Some standard content:
HG/T 2837 ---1997
This standard is proposed after the revision of GB/T10532-1989 "Sodium hexametaphosphate as water treatment agent". The revised standard name is changed to "Sodium polymetaphosphate as water treatment agent". In terms of technical content, this standard is basically the same as GB/T10532-1989, and has been rewritten according to the requirements of GB/T1.1-1993.
This standard adopts the American Water Works Association standard AWWAB502-1983 "Glass Sodium Metaphosphate" in a non-equivalent manner. The main differences from AWWAB502:1983 are:
The total phosphate (in terms of P) content is higher than that of AWWAB502:1983, and the inactive phosphate index is added; the operating conditions of various test methods are not exactly the same.
GB/T10532-1989 shall be abolished from the date of entry into force of this standard. Appendix A of this standard is a reminder appendix.
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 Tianjin Chemical Research Institute of the Ministry of Chemical Industry and Chengdu Chemical Research and Design Institute. The main drafters of this standard are Huang Jiapeng, Wang Shuquan and Shao Hongqian. This standard was first issued in 1989 and revised for the first time in 1996. 148
1CS 13. 060. 99
Registration No. 148: 1997
Chemical Industry Standard of the People's Republic of China
Water treatment agents
Sodium polymetaphosphate
Water treatment chermicals-Sodium polymetaphosphate Scope
HG/T2837 1997
This standard specifies the technical requirements, sampling, test methods, marking, packaging, transportation and storage of water treatment agent sodium polymetaphosphate. This product is mainly used as a corrosion inhibitor for industrial circulating cooling water. Molecular formula: NaPOJ,
2 Cited standards
The clauses contained in the following standards constitute the clauses 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/T601-1988 Preparation of standard solutions for titration analysis (volume analysis) of chemical reagents GB/T 602---1988
GB/T 603---1988
GB/T1250---1989
GB/T 6678- - 1986
GB/T 6682--1992
GB/T8946-1988
3 Technical requirements
Preparation of standard solution for determination of impurities (neqISO6353-1:1982) Chemical reagents
Preparation of preparations and products used in test methods for chemical reagents (neoISO6353-1:1982) Expression and determination methods of limit values General rules for sampling of chemical products
Specifications and test methods for water used in analytical laboratories Plastic woven bags
3.1 Appearance: White fine granules.
3.2 Water treatment agent sodium polymetaphosphate shall meet the requirements of Table 1. Table 1
Total phosphate (in terms of P0,) content, %
Inactive phosphate (in terms of P0:) content, %
Water-insoluble matter content, %
Iron (Fe) content, %
pH value (1% aqueous solution)
Solubility
Average degree of polymerization n
Approved by the Ministry of Chemical Industry of the People's Republic of China on February 4, 1997Superior product
Qualified product
Implemented on October 1, 1997
4 Sampling
HG/T 2837-—1997
4.1 Determine the number of sampling units according to the provisions of Article 6.6 of GB/T6678. 4.2 Use a sampling tube to insert it along the vertical center line of the packaging bag to two-thirds of the bag depth for sampling. Mix the sample, reduce it to about 500g by quartering, and immediately put it into two clean and dry wide-mouth bottles and seal them. Paste labels on the bottles, indicating: manufacturer name, product name, batch number, sampling phase II and name of the sampler. One bottle is for inspection and the other is kept for three months for reference. 4.3 If one of the indicators in the test results does not meet the requirements of this standard, re-sample from twice the amount of packaging units for verification. If one of the indicators does not meet the requirements of this standard, the entire batch of products cannot be accepted. 5 Test method
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 solutions, impurity standard solutions, preparations and products required in the test, unless otherwise specified, are prepared in accordance with the provisions of GB/T601, GB/T602 and GB/T603. The rounded value comparison method specified in GB/T1250 is used to determine whether the test results meet the standards. 5.1 Determination of total phosphate content
5.1.1 Summary of method
The sample is completely hydrolyzed into orthophosphate in an acidic solution. After adding quinoline phosphomolybdic acid solution, quinoline phosphomolybdic acid precipitate is generated, filtered, washed, dried, weighed,
5.1.2 Reagents and materials
5.1.2.1 Nitric acid;
5.1.2.2 Nitric acid: 1+1 solution;
5.1.2.3 Quinoline molybdate solution;
Preparation method:
