Some standard content:
Chemical Industry Standard of the People's Republic of China
Subject Content and Scope of Application
HG/T 2517-93
This standard specifies the technical requirements, test methods, inspection rules, as well as marking, packaging, transportation and storage of industrial trisodium phosphate. This standard applies to trisodium phosphate obtained by crystallization of phosphoric acid with soda ash or caustic soda. This product is mainly used as a water softener, boiler cleaning agent and detergent, and is also used as a non-metallic rust inhibitor, fabric mercerizing enhancer, etc. Molecular formula: NaPO, 12H, 0
Relative molecular mass: 380.12 (according to the international relative atomic mass of 1989) 2 Reference standards
GB/T 601
GB/T 602
GB/T 603
GB/T 604
Chemical reagents Preparation of standard solutions for titration analysis (volumetric analysis) Chemical reagents
Preparation of standard solutions for impurity determination
Preparation of preparations and products used in test methods Chemical reagents
Chemical reagents Acid-base indicators General method for determination of pH color range Chemical reagents General method for determination of arsenic (arsenic spot method) GB/T 610.1 *
GB1250
Expression method and determination method of limit values GB/T 3049
GB/T 3050
GB/T 6678
GB/T 6682
General method for determination of iron content in chemical products Phenanthroline spectrophotometric method General method for determination of chloride content in inorganic chemical products Potentiometric titration method General rules for sampling of chemical products
Specifications and test methods for water used in analytical laboratories GB8946 Plastic woven bags
3 Technical requirements
3.1 Appearance: white or slightly yellow crystals
3.2 Industrial trisodium phosphate shall meet the requirements of the following table
Trisodium phosphate (Na ,PO),-12H2O),% methyl orange alkalinity (in Naz()),%
insoluble matter content,%
sulfate (in SO,) content,%
chloride (in CI),%
approved by the Ministry of Chemical Industry of the People's Republic of China on September 8, 1993. Superior product
16.5~19.0
First-class product
Qualified product
16.0~19. 0
15.5～19.0
1994-07-01 implementation
Iron (Fe) content, %
Arsenic (As) content.%
4Test method
HG/T2517---93
Superior product
Qualified product
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.
4.1 Determination of trisodium phosphate content
4.1.1 Summary of method
In an acidic medium, all phosphates in the test solution form precipitates with the added precipitant quinoline molybdate. The content of trisodium phosphate is calculated by filtering, drying, weighing and calculating.
4.1.2 Reagents and materials
4.1.2.1 Nitric acid (GB626) 1+1 solution;
4.1.2.2 Preparation of quinoline molybdate solution:
Weigh 70g sodium molybdate (HG3-1087) and dissolve it in 100mL water;h.
Weigh 60g citric acid (GB9855) and dissolve it in 150mL water and 85mL nitric acid (GB626);c.
Pour solution a into solution b under stirring; add 35mL nitric acid (GB626) and 5mL quinoline to 100mL water;d.
Pour solution d into solution c. After standing for 12h, filter with a filter, add 280mL acetone (GB686), dilute to 1000mL with water, and mix well.e.
