HG/T 2431-1993 Water treatment agent scale inhibitor and corrosion inhibitor Ⅲ
Some standard content:
Chemical Industry Standard of the People's Republic of China
Water Treatment Agent
Subject Content and Scope of Application
Scale and Corrosion Inhibitor III
HG/T 2431-.93
This standard specifies the scope of application, technical requirements, test methods, inspection rules, marking, packaging, transportation, storage and safety requirements of scale and corrosion inhibitor products.
This standard is applicable to all-organic scale and corrosion inhibitors with acrylic acid-acrylic acid ester copolymers, hydroxyethyl diphosphonic acid and (methyl) hydrazine as the main ingredients, and does not contain heavy metals, sulfonic acid, and phosphonic acid. This product is mainly used as a scale and corrosion inhibitor for water treatment. 2 Reference standards
GB191 Pictorial symbols for packaging, storage and transportation
Preparation of standard solutions for titration analysis (volume analysis) of chemical reagents GB601
GB603 Preparation of preparations and products used in chemical reagent test methods GB1250 Expression and determination methods of limit values GB6682 Specifications and test methods for water used in analytical laboratories 3 Technical requirements
3.1 Appearance: colorless or light yellow transparent liquid. 3.2 Scale inhibitors and corrosion inhibitors should meet the requirements of Table 1. Table 1
Content of phosphonate (in PO), %
Content of phosphorous acid (in P", %
Content of hydrocarbon (in CHNHNN), %
Solid content·%
pH1% aqueous solution)
Density (20C)+8/cma
4Test method
First-class product
7.30±0.30
Qualified product
7.30±0.50
1.12~1.17
3. 50±1. 00
The reagents and water used in this standard, unless otherwise specified, refer to analytically pure reagents and grade 3 water that meets the requirements of GB6682. The standard solutions and preparations required for the test shall be prepared in accordance with the requirements of GB601 and GB603 unless otherwise specified. 4.1 Determination of phosphonate content
4.1.1 Summary of the method
Approved by the Ministry of Chemical Industry of the People's Republic of China on April 22, 1993 and implemented on January 1, 1994
HG/T2431-93
In acidic media, phosphonates and phosphorous acid are soluble in sulfuric acid and persulfate. In the presence of ammonium molybdate, heat, oxidize and remove phosphoric acid. Use ammonium molybdate, potassium antimony tartrate and phosphoric acid to react to form antimony phosphomolybdic acid complex, reduce it to "antimony phosphomolybdic blue" with antimony acid, and determine the total phosphate (as PO-) content by absorptiometry. Then subtract the content of phosphate (as PO-) and phosphorous acid (as PO-) to calculate the phosphate content. 4.1.2 Reagents and materials
4.1.2.1 Phosphate (as PO-) standard preparation solution: 1 ml solution contains 0.500 mg PO-. Weigh 0.7165 g of potassium dihydrogen phosphate (G 200 g) that has been dried to constant weight at 100°C to 105°C. B1274), accurate to 0.0002g. Place in a beaker, add water to dissolve, transfer to a 1000ml volumetric flask, dilute to scale with water, and shake; 4.1.2.2 Phosphate (as PO-) standard solution: 1mL solution contains 0.020mg PO-. Pipette 20.00ml. Phosphate standard solution (4.1.2.1) into a 500mlL volumetric flask, dilute to scale with water, and stir. 4.1.2.3 Ammonium molybdate solution: weigh 6.0g ammonium molybdate (GB657) and dissolve in about 500mL water, add 0.2g potassium antimony tartrate and 83mL sulfuric acid (GB6 25), dilute to 1000mL with water after cooling, roll evenly. Store in a brown reagent bottle, storage period 6 months; 4.1.2.4 Ascorbic acid solution: weigh 17.6g ascorbic acid and dissolve in about 50mL water, add 0.2g disodium ethylenediaminetetraacetate (GB1401) and 8mL formic acid, dilute to 1000m with water, shake the spoon. Store in a brown reagent bottle. Storage period 15d, 4.1.2.5 Sulfuric acid (GB625): c(1/2HzSO)-1mol/L solution; 4.1.2.6 Ammonium persulfate (GB656): 24.0g/L solution, this storage period is 7 days. 4.1.3 Instruments and equipment
General laboratory instruments and
4.1.3.1 Spectrophotometer: wavelength range 400~800mm; 4.1.3.2 Adjustable electric furnace: 800W.
4.1.4 Analysis steps
4.1.4.1 Preparation of test solution
4.1.4.1.1 Weigh about 3.0g of sample accurately to 0.0002g. Dissolve in water and transfer to a 500mL volumetric flask, dilute to scale with water, and shake well.
