL beaker, add 10 mL of nitric acid solution, add water to a total volume of about 100 mL, heat and boil for 5 minutes, add 50 mL of quinoline molybdate solution, cover the surface with blood, heat in a water bath until the content in the beaker reaches (75 ± 5) ° C, and keep warm for 30 seconds (do not use open flames or stir during the addition of reagents and heating to avoid condensation). Cool, stir 3 to 4 times during the cooling process, and filter with a glass sand crucible that has been dried to constant weight at (180 ± 5) ° C in advance. First, filter the supernatant liquid, rinse the precipitate with a washing bottle 6 times by decantation method, using about 30 mL of water each time. Finally, transfer the precipitate into a glass crucible for filtration, and then wash the precipitate with water 4 times. Place the glass crucible together with the precipitate in an electric oven and start counting from the time the temperature stabilizes. Dry it at (180 ± 5) °C for 45 min. Take it out and cool it slightly, then place it in a desiccator to cool to room temperature and weigh it. 4.1.5 Expression of analysis results
The content of disodium hydrogen phosphate (calculated as NazHPO4·12H2O) expressed as mass percentage (Xi) shall be calculated according to formula (1): Xi = (m-m-a)X0.1618
404. 5(ml-m2)
m×500
×100=
·（1）
Wherein: mt-
HG/T2965—2000
the mass of quinoline phosphomolybdic acid precipitate generated in the test solution, g; the mass of quinoline phosphomolybdic acid precipitate generated in the vacuum solution, g; m --
the mass of the sample, g;
0.1618—·the coefficient for converting quinoline phosphomolybdic acid into disodium hydrogen phosphate. 4.1.6 Allowable difference
The arithmetic mean of the parallel determination results shall be taken as the determination result. The absolute difference of the parallel determination results shall not exceed 0.3%. 4.2 Determination of sulfate content
4.2.1 Method summary
In an acidic medium, sulfate ions and barium ions generate insoluble barium sulfate. The sulfate content is calculated based on the mass of barium sulfate. 4.2.2 Reagents and solutions
4.2.2.1 Barium chloride solution: 20g/L.
4.2.2.2 Hydrochloric acid solution: 1+1.
4.2.2.3 Silver nitrate solution: 17g/L.
4.2.2.4 Methyl orange indicator solution: 1g/.
4.2.3 Instruments and equipment
4.2.3.1 Glass sand crucible: pore size is 5μm~15um; 4.2.3.2 Electric oven: The temperature can be controlled at (180 ± 5) ℃. 4.2.4 Analysis steps
4.2.4.1 Preparation of test solution A
Weigh about 25g of sample (accurate to 0.01g), place it in a 250mL volumetric flask, dilute it with water to the mark, and shake it. Dry filter the solution and discard the first 20mL of filtrate. This solution is used for the determination of sulfate, chloride, fluoride and arsenic content. 4.2.4.2 Determination
Use a pipette to transfer 100mL of test solution A, place it in a 500mL beaker, add 250mL of water and 2 drops of methyl orange indicator solution, add hydrochloric acid solution until it turns orange, then add 6mL in excess, heat to boiling, and add 15mL of barium chloride solution under constant stirring. Heat to boiling again and keep warm in a boiling water bath for 1h. Use a glass sand crucible that has been pre-weighed at (180±5)℃ to filter the upper clear liquid, and then use hot water to wash the precipitate 3 times by pouring. Move the precipitate into the glass sand. Continue to wash the precipitate and the inner wall of the glass sand with hot water until no chloride ion reaction occurs after adding 1 drop of silver nitrate solution to every 5ml of filtrate. Place the glass sand crucible together with the precipitate in an electric oven and dry at (180±5)℃ to constant weight.
Conduct a blank test at the same time.
4.2.5 Expression of analysis results
The sulfate content (in terms of SO,) expressed as mass percentage (X,) is calculated according to formula (2): Xz = (m2 -m2)X0. 411 6
6 × 100 = 102. 9 (ml - m2)
m×250
Wherein: m2-mass of barium sulfate precipitate generated by the test solution, g; m1\—mass of barium sulfate precipitate generated by the blank solution, g; m——mass of the sample, g;
0.4116——coefficient for converting barium sulfate to sulfate. 4.2.6 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 0.03%. 4.3 Determination of chloride content
4.3.1 Summary of method
Same as Chapter 2 of GB/T3050--2000.