Store in polyethylene bottles. 4.1.3 Instruments and equipment
4.1.3.1 Filter: pore size 5~15μm; 4.1.3.2 Electric oven: temperature can be controlled at 180±5℃ or 250±10℃. 4.1.4 Analysis steps
4.1.4.1 Preparation of test solution
Weigh about 5g of sample, accurate to 0.0002g, put it in a beaker, dissolve it with water and transfer it all to a 250ml volumetric flask, dilute it with water to the scale, shake it well, dry filter it into a conical flask (discard the first 20mL of filtrate) and set aside. 4.1.4.2 Determination
Use a pipette to transfer 10 mL of the test solution into a 400 mL beaker, add 10 mL of nitric acid solution and 90 ml of water, add 50 mL of quinoline molybdate solution, cover with surface III, heat on a hot plate or in a water bath until the contents of the beaker reach ±5°C, keep warm for 30 seconds (open flames must not be used during the addition of reagents and heating, and stirring is not allowed to prevent condensation). Take out and cool to room temperature, stirring 3 to 4 times during the cooling process. Filter with a crucible filter that has been pre-dried to constant weight at 180 ±5°C or 250 ±10°C. First filter the upper clear liquid, rinse the precipitate 6 times with a washing bottle by pouring method, using about 30 mL of water each time, and finally transfer the precipitate to a crucible filter for filtration, then wash the precipitate 4 times with water, place the crucible filter together with the precipitate in an electric oven, and start from the time when the temperature stabilizes, control the temperature at 180 ±5°C to dry for 45 minutes or control the temperature at 250 ±10°C to dry for 15 minutes. After taking it out and cooling it slightly, place it in a desiccator to cool it to room temperature and weigh it. At the same time, perform a blank test. 4.1.5 Expression of analysis results
The content of trisodium phosphate (in terms of NasPO4·12H,O) expressed as mass percentage (X,) is calculated according to formula (1): 58
Wherein: m,-
HG/T 2517-93
(m =m)X0.1717 × 100
m×250
429.2(ml - m2)
The mass of quinoline phosphomolybdic acid precipitate generated in the test solution, g; The mass of quinoline phosphomolybdic acid precipitate generated in the blank test solution, g, The mass of the sample, g;
0.1717-The coefficient for converting quinoline phosphomolybdic acid into trisodium phosphate. 4.1.6 Allowable difference
The arithmetic mean of the parallel determination results shall be taken as the determination result. The absolute difference between the two parallel determination results shall not exceed 0.2%. 4.2 Determination of the alkalinity of methyl orange
4.2.1 Summary of the method
The test solution is alkaline and is titrated with a standard hydrochloric acid titration solution. The alkalinity is calculated by the consumption of the standard hydrochloric acid titration solution. 4.2.2 Reagents and materials
4.2.2.1 Sodium chloride (GB1266);
4.2.2.2 Hydrochloric acid (GB622): c (HCl) is about 0.5 mol/L standard titration solution; 4.2.2.3 Methyl orange: 1 g/L indicator solution;
4.2.2.4 Water without carbon dioxide.
4.2.3 Analysis steps
Weigh about 2g of sample, accurate to 0.0002g, place in a 250mL conical flask, add 50mL of carbon dioxide-free water and 5g of sodium chloride, dissolve, add 2 drops of methyl orange indicator solution, and titrate with hydrochloric acid standard titration solution until the orange color is the end point. 4.2.4 Expression of analysis results
The alkalinity of methyl orange (in terms of NazO) (X,) expressed as mass percentage is calculated according to formula (2): V: c X 0. 030 99 × 100
The volume of standard hydrochloric acid solution consumed in titration, mL; Where: V-bzxZ.net
The actual concentration of standard hydrochloric acid solution, mol/LThe mass of the sample, g;
(2)
The mass of sodium oxide equivalent to 1.00mL standard hydrochloric acid solution [c(HCl)=1.000mol/L>, expressed in grams.
4.2.5 Allowable difference
The arithmetic mean of the parallel determination results shall be taken as the determination result. The absolute difference between the two parallel determination results shall not exceed 0.1% . 4.3 Determination of insoluble matter content
4.3.1 Method summary
Dissolve the sample in water, adjust the solution to pH 6.8 with hydrochloric acid, and filter it with a crucible filter. Calculate the insoluble matter content by drying and weighing.
