Some standard content:
GB/T4553--2002
This standard is not equivalent to the technical requirements for Class B products in the Russian standard (OT828: 1977 (1999) "Industrial Sodium Nitrate" to revise the national standard GIB/T4553-1993 "Industrial Sodium Nitrate". The main technical differences between this standard and the Russian national standard 1OCT828: 1977 (1999) "Industrial Sodium Nitrate" are: no classification of the standard;
——The moisture and iron content indicators have been adjusted according to the actual situation in my country; in order to make The sodium nitrate content is closer to the true value, and the sodium carbonate content index is added; in order to prevent the product from agglomerating, a small amount of anti-caking agent is added to some products, so the looseness requirements are specified for the products with anti-caking agent added;
-Since the chromium content in our products is very low, the chromium content index is cancelled: the items that should be subtracted from the impurities in the calculation of the sodium nitrate content are increased to include the contents of calcium, magnesium, sulfate, and sodium carbonate; -The determination of the contents of calcium, magnesium, sulfate, and sodium carbonate is specified in the analytical method. The main technical differences between this standard and GB/T4553--1993 are:… 1. Cancel the classification of products;
Adjust the indicators of Class 1 products in the original standard; In order to eliminate the interference of nitrite in the product, the determination method of chloride content has been improved to make the determination method more perfect; In the calculation of sodium nitrate content, the impurities removed in the original standard have been simplified. This standard replaces GB/T4553-1993 from the date of implementation. This standard is proposed by the China Petroleum and Chemical Industry Association. This standard is under the jurisdiction of the Inorganic Chemical Subcommittee of the National Chemical Standardization Technical Committee. Drafting unit of this standard: Tianjin Chemical Industry Association Industrial Research and Design Institute, Dahua Group Co., Ltd., Hangzhou Electrochemical Group Co., Ltd. Longhua Plant, Shandong Haihua Weifang Ammonium Nitrate Plant.
The main drafters of this standard are Lu Siwei, Jiang Mi, Liang Qiong, and Wang Jinzhong. This standard was first issued in 1984 and revised for the first time in 1993. This standard is entrusted to the Inorganic Chemical Subcommittee of the National Technical Committee for Chemical Standardization for interpretation. 261
1 Scope
National Standard of the People's Republic of China
Industrial Sodium Nitrate
Sodiun nitrate for industrial useGB/T 4553 -2002
Replaces GB/T4553-:1993
This standard specifies the requirements, test methods, inspection rules, and marking, labeling, packaging, transportation, storage and safety of industrial sodium nitrate. This standard applies to industrial sodium nitrate. This product is an important chemical raw material and is widely used in glass, explosives, dyes, metallurgy, machinery, sugar and porcelain industries.
Molecular formula: NaNO
Relative molecular mass: 84.99 (according to the 1999 international relative atomic mass) 2 Reference standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB190-1990 Dangerous Goods Packaging Marking
GB 191—2000
Pictorial marking for packaging, storage and transportation (eqvISO780:1997)GB/T 601—1988
GB/T 602.---1988
GB/T 603—1988
Chemical reagents-Preparation of standard solutions for titration analysis (volume analysis) Preparation of standard solutions for determination of impurities in chemical reagents Preparation of preparations and products used in chemical reagent test methods GB/T 1250--1989
GB/T 3049--1986
GB/T 3051 --2000bZxz.net
GB/T 3600-2000
GB/T 66781986
GB/T 6682—1992
3 Requirements
Methods for expressing and determining limit values General method for determining iron content in chemical products (neq 1SO 6685:1982)
O-phenanthroline spectrophotometric method
General method for determining chloride content in inorganic chemical products Mercury titration method (neqISO5790:1979)
Determination of ammonia nitrogen content in fertilizers Formaldehyde method
General rules for sampling of chemical products
Specifications and test methods for water used in analytical laboratories (neqISO3696:1987) 3.1 Appearance: White fine crystals, with light gray or light yellow allowed. 3.2T. Industrial sodium nitrate should meet the requirements of Table 1. Table 1 Requirements
Mass fraction of sodium nitrate (NaN()) (dry basis)Mass fraction of water
Approved by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China on May 29, 2002 262
Qualified products
Implemented on December 1, 2002
Mass fraction of water-insoluble matter
Mass fraction of chloride (calculated as NaCl) (on basis)Mass fraction of sodium nitrite (NaN(),) (dry basis)Mass fraction of sodium carbonate (Na,CO),) (dry basis)Mass fraction of iron (Fe)
Looseness
Note: 1. The moisture content shall be subject to factory inspection;
GB/T4553--2002
Table 1 (end)
Superior products
2. The looseness index is a control item for products with anti-caking agents. 4 Test methods
The reagents and water used in this standard refer to analytical pure reagents and grade 3 water specified in GB/T6682 unless otherwise specified. The standard titration solutions, impurity standard solutions, preparations and products used in the test are prepared in accordance with the provisions of GB/T601, GB/T602 and GB/T603 unless otherwise specified. Safety tips: The strong acids and alkalis used in the test are corrosives. Be careful when operating. If they splash on the skin, rinse immediately with plenty of water. Mercury-containing waste liquid after fluoride content determination should be centrally treated and discharged. 4.1 Determination of moisture
4.1.1 Instruments and equipment
Weighing bottle: 50mm×30mm.