Solution 1: weigh 70g sodium molybdate and dissolve it in 150ml water; Solution: weigh 60g citric acid and dissolve it in a mixture of 85ml nitric acid (5.1.2.1) and 150ml water; Solution II: weigh 5ml quinoline and dissolve it in a mixture of 35ml nitric acid (5.1.2.1) and 100ml water. Under constant stirring, first slowly add solution 1 to solution II. Then slowly add solution II to solution II. Mix well. Let stand for 24h and filter. Add 280ml acetone to the filtrate, dilute with water to 1000ml, and mix well. Store in colored glass bottles or polyethylene bottles. 5.1.3 Instruments and equipment
General laboratory instruments and
5.1.3.1 Filter: The pore size of the filter plate is 5μm~~15μm, 5.1.4 Analysis steps
Weigh about 2g of sample (accurate to 0.0002g), place it in a 100ml beaker, and dissolve it in water at room temperature. Transfer all to a 500ml volumetric flask. Dilute with water to the scale and shake well. Take 15.00ml of the test solution, place it in a 400ml tall beaker, add 15ml nitric acid (5.1.2.2) and 70ml water. Boil slightly for 15min, add 50ml of quinoline molybdate solution while hot, and boil slightly for 1min. Cool to room temperature. Filter by decantation using a crucible filter that has been constant weight at the test temperature. Wash the precipitate in a beaker three times, using about 15 ml of water each time. Transfer the precipitate to a filter and continue washing with water. The total washing water used is about 150 ml. Dry at 180°C ± 5°C for 45 min, or at 250°C ± 5°C for 30 min. Cool in a desiccator and weigh. 5.1.5 Expression of analytical results
The total phosphate (P) content (X,) expressed as mass percentage is calculated according to formula (1): X = m×0.03207×100
m×500
Where: m. mass of quinoline phosphomolybdic acid precipitate, g; mass of sample, .
HG/T 2837-:1997
0.03207---The coefficient for converting quinoline phosphomolybdic acid into phosphorus pentoxide. 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 inactive phosphate content
5.2.1 Method summary
Add sodium chloride to the test solution to form a precipitate of sodium hexamethaphosphate, which is filtered. Add acid to the filtrate to hydrolyze the remaining phosphate into orthophosphate. Add quinoline phosphomolybdic acid precipitate after adding quinoline molybdate solution. Filter, wash, dry and weigh. 5.2.2 Reagents and materials
Reagents and materials specified in Article 5.1.2 and
5.2.2.1 Fluorinated sodium chloride (BaCl2*2H.0): 25g/1. solution. 5.2.3 Instruments and equipment
General experimental instruments and
5.2.3.1 Glass filter: The pore size of the filter plate is 5m~15um; 5.2.4 Analysis steps
Weigh 50.00ml of test solution and place it in a 100mL volumetric flask. Add 30ml of barium chloride solution while shaking continuously. Shake thoroughly to precipitate completely. Dilute with water to the mark and shake to dry filter. Transfer 50.00ml of filtrate and place it in a 400mL tall beaker. Add 15ml of nitric acid (5.1.2.2) 35 ml of water. Boil for 15 minutes, add 20 ml of quinoline molybdate solution while hot, and boil for 1 minute. Cool to room temperature. Filter by decantation using a sweet volute filter that has a constant weight at the test temperature. Wash the precipitate in a beaker three times, using 15 ml of water each time. Transfer the precipitate to the volute filter and continue washing with water. The total amount of washing water used is about 150 ml. Dry at 180°C ± 5°C for 45 minutes, or at 250°C ± 5°C for 30 minutes. Cool in a desiccator and weigh. 5.2.5 Expression of analysis results
The inactive phosphate (in terms of P05) content (X2) expressed as mass percentage is calculated according to formula (2): Xz m,X0. 032 07,
m×%×100
where n·mass of quinoline phosphoaluminate precipitate g
mmass of sample, g
0.0327coefficient of quinoline phosphomolybdate converted to phosphorus pentoxide. 5.2.6 It is allowed to take the arithmetic mean of the parallel measurement results as the measurement result. The absolute difference between the two parallel measurement results shall not exceed 0.3%. 5.3 Determination of water-insoluble matter content
5.3.1 Instruments and equipment
General laboratory instruments and
5.3.1.1 Shoe filter: the pore size of the filter plate is 5um-~15um; (2)
5.3.2 Analysis steps
Weigh about 30g of the ground sample (accurate to 0.01g), place it in a 400ml beaker, add 200ml water, and heat to boiling to dissolve it. Filter while hot through a filter that has been slowly weighed at 105°C ~ ~ 110°C. Wash 10 times with hot water, 20 ml of water each time, and dry at 105°C to constant weight. bzxz.net
5.3.3 Expression of analysis results
HG/T 2837
The water-insoluble content (X:) expressed as a mass percentage is calculated according to formula (3): X a ma
Where: mThe mass of the spiral filter·gm…The mass of the water-insoluble matter and the glass filter·gThe mass of the sample· .
