Some standard content:
Chemical Industry Standard of the People's Republic of China
Industrial Ammonium Thiocyanate
This standard is equivalent to the international standard ISO3622-1976 "Specifications for Photographic Grade Ammonium Thiocyanate" Subject Content and Scope of Application
HG/T 2154-91
This standard specifies the technical requirements, test methods, inspection rules, and marking, packaging, transportation and storage of industrial ammonium thiocyanate. This standard applies to industrial ammonium thiocyanate. This product is mainly used as a raw material for the production of pesticides and an electroplating additive. Molecular formula: NH, CNS
Relative molecular mass: 76.12 (according to the international relative atomic mass in 1987) 2 Reference standards
GB 190
GB3049
GB6678
Dangerous goods packaging mark
Chemical reagents
Chemical reagents
Preparation of standard solution for titration analysis (volumetric analysis) Preparation of standard solution for impurity determination
Preparation of preparations and products used in chemical reagent test methods General method for determination of iron content in chemical products O-phenanthroline spectrophotometric method General rules for sampling of chemical products
GB 6682
3 Technical requirements
Specifications for laboratory water
Appearance: white or slightly red crystals.
Industrial ammonium thiocyanate should meet the requirements of the following table: Table 1
Ammonium thiocyanate (NH.CNS) content, %
Appearance of solution (100g/L)
pH value (50g/L solution)
Chloride (NH,CI) content, %
Sulfate ((NH)SO.) content, %Ignition residue content, %
Heavy metal (Pb) content, %
Superior product
Clear without sediment
Ministry of Chemical Industry of the People's Republic of China 1991-09-16 Approval designation
First-class product
Qualified product
Clear and without sediment except for a little flocculent matter4.5~6.0
1992-01-01 implementation
Iron (Fe) content, %
Sulfide (as S) content, %
4Test method
HG/T2154—91
Continued Table 1
Superior product
Qualified product
The reagents and water used in this standard, unless otherwise specified, refer to analytical pure reagents and the third-grade water specified in GB6682. The standard solutions, impurity standard solutions, preparations and products required in the test, unless otherwise specified, shall be prepared in accordance with the provisions of GB601, GB602 and GB603.
4.1 Determination of ammonium thiocyanate content
4.1.1 Summary of method
Add excess silver nitrate to the acidic solution to generate silver thiocyanate, and then use ammonium ferric sulfate as an indicator to back-titrate with ammonium thiocyanate standard titration solution
4.1.2 Reagents and materials
4.1.2.1 Nitric acid (GB626) solution: 1+9;4.1.2.2 Ammonium ferric sulfate (GB1279) solution: 50g/L;4.1.2.3 Silver nitrate (GB670) standard titration solution: c (AgNO) about 0.1mol/L;4.1.2.4 Ammonium thiocyanate (GB660) standard titration solution: c (NH, CNS) about 0.1mol/L;4.1.2.4.1 Preparation: Weigh 7.61g of ammonium thiocyanate, dissolve it in 1000mL of water, and shake well. 4.1.2.4.2 Calibration: Weigh about 0.5g of standard silver nitrate dried to constant weight in a sulfuric acid dryer, accurate to 0.0002g, dissolve in 100mL of water, add 2mL of ammonium ferric sulfate solution and 5mL of nitric acid. Titrate with ammonium thiocyanate standard titration solution under shaking until the solution turns light brown-red and does not disappear for 30s.
4.1.2.4.3 Calculate the concentration (c) of the standard ammonium thiocyanate solution according to formula (1): m
c = V × 0. 169 9
Wherein: m-
the mass of silver nitrate, g;
the volume of the standard ammonium thiocyanate solution consumed in the titration, mL; (1)
0.1699-the mass of silver nitrate in grams equivalent to 1.00mL of the standard ammonium thiocyanate solution [c(NH,CNS) 1.000mol/L].