4.1.2 Analysis steps
Use a weighing bottle that has been dried to constant weight at 105℃~110℃ in advance to weigh about 5g of the sample, accurate to 0.0002g. Dry at 105C~~110℃ to constant weight.
4.1.3 Expression of analysis results
The mass fraction of water, W, is expressed in %, and is calculated according to formula (1): m2ml ×100
Where: m—. The mass of the sample after drying to constant weight, in grams (g); m—. The mass of the sample, in grams (g). m
The calculation result is expressed to one decimal place. 4.1.4 Allowable difference
Take the arithmetic mean of the parallel determination results as the determination result, and the absolute difference of the parallel determination results shall not exceed 0.02%. 4.2 Determination of water-insoluble matter content
4.2.1 Reagents and materials
Diphenylamine-sulfuric acid solution: Weigh 1g of diphenylamine and dissolve it in 100mL of sulfuric acid. 4.2.2 Instruments and equipment
Glass crucible: The pore size of the filter plate is 5μm~15μm. 4.2.3 Analysis steps
(1))
Weigh about 100g of sample, accurate to 0.1g. Place it in a 400mL beaker, add about 150mL of water, and heat to boiling to completely dissolve the sample. Filter it in a glass crucible that has been dried to constant weight at 105°C~110°C in advance, and wash it with hot water until the residue contains no nitrate ions (no overflow when checked with diphenylamine sulfuric acid solution). The residue and glass crucible are dried to constant weight at 105°C~~110°C. 4.2.4 Expression of analysis results
The mass fraction W of water-insoluble matter is expressed in %, calculated according to formula (2): W, m = \ × 100
Where: m.--... The mass of water-insoluble matter and glass crucible after drying to constant weight, in grams (g); mg
The mass of glass crucible after drying to constant weight, in grams (g); m- The mass of the sample, in grams (g). The calculation result is expressed to two decimal places. 4.2.5 Permissible difference
The arithmetic mean of the parallel determination results is taken as the determination result, and the absolute difference of the parallel determination results shall not exceed 0.008%. 4.3 Determination of chloride content
4.3.1 Summary of the method
Same as Chapter 3 of GB/T3051-2000.
