Some standard content:
Chemical Industry Standard of the People's Republic of China
Dibasic Lead Phosphite
1 Subject Content and Scope of Application
HG 2339-92
This standard specifies the technical requirements, test methods, inspection rules and marking, packaging, transportation and storage requirements of dibasic lead phosphite products. This standard applies to powdered dibasic lead phosphite directly synthesized by adding phosphorous acid to the yellow lead suspension method. This product is mainly used as a heat stabilizer for polyvinyl chloride.
Molecular formula: 2PbO·PbHPO3·1/2H2ORelative molecular mass: 742.5 (according to the international relative atomic mass in 1989) 2 Reference standards
Preparation of standard solution for titration analysis (volumetric analysis) of chemical reagents GB603 Preparation of preparations and products used in chemical reagent test methods GB6682 Specifications for laboratory water
3 Technical requirements
3.1 Appearance: Superior and first-class products are white powder, qualified products are white or slightly yellow powder, without obvious mechanical impurities. 3.2 Technical indicators
Dibasic lead phosphite should meet the requirements of Table 1. Table 1
Lead content (in terms of Pb)
Phosphorous acid (H,PO),)
Heating loss
Sieve residue (75um sieve)
Test method
Superior quality
10.0~12.0
First-class quality
89.0～91, 0
10.0~12.0
%(m/m)
Qualified quality
88.5~91.5
9. 0~~12. 0
The standard titration solutions, preparations and products used in this standard shall be prepared in accordance with the provisions of GB601 and GB603 unless otherwise specified.
The experimental water in this standard shall meet the specifications of Grade 3 water in GB6682. 4.1 Determination of lead content (in terms of PbO)
4.1.1 Principle of the method
After the sample is dissolved in ammonium acetate solution, the lead is titrated with sodium ethylenediaminetetraacetate (EDTA) standard titration solution in a medium with a pH of 5 to 6, using xylenol orange as an indicator. 4.1.2 Reagents and materials
Approved by the Ministry of Chemical Industry of the People's Republic of China on June 1, 1992 288
Implemented on July 1, 1993
4.1.2.1 Ammonium acetate solution: 300 g/l.Www.bzxZ.net
HG 2339-92
4.1.2.2 EDTA standard titration solution: c(EDTA) = 0.04 mol/L. 4.1.2.3-cresol orange indicator: 2 g/L. 4.1.3 Analysis steps
Weigh 0.3g of the sample (accurate to 0.0001g), place it in a 250ml conical flask, add 25ml of ammonium acetate (4.1.2.1), heat to dissolve. After cooling, add 40ml of water, add 3-5 drops of xylenol orange indicator (4.1.2.3), and titrate with EDTA standard titration solution (4.1.2.2) until the solution changes from red to bright yellow, which is the end point. 4.1.4 Expression of results
The lead content is expressed as the mass percentage r of lead monoxide (PbO) and is calculated according to formula (1): cV×0.223 2×100
Wherein: the actual concentration of EDTA standard titration solution, mol/L; VEDTA standard titration solution dosage, mL; -mass of the sample, g
(1)
0.2232--the mass of lead oxide expressed in grams equivalent to 1.00mLEDTA standard titration solution c(EDTA)=1.000mol/L).
4.1.5 Allowable difference
...The difference between the results of two parallel determinations shall not exceed 0.4%, and the arithmetic mean shall be taken as the determination result. 4.2 Determination of phosphorous acid content
4.2.1 Reagents and materials
4.2.1.1 Nitrilotriacetic acid solution: 20g/L. Weigh 20g of nitrilotriacetic acid, dissolve it in an appropriate amount of water without carbon dioxide, add 3-4 drops of neutral red-methylene blue mixed indicator, and add 8g of sodium hydroxide to dissolve the nitrilotriacetic acid. Then adjust the solution to a blue-purple pH value of about 6.8-7.0 with 0.1mol/L sodium hydroxide solution (or directly adjust the pH value with an acidometer). Then dilute to 1000mL for use. The pH value of the nitrilotriacetic acid solution should be checked once a month.
4.2.1.2 Standard hydrochloric acid titration solution: c(HCI)=0.1mol/L. 4.2.1.3 Bromocresol green-methyl red mixed indicator: 3 parts of 10g/L bromocresol green ethanol solution and 1 part of 10g/L methyl red ethanol solution are mixed evenly.
4.2.1.4 Neutral red-methylene blue mixed indicator: 1 part of 10g/L. Neutral red ethanol solution and 1 part of 10g/L methylene blue ethanol solution are mixed evenly.
4.2.2 Analysis steps
Weigh 0.5g of the sample (accurate to 0.0001g), place it in a 250mL conical flask, and moisten the sample with a small amount of water. Add 30ml of nitrilotriacetic acid solution (4.2.1.1) and heat to dissolve. After cooling, add 4 to 6 drops of bromocresol green-methyl red mixed indicator (4.2.1.3), and titrate with 0.1mol/l hydrochloric acid standard titration solution (4.2.1.2) until the solution changes from green to purple, which is the end point. Perform a blank test at the same time. 4.2.3 Expression of results
The content of phosphorous acid (H:PO) is expressed as mass percentage r2 and calculated according to formula (2): =m:(V)x0.23 2100 0.367 4
Wherein: -----lead content, %;
---actual concentration of hydrochloric acid standard titration solution, mol/L. Volume of hydrochloric acid standard titration solution consumed by the sample, mL; V. -—-volume of hydrochloric acid standard titration solution consumed by the blank, mL; mmass of the sample, g;
0.2232---mass of lead monoxide equivalent to 1.00mL hydrochloric acid standard titration solution Lc (HC1) 1.000mol/1], expressed in grams 289
0. 367 4—
HG 2339—92
Conversion constant of phosphorous acid and lead oxide.
