Some standard content:
National Standard of the People's Republic of China
Industry
1 Subject content and scope of application
Industry
Asia
Nitric acid
Sodium nitrite for industrial use Sodium
GB2367-90
replaces GB2367-80
This standard specifies the technical requirements, test methods, inspection rules, marking, packaging, transportation and storage of industrial sodium nitrite. This standard applies to industrial sodium nitrite produced from nitrogen oxide gas during the production of nitric acid. This product is mainly used as raw materials for manufacturing nitro compounds, azo dyes, etc. and as mordant, bleaching agent, metal heat treatment agent, cement early strength agent and antifreeze for fabric dyeing. Molecular formula: NaNO
Relative molecular mass: 69.00 (according to the 1987 international atomic weight) 2 reference standards
GB190 dangerous goods packaging mark
GB191
GB601
GB603
Illustrated marks for packaging, storage and transportation
Preparation of standard solutions for chemical reagent titration analysis (volume analysis) Preparation of preparations and products used in chemical reagent test methods GB3051
GB6678|| tt | 3.2 Industrial sodium nitrite should meet the requirements in the following table: indicator item
sodium nitrite (NaNO,) content (on a dry basis), % sodium nitrate (NaNO,) content (on a dry basis), % fluorine Chemical (based on NaCI) content (on a dry basis), % water-insoluble matter content (on a dry basis), %
moisture content, %
4 test methods
excellent products
99.0
0.80
0.10
0. 05
1.8
refers to
first-class product||tt| |98.5
1.00
0.17
0.06
2.0
standard
qualified product
98.0
1.90
0.10
2.5
The reagents and water used in this standard refer to analytical pure reagents and distilled water or water of equivalent purity unless other requirements are noted. The standard solutions, preparations and products required in the test shall be prepared in accordance with the provisions of GB601 and GB603 unless other provisions are noted. 4.1 Determination of sodium nitrite content
State Bureau of Technical Supervision approved on 1990-12-30 for implementation on 1992-01-01
90
GB2367-
4.1.1 method Summary
In acidic solution, potassium permanganate is used to oxidize sodium nitrite. Calculate the sodium nitrite content based on the consumption of potassium permanganate standard titration solution.
4.1.2 Reagents and materials
4.1.2.1 Sulfuric acid (GB625): 1+29 solution. After preparing the sulfuric acid solution in proportion, heat it to about 70°C, and add dropwise the potassium permanganate standard titration solution until the solution turns reddish. Cool and set aside; 4.1.2.2 Sulfuric acid (GB625): 1+5 solution. The preparation method is the same as 4.1.2.1; 4.1.2.3 Potassium permanganate (GB643): c (1/5KMnO,) about 0.1mol/L standard titration solution; 4.1.2.4 Sodium oxalate ((GB1289): c (1/2Na2C .0,) about 0.1mol/L standard titration solution; weigh about 6.7g sodium oxalate, dissolve it in 300mL sulfuric acid solution (4.2.2.1), dilute to 1000mL with water, shake well, and calibrate with potassium permanganate standard titration solution. .
4.1.3 Analysis steps
Weigh 2.5~2.7g sample, accurate to 0.0002g, place it in a 250mL beaker, add water to dissolve, transfer it all to a 500mL volumetric flask, and dilute to the mark with water. , shake well. In a 300mL Erlenmeyer flask, add approximately 40mL of potassium permanganate standard titration solution using a pipette, add 10mL of sulfuric acid solution (4.1.2.2), and heat to 40°C. Add 10 mL of sodium oxalate standard titration solution to the pipette, heat to 70~80°C, and continue to titrate with potassium permanganate standard titration solution until the solution turns light pink and does not disappear for 30 seconds
4.1.4 Analyze the results. The expression of
The sodium nitrite (NaNO2) content (X,) expressed as mass percentage is calculated according to formula (1): -V2C2)
25×(100-X)
m×500
m(100-Xs)
100
---High manganese Actual concentration of potassium acid standard titration solution, mol/L; in the formula: -
W
C2-
V2-
--Add and titrate without high The total volume of the potassium manganate standard titration solution, mL; the actual concentration of the sodium oxalate standard titration solution, mol/L; the volume of the sodium oxalate standard titration solution added, mL; XsbZxz.net
m
Press 4.5 Moisture content measured by the strip, %;
Sample mass, g;
...(1)
and 1.00mL potassium permanganate standard titration solution c (1/5KMnO .)=1.000mol/L) equivalent to the mass of sodium nitrite 0.034 50--
sodium expressed in grams.