4.3.2 Reagents and materials
Urea;
Other reagents used are the same as Chapter 4 of GB/T3051-2000. 4.3.3 Instruments and equipment
Microburette: the graduation value is 0.01ml or 0.02mL. 4.3.4 Analysis steps
4.3.4.1 Preparation of reference solution
·(2)
Add 50mL of water and 3g of urea to a 250mL conical flask and heat to dissolve. Add nitric acid (1+i) solution dropwise at a slight boil until no small bubbles are generated and cool. Add 2 to 3 drops of bromophenol blue indicator solution, adjust with sodium hydroxide (1 mol/L) solution until the solution turns blue, and adjust with nitric acid (1 mol/L) solution until the solution turns from blue to yellow and then add 2 to 6 drops in excess. Add 1.0mL of diphenylazocarbonylhydrazide indicator solution and titrate with a microburette with a concentration of c[1/2Hg (NO.), J of 0.05mol/L of mercuric nitrate standard titration solution until it turns purple-red. Record the volume of mercuric nitrate standard titration solution used. This solution is prepared before use. 4.3.4.2 Preparation of test solution
Weigh about 100g of the sample, accurate to 0.01g. Place in a 400mL beaker, add about 150mL of water, heat to boiling, and dissolve the sample completely. Cool to room temperature, transfer all to a 500mL volumetric flask, dilute to scale with water, shake to obtain test solution A, which is used to determine the content of chloride, calcium nitrate, magnesium nitrate, sodium nitrite, sodium carbonate, and ammonium salt. 4.3.4.3 Determination
Use a pipette to transfer 50ml of test solution A and place in a 250mL conical flask. Add 3g of urea and heat to dissolve. Add nitric acid (1+1) solution dropwise at a slight boil until no small bubbles are generated, and cool. Add 2 drops of bromophenol blue indicator solution. Use sodium hydroxide (1mol/L) solution to adjust the solution to blue, and then use nitric acid (1mol/L) solution to adjust the solution from blue to yellow and add 2 to 6 drops in excess. Add 1.0mL of diphenylazocarbonyl hydrazide indicator solution and titrate with a standard titration solution of mercuric nitrate with a concentration of c[1/2Hg(NO,) of about 0.05 mol/1. until the solution changes from yellow to the same purple-red as the reference solution.
Collect the mercury-containing waste liquid after titration in a bottle and treat it according to the method specified in Appendix D of GB/T3051-2000. 4.3.5 Expression of analysis results
The chloride content (in terms of NaCl) expressed as mass fraction (%) (W:) is calculated according to formula (3): cMl(V - V.)/1 000]
W, = m×[iM (W.700100(50/00) × 1 ... 4553--2002
c---The accurate value of the concentration of the standard titration solution of mercuric nitrate. The unit is mole per liter (mol/L); m---The value of the mass of the sample, the unit is gram (g); WI---The mass fraction of water, the value is expressed in %; M.---The value of the molar mass of sodium chloride, the unit is gram per mole (g/mol.) (M=58.44). The calculation result is expressed to two decimal places
4.3.6 Allowable difference
The arithmetic mean of the parallel determination results is taken as the determination result, and the absolute difference of the parallel determination results shall not exceed 0.01%. 4.4 Determination of calcium nitrate and magnesium nitrate content
4.4.1 Summary of method
Adjust the solution pH to greater than 12, use calcium carboxylic acid (or sodium calcium carboxylate) as an indicator, and use disodium ethylenediaminetetraacetic acid standard titration solution to titrate calcium nitrate. Use chrome black T as an indicator, and use disodium ethylenediaminetetraacetic acid standard titration solution of the same concentration to titrate the total amount of calcium nitrate and magnesium nitrate at pH=10. Calculate the magnesium nitrate content by the difference in the standard titration solution consumed in the two titrations. 4.4.2 Reagents and materials
4.4.2.1 Sodium hydroxide solution: 80g/L; 4.4.2.2 Ammonia-ammonium chloride buffer solution: 1 : pH ~ 10; 4.4.2.3 Triethanolamine solution: 1+2 solution; 4.4.2.4 Sodium sulfide solution: 100g/L;
4.4.2.5 Disodium ethylenediaminetetraacetic acid (EDTA) standard titration solution: c(EDTA) is about 0.05mol/L; 4.4.2.6 Disodium ethylenediaminetetraacetic acid (EDTA) standard titration solution: c(EDTA) is about 0.005mol/L; Use a pipette to transfer 100ml of disodium ethylenediaminetetraacetic acid standard titration solution (4.4.2.5), place it in a 1000mL volumetric flask, dilute to the scale with water, and shake to hook.
4.4.2.7 Calcium carboxylate indicator: Weigh 1.0g calcium carboxylate (or sodium calcium carboxylate), mix with 100g dry sodium chloride and grind. 4.4.2.8 Eriochrome black T indicator.