4.3.2 Reagents and materials
4.3.2.1 Hydrochloric acid (GB622) solution: 1+1; 4.3.2.2 Phenol red (HG3-959): 0.4g/L indicator solution, prepared according to Table 8 of GB.604. 4.3.3 Instruments and equipment
4.3.3.1 Wax filter: pore size is 5-15μm; 4.3.3.2 Electric oven: temperature can be controlled to work at 105-110℃. 4.3.4 Analysis steps
HG/T 2517-93
Weigh about 25g of sample, accurate to 0.01g, put it in a 500mL beaker, add 400mL water and 10mL hydrochloric acid solution, heat to dissolve, add 2mL phenol red indicator solution, and add hydrochloric acid solution dropwise until the solution turns yellow (pH is about 6.8). Reheat to boiling, and transfer all insoluble matter to a sieve filter at constant weight at 105-110℃ while hot to filter. Wash the insoluble matter and filter with hot water 10 times, 20mL water each time. Place the sieve filter together with the insoluble matter in an electric oven and dry at 105-110℃ to constant weight. 4.3.5 Expression of analysis results
The insoluble content (X.) expressed as a mass percentage is calculated according to formula (3): ml×100
Wherein: m,-
-the mass of the insoluble matter, g;
-the mass of the sample, g.
4.3.6 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%. 4.4 Determination of sulfate content
4.4.1 Summary of method
In the hydrochloric acid medium, the sulfate ions in the sample form a precipitate with the added barium chloride. The sulfate content is calculated by filtering, drying and weighing.
4.4.2 Reagents and materials
4.4.2.1 Chloroform (GB652): 50g/L solution; 4.4.2.2 Hydrochloric acid (GB622): 1+1 solution; 4.4.2.3 Hydrochloric acid (GB622): 1+59 solution; 4.4.2.4 Silver nitrate (GB670): 17g/L solution; 4.4.2.5 Methyl orange 1g/L indicator solution.
4.4.3 Instruments and equipment
4.4.3.1 Wax filter: pore size 5~15μm; 4.4.3.2 Electric oven: temperature can be controlled to work at 1805℃. 4.4.4 Analysis steps
4.4.4.1 Preparation of test solution
Weigh about 20g of sample, accurate to 0.002g, place in a beaker, dissolve in water and transfer to a 250mL volumetric flask, dilute with water to scale, shake well, dry filter into a conical flask (discard the initial 20mL solution) for later use. 4.4.4.2 Determination
Use a pipette to transfer 100mL of test solution into a 500mL beaker, add 2 drops of methyl orange indicator solution, add hydrochloric acid solution (4.4.2.2) until it turns red, and then add 15mL in excess. Add water to a solution volume of about 350mL, heat to boiling, add 30mL of hot barium chloride solution under constant stirring, and keep warm in a boiling water bath for 1h. Filter with a crucible filter at 180±5℃ for constant weight. First, filter the supernatant, wash the precipitate three times with hydrochloric acid solution (4.4.2.3) by pouring method, transfer all the precipitate into the crucible, wash the inner wall of the crucible three times, using about 10 mL of washing solution each time, and finally wash the precipitate with hot water until the filtrate is free of chloride ions (check with silver nitrate solution). Place the filter together with the precipitate in an electric oven at 180±5℃ and dry to constant weight.
4.4.5 Expression of analysis results
The sulfate content (in terms of SO,) expressed as mass percentage (X) is calculated according to formula (4): X = m×0.411 6×100
m×250
Wherein: m, -…mass of barium sulfate precipitate, g; 490
(4)
mass of the sample, g;
HG/T 2517-93
0.4116——coefficient for converting barium sulfate to sulfate. 4.4.6 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 0.02%. 4.5 Determination of chloride content
4.5.1 Summary of the method
Same as Article 2 of GB/T3050.
4.5.2 Reagents and materials
Same as Article 4 of GB/T3050.
4.5.3 Instruments and equipment
Same as Article 3 of GB/T3050.