The result should be expressed to one decimal place.
4.1.5 Allowable difference
The difference between two parallel measurement results shall not be greater than 0.2%. Take the arithmetic mean as the measurement result. 4.2 Determination of cobalt nitrate content
4.2.1 Method summary
Add methanol to the test solution, and react with nitrite to form methyl nitrite under the action of sulfuric acid. Evaporate to remove it. Then add excess ferrous ammonium sulfate to reduce sodium nitrate, and back-titrate with potassium permanganate standard titration solution. 4.2.2 Reagents and materials
4.2.2.1 Methanol (GB683);
4.2.2.2 Sulfuric acid (GB625);
4.2.2.3 Sulfuric acid (GB625): 1+5 solution; 4.2.2.4 Sodium hydroxide (GB629): 200g/L solution; GB2367-90
4.2.2.5 Sodium hydroxide (GB629): 1g/L solution; 4.2.2.6 Ferrous ammonium sulfate [Fe(NH) 2(SO4)2·6H20)(GB661): c[Fe(NH)2(SO,)2) about 0.2mol/L solution; weigh 80g ferrous ammonium sulfate and dissolve in 300mL1+8 sulfuric acid (GB625) solution medium, add 700mL water and shake well. 4.2.2.7 Potassium permanganate (GB643): c (1/5KMnO.) approximately 0.1mol/L standard titration solution; 4.2.2.8 Phenol sulfide (HGB3039): 10g/L solution. 4.2.3 Analysis steps
Weigh about 3g of sample, accurate to 0.0002g, place it in a 500mL Erlenmeyer flask, add 10mL of water to dissolve. Add 10 mL of methanol, and dropwise add 15 mL of sulfuric acid solution (4.2.2.3) while shaking continuously. Control the adding speed of sulfuric acid to avoid excessive generation of methyl nitrite. Wash the inner wall of the Erlenmeyer flask with water and heat to a gentle boil for 2 minutes. After cooling, add 2 drops of phenolphthalein indicator solution and neutralize with sodium hydroxide solution (4.2.2.4) until it turns pink [near the end point, neutralize with sodium hydroxide solution (4.2.2.5)). The solution was evaporated to 1015 mL under slight boiling. Cool and wash the inside of the bottle with a small amount of water. Use a pipette to add 25 mL of ferrous ammonium sulfate solution, and slowly add 25 mL of sulfuric acid along the bottle wall while shaking continuously (4.2.2.2). Heat and boil slightly until the solution changes from brown to bright yellow. Remove the Erlenmeyer flask and cool quickly to room temperature. Add 250 to 300 mL of water and titrate with potassium permanganate standard titration solution until the solution turns slightly red and does not disappear for 30 seconds. Do a blank test at the same time.
4.2.4 Expression of analysis results
The sodium nitrate (NaNO:) content (X2) expressed as mass percentage is calculated according to formula (2): X2 = o- V)eX 0.028 3
Medium: c-
283(V. - V.)c
m(100-Xs)
V. - The volume of potassium permanganate standard titration solution consumed in the blank test, mL; V, - - the volume of potassium permanganate standard titration solution consumed in the measurement, mL; Xs - the moisture measured in Article 4.5, % ;m——sample mass, g;
(2)
0.0283——with 1.00mL potassium permanganate standard titration solution (c(1/5KMnO,)=1.000mol/L) Equivalent mass of sodium nitrate in grams.