4.3.2 Reagents and solutions
Same as Chapter 4 of GB/T3050--2000.
4.3.3 Apparatus and equipment
Same as Chapter 3 of GB/T3050--2000.
4.3.4 Analysis steps
HG/T 2965-2000
Pipette 10 ml of test solution A into a 50 ml beaker, add 1 drop of bromophenol blue indicator solution, adjust the test solution to yellow with sodium hydroxide solution or nitric acid solution, and add 30 ml of ethanol so that the volume ratio of test solution to ethanol is 1:3. The following operations are measured according to 5.2 of GB/T30502000.
4.3.5 Expression of analytical results
The chloride content (in terms of Cl) expressed as mass percentage (X.) is calculated according to formula (3): X-
Wherein: V-
(Vi - V2) cX 0. 035 45
m×250
88. 62 X c(Vi - V2)
The volume of the standard silver nitrate solution consumed in the titration of the test solution, mL; The volume of the standard silver nitrate solution consumed in the titration of the blank solution, mL; The actual concentration of the standard silver nitrate solution, mol/L; The mass of the sample, g;
·(3)
The mass of chlorine in grams equivalent to 1.00 mL of the standard silver nitrate solution [c(AgNO,)=1.000mol/L].
4.3.6 Allowable difference
The arithmetic mean of the parallel determination results shall be taken as the determination result. The absolute difference of the parallel determination results shall not exceed 0.002%. 4.4 Determination of arsenic content
4.4.1 Silver diethyldithiocarbamate spectrophotometry (arbitration method) 4.4.1.1 Method summary
Same as Chapter 2 of GB/T7686-1987.
4.4.1.2 Reagents and materials
Same as Chapter 3 of GB/T7686-1987.
4.4.1.3 Instruments and equipment
Same as Chapter 4 of GB/T7686-1987.
4.4.1.4 Analysis steps
a) Drawing of working curve
Draw according to 5.3 of GB/T7686-1987.
b) Determination
Use a pipette to transfer 5 mL of test solution A into the conical flask of the arsenic generator, add 10 mL of hydrochloric acid solution, and add water to about 40 mL. The following operation is carried out according to 5.4 of GB/T7686-1987, from adding 2 mL of potassium iodide solution, adding 2 mL of stannous chloride solution, and... ". The corresponding content of the monument is found from the working curve. 4.4.1.5 Expression of analysis results
The arsenic (As) content (X) expressed as mass percentage is calculated according to formula (4): X4 mi ×103
m×250
Where: m, --
-the arsenic content found from the working curve, mg; the mass of the sample, g.
4.4.1.6 Tolerance
×100=
HG/T 2965--2000
The arithmetic mean of the parallel determination results shall be taken as the determination result. The absolute difference of the parallel determination results shall not exceed 0.0005%. 4.4.2 Arsenic spot method
4.4.2.1 Method summary
Same as Chapter 3 of GB/T601.1-1988.
4.4.2.2 Reagents and materials
a) Arsenic-free zinc particles.
b) Hydrochloric acid solution: 1+1.
c) Potassium iodide solution: 150g/L.
d) Substance of iodine Tin solution: 400g/L.
e) Lead acetate cotton.
f) Mercuric bromide test paper.
g) Monument standard solution: 1mL solution contains 2.5μmAs. 4.4.2.3 Instruments and equipment
Same as Chapter 5 of GB/T610.1-1988.
4.4.2.4 Analysis steps
Use a pipette to transfer 5mL of test solution A into a test bottle and add 30mL of water to dissolve. Add 10mL of hydrochloric acid solution and shake well. Add 2mL of potassium iodide solution and 1mL of stannous chloride solution. Liquid, shake the hook, and let it stand for 15 minutes. Add 2.5g of arsenic-free zinc particles, assemble the device immediately, and place it in a dark place at 25℃~~30℃ for 1h~1.5h. The brown-yellow color of the mercuric bromide test paper shall not be darker than the standard. The standard is to use a pipette to transfer 10.00mL of arsenic standard solution, and treat it in the same way as the sample except that no sample is added. 4.5 Determination of fluoride content
4.5.1 Summary of the method
After the sample is dissolved, in an acidic medium with a pH of 5.5-6.0, use a saturated calomel electrode as the reference electrode and a fluoride ion selective electrode as the reference electrode. Measuring electrode, determine the fluoride content by working curve method. 4.5.2 Reagents and materials
4.5.2.1 Hydrochloric acid solution: 1+4.
4.5.2.2 Nitric acid solution: 1+15.
4.5.2.3 Sodium hydroxide solution: 100g/L. 4.5.2.4 Buffer solution.
Dissolve 270g sodium citrate dihydrate (Na:C,HsOz·2HzO) and 24g citric acid (C.HsO, 2H2O) in 800ml. water, then dilute to 1000mL with water.
