Some standard content:
Record number: 7255-2000
HG/T 2967-2000
This standard is a revision of the original chemical industry standard HG/T2967-1988 "Sodium Sulfite Anhydrous" by adopting the Japanese Industrial Standard JISK1419:1958 (confirmed in 1988) "Sodium Sulfite Anhydrous" in a non-equivalent manner. The main technical differences between this standard and the Japanese Industrial Standard are as follows: The Japanese Industrial Standard is divided into 2 grades. In order to make rational use of resources, this standard is divided into three grades, among which the indicators of the superior products are better than or equal to the first-grade products of the Japanese Industrial Standard. This standard adds the water-insoluble content index, and the index value is determined according to the production and use conditions. The main technical differences between this standard and HG/T2967-1988 are as follows: The iron content and free alkali (calculated as Na2CO) content indicators in qualified products are adjusted. This standard will replace HG/T2967-1988 from the date of implementation. This standard was proposed by the Policy and Regulations Department of the State Administration of Petroleum and Chemical Industry. This standard is under the jurisdiction of the Inorganic Chemical Branch of the National Technical Committee for Chemical Standardization. The drafting units of this standard are: Tianjin Chemical Research and Design Institute, Guangdong Zhongcheng Chemical Co., Ltd. The participating units of this standard are: Yongjia County Chemical Plant, Zhejiang Province. The main drafters of this standard are: Guo Fengxin and Fang Shengping. This standard was first issued as a national standard in 1988, adjusted to a chemical industry standard in 1992, and converted to HG/T2967--1988 in 1997.
This standard is entrusted to the Inorganic Chemical Branch of the National Technical Committee for Chemical Standardization for interpretation. 925
1 Scope
Chemical Industry Standard of the People's Republic of China
Industrial Anhydrous Sodium Sulphite
Anhydrous Sodium Sulphite for Industrial UseHG/T 2967--2000
Replaces HG/T 2967-1988
This standard specifies the requirements, test methods, inspection rules, marking, labeling, packaging, transportation and storage of industrial anhydrous sodium sulfite. This standard applies to industrial anhydrous sodium sulfite. The product is mainly used as a bleaching agent in the leather and tanning industry and plant fiber, and as a reducing agent in industrial production.
Molecular formula: Na2SO
Relative molecular mass: 126.04 (according to the 1997 international relative atomic mass) 2 Referenced Standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard was published, the versions shown were all valid. All standards are subject to revision. Parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T601-1988 Chemical reagents
Preparation of standard solutions for titration analysis (volume analysis) Preparation of standard solutions for impurity determination (neqISO6353-1:1982) GB/T602-—1988 Chemical reagents
GB/T 603-1988
Preparation of preparations and products used in chemical reagent test methods (neqISO6353-1:1982) GB/T1250--1989 Methods for expressing and determining limit values GB/T 3049—1986
GB/T 6678-1986
GB/T 6682--1992
3 Requirements
General method for determination of iron content in chemical products Phenanthroline spectrophotometric method (neqISO6685:1982) General rules for sampling of chemical products
Specifications and test methods for water used in analytical laboratories (neqISO3696:1987) 3.1 Appearance: white crystalline powder.
3.2 Industrial anhydrous sodium sulfite shall meet the requirements of Table 1. Table 1 Requirements
Sodium sulfite (Naz SO),) content
Iron (Fe) content
Water-insoluble matter content
Superior quality
Free alkali (calculated as Naz CO:) content
Sulfate (calculated as NazSO) content
Nitride (calculated as NaCl) content
Approved by the State Administration of Petroleum and Chemical Industry on 2000-05-23 926
First-class quality
Qualified quality
Implemented on 2000-12-01
4 Test method
HG/T 2967—2000
The reagents and water used in this standard, unless otherwise specified, refer to analytical pure reagents and grade 3 water specified in GB/T6682. The standard titration solution, impurity standard solution, preparation and products used in the test, unless otherwise specified, are prepared in accordance with the provisions of GB/T601, GB/T602 and GB/T603.
Safety Tips: The strong acids and alkalis used in this standard are corrosive. Users should be careful when handling them to avoid splashing on the skin. If splashed on the skin, rinse immediately with plenty of water and seek timely treatment for severe cases. 4.1 Determination of Sodium Sulfite Content
4.1.1 Method Summary
In a weakly acidic solution, iodine is used to oxidize sulfite to sulfate. Using starch as an indicator, sodium thiosulfate solution is used to titrate the excess iodine.
4.1.2 Reagents and Materials
4.1.2.1 Hydrochloric acid solution: 1+1.
z) Approximately 0.1moi/L.