4.1.4.1.2 Pipette 10.00mL of test solution (4.1.41.1) into a 1000mL volumetric flask, dilute to scale with water, and shake well. 4.1.4.2 Determination
4.1.4.2.1 Determination of total phosphate (in terms of PO) content Pipette 20.00mL of solution (4.1.4.1.2) into a 50mL conical flask, add 1mL of sulfuric acid solution (4.1.2.5) and 5mL of ammonium persulfate solution (4.1.2.6). Heat to boiling on an electric stove, keep for 10 minutes, until the volume of the solution is half of the original. Remove and cool to room temperature, then transfer all to a 50mL colorimetric tube, add 5mL ammonium molybdate solution (4.1.2.3), 3ml ascorbic acid solution (4.1.2.4), dilute to scale with water, and shake well. Place at 25C ~ 30℃ for 10 minutes, use a 1cm colorimetric III at 710mm, and use the reagent blank as a reference to determine its absorbance. 4.1.4.2.2 Determination of orthophosphate (in terms of PO) content Pipette 10.00mL test solution (4.1.4.1.1) into a 50mL colorimetric tube, add 20mL water, 5mL ammonium silver solution (4.1.2.3), 3ml ascorbic acid solution (4.1.2.4), dilute to scale with water, and shake well. Place at 25℃～30℃ for 10min, and measure its absorbance at 710nm with 1cm colorimetric tube, with reagent blank as reference. 4.1.4.3 Drawing of phosphate (in terms of PO-) working curve Take 7 50mL colorimetric tubes and add 0.00, 1.00, 2.00, 3.00, 4.00, 5.00, 6.00mL phosphate standard solution (4.1.2.2) in turn, add 20mL water, 5mL ammonium chloride solution (4.1.2.3), 3mL ascorbic acid solution (4.1.2.4) to each tube, dilute to scale with water, shake well and place at 25℃~30℃ for 10min. Use 1cm colorimetric tube at 710nm with reagent blank as reference, and measure its absorbance. Draw the working curve with the number of milligrams of phosphate (in terms of PO-) as the horizontal axis and the corresponding absorbance as the vertical axis. 4.1.5 Expression of analysis results
4.1.5.1 The total phosphate (as PO3-) content X expressed as mass percentage is calculated according to formula (1): X, - m×10-3
m×500×1000
Wherein: m.
HG/T 2431-93
The amount of total phosphate (as PO-) in the sample solution is obtained from the working curve, mg; the mass of the sample, g.
4.1.5.2 The orthophosphate (as PO-) content X2 expressed as mass percentage is calculated according to formula (2). X, = mz×10-3
Wherein: m2…·The amount of orthophosphate (as PO-) in the sample solution is obtained from the working curve, g; m
-the mass of the sample, g.
4.1.5.3 Phosphate content (in PO-) expressed as a percentage by mass X:, calculated according to formula (3). Xg-X, —X2-XX1.203
Wherein: X—phosphorous acid content (in PO-) expressed as a percentage by mass measured in Article 4.2, %; 1.203—the coefficient for converting phosphorous acid (in PO-) into phosphate (in PO-). 4.1.6 Allowable difference
The arithmetic mean of the parallel determination results is taken as the determination result. The absolute difference between the results of two parallel determinations shall not exceed 0.30%. 4.2 Determination of phosphorous acid content
4.2.1 Summary of the method
(3)
Under the condition of pH 6.5-7.2, phosphorous acid is oxidized by iodine to orthophosphoric acid, and the excess iodine is titrated with sodium thiosulfate to determine the phosphorous acid content.
4.2.2 Reagents and materials
Ammonium borate: saturated solution;
Iodine (GB675): c(1/212)=0.1mol/L solution;4.2.2.2
Sulfuric acid (GB625): 1+4 solution;
4.2.2.3 InbZxz.net
4.2.2.4 Sodium thiosulfate (GB637): standard titration solution c (Na2S, O3) = 0.1 mol/L; 4.2.2.5 Soluble starch: 5 g/L solution. 4.2.3 Determination steps
4.2.3.1 Weigh 2.5 g of sample, accurate to 0.0002 g. In a 250 mL iodine volumetric flask, add about 20 mL of water, 12 mL of saturated ammonium borate solution (4.2.2.1), and 15.00 mL of iodine solution (4.2.2.2), and immediately cover the bottle stopper and seal it with water. Place it in a dark place for 10~~15 minutes, then add 15 ml of sulfuric acid solution (4.2.2.3), and titrate with sodium thiosulfate standard titration solution (4.2.2.4) until it turns light yellow, then add 3 mL of starch solution (4.2.2.5) and continue titrating until the blue color disappears, which is the end point. 4.2.3.2 Blank test
In the blank test, except that no sample is added, the same analytical steps, reagents and dosages (except the dosage of standard solution in titration) as those of the determination shall be used. Parallel operation shall be performed.