4.2.4 Allowable error
The difference between the results of two parallel determinations shall not exceed 0.2%, and the arithmetic mean shall be taken as the determination result. 4.3 Determination of heating loss
4.3.1 Instruments and equipment
4.3.1.1 Weighing bottle: 50mm in diameter, 30mm in height. 4.3.1.2 Oven: sensitivity is ±2°C.
4.3.1.3 Dryer: contain appropriate desiccant (such as silica gel). 4.3.2 Analysis steps
Weigh 10g of the sample (accurate to 0.0001g), place it in a weighing bottle that has been dried to constant weight at 105-110°C in advance, move it to the oven, and open the bottle cap. Make the sample layer to be tested in the weighing bottle and the mercury ball of the oven thermometer at the same level, and the vertical distance shall not exceed 100mm. Keep the temperature at 105-110℃ for 2h, cover the bottle, take out the weighing bottle, put it in a dryer, cool it to room temperature (not less than 30min), and weigh it. 4.3.3 Expression of results
Heating loss is expressed as mass percentage x3, calculated according to formula (3): m-m2
Where: ml-mass of weighing bottle and sample before drying, g; m2——mass of weighing bottle and sample after drying, g; m——mass of sample, g.
4.3.4 Allowable difference
The difference between the results of two parallel determinations shall not exceed 0.06%, and the arithmetic mean shall be taken as the determination result. 4.4 Determination of sieve residue
4.4.1 Instruments and equipment
4.4.1.1 Test sieve: diameter 75mm×25mm/0.075mm. 4.4.1.2 Soft brush; the length of the hair is about 30mm and the width is about 30mm. 4.4.1.3 Oven: sensitivity is ±2℃. 4.4.1.4 Desiccator: contain appropriate desiccant (such as silica gel). 4.4.2 Analysis steps
Weigh 50g sample (accurate to 0.01g), place it in a 200ml beaker, add water to moisten it, then pour it into the test sieve, carefully rinse it with tap water and a soft brush, so that all the sample that can pass through the sieve can pass through the sieve. After rinsing, place the sieve residue together with the test sieve in an oven, dry it at 105-110℃ for 1h, take it out and place it in a desiccator, and cool it to room temperature (not less than 30min). Then transfer all the sieve residue to a constant weight surface dish and weigh it.
4.4.3 Expression of results
The sieve residue is expressed as mass percentage, calculated according to formula (4): ml×100
Where: m1-mass of the sieve residue after drying·g; m mass of the sample, g.
5Test rules
5.1 The quality inspection department of the manufacturer shall be responsible for the inspection of dibasic lead phosphite. The manufacturer shall ensure that each batch of products meets the technical requirements of this standard.
HG 2339-92
5.2 The user may inspect and accept the dibasic lead phosphite received in accordance with the provisions of this standard. 5.3
The daily output of dibasic lead phosphite products is considered as one batch. 5.4 When sampling, determine the number of sampling units according to Table 2. Table 2
Number of units of total material
82~101
102~125
Minimum number of sampling units
5.5 Sampling method: Insert the U-shaped metal tube sampling probe from top to bottom into 2/3 of the material. After rotating three times, carefully withdraw the probe and pour the sample in the probe into a dry and clean container. Mix the sample evenly and pack it into two bottles. Cover the bottle caps tightly and paste labels with the manufacturer name, product name, batch number, sampling date and sampler. One bottle is inspected by the quality inspection department and the other bottle is kept for six months for reference. The sample volume of each bottle should be at least three times the required volume for testing. 5.6 If the test results do not meet the requirements of this standard, samples should be taken from the packaging of the batch number at twice the amount for re-testing. If one indicator still does not meet the requirements of this standard, the whole batch of products cannot be accepted. 5.7 When the supply and demand parties have objections to the product quality, arbitration can be conducted in accordance with this standard. The arbitration institution shall be selected by both parties through consultation. 6 Marking, packaging, transportation and storage
6.1 Dibasic lead phosphite is packaged in plastic woven bags lined with plastic film bags. The bags should be marked with: manufacturer name, product name, trademark, grade, this standard number, net weight and production date. The net weight of each bag is 25kg. Each batch of packaged products should be accompanied by a product certificate, which includes: manufacturer name, product name, batch number, technical indicators and this standard number.
6.2 Prevent moisture during transportation and avoid contact with open flames. The packaging bags must not be damaged. 6.3 Dibasic lead phosphite should be stored in a dry and ventilated place, and should not be piled in the open air to prevent moisture. The storage period is half a year. 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 Shanxi Chemical Industry Research Institute. This standard was drafted by the State-owned Wenzhou Plastic Additives General Factory of Wenzhou Plastic Additives Industry Group Corporation. The main drafters of this standard are Chen Zhenzhen, Lin Xuejin and Li Junqing. From the date of implementation of this standard, the former Ministry of Chemical Industry Standard HG2-1054-77 "Dibasic Lead Phosphite" will be invalid.
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