4.4.3 Analysis steps
Use a pipette to transfer 50mL of test solution A into a 250mL conical flask, add 1~~2 drops of hydrochloric acid (1+1) solution, 2ml triethanolamine solution, 5ml ammonia-ammonium chloride buffer solution A, and about 50mg chromium black T indicator, and titrate with disodium ethylenediaminetetraacetic acid standard titration solution (4.4.2.6) until pure blue is the end point. Record the volume V of disodium ethylenediaminetetraacetic acid standard titration solution (4.4.2.6) consumed for calculating the magnesium nitrate content.
Use a pipette to transfer 50mL of test solution A to a 250mL conical flask, add 1-2 drops of hydrochloric acid (1+1) solution, 2mL of triethanolamine and 2mL of sodium sulfide solution, add 5mL of sodium hydroxide solution, add about 0.1g of calcium carboxylate indicator, and titrate with disodium ethylenediaminetetraacetic acid standard titration solution (4.4.2.6) until pure blue is the end point. Record the volume V of disodium ethylenediaminetetraacetic acid standard titration solution (4.4.2.6) consumed, which is used to calculate the calcium nitrate content. 4.4.4 Expression of analysis results
The mass fraction of calcium nitrate [Ca(NO:)2] content W4, expressed in %, is calculated according to formula (4): W.= m×[1-(w/100)X(50/500)×100(V,/1 000)cM
. (4)
The volume of the standard titration solution of disodium ethylenediaminetetraacetic acid (4.4.2.6) consumed in the titration of calcium nitrate, in milliliters. Where: V—
liter (ml);
--the exact value of the concentration of the standard titration solution of disodium ethylenediaminetetraacetic acid, in moles per liter (mol/L); m—the mass of the test sample in the test solution A, in grams (g); W. The mass fraction of water, expressed in %; M—the molar mass of calcium nitrate, in grams per mole (g/mol) (M=164.1). The calculation result is expressed to two decimal places. 265
GB/T 4553- 2002
Mass fraction of magnesium nitrate [Mg(NO,)] Ws, expressed in %, is calculated according to formula (5): [(V - V)/1 000cM
W;=mx((./100))x (50/500)
（5）
Wherein: V-the volume of the standard ethylenediaminetetraacetic acid disodium solution (4.4.2.6) consumed when titrating the combined amount of calcium nitrate and magnesium nitrate, in milliliters (ml);
the volume of the standard ethylenediaminetetraacetic acid disodium solution (4.4.2.6) consumed when titrating calcium nitrate, in milliliters (mL);
-the exact concentration of the standard ethylenediaminetetraacetic acid disodium solution, in moles per liter (mol/L); m-the mass of the sample in the test solution A, in grams (g); W,---the mass fraction of water, expressed in %; M--the molar mass of magnesium nitrate, in grams per mole (g/mol) (M=148.3). The calculation result is expressed to two decimal places. 4.4.5 Allowable difference
The arithmetic mean of the parallel determination results shall be taken as the determination result, and the absolute difference of the parallel determination results shall not exceed 0.01%. 4.5 Determination of sulfate content
4.5.1 Gravimetric method-arbitration method
4.5.1.1 Summary of method
Convert sodium nitrate into sodium chloride with hydrochloric acid. Use barium chloride to precipitate sulfate ions into barium sulfate in an acidic medium, and weigh the mass of the generated barium sulfate.
4.5.1.2 Reagents and materials
a) Hydrochloric acid;
b) Hydrochloric acid solution: 1+1;
c) Sodium chloride solution: 100g/L;
d) Silver nitrate solution: 17g/L.