4.1.3 Analysis steps
Weigh about 0.3g of the sample, accurate to 0.0002g, place it in a 250ml conical flask, add 50mL of water to dissolve it, add 5mL of nitric acid solution, add 50mL of the standard silver nitrate solution with a pipette, and shake well. Add 2mL of ammonium ferric sulfate solution and titrate with ammonium thiocyanate standard titration solution until the solution turns light brown and remains unchanged for 30s. 4.1.4 Expression of analytical results
The content of ammonium thiocyanate (NH.CNS) expressed as mass percentage (X,) is calculated according to formula (2): Vic -Vc2) × 0. 076 12 × 100 = 7.612(Vig-Vc)X
Wherein: (, — actual concentration of silver nitrate standard titration solution, mol/I; V, — volume of silver nitrate standard titration solution added, mL; C2
actual concentration of ammonium thiocyanate standard titration solution, mol/L; m
HG/T 2154- 91
V — volume of ammonium thiocyanate standard titration solution consumed in titration, mL; m Sample mass, g;
0.07612—The mass of ammonium thiocyanate equivalent to 1.00ml of silver nitrate standard titration solution c(AgNO,)=1.000mol/L>, expressed in grams.
The result should be expressed to one decimal place.
4.1.5 Allowable difference
The difference between two parallel determination results shall not exceed 0.2%. The arithmetic mean is taken as the determination result. 4.2 Solution appearance
4.2.1 Determination steps
Weigh 10.0±0.1g sample and dissolve it in 100mL water. Observation Its clarity and whether there is any sediment. 4.3 Determination of pH value
4.3.1 Summary of method
Measure the pH value of the test solution with an acidometer equipped with a glass measuring electrode and a saturated calomel reference electrode. 4.3.2 Reagents and materials
4.3.2.1 Water without carbon dioxide.
4.3.3 Instruments and equipment
4.3.3.1 Acidometer: The graduation value is 0.1 pH unit. 4.3.4 Analysis steps
Weigh 5.00±0.01g of sample and place it in a 150ml beaker. Add 100m L is dissolved in water without carbon dioxide, and its pH value is measured with an acidometer.
The result should be expressed to one decimal place.
4.3.5 Allowable difference
The difference between two parallel determination results shall not exceed 0.2 pH units. The arithmetic mean is taken as the determination result. 4.4 Determination of fluoride content
4.4.1 Summary of method
Under alkaline conditions, thiocyanate is decomposed with hydrogen peroxide, and then the test solution is acidified, and silver nitrate and chloride ions are added to generate a white insoluble product, which is compared with the ammonium chloride standard solution treated in the same way. 4.4.2 Reagents and materials Materials
4.4.2.1 Sodium hydroxide (GB629);
4.4.2.2 Nitric acid (GB626) solution: 1+9;4.4.2.3 Hydrogen peroxide (GB6684) solution: 1+4;4.4.2.4 Silver nitrate (GB670) solution: 100g/L;4.4.2.5 Ammonium chloride (GB658) standard solution: 0.100mgNH,Cl/mL. Weigh 0.100±0.001g ammonium chloride, dissolve it in nitric acid solution, transfer it into a 1000mL volumetric flask, dilute it to the mark with nitric acid solution, and shake well.
4.4.3 Analysis steps
Weigh 1.000.01g of the sample, place it in a 250mL conical flask, add 30mL of hydrogen peroxide solution to dissolve, add 1g of sodium hydroxide, shake until the violent reaction stops, then add 30mL of hydrogen peroxide solution, boil for 2min, cool to room temperature, transfer to a 100ml volumetric flask, and dilute to the scale. Use a pipette to transfer 10mL of this test solution, place it in a 50mL colorimetric tube, add 10mL of nitric acid solution and 1ml of silver nitrate solution, dilute to the scale with water, shake well, and let it stand for 5min. The turbidity presented shall not be greater than the standard. The standard is to take 10.00mL (superior products, first-class products) and 20.00mL (qualified products) of ammonium chloride standard solution and place them in a 250mL conical flask, and treat them in the same way as the sample.
4.5 Determination of sulfate content
4.5.1 Method Summary
HG/T 2154—91
When barium nitride is added to an acidic medium, it reacts with sulfate ions in the test solution to form a white precipitate. Compare with the ammonium sulfate standard solution treated in the same way.