4.5.4 Analysis steps
4.5.4.1 Preparation of test solution
Weigh about 10g of sample, accurate to 0.01g, dissolve in water, transfer to a 100mL volumetric flask and dilute to the mark, shake, dry filter into a conical flask (discard the first 20mL of filtrate) for later use. 4.5.4.2 Preparation of blank test 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 carried out at the same time as the sample. 4.5.4.3 Determination
According to the chloride content in the sample, use a pipette to take 1.0~~5.0mL of the test solution and the corresponding water, and place them in 50mL beakers respectively. Add 1 drop of bromophenol blue indicator solution to each beaker, adjust the test solution to yellow with nitric acid solution, add ethanol, and make the volume ratio of ethanol to the test solution 3:1, and the total volume is not more than 40mL. Use silver nitrate standard titration solution [c (AgNO,) = 0.005mol/L) for titration, and start according to GB/T3050 Section 4.7.3 "Put in electromagnetic stirring bar", but do not add 4mL of silver nitrate standard titration solution again. 4.5.5 Expression of analysis results
The chloride content (in terms of Cl) expressed as mass percentage (X.) is calculated according to formula (5):X VV):sX 0. 035 45 × 100
m×100
- 354. 5c : (V. - V.)
Wherein: V. -——Volume of silver nitrate standard titration solution consumed by titrating the test solution, mL; Vs
-Volume of silver nitrate standard titration solution consumed by titrating the blank test solution, mL; Volume of the test solution taken in the titration, mL; -Actual concentration of silver nitrate standard titration solution, mol/Im -——Mass of the sample, g;
(5)
0.03545-Mass of chlorine in grams equivalent to 1.00mL silver nitrate standard titration solution [c(AgNO3)=1.000mol/LJ.
4.5.6 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%. 4.6 Determination of iron content
4.6.1 Summary of the method
Same as Article 2 of GB/T3049.
4.6.2 Reagents and materials
Same as Article 3 of GB/T3049.
4.6.3 Instruments and equipment
Same as Article 4 of GB/T3049.
4.6.4 Analysis steps
4.6.4.1 Drawing of working curve
HG/T 2517 93
Draw the working curve using a 3 cm absorption cell and the corresponding iron standard solution according to Article 5.3 of GB/T3049. 4.6.4.2 Preparation of test solution
Weigh about 1.0 g of the sample to an accuracy of 0.01 g, place it in a 100 mL volumetric flask, add water to about 60 mL, and adjust the solution pH to close to 2 with hydrochloric acid solution (check with precision pH test paper). 4.6.4.3 Preparation of blank test solution
Except for not adding the sample, the amount of other reagents added is exactly the same as that of the test solution, and the same treatment is carried out at the same time as the sample. 4.6.4.4 Determination
Add 2.5mL ascorbic acid solution, 10mL buffer solution, and 5mL o-phenanthroline solution to the test solution and blank test solution, respectively, dilute to the scale with water, and shake well.
Use a 3cm absorption cell, measure the absorbance according to the provisions of Article 5.4 of GB/T3049, and find out the mass of iron in the test solution and blank test solution according to the working curve.
4.6.5 Expression of analysis results
The iron (Fe) content (X.) expressed as mass percentage is calculated according to formula (6): X. = ml= m2 × 100
Wherein: m.
The mass of iron in the test solution, g;
m2The mass of iron in the blank test solution, g, the mass of the sample, 8.
4.6.6 Allowable difference
The arithmetic mean of the parallel determination results shall be taken as the determination result. The absolute difference between the two parallel determination results shall not exceed 0.002%. 4.7 Determination of arsenic content
4.7.1 Summary of the method
Same as Article 3 of GB/T610.1.
4.7.2 Reagents and materials
Same as Article 4 of GB/T610.1 and
4.7.2.1 Arsenic standard solution: 1mL of solution contains 0.0010mgAs solution: (6)
Use a pipette to transfer 1.0mL of the arsenic standard solution prepared according to GB/T602 into a 100mL volumetric flask, dilute to the mark with water, and shake well. This solution is prepared before use.
4.7.3 Instruments and equipment
Same as Article 5 of GB/T610.1.