4.5.2.5 Fluoride standard solution: 0.10mgF/mL. 4.5.2.6 Potassium bromophenol green indicator solution: 1g/L. 4.5.3 Instruments and equipment
Fluoride ion selective electrode.
4.5.3.2 Saturated calomel electrode.
4.5.3.3 Potentiometer.
4.5.3.4 Electromagnetic stirrer and stirring bar.
4.5.4 Analysis steps
4.5.4.1 Drawing of working curve
Use a pipette to take the liquid with the fluorine content of 1.00mL, 2.00mL, 3.00mL, 5.00mL, 10.100mL of fluoride standard solution are placed in 50mL volumetric flasks, and 1mL of hydrochloric acid solution, 5 drops of buffer solution, and 2 drops of bromophenol green indicator solution are added to each. Adjust the solution to blue with sodium hydroxide solution, and then adjust it to yellow with nitric acid solution, add 20mL of buffer solution, dilute to the scale with water, and shake well. Pour the solution into a clean and dry 50mL beaker, place it on an electromagnetic stirrer, put a stirrer, insert the fluoride ion selective electrode and saturated 916
HG/T 2965--2000
calomel electrode connected to the potential into the solution, start the stirrer, measure the potential value of the solution, and record the potential value at equilibrium. Draw a working curve with the logarithm of the fluorine content as the horizontal axis and the corresponding potential value as the vertical axis. 4.5.4.2 Determination
Use a pipette to transfer 10.00 ml of test solution A into a 50 ml volumetric flask, add 10 ml of water, and perform the following operations as in 4.5.4.1 from "add 1 ml of hydrochloric acid solution" to "..... record the potential value at equilibrium.". Find the logarithm of the corresponding fluorine content from the working curve, and find the antilogarithm to obtain the fluorine content.
4.5.5 Expression of analysis results
The fluoride content (in terms of F) expressed as mass percentage (X:) is calculated according to the following formula (5): ×100 = 2. 5×ml
X, = mi X10-3
m×250
Wherein: mi——fluorine content found and calculated from the working curve, mg; m. mass of the sample, ..
4.5.6 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 0.002%. 4.6 Determination of water-insoluble matter
4.6.1 Instruments and equipment
4.6.1.1 Glass sand: pore size is 5μm15μm. 4.6.1.2 Electric oven: control the temperature at 105℃~110℃. 4.6.2 Points Analysis steps
Weigh about 50g of sample (accurate to 0.01g), place it in a 500ml beaker, add 250mL of water, and heat to boil. While hot, filter it with a glass crucible that has been kept constant at 105℃110℃, and wash the beaker and water-insoluble matter 10 times with hot water. Place the glass crucible together with the water-insoluble matter in an electric oven at 105℃～110℃ and dry until constant weight. 4.6.3 Expression of analysis results
The water-insoluble matter (X.) expressed as mass percentage is calculated according to formula (6): X. =me=m×100
-the mass of the glass crucible and the water-insoluble matter, g; where: mz 3
ml——mass of glass sand crucible, g;
m——mass of sample, g.
4.6.4 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 0.002%. 4.7 Determination of pH value
4.7.1 Summary of method
Immerse the indicator electrode and the reference electrode in the solution to be tested to form a primary cell, whose electromotive force is related to the pH value of the solution. The pH value of the solution can be obtained by measuring the electromotive force of the primary cell. 4.7.2 Instruments and equipment
4.7.2.1 Acidity meter: The accuracy is 0.1 pH unit. 4.7.2.2 Glass electrode: Use Soak in water for more than 24 hours before use, clean after use, and store in water. 4.7.2.3 Saturated calomel electrode.
4.7.3 Analysis steps
Weigh about 1.0g of sample, place in a 150ml beaker, and accurately add 100ml of water without carbon dioxide to dissolve. Determine the pH value of the sample solution.