4.5.1.3 Analysis steps
Weigh about 10g of sample, accurate to 0.01g. Place in a 100mL beaker, moisten with a small amount of water, add 10mL of hydrochloric acid, and place in a water bath.Evaporate to dryness. Add 10mL hydrochloric acid and evaporate again, repeat evaporation three times. Add 50mL water to dissolve the residue, add 4mL hydrochloric acid solution to acidify. Filter with medium-speed filter paper, wash the precipitate with water to a solution volume of about 250mL. Boil, add 10mL barium chloride solution dropwise with constant stirring (add in about 90s). Continue boiling for 2min with constant stirring, leave overnight or place in a boiling water bath for 2h. Filter with slow quantitative filter paper, wash the precipitate with hot water until there is no chloride ion (take 5mL filtrate, add 1mL silver nitrate solution and mix, no precipitate appears after 5min). Transfer the filter paper and the precipitate into porcelain that has been calcined to constant weight at 800℃±25℃ in advance, and ash. Calcined to constant weight at 800℃±25℃. 4.5.1.4 Expression of analytical results
Sulfate content is expressed as the mass fraction W of sodium sulfate (Na2SO). The value is expressed in %, calculated according to formula (6): (m = mz)M
W. = mx[two (w)M00]×100
Wherein: m,-
The mass of the crucible and the precipitate after drying to constant weight, in grams (g); m2--The mass of the crucible after drying to constant weight, in grams (g); m---The mass of the sample, in grams (g); W,---The mass fraction of water measured according to Article 4.1, expressed in %; M-The coefficient for converting barium sulfate into sodium sulfate (M-0.6086). The calculation result is expressed to two decimal places. 4.5.1.5 Allowable difference
The arithmetic mean of the parallel determination results is taken as the determination result, and the absolute difference of the parallel determination results shall not exceed 0.01%. 266
4.5.2 Visual turbidimetry
4.5.2.1 Method summary
GB/T 4553 --2002
In slightly acidic medium, sulfate ions are precipitated with barium chloride and compared with barium sulfate standard suspension. 4.5.2.2 Reagents and materials
a) Hydrochloric acid;
b) Hydrochloric acid solution: 1+1;
c) Potassium sulfate-ethanol solution: 0.2g/L;
d) Barium chloride solution: 250g/L;
e) Sulfate standard solution; 1mL contains 0.1mgsO4.4.5.2.3 Analysis steps
Add 1.0mL hydrochloric acid solution, 1.0mL potassium sulfate-ethanol solution, and 5mL chloride solution to several 50mL colorimetric tubes. Weigh a certain amount of sample (containing about 0.2 mg of SO-) to an accuracy of 0.01 g. Place it in a 100 ml beaker, add a small amount of water to moisten it, add 5 ml to 10 ml of hydrochloric acid, and evaporate to dryness. Add another 5 ml of hydrochloric acid and evaporate to dryness, then add a small amount of water to dissolve the residue. At the same time, use a pipette to transfer 1.00 ml, 1.50 ml, 2.00 ml, 2.50 ml, and 3.00 ml of sulfate standard solution, place them in a 100 ml beaker, and treat them in the same way as above. Filter the treated sample and sulfate standard solution into the aforementioned 50 ml colorimetric tube, dilute with water to the scale, shake well, place in a 50°C water bath for 20 minutes, and then visually compare the turbidity of the sample solution with that of the standard turbidity solution. Select a standard turbidity solution with the same or similar turbidity, and record the mass of sulfate contained in it. 4.5.2.4 Expression of analysis results
Sulfate content is measured as the mass fraction W of sodium sulfate (Na2SO4), and the value is expressed in %, calculated according to the following formula (7): m,M
W, = m×[1-(W.4/100)]
Wherein: m-——the mass of sulfate (SO4) in the standard tube equivalent to the test tube, in grams (g); the mass of the test sample, in grams (g); m
WI——the mass fraction of water, expressed in %; M——the coefficient for converting sulfate to sodium sulfate (M=1.479). The calculation result is expressed to two decimal places. 4.5.2.5 Allowable difference
The arithmetic mean of the parallel determination results is taken as the determination result, and the absolute difference of the parallel determination results shall not exceed 0.01%. 4.6 Determination of sodium nitrite content
4.6.1 Method summary
Use the test solution to titrate the acidic potassium permanganate standard solution. The nitrite in the test sample can reduce potassium permanganate and make its color disappear. Calculate the sodium nitrite content based on the consumption of the test solution. 4.6.2 Reagents and materials
4.6.2.1 Sulfuric acid solution: 1+20;
4.6.2.2 Potassium permanganate standard titration solution: c(1/5KMnO,) about 0.1mol/L; 4.6.2.3 Potassium permanganate standard titration solution: c(1/5KMnO,) about 0.01mol/L; Use a pipette to transfer 100mL of potassium permanganate standard titration solution (4.6.2.2), place it in a 1000mL volumetric flask, dilute to the mark with water, and shake well.