The result should be expressed to two decimal places.
4.2.5. Allowable difference
The difference between the results of two parallel measurements shall not be greater than 0.05%. Take the arithmetic mean as the measurement result. 4.3 Determination of chloride content
4.3.1 Method summary
In the acidic solution, add urea to decompose sodium nitrite. In a slightly acidic aqueous solution, mercury nitrate is used to convert nitrogen ions into weakly ionized mercury chloride. Use the diphenyl azocarbon hydrazide indicator to form a purple-red complex with excess mercury ions to determine the end point. 4.3.2 Reagents and materials
Reagents and materials specified in Article 4 of GB3051 and the following materials. 4.3.2.1 Urea (GB696);
4.3.2.2 Reference solution: Add 100 mL water and 3 drops of bromophenol blue indicator solution to a 250 mL Erlenmeyer flask, and dropwise add 1+15 nitric acid solution until it turns from blue to yellow. And overdose by 5 drops. Add 1 mL of diphenyl azocarbon hydrazide indicator solution, use a microburette, and titrate with 0.05 mol/L mercury nitrate standard titration solution until it reaches purple red. Record the volume used. This solution is prepared before use. 4.3.3 Instruments and equipment
4.3.3.1 Microburette: The graduation value is 0.01 or 0.02mL. 4.3.4 Analysis steps
GB2367-90
Weigh about 5g of the sample, accurate to 0.01g, place it in a 250mL Erlenmeyer flask, and dissolve it in 50mL of water. Add 3g of urea and wait until it dissolves before heating. Add 1 to 1 nitric acid solution dropwise at a slight boil until the sodium nitrite is completely decomposed (no tiny bubbles are produced). Cool to room temperature. Add 2 to 3 drops of bromophenol blue indicator solution, add sodium hydroxide solution dropwise until the solution turns blue, then add 1+15 nitric acid solution dropwise until it turns yellow, and add 2 to 6 drops in excess, add 1 mL of diphenyl azocarbon For hydrazide indicator solution, use a microburette and titrate with 0.05mol/L mercury nitrate standard titration solution until the solution changes from yellow to purple-red, which is the same color as the reference solution. 4.3.5 Expression of analysis results
The chloride (calculated as NaCI) content (X3) expressed as mass percentage is calculated according to formula (3): (V-Vo)c× 0. 058 5×100=| |tt||585×(V-Vo)c
Xa=-
m× 100- x
m(100-X,)
100|| tt||In the formula: c-
V
V.
The actual concentration of the mercury nitrate standard titration solution, mol/L; the volume of the mercury nitrate standard titration solution consumed in the titration, mL: the volume of the mercury nitrate standard titration solution consumed when preparing the reference solution, mL: - Moisture content measured according to Article 4.5, %;
1.00mL of mercury nitrate standard titration solution (cC1/2Hg(NO)2)=1.000mol/L) is equivalent to the mass of sodium chloride expressed in grams.
The result should be expressed to two decimal places.
4.3.6 Allowable difference
The difference between two parallel measurement results shall not be greater than 0.01%. Take the arithmetic mean as the measurement result. 4.4 Determination of water-insoluble content
4.4.1 Reagents and materials
4.4.1.1 Hydrochloric acid (GB622);
4.4.1.2 Starch (HGB3095)-potassium iodide (GB1272) test paper. 4.4.2 Instruments and equipment
4.4.2.1 Pot filter: filter plate pore size 5~15um. 4.4.3 Analysis steps
Weigh about 100g of the sample, accurate to 0.1g, place it in a 500mL beaker, add 300mL of water, and heat to dissolve. Filter with a crucible filter that has been dried to constant weight at 105 to 110°C. Wash with hot water until there are no nitrite ions (take about 20mL of washing liquid, add 2 drops of hydrochloric acid, and check with starch-potassium iodide test paper). Dry at 105~110℃ to constant weight. 4.4.4. Expression of analysis results
The water-insoluble matter content (X,) expressed as mass percentage is calculated according to formula (4): X,
where: ml-
2-ml
×100
m2
100-Xs
mx
Mass of crucible filter, g;
100
m2 water-insoluble matter and the mass of the filter, g;
The result should be expressed to two decimal places.