4.5.2 Reagents and Materials
4.5.2.1 Hydrochloric acid (GB622) solution: 1+9; 4.5.2.2 Barium chloride (GB652) solution: 100g/14.5.2.3 Ammonium sulfate (GB1396) standard solution: 0.100mg (NH.), S()4/mL. Weigh 0.100±0.001g ammonium sulfate, dissolve it in water, transfer it into a 1000mg volumetric flask, dilute to the mark, and shake well. 4.5.3 Analysis steps
Weigh 1.00±0.01g of sample, place in a 50mL colorimetric tube, add 30mL of water to dissolve, add 0.5mL of hydrochloric acid solution and 1mL of barium chloride solution, dilute to scale, shake well, and leave for 15 minutes. The turbidity should not be greater than the standard. The standard is to take 6.00mL (superior product), 10.00mL (-~quality product), 20.00mL (qualified product) of ammonium sulfate standard solution and treat it in the same way as the sample.
4.6 Determination of ignition residue content
4.6.1 Instruments and equipment
4.6.1.1 Porcelain: 30mL.
4.6.2 Analysis steps
Use porcelain that has been calcined to constant weight at 600±50℃ to weigh about 5g of sample, accurate to 0.0002g, and heat to 300℃ in a fume hood until it is completely volatilized. Then calcine at 600±50℃ to constant weight. 4.6.3 "Expression of analysis results
The ignition residue content expressed as mass percentage (X,) is calculated according to formula (3): Xg-me2㎡×100
Wherein: ml
-mass of porcelain, g;
-mass of porcelain and test material, g;
m:-mass of porcelain crucible and ignition residue, g. The result should be expressed to two decimal places.
4.6.4 Allowable error
The difference between the results of two parallel determinations shall not exceed 0.02%. The arithmetic mean is taken as the determination result. 4.7 Determination of heavy metal content
4.7.1 Summary of method
Under acidic conditions, saturated hydrogen sulfide water is added to react with the heavy metals in the test solution to generate brown sulfide, which is compared with the lead standard solution treated in the same way.
4.7 .2 Reagents and materials
4.7.2.1 Hydrochloric acid (GB622) solution: 1+99; 4.7.2.2 Ammonia (GB631) solution: 1+9; 4.7.2.3 Saturated hydrogen sulfide water: Prepare immediately before use; 4.7.2.4 Lead standard solution: 0.0100mgPb/mL, prepare immediately before use. Use a pipette to transfer 10mL of the lead standard solution prepared according to GB602, place it in a 1000mL volumetric flask, dilute to the mark with water, and shake well.
4.7.2.5 p-Nitrophenol solution: 2.5g/L ethanol (GB679). 4.7.3 Analysis steps
Weigh 2.00±0.01g of the sample, place it in a 50ml colorimetric tube, add 20mL of water to dissolve, add 1 drop of p-nitrophenol indicator solution, and add 36.1
HG/T 2154-91
Ammonia solution, make the test solution yellow, then add hydrochloric acid solution until the test solution becomes colorless, then add 0.5mL in excess, add 5mL of newly prepared saturated hydrogen sulfide water, dilute to the scale with water, and shake well. The color should not be darker than the standard. The standard is to take 4.00mL of lead standard solution and treat it in the same way as the test sample. 4.8 Determination of iron content
4.8.1 Summary of the method
Same as Article 2 of GB3049.
4.8.2 Reagents and materials
Same as Article 3 of GB3049.
4.8.3 Instruments, equipmentwww.bzxz.net
4.8.3.1 Spectrophotometer: with 0.5cm and 3cm thick absorption cell. 4.8.4. Analysis steps
4.8.4.1 Drawing of working curve
According to the provisions of Article 5.3 of GB3049, draw the working curve, using 0.5cm and 3cm absorption cells. 4.8.4.2 Determination
Weigh about 2g of sample, accurate to 0.01g, put it in a 100mL beaker, add 60mL of water to dissolve; add 60mL of water to another beaker as a blank test solution. The following is in accordance with the provisions of Article 5.4 of GB3049, using 3cm (superior products) and 0.5cm (equal products, qualified products) absorption cells respectively, starting from "adjust the pH to about 2 with hydrochloric acid solution or ammonia water." 4.8.5 Expression of analysis results
The iron (Fe) content (X) expressed as a mass percentage is calculated according to formula (4): Xg
m × 1 000
X 100 =
Wherein: m, the mass of iron found from the working curve according to the measured absorbance of the test solution, mg; m. -——the mass of iron found from the working curve according to the measured absorbance of the blank test solution, mg; m-the mass of the sample, g.