5.3.4 Allowable difference
The arithmetic mean of the parallel determination results is taken as the determination result. The absolute difference between the two parallel determination results shall not exceed 0.01%. 5.4 Determination of iron content
5.4.1 Method extraction
Use ascorbic acid to reduce the trivalent iron in the test solution to divalent iron. At a pH of 2-9, the divalent iron ions react with o-phenanthroline to form an orange-red complex. Use a spectrophotometer to measure its absorbance at the maximum absorption wavelength (510nm). 5.4.2 Reagents and materials
5.4.2.1 Hydrochloric acid: 1+1 solution.
5.4.2.2 Ammonia 1+3 solution.
5.4.2.3 Glacial acetic acid-sodium acetate buffer solution: pH~4.5. 5.4.2, 4 Ascorbic acid: 20g/1. Solution, shelf life 10 days. 5.4.2.5 Ortho-Phenyline: 2g/L solution.
5.4.2.6 Iron standard solution: 0.010mgFe/mL. Prepare according to GB/T602, transfer 100.00mL, place in a 1000ml volumetric flask, dilute with water to the scale, and shake well. Only for use on the same day. 5.4.3 Instruments and equipment
General laboratory instruments and
5.4.3.1 Division Photometer: with an absorption cell of 3 cm thickness. 5.4.4 [Drawing of the plot line
In L: 100ml volumetric flasks, add 0 (reagent blank solution), 1.00mL, 2.00mL, 4.00ml, 6.00mL, 8.00ml, 10.00ml of iron standard solution respectively. Each volumetric flask is treated in the same way as follows: add water to about 40ml. Use hydrochloric acid to adjust the solution pH to close to 2 (check with precision pH test paper). Add 2.5mL ascorbic acid solution, 10ml buffer solution, 5m o-phenanthroline solution, dilute to the scale with water, and shake well. Use the spectrophotometer. , use a 3cm absorption cell, at a wavelength of 510nm, with water as the reference to determine the absorbance. Subtract the absorbance of the reagent blank solution from the absorbance of the standard reference solution, and draw a working curve with the iron content (mg) as the horizontal axis and the corresponding absorbance as the vertical axis.
5.4.5 Analysis steps
5.4.5.1 Preparation of test solution
Weigh about 2.5g of sample (accurate to 0.01g). Place in a 250ml beaker. Add 100ml of water and 10mL of hydrochloric acid, heat to a slight boil for 15min, and cool. Transfer all to a 250mL volumetric flask, dilute with water to the scale, and shake well. 5.4.5.2 Preparation of blank test solution
Add 100mL of water and 10mL of hydrochloric acid to a 250ml beaker, heat to a slight boil for 15min, cool, transfer all to a 250ml volumetric flask, dilute with water to the scale, and shake well.
5.4.5.3 Color development
Pipette 10.00ml of test solution and 10.00ml of blank test solution into 100ml volumetric flasks respectively, add 30ml of water, and adjust the pH to close to 2 with ammonia water (check with precision pH test paper). For example, 2.5ml of ascorbic acid solution, 10ml of buffer solution, and 5ml of o-phenanthroline solution. Dilute to the scale with 152
water and shake the hook.
5.4.5.4 Determination of absorbance
HG/T 2837--1997
Use a spectrophotometer. Use a 3cm absorption cell and measure the absorbance at a wavelength of 510nm with water as a reference. 5.4.6 Expression of analytical results
The iron (Fe) content (X,) expressed as mass fraction is calculated according to formula (4): X,
m×2×1000
2. 5X(m1m)
Formula m--
The amount of iron found from the working curve based on the measured absorbance of the test solution, mgm.--——The amount of iron found from the working curve based on the measured absorbance of the blank test solution, mg; the mass of the sample, g.
5.4.7 Allowable difference
Take the arithmetic mean of the parallel determination results as the determination result. The absolute difference between the two parallel determination results shall not exceed 0.01%. 5.5 Determination of pH value
5.5.1 Instruments and equipment
General laboratory instruments and
5.5.1.1 Acidity meter: accuracy 0.02 pH unit. Equipped with saturated calomel reference electrode and glass measuring electrode or composite electrode. 5.5.2 Analysis steps
(4)
Weigh 1.00g ± 0.01g sample and place it in a 250mL beaker. Dissolve it in 100mL cold distilled water without carbon dioxide. Determine the pH value of the solution at room temperature.