4.4.5 Allowable difference
(m2-m)×104
m(100-X,)
The difference between the results of two parallel measurements shall not be greater than 0.01% . Take the arithmetic mean as the measurement result. .(4)
4.5 Determination of moisture
4.5.1 Instruments and equipment
4.5.1.1 Weighing bottle: Φ50×30mm.
4.5.2 Analysis steps
GB2367-90
Weigh about 5g of the sample in a weighing bottle that has been dried to constant weight at 105~110℃, accurate to 0.0002g . Dry at 105~110℃ to constant weight.
4.5.3 Expression of analysis results
Moisture content (Xs) expressed as mass percentage is calculated according to formula (5): ;
Sample mass, name.
The result should be expressed to one decimal place.
4.5.4 Allowable difference
m-ml×100
m
The difference between two parallel measurement results shall not be greater than 0.1%. Take the arithmetic mean as the measurement result. 5 Inspection Rules
·(5)
5.1 Industrial sodium nitrite shall 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 sodium nitrite shipped from the factory meets the requirements of this standard. Each batch of industrial sodium nitrite leaving the factory should be accompanied by a quality certificate, which includes: manufacturer name, product name, grade, batch number, net weight, production date, proof that product quality complies with this standard, and this standard number. 5.2 The user unit has the right to inspect and accept the industrial sodium nitrite received in accordance with the provisions of this standard. 5.3 The weight of each batch of products shall not exceed 60t. 5.4 Determine the number of sampling units according to 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 sample. Mix the collected samples evenly, divide them into about 500g using the quartering method, immediately put them into two dry, clean wide-mouth bottles, and seal them. A label should be attached to the bottle, indicating: manufacturer name, product name, grade, batch number, sampling date, and name of the sampler. One bottle is used for testing and the other bottle is kept for one month for future reference. 5.5 If any indicator in the inspection results does not meet the requirements of this standard, samples should be taken from twice the amount of packaging bags for verification. If even one indicator of 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 product quality, they shall be handled in accordance with the provisions of the "Interim Measures for National Product Quality Arbitration and Inspection". 6 Marking, packaging, transportation and storage
6.1 There should be a strong and clear black mark on the packaging bag, including: manufacturer name, product name, trademark, grade, batch number or production date, net weight, this standard number and The "Oxidant Symbol in Figure 9" and the "Drugs Symbol in Figure 11" stipulated in GB190 and the "Heat Awareness Symbol in Figure 4" and Moisture Awareness Symbol in Figure 6 stipulated in GB191. And a 10cm wide black strip should be painted in the middle of the back of the packaging bag. 6.2 Industrial sodium nitrite is packed in plastic woven bags lined with polyethylene plastic bags. Net weight per bag is 25 or 50kg. If special packaging is required, both parties shall negotiate separately.
6.3. Industrial sodium nitrite should be transported in railway boxcars or other vehicles with curtains and covers. Do not mix, store or transport with strong reducing agents, flammable and explosive materials, food, feed and paint additives. 6.4 Industrial sodium nitrite should be stored in a cool, dry place and protected from heat and sunlight. Additional notes:
GB2367-90
This standard is proposed by the Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of the Tianjin Chemical Industry Research Institute of the Ministry of Chemical Industry. This standard is drafted by the Fertilizer Factory of Jilin Chemical Industry Company and the Tianjin Chemical Industry Research Institute of the Ministry of Chemical Industry. The main drafters of this standard are Yang Anqun, Huang Jiapeng, Wang Qi, and Gao Hong. This standard refers to "OCT19906-74 (revised in 1985) "Industrial Sodium Nitrite".
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