5 Inspection rules
HG/T2965--2000
5.1 All items specified in this standard are factory inspection items. 5.2 Each batch of products shall not exceed 30t.
5.3 Determine the number of sampling units in accordance with the provisions of 6.6 of GB/T6678-1986. Each plastic woven bag is a packaging unit. When sampling, insert the sample obliquely from the top of each selected packaging bag to 3/4 of the depth of the material layer, take out no less than 50g of sample with a sampler, mix the sample, and reduce it to about 200g by quartering. Immediately put it into two clean and dry wide-mouth bottles with ground stoppers and seal them. Paste labels on the bottles, indicating: manufacturer name, product name, batch number, sampling date and name of the sampler. One bottle is used for inspection, and the other bottle is kept for three months for reference. 5.4 Industrial disodium hydrogen phosphate shall be inspected by the quality supervision and inspection department of the manufacturer in accordance with the provisions of this standard. The manufacturer shall ensure that all industrial disodium hydrogen phosphate shipped from the factory meets the requirements of this standard. 5.5 The user has the right to inspect and accept the industrial disodium hydrogen phosphate received in accordance with the provisions of this standard, and the inspection and acceptance shall be carried out within one month from the date of arrival.
5.6 If one of the indicators in the test results does not meet the requirements of this standard, samples should be taken from twice the amount of packaging for re-testing. If only one indicator in the re-test results does not meet the requirements of this standard, the entire batch of products shall be unqualified. 5.7 Determine whether the test results meet the standards according to the rounded value comparison method specified in GB/T1250. 6 Marks and labels
6.1 The packaging bags of industrial disodium hydrogen phosphate should have firm and clear marks, including: manufacturer name, factory address, product name, trademark, grade, net content, batch number or production date, production license number, and this standard number. 6.2 Each batch of industrial disodium hydrogen phosphate shipped from the factory should be accompanied by a quality certificate. The contents include: manufacturer name, factory address, product name, trademark, grade, net content, batch number or production date, proof that the product quality meets this standard and this standard number. Packaging, transportation, storage
7.1 The inner packaging of industrial disodium hydrogen phosphate adopts polyethylene film bags with a thickness of 0.07mm. The outer packaging adopts plastic woven bags. The net content of each bag is 50kg. If the user has special requirements for packaging, it can be negotiated. 7.2 The film bag for industrial disodium hydrogen phosphate packaging should be tied twice 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 edge of the bag, and the opening should be 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 should be neat and the stitch length should be uniform. There should be no leakage or skipping. 7.3 Industrial disodium hydrogen phosphate should be covered during transportation to prevent sun exposure and rain. 7.4 Industrial disodium hydrogen phosphate should be stored in a dry warehouse to prevent rain, moisture and sun exposure. 9181 pH unit. 4.7.2.2 Glass electrode: Soak in water for more than 24 hours before use, clean after use, and store in water. 4.7.2.3 Saturated calomel electrode.
4.7.3 Analysis steps
Weigh about 1.0g of sample, place in a 150ml beaker, and accurately add 100ml of water without carbon dioxide to dissolve. Determine the pH value of the sample solution.
5 Inspection rules
HG/T2965--2000
5.1 All items specified in this standard are factory inspection items. 5.2 Each batch of products shall not exceed 30t.
5.3 Determine the number of sampling units in accordance with the provisions of 6.6 of GB/T6678-1986. Each plastic woven bag is a packaging unit. When sampling, insert the sample obliquely from the top of each selected packaging bag to 3/4 of the depth of the material layer, take out no less than 50g of sample with a sampler, mix the sample, and reduce it to about 200g by quartering. Immediately put it into two clean and dry wide-mouth bottles with ground stoppers and seal them. Paste labels on the bottles, indicating: manufacturer name, product name, batch number, sampling date and name of the sampler. One bottle is used for inspection, and the other bottle is kept for three months for reference. 5.4 Industrial disodium hydrogen phosphate shall be inspected by the quality supervision and inspection department of the manufacturer in accordance with the provisions of this standard. The manufacturer shall ensure that all industrial disodium hydrogen phosphate shipped from the factory meets the requirements of this standard. 5.5 The user has the right to inspect and accept the industrial disodium hydrogen phosphate received in accordance with the provisions of this standard, and the inspection and acceptance shall be carried out within one month from the date of arrival.