4.6.3 Analysis steps
Add about 50ml of sulfuric acid solution to a 250ml conical flask. Heat to 40°C~50°C. Titrate with potassium permanganate standard titration solution (4.6.2.3) until it turns slightly red and then accurately add 1.00ml. Titrate the potassium permanganate standard solution in the conical flask with test solution A until the red color just disappears.
4.6.4 Expression of analysis results
GB/T 45532002
The mass fraction of sodium nitrite (NaVO3) content is W:, expressed in %, calculated according to the following formula (8): (V./1 000)cM
W.= m×(V/500)0=(w.710)×100 Where: V,--the value of the volume of potassium permanganate standard titration solution accurately added, in milliliters (mL); V
the value of the volume of test solution A consumed in titration, in milliliters (ml); C---the accurate value of the concentration of potassium permanganate standard titration solution, in moles per liter (mol/L); m--...the value of the mass of the test material in test solution A, in grams (g); W,·...the mass fraction of water, expressed in %; M-the value of the molar mass of sodium nitrite, in grams per mole (g/mol) (M=34.50). The calculation result is expressed to two decimal places. 4.6.5 Allowable difference
The arithmetic mean of the parallel determination results is taken as the determination result. The absolute difference of the parallel determination results shall not exceed: 0.003% for superior and first-class products and 0.01% for qualified products.
4.7 Determination of sodium carbonate content
4.7.1 Summary of the method
Use bromocresol green-methyl red as the indicator and titrate with sulfuric acid standard titration solution. 4.7.2 Reagents and materials
4.7.2.1 Standard sulfuric acid titration solution: c(1/2H,SO,) about 0.1mol/L; 4.7.2.2 Bromocresol green-methyl red mixed indicator solution. 4.7.3 Analysis steps
Use a pipette to transfer 25mL of test solution A, place it in a 250mL conical flask, add 3~~4 drops of bromocresol green-methyl red mixed indicator solution, titrate with sulfuric acid standard titration solution until the solution changes from green to dark red, boil for 2min, cool rapidly, and continue to titrate with sulfuric acid standard titration solution until the solution turns dark red.
4.7.4 Expression of analysis results
The mass fraction Wg of sodium carbonate (Na2CO,) is expressed in %, calculated according to the following formula (9): W,= m× (25/5)0(w./100)×100(V/1 000)cM
Wherein: V--the volume of sulfuric acid standard titration solution consumed in titration, in milliliters (ml); the exact value of the concentration of sulfuric acid standard titration solution, in moles per liter (mol/L); m--the mass of the sample in test solution A, in grams (g); W.·.·the mass fraction of water, expressed in %; M--the molar mass of sodium carbonate, in grams per mole (g/mol) (M=52.99). The calculation result is expressed to two decimal places. 4.7.5 Allowable difference
Take the arithmetic mean of the parallel determination results as the determination result, and the absolute difference of the parallel determination results shall not exceed 0.01%. 4.8 Determination of ammonium salt content
Use 10g/L test solution and add Nessler's reagent for identification. When there is ammonia (NH.) reaction, use this method for determination. 4.8.1 Method summary
Same as Chapter 3 of GB/T3600--2000.
4.8.2 Reagents and materials
Same as 4.1 of GB/T 3600-2000.