5.5.3 Allowable difference
Take the arithmetic mean of the parallel determination results as the determination result. The absolute difference between the two parallel determination results shall not exceed 0.02 pH unit. 5.6 Solubility test
5.6.1 Analysis steps
Add 100mL of 10C~38C water to a 250ml beaker, place it on an electromagnetic stirrer, and place a long Stirring bar with a diameter of 3.5 cm4.0 cm. Add 5.0 g ± 0.1 g of sample under stirring. The sample should be completely dissolved within 20 min. 5.7 Determination of average degree of polymerization
5.7.1 Summary of method
Determine the terminal phosphorus content of the sample by potentiometric titration. The ratio of twice the total phosphorus content to the terminal phosphorus content is the average degree of polymerization. 5.7.2 Reagents and materials
5.7.2.7 Hydrochloric acid: c(HCl) solution of about 1 mol/L. 5.7.2.2 Sodium hydroxide: c(NaOH) standard titration solution of about 0.15 mol/L. 5.7.3 Instruments and equipment
General laboratory instruments and
5.7.3.1 Acidity meter: accuracy 0.02 pH unit. Equipped with saturated calomel reference electrode and glass measuring electrode. 5.7.4 Analysis steps
5.7.4.1 Preparation of test solution
Weigh about 2.5g of sample (accurate to 0.0002g), place it in a 100ml beaker, and add a small amount of water to dissolve. Transfer all to a 250ml volumetric flask, dilute with water to the mark, and shake well. 5.7.4.2 Determination of terminal phosphorus content
Pipette 50.00ml of test solution, place it in a 250ml beaker, and add 50ml of water. Place the beaker on an electromagnetic stirrer, put it in an electromagnetic stirrer, and start the stirrer. Insert the glass measuring electrode and saturated calomel reference electrode into the solution and connect them to the acidometer. Adjust the zero point setting. Add hydrochloric acid solution until the solution pH is about 3. Then titrate with sodium hydroxide standard titration solution. Record the total volume and corresponding pH value after each addition of sodium hydroxide standard titration solution. When the pH is between 4 and 5 and 9 and 10, only add 0.10mL. Calculate ApH and i△\pH△pH to the maximum value and then record a pH value. See Appendix A for the recording format. 5.7.4.3 Calculation
The volume (V) of the sodium hydroxide standard titration solution consumed in titrating the end group phosphorus content shall be calculated according to (5): )-V+0.1×)
V={Vz+0.1×)
Wherein: V, when pH is between 4 and 5, the total volume of the sodium hydroxide standard titration solution added before △rH reaches its maximum value, mL; V, when pH is between 9 and 10, the total volume of the sodium hydroxide standard titration solution added before ApH reaches its maximum value, mL. h, when pH is between 4 and 5, the last positive value of ApH: h\---when pH is between 9 and 10. A\the last positive value of pH; B, when pH is between 4 and 5, the sum of the absolute values of the last positive value and the first negative value of ApH; B, when pH is between 9 and 10, the sum of the absolute values of the last positive value and the first negative value of △pH. 5.7.5 Expression of analysis results
The average degree of polymerization (n) is calculated according to formula (6): 2X
VX0.070.97×100
m×250
Wherein: X is the total phosphate content (in terms of P2O2) measured in Article 5.1, %; V is the volume of the standard sodium hydroxide solution consumed in titrating the terminal phosphorus content, mL;. The actual concentration of the standard sodium hydroxide solution, mol/L… The mass of the sample·name;
(6)
The mass of phosphorus pentoxide expressed in grams equivalent to 1.00mL of sodium hydroxide solution Ec (NaOH) 1.000mol/L 0.070 9 :*-
5.7.6 Allowable difference
The arithmetic mean of the parallel determination results is taken as the determination result, and the absolute difference between the two parallel determination results shall not exceed 0.5.6 Marking. Packaging, transportation, storage
6.1 The packaging bag of the water treatment agent sodium polymetaphosphate shall be painted with a firm mark, including the manufacturer's name, product name, grade, trademark, batch number or production date, net weight, address and this standard number. 6.2 Each batch of water treatment agent sodium polymetaphosphate shall be accompanied by a quality certificate. The content includes: manufacturer's name, product name, grade, trademark, batch number or production date, net weight, proof that the product quality meets this standard and this standard number. 6.3 Water treatment agent sodium polymetaphosphate is double-layer packaged. The inner packaging is a polyethylene plastic film bag with a thickness of not less than 0.08mm, and the outer packaging is a polypropylene plastic woven bag. Its performance and inspection methods shall comply with the relevant provisions of GB8946B. The inner bag is tied with nylon rope or string of the same quality twice, and the outer bag is sewn with a bag sewing machine, with a stitch length of 6mm to 7mm, neat stitches, and even stitch lengths. No leaking or skipping. Net weight of each bag is 25kg or 50kg
6.4 During transportation, it must be protected from rain and sunlight and stored in a ventilated and dry warehouse. 154
HG/T 2837—1997
Appendix A
(Suggestive Appendix)
Example of average polymerization degree determination test record format Average polymerization degree determination test record See Table A1. Table A1
Volume of sodium hydroxide standard solution, ml
V=7.70+0.1×0.04+0.01
=4.71(ml.)
3.00+0.1 X
0.11+0.05
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