5.6 If one of the indicators in the test results does not meet the requirements of this standard, samples should be taken from twice the amount of packaging for re-testing. If only one indicator in the re-test results does not meet the requirements of this standard, the entire batch of products shall be unqualified. 5.7 Determine whether the test results meet the standards according to the rounded value comparison method specified in GB/T1250. 6 Marks and labels
6.1 The packaging bags of industrial disodium hydrogen phosphate should have firm and clear marks, including: manufacturer name, factory address, product name, trademark, grade, net content, batch number or production date, production license number, and this standard number. 6.2 Each batch of industrial disodium hydrogen phosphate shipped from the factory should be accompanied by a quality certificate. The contents include: manufacturer name, factory address, product name, trademark, grade, net content, batch number or production date, proof that the product quality meets this standard and this standard number. Packaging, transportation, storage
7.1 The inner packaging of industrial disodium hydrogen phosphate adopts polyethylene film bags with a thickness of 0.07mm. The outer packaging adopts plastic woven bags. The net content of each bag is 50kg. If the user has special requirements for packaging, it can be negotiated. 7.2 The film bag for industrial disodium hydrogen phosphate packaging should be tied twice 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 edge of the bag, and the opening should be 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 should be neat and the stitch length should be uniform. There should be no leakage or skipping. 7.3 Industrial disodium hydrogen phosphate should be covered during transportation to prevent sun exposure and rain. 7.4 Industrial disodium hydrogen phosphate should be stored in a dry warehouse to prevent rain, moisture and sun exposure. 9181 pH unit. 4.7.2.2 Glass electrode: Soak in water for more than 24 hours before use, clean after use, and store in water. 4.7.2.3 Saturated calomel electrode.
4.7.3 Analysis steps
Weigh about 1.0g of sample, place it in a 150ml beaker, and accurately add 100ml of water without carbon dioxide to dissolve. Determine the pH value of the sample solution.
5 Inspection rules
HG/T2965--2000
5.1 All items specified in this standard are factory inspection items. 5.2 Each batch of products shall not exceed 30t.
5.3 Determine the number of sampling units in accordance with the provisions of 6.6 of GB/T6678-1986. Each plastic woven bag is a packaging unit. When sampling, insert the sample obliquely from the top of each selected packaging bag to 3/4 of the depth of the material layer, and use the sampler to take out no less than 50g of sample. After mixing the sample, reduce it to about 200g by quartering method, and immediately put it into two clean and dry wide-mouth bottles with ground stoppers and seal them. Paste labels on the bottles, indicating: manufacturer name, product name, batch number, sampling date and name of the sampler. One bottle is used for inspection, and the other bottle is kept for three months for reference. 5.4 Industrial disodium hydrogen phosphate shall be inspected by the quality supervision and inspection department of the manufacturer in accordance with the provisions of this standard. The manufacturer shall ensure that all industrial disodium hydrogen phosphate shipped from the factory meets the requirements of this standard. 5.5 The user has the right to inspect and accept the industrial disodium hydrogen phosphate received in accordance with the provisions of this standard, and the inspection and acceptance shall be carried out within one month from the date of arrival.
5.6 If one of the indicators in the test results does not meet the requirements of this standard, samples should be taken from twice the amount of packaging for re-testing. If only one indicator in the re-test results does not meet the requirements of this standard, the entire batch of products shall be unqualified. 5.7 Determine whether the test results meet the standards according to the rounded value comparison method specified in GB/T1250. 6 Marks and labels
6.1 The packaging bags of industrial disodium hydrogen phosphate should have firm and clear marks, including: manufacturer name, factory address, product name, trademark, grade, net content, batch number or production date, production license number, and this standard number. 6.2 Each batch of industrial disodium hydrogen phosphate shipped from the factory should be accompanied by a quality certificate. The contents include: manufacturer name, factory address, product name, trademark, grade, net content, batch number or production date, proof that the product quality meets this standard and this standard number. Packaging, transportation, storage
7.1 The inner packaging of industrial disodium hydrogen phosphate adopts polyethylene film bags with a thickness of 0.07mm. The outer packaging adopts plastic woven bags. The net content of each bag is 50kg. If the user has special requirements for packaging, it can be negotiated. 7.2 The film bag for industrial disodium hydrogen phosphate packaging should be tied twice 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 edge of the bag, and the opening should be 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 should be neat and the stitch length should be uniform. There should be no leakage or skipping. 7.3 Industrial disodium hydrogen phosphate should be covered during transportation to prevent sun exposure and rain. 7.4 Industrial disodium hydrogen phosphate should be stored in a dry warehouse to prevent rain, moisture and sun exposure. 918
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