4.8.3 Analysis steps
GB/T 4553--2002
Use a pipette to transfer 50mL of test solution A and place it in a 250ml conical flask. The following operations are in accordance with 4.3. Start from "add 1 drop of methyl red indicator solution". At the same time, do a blank test. 4.8.4 Expression of analysis results
The ammonium salt content is measured as the mass fraction Wi of ammonium nitrate (NH.NO:), and the value is expressed in %, calculated according to formula (10): [(V, - V.)/1 000)]cM
Where::
Wo= m× (50/500)X[1 (W./100)]X 100
The volume of sodium hydroxide standard titration solution consumed when titrating the test solution, in milliliters (mL); V. -The volume of sodium hydroxide standard titration solution consumed in the blank test, in milliliters (mL); The exact value of the concentration of the sodium hydroxide standard titration solution, in moles per liter (mol/L); m-
-The mass of the sample in the test solution A, in grams (g); ·The mass fraction of water, expressed in %; W
The molar mass of ammonium nitrate, in grams per mole (g/mol) (M=80.04). M
The calculated result is expressed to two decimal places. 4.8.5 Allowable difference
The arithmetic mean of the parallel determination results is taken as the determination result, and the absolute difference of the parallel determination results shall not exceed 0.02%. 4.9 Determination of sodium nitrate content
4.9.1 Summary of the method
Subtracting the total amount of impurities from 100 is the sodium nitrate content. 4.9.2 The mass fraction of the total impurity content W1, expressed in %, is calculated according to formula (11): W1:
Wtotal=W,+W +W+Ws+W(or W)+W:+W,+Wi.W - -
The mass fraction of water-insoluble matter, expressed in %; W. - The mass fraction of chloride, expressed in %; W.--The mass fraction of calcium nitrate, expressed in %; Ws-
W(or W,)
-The mass fraction of magnesium nitrate, expressed in %; The mass fraction of sodium sulfate, expressed in %; The mass fraction of sodium nitrite, expressed in %; -The mass fraction of sodium carbonate, expressed in %; The mass fraction of ammonium mononitrate, expressed in %. 4.9.3 Expression of analysis results
The mass fraction of sodium nitrate (NaNO:) content W12, expressed in %, is calculated according to formula (12): 4.10 Determination of iron content
4.10.1 Summary of method
Same as Chapter 2 of GB/T3049-1986.
4.10.2 Reagents and materials
Same as Chapter 3 of GB/T3049.--1986.
4.10.3 Apparatus and equipment
Same as Chapter 4 of GB/T3049-1986.
4.10.4 Analysis steps
4.10.4.1 Drawing of working curve
W12 = 100 — Wn
According to the provisions of 4.3.1 of GB/T3049-1986, use a 3 cm absorption cell to draw the working curve. 4.10.4.2 Determination
·(11)
·(12)
Weigh 2g~~5g of sample, accurate to 0.01g, and place it in a 250mL beaker. Add 20mL of water to dissolve, then add 4ml.(1+3)269
GB/T 4553—2002
hydrochloric acid solution, heat and boil for 2min, filter if necessary. Adjust the pH to about 2 with ammonia or hydrochloric acid (check with precision pH test paper). Transfer all the solution to a 100mL volumetric flask and add water to about 60mL. The following operations are carried out according to the provisions of 4.4.1 of GB/T3049-1986, starting with the addition of 2.5mL of ascorbic acid. . At the same time, a blank test is performed. 4.10.5 Expression of analysis results
The mass fraction of iron (Fe) content Wt3, expressed in %, is calculated according to formula (13): W =
(mi - mo) × 10-3
× 100
Where: m-the value of the mass of iron contained in the test solution found from the working curve, in milligrams (mg); m. *--the value of the mass of iron contained in the blank test found from the working curve, in milligrams (mg); m
the value of the mass of the sample, in grams (g). 4.10.6 Allowable difference
The arithmetic mean of the parallel determination results shall be taken as the determination result; the absolute difference of the parallel determination results shall not exceed 0.0005%. 4.11 Determination of looseness
4.11.1 Summary of method
(13)
Let the bagged samples that have been stacked for a certain period of time fall freely from a height of 1m onto a hard plane, and weigh the mass of the samples remaining on the sieve after sieving.
4.11.2 Instruments and equipment
4.11.2.1 Test sieve: 950mm long, 600mm wide, with a wooden frame about 120mm high, and a mesh aperture of 4.75mm; 4.11.2.2 Stopwatch;
4.11.2.3 Scale: 10kg, graduation value 0.1kg. 4.11.3 Analysis steps
Select the seventh layer of bags from the stacked bagged products in the warehouse as the test sample. Weigh the test bag and use a machine or manual to make it fall freely from a height of 1m onto a flat and hard surface. Turn the bag over, then pour the sample in the bag into the sieve and sieve it at a frequency of 1 time/s. The sieving stroke is 400mm and the time is 1min. Weigh the mass of the sieve residue after sieving. The number of test bags should not be less than 3 bags. 4.11.4 Expression of analysis results
The looseness (W14) expressed as the mass fraction (%) of the sample with a particle size less than 4.75mm is calculated according to formula (13): W14=
Where: m-mass of the sample in the bag before sieving, kg; m,---mass of the sample on the sieve after sieving, kg; n---number of bags of sample used in the test.