4.2.4 Expression of analytical results
The phosphorous acid (in terms of PO-) content X4 expressed as mass percentage is calculated according to formula (4): X4 = (V.-V)Xcx0.03948)
(V.-V)XcX3.948
（4）
Wherein: V. - The volume of sodium thiosulfate standard titration solution consumed in the blank test, mL; The volume of sodium thiosulfate standard titration solution consumed by the titration sample, mL; V
The concentration of sodium thiosulfate standard titration solution, mol/L; 139
HG/T2431-93
0.03948: The mass of phosphorous acid (in terms of PO) expressed in grams equivalent to 1.00mL of sodium thiosulfate standard titration solution Lc (Na2S2O)-1.000mol/1:
The mass of the sample, at most,
4.2.5 It is allowed to take the arithmetic mean of half a row of measurement results as the measurement result. The absolute difference between two parallel measurement results shall not exceed 0.03%. 4.3 Determination of azole content
4.3.1 Reagents and materials
4.3.1.1 Potassium hydroxide: c(KOH)m0.1mol/L solution; 4.3.1.2 Benzotriazole standard solution: 1mL solution contains 0.1mgC.H,NHN:N. Weigh 0.1000g of benzotriazole to an accuracy of 0.0002g, add 10mL of potassium hydroxide solution (4.3.1.1) to dissolve it. Transfer all to a 1000ml volumetric flask, dilute to the mark with water, and shake well. 4.3.2 Instruments and equipment
General laboratory instruments and
4.3.2.1 UV spectrophotometer with 1 cm quartz colorimeter 1. 4.3.3 Analysis steps
4.3.3.1 Determination
Weigh about 0.3g of sample, accurate to 0.0002g, dissolve it in water and transfer it to a 1000mL volumetric flask, dilute it to the scale with water, and spread it evenly. Use a 1cm quartz colorimeter to measure its absorbance at 259mm with water as reference. 4.3.3.2 Drawing of working curve
Take 6 100mL volumetric flasks and add 0.00, 0.50, 1.00, 2.00, 3.00, 4.00mL of benzotriazole standard solution (4.3.1.2) in turn, dilute it to the scale with water, and shake it evenly. Use a 1 cm quartz cuvette to measure the absorbance at 259 nm with water as reference, and draw a working curve with the number of milligrams of benzotriazole as the horizontal axis and the corresponding absorbance as the vertical axis. 4.3.4 Expression of analysis results
The content of azoles (in terms of C, H, NHN: N) expressed as mass percentage Xs is calculated according to formula (5): Xs r
m×1000
Where: m\-the amount of benzotriazole (in terms of CH, NHN: N) in the sample solution obtained from the working curve, mg; m-the mass of the sample·&.
4.3.5 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 0.04%. 4.4 Determination of aptamer content
4.4.1 Instruments and equipment
General laboratory instruments and
4.4.1.1 Weighing bottle: 60mm×30mm;
4.4.1.2 Constant temperature drying oven
4.4.2 Determination steps
Weigh about 0.8g of sample, accurate to 0.0002g, and place it in a weighing bottle (4.4.1.1) that has been weighed to a constant weight. Shake it carefully to allow the sample to flow naturally and form a uniform film in the bottle. Place it in a drying oven (4.1.2), gradually heat it to 120°C, dry it at 120°C±2°C for 6h, take it out and place it in a desiccator, cool it to room temperature, and weigh it. 4.4.3 Expression of analysis results
Solid content X expressed as mass percentage. , calculated according to formula 6: 140
Wherein: mt---mass of weighing bottle, g;
HG/T 2431--93
X-mami
m2---mass of sample and weighing bottle after drying, g, m--mass of sample, g.