The results obtained should be expressed to four decimal places for superior and first-class products, and to three decimal places for qualified products. 4.8.6 Allowable difference
. (4)
The difference between the results of two parallel determinations shall not exceed 0.0001% for superior products, 0.0005% for first-class products, and 0.001% for qualified products. The arithmetic mean shall be taken as the determination result.
4.9 Determination of sulfide content
4.9.1 Summary of the method
In an ammonia medium, the sulfide ions in the sample react with silver nitrate to form a black precipitate, which is compared with the silver standard solution treated in the same way. 4.9.2 Reagents and materials
4.9.2.1 Ammonia water (GB631):
4.9.2.2 Sodium sulfide (HG3-903) solution: 10g/L; 4.9.2.3 Silver nitrate (GB670) solution: 100g/1; 4.9.2.4 Silver nitrate (GB670) standard solution: c (AgNO.) = 0.00100mol/L. Weigh 0.170g of silver nitrate, dissolve it in water, transfer it to a 1000mL volumetric flask, dilute to the mark, and shake well. 4.9.3 Analysis steps
Weigh 0.96±0.01g of sample and dissolve it in 25mL of water. Transfer this solution to a 50mL colorimetric tube containing 20mL of ammonia water and 2mL of silver nitrate solution (4.9.2.3), heat it in a boiling water bath for 15min, dilute to the scale after cooling, and shake well. The color should not be darker than the standard.
The standard is to take 3.00mL of silver nitrate standard solution (4.9.2.4) in a 50mL colorimetric tube, add 20mL of nitrogen water and 25mL of water, and add a few drops of sodium sulfide solution. Heat it in a boiling water bath for 15min, dilute to the scale after cooling, and shake well. 365
HG/T2154—91
Note: The test solution may form explosive compounds during storage. After inspection, it should be immediately handled and the container used should be cleaned. 5 Inspection rules
5.1 Industrial ammonium thiocyanate should be inspected by the quality supervision and inspection department of the manufacturer in accordance with the provisions of this standard. The manufacturer should ensure that all industrial ammonium thiocyanate shipped from the factory meets the requirements of this standard. Each batch of industrial ammonium thiocyanate shipped from the factory should be accompanied by a quality certificate. The content includes: manufacturer name, product name, grade, batch number, net weight, production date, product quality certificate of compliance with this standard and this standard number. 5.2 The user unit has the right to accept the industrial ammonium thiocyanate received in accordance with the provisions of this standard. The acceptance should be carried out within one month from the date of arrival of the goods.
5.3 Each batch of products shall not exceed 5t.
5.4 Determine the number of sampling units in accordance with the provisions of Article 6.6 of GB6678. When sampling, insert the sampler vertically from the center of the packaging bag to three-quarters of the depth of the material layer to take a sample. Mix the sample, reduce it to about 500g by quartering, and immediately put it into two dry, clean wide-mouth bottles and seal them. Paste labels on the bottles, indicating: manufacturer name, product name, grade, batch number, sampling date, name of the sampler. One bottle is used for inspection. The other bottle is kept for three months for reference. 5.5 If one indicator in the inspection result does not meet the requirements of this standard, re-sample from twice the amount of packaging bags for verification. If even one indicator in the verification result does not meet the requirements of this standard, the entire batch of products cannot be accepted. 5.6 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". 6 Marking, packaging, transportation and storage
6.1 The packaging bag must have a firm and clear mark. The contents include: manufacturer name, product name, trademark, grade, batch number or production date, net weight, this standard number and the toxic substance mark specified in GB190. 6.2 Industrial ammonium thiocyanate should be packed in plastic woven bags lined with polyethylene plastic bags, with a net weight of 25 or 40 kg per bag. 6.3 Industrial ammonium thiocyanate should be stored in a cool, dry place and should not be mixed with acids, flammable materials, oxidants and food for storage or transportation. Additional remarks:
This standard was 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 the Tianjin Chemical Research Institute of the Ministry of Chemical Industry. This standard was drafted by Zhejiang Dongyang Chemical Industry and Trade Company and the Tianjin Chemical Research Institute of the Ministry of Chemical Industry. The main drafters of this standard are Shan Chengfang, Wang Qi and Wang Xiangming. 366
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