4.7.4 Analysis steps
Weigh 0.1g of the sample to an accuracy of 0.018 and place it in a wide-mouth bottle. The following operations are determined according to the method specified in Article 6 of GB/T610.1.
Preparation of arsenic standard color spots: Use a pipette to transfer 5mL of the arsenic standard solution into a wide-mouth bottle and treat it in the same way as the sample. 5 Inspection rules
5.1 All technical indicators listed in this standard are type inspection items, among which trisodium phosphate, methyl orange alkalinity, insoluble matter, sulfate and chloride are factory inspection items. Under normal production conditions, type inspection shall be carried out at least once every three months. 5.2 Industrial trisodium 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 trisodium phosphate products leaving the factory meet the requirements of this standard. Each batch of products leaving the factory shall be accompanied by a quality certificate, including: manufacturer name, product name, grade, net weight, batch number or production date, proof that the product quality meets this standard and the number of this standard. 5.3 The user has the right to accept the industrial trisodium phosphate received in accordance with the provisions of this standard. 5.4 Each batch of products shall not exceed 60t.
5.5 Determine the number of sampling units in accordance with Article 6.6 of GB/T6678. When sampling, the sampler should be inserted vertically from the center of the packaging unit to 3/4 of the depth of the material layer. After the sample is fully mixed, it should be divided into 500g by quartering and sealed in two dry, clean bottles with ground stoppers. Labels are attached to the bottles, indicating the manufacturer's name, product name, grade, batch number, sampling date and name of the sampler. One bottle is for inspection and the other bottle is kept for two months for reference. 5.6 If one of the indicators in the inspection results does not meet the requirements of this standard, re-sampling should be carried out from twice the amount of packaging units. If the verification results show that only one indicator does not meet the requirements of this standard, the entire batch of products cannot be accepted. 5.7 When the supply and demand parties have objections to the product quality, they should handle it in accordance with the provisions of the "Interim Measures for National Product Quality Arbitration Inspection". 5.8 This standard adopts the rounded value comparison method specified in GB1250 to determine whether the inspection results meet the standard. 6 Marking, packaging, transportation, storage
6.1 The packaging bags of industrial trisodium phosphate should be printed with firm and clear markings, including: manufacturer name, product name, trademark, grade, net weight, batch number or production date and this standard number. 6.2 Industrial trisodium phosphate is double-packed. The inner packaging is a polyethylene plastic film bag with a specification size of 950mm×500mm and a thickness of 0.08mm or 750mm×400mm and a thickness of 0.08mm; the outer packaging is a plastic woven bag with a specification size of 800mm×450mm or 600mm×350mm, and its performance and inspection methods should comply with the provisions of GB8946B. The net weight of each bag of industrial trisodium phosphate is 50kg or 25kg.
6.3 For the packaging of industrial trisodium phosphate, the inner bag is tied with vinyl rope or other ropes of equivalent quality, or sealed with other equivalent methods; the outer bag is folded at a distance of not less than 30mm from the bag edge, and the outer bag is sewn with vinyl thread or other thread of equivalent quality at a distance of not less than 15mm from the bag edge. The stitch length is 7-12mm, the stitches are neat and uniform, and there is no leakage or skipping. 6.4 During transportation, there should be a cover to prevent rain. 6.5 Industrial trisodium phosphate should be stored in a cool and dry place to prevent rain and sun. Additional remarks:
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 the Tianjin Chemical Research Institute of the Ministry of Chemical Industry. This standard is drafted by the Tianjin Chemical Research Institute of the Ministry of Chemical Industry and Kunming Phosphate Fertilizer Plant of Yunnan. The main drafters of this standard are Li Guangming, Lu Siwei, Zhou Jiguang and Liu Jianguo. This standard refers to the Japanese standard JISK1437--56 (confirmed in 1988) "Sodium Phosphate". From the date of implementation of this standard, the original national standard GB1607-79 "Industrial Trisodium Phosphate" will be invalidated.
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