4.4.4 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 0.30%. 4.5 Determination of pH value
4.5.1 Instruments and solutions
General laboratory instruments and
4.5.1.1 Acidometer, the graduation value is 0.02pH. 4.5.1.2 pH standard solution: pH = 4.00. 4.5.2 Analysis steps
4.5.2.1 Preparation of test solution
(6)
Weigh 1.0g of sample accurately to 0.01g, place in a beaker, add water to dissolve, transfer to a 100mL volumetric flask, dilute with water to the scale, and shake.
4. 5.2.2 Determination
Pour the test solution (4.5.2.1) into a 50mL dry beaker, immerse the calomel electrode and glass electrode in the test solution, and use the pH meter (4.5.1.1) positioned with the pH-4.00 standard solution (4.5.1.2) to determine the pH value of the test solution. 4.5.3 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 0.05pH. 4.6 Density determination
4.6.1 Instruments
General laboratory instruments and
4.6.1.7 Density meter: 1.100~1.200, graduation value is 0.001g/cm*; 4.6.1.2 Glass measuring cylinder: 250mL;
4.6.1.3 Thermometer: graduation value is 1℃C. 4.6.2 Determination steps
Pour the sample into a clean and dry measuring cylinder (4.6.1.2), without any bubbles. Gently place the clean and dry density meter (4.6.1.1) into the sample at 20℃, with the lower end of the density meter (4.6.1.1) at least 2cm away from the bottom of the cylinder and not touching the cylinder wall. The liquid on the exposed part of the upper end of the density meter should not exceed 2-3 graduations. After the density meter is stable in the sample, read the scale at the lower edge of the meniscus of the density meter, which is the density of the sample. 4.6.3 Allowable difference
The arithmetic mean of the parallel measurement results shall be taken as the measurement result, and the absolute difference between the two parallel measurement results shall not exceed 0.005g/cm. 5 Inspection rules
5.1 The scale and corrosion inhibitors shall be inspected by the quality supervision department of the manufacturer, and the manufacturer shall ensure that the products leaving the factory meet the requirements of this standard. 5.2 The user has the right to inspect the received products in accordance with the provisions of this standard to check whether their quality meets the requirements of this standard. 5.3 Products shall be inspected in batches, and the weight of each batch shall not exceed 5t. 5.4 Each batch of products leaving the factory shall be accompanied by a quality certificate, the contents of which shall include: product name, manufacturer name, grade, production date, batch number, net weight and this standard number.
5.5 When sampling, the number of sampling barrels shall be selected according to the provisions of Table 2. 141
Total number of barrels per batch
82~101
102125
126～151
152~181
182~216
HG/T2431-93
Minimum number of barrels selected
Total number of barrels
When sampling, the sample shall be fully stirred first, and then a glass tube or polyethylene plastic tube shall be inserted into the barrel at two-thirds of the depth to take the sample. The sample of each barrel shall not be less than 100mL, and the total amount shall not be less than 1000mL. After being fully mixed, the sample shall be placed in two clean, dry bottles with ground stoppers, sealed, and labeled with the manufacturer name, product name, grade, batch number and sampling date. One bottle shall be inspected by the quality supervision department, and the other bottle shall be kept for one year for future reference.
5.6 If one of the indicators in the inspection results does not meet the requirements of this standard, a new sample shall be taken from the packaging unit of twice the amount for verification. If even one of the indicators in the verification results does not meet the requirements of this standard, the entire batch of products shall be considered unqualified and cannot be accepted. 5.7 When the supply and demand parties have objections to the product quality, they shall be handled in accordance with the provisions of the "Interim Measures for National Product Quality Arbitration Inspection". 5.8 The rounded value comparison method specified in GB1250 shall be used to determine whether the inspection results meet the standards. 6 Packaging, marking, transportation and storage
6.1 Scale and corrosion inhibitors are packaged in polyethylene barrels or plastic-lined iron barrels, with a net weight of 25kg or 200kg per barrel. 6.2 The packaging barrels shall be firmly and clearly marked, including: manufacturer name, product name, specification, grade, production date, batch number, net weight, trademark and this standard number. And painted with the "upward" sign in accordance with GB191, the maximum temperature is -5℃. 6.3 This product should be stored at room temperature, keep ventilation, avoid exposure to sunlight, the storage period is one year. 6.4 This product is suitable for transportation by conventional transportation methods. Additional remarks:
This standard is proposed by the Science and Technology 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. This standard was drafted by Tianjin Chemical Research Institute of the Ministry of Chemical Industry, and the main drafters of this standard are Wang Li, Qian Huilin, Zhou Honghui, Zhang Taishan, and Shao Weiren. 142
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