5 Inspection rules
5.1 This standard recommends the use of type inspection and routine inspection. 5.1.1 Type inspection
. (14)
All 8 indicators specified in the requirements are type inspection items. Under normal production conditions, type inspection shall be carried out at least once every 15 days. The production stability period of products with anti-caking agents is 6 months. 5.1.2 Routine inspection
The sodium nitrate, moisture, water-insoluble matter, chloride, sodium nitrite, sodium carbonate and iron content specified in the requirements are routine inspection items and shall be inspected batch by batch.
5.2 Each batch of products shall not exceed 100t.
5.3 Determine the number of sampling units in accordance with the provisions of GB/T6678. Each plastic woven bag is a packaging unit. When sampling, insert the sample obliquely from the top of each selected 270
GB/T4553—2002
packaging bag to 3/4 of the material layer depth, take out no less than 50g of sample with a sampler, mix the sample, and reduce it to about 500g by quartering method, and immediately put it into two clean and dry wide-mouth bottles with ground stoppers and seal them. Paste labels on the bottles, indicating: manufacturer name, product name, batch number, sampling date and name of the sampler. One bottle is used for inspection, and the other bottle is kept for three months for reference. 5.4 Industrial sodium nitrate should be inspected by the quality supervision and inspection department of the manufacturer in accordance with the requirements of this standard, and the manufacturer should ensure that each batch of products shipped from the factory meets the requirements of this standard.
5.5 The user has the right to accept the industrial sodium nitrate products received in accordance with the provisions of this standard, and the acceptance time shall be within one month after the arrival of the goods.
5.6 If any index of the test result does not meet the requirements of this standard, re-sample from twice the number of sampling units should be re-tested. If even one index of the re-test result does not meet the requirements of this standard, the entire batch of products shall be considered unqualified. 5.7 The rounded value comparison method specified in GB/T1250 shall be used to determine whether the test results meet the standards. 6 Marking and labeling
6.1 Industrial sodium nitrate packaging bags should have firm and clear markings, including: manufacturer name, factory address, product name, trademark, grade, net weight, batch number or production date and this standard number, as well as the "oxidant mark" specified in GB190 and the "heat-averse" and "moisture-averse" marks specified in GB191. A 10cm wide horizontal red stripe should be painted in the middle of the back of the packaging bag. 6.2 Each batch of industrial sodium nitrate shipped from the factory should be accompanied by a quality certificate. The contents include: manufacturer name, factory address, product name, trademark, grade, net content, batch number or production date, proof that the product quality complies with this standard and this standard number. 7 Packaging, transportation, purchase and storage
7.1 Industrial sodium nitrate is double-packed. The inner packaging is a polyethylene plastic film bag and the outer packaging is a plastic woven bag. The net content of each bag is 25kg or 50kg. If the user has special requirements for packaging, it can be negotiated. 7.2. For the packaging of industrial sodium nitrate, the film bag is tied twice with vinyl rope or rope 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 opening is sewed with vinyl thread or other thread of equivalent quality at a distance of not less than 15mm from the bag edge. The stitches are neat and the stitch length is uniform. There is no leakage and jumper phenomenon. 7.3 Industrial sodium nitrate should be covered during transportation to prevent rain and moisture. 7.4 Industrial sodium nitrate should be stored in a ventilated and dry warehouse. It should be prevented from rain and moisture, and avoid direct sunlight. It should be avoided from being transported and stored together with acids, metal powders, sawdust, gauze, paper, sugar, sulfur and other organic flammables and reducing substances. 7.5 When transporting and stacking industrial sodium nitrate, it should be handled with care to prevent friction and collision. The distance between stacks and stacks and between stacks and walls should be 0.7m to 0.8m.
8 Safety requirements
8.1 Sodium nitrate is a primary inorganic oxidant. When heated to 380°C, it decomposes into sodium nitrite and oxygen. When heated to a higher temperature, it generates a mixed gas of oxygen, nitrogen and nitrogen oxides. When mixed with organic matter, sulfur or sulfites, it can cause combustion and explosion. Fires caused by sodium nitrate can be extinguished with a large amount of water.
8.2 Fire-fighting equipment and first-aid medicines should be available in the production and storage places of sodium nitrate. 271
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