4.1.2.2 Iodine solution: c
4.1.2.3 Sodium thiosulfate standard titration solution: c(Na2SzO3) about 0.1 mol/L. 4.1.2.4 Starch indicator solution: 5g/1 (useable for two weeks). 4.1.3 Analysis steps
Quickly weigh about 0.2g of the sample (accurate to 0.0002g), place it in a 250mL iodine volumetric flask that has been pre-added with 40.00ml iodine solution and 30mL~~50mL water with a burette, add 2ml of hydrochloric acid solution, immediately cover the bottle with a stopper, seal it with water, shake it slowly to dissolve, and place it in a dark place for 5min. When the sodium thiosulfate standard titration solution is titrated to a light yellow color, add about 3ml of starch indicator solution, and continue titrating until the blue color disappears, which is the end point.
Perform a blank test at the same time.
4.1.4 Expression of analytical results
The sodium sulfite (NazSO3) content (X,) expressed as mass percentage is calculated according to formula (1): X1 (VV)×0.6302×100m6.302×c(VV)m
Wherein: V
actual concentration of sodium thiosulfate standard titration solution, mol/L; V
-volume of sodium thiosulfate standard titration solution consumed by titrating blank test solution, mL; Vi
-volume of sodium thiosulfate standard titration solution consumed by titrating test solution, mL; m
mass of sample, g;
(1)
mass of sodium sulfite equivalent to 1.00mL sodium thiosulfate standard titration solution Lc(Na2SzO:)1.000mol/L］expressed in grams.
4.1.5 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 0.3%. 4.2 Determination of iron content
4.2.1 Summary of method
Use ascorbic acid to reduce the trivalent iron ions in the test solution to divalent iron ions. At pH 2~~9, the divalent iron ions and o-phenanthroline form an orange-red complex. The absorbance is measured at the maximum absorption wavelength (510nm) with a spectrophotometer. 4.2.2 Reagents and materials
According to Chapter 3 of GB/T3049-1986 and hydrochloric acid. 4.2.3 Instruments and equipment
According to Chapter 4 of GB/T3049:-1986.
4.2.4 Analysis steps
4.2.4.1 Drawing of working curve
HG/T 2967-2000
According to 5.3 of GB/T3049-1986, use a 3cm absorption cell and the corresponding iron standard solution to draw the working curve. 4.2.4.2 Preparation of test solution
Weigh about 1g of sample (accurate to 0.01g), place it in a 150ml beaker, dissolve it with 10mL of water, add 5ml of hydrochloric acid, and evaporate it on a water bath. After dissolving the residue with water, transfer it all to a 100mL volumetric flask. Superior and first-class products are used directly for determination; qualified products are diluted with water to the scale, shake the hook, and use a pipette to absorb 25mL, place it in a 100ml volumetric flask for determination. 4.2.4.3 Preparation of blank test solution
Except for the absence of sample, the amount of other reagents added is exactly the same as that of the test solution and is processed at the same time. 4.2.4.4 Determination
Add water to the volumetric flask containing the test solution and blank test solution to 60ml. The following operations are in accordance with GB/T30491986 5.4 stipulates that it starts from "adjusting the pH to about · with hydrochloric acid solution or ammonia solution" and ends with "measuring the absorbance of the test solution and the blank test solution".
Use a 3cm absorption cell and measure the absorbance according to 5.4 of GB/T3049-1986. Calculate the mass of iron in the test solution and the blank test solution according to the working curve.
4.2.5 Expression of analysis results
The iron (Fe) content (X2) expressed as mass percentage is calculated according to formula (2): (ml=m)×10 × 100= 0.1×(ml-m2)X, =
Where: mi is the mass of iron in the test solution found from the working curve, mg; m2-… is the mass of iron in the blank test solution found from the working curve, mg; m is the mass of the sample, g.
4.2.6 Allowable difference
Take the arithmetic mean of the parallel determination results as the determination result. The absolute difference of the parallel determination results is not more than 0.0005% for superior and first-class products; not more than 0.008% for qualified products. 4.3 Determination of water-insoluble content
4.3.1 Instruments and equipment
4.3.1.1 Glass sand crucible: the pore size of the filter plate is 5μm~15μm. 4.3.1.2 Electric constant temperature drying oven: can control the temperature of 105℃~110℃. 4.3.2 Analysis steps
Weigh about 25g of sample (accurate to 0.01g) and place it in a 400ml beaker, and dissolve it in 250mL boiling water. Cover with a watch glass and keep it warm in a boiling water bath for 1h. Remove it and put it to room temperature, filter it with a glass sand crucible that has been dried to constant weight at 105℃~～110℃ by pouring method, and wash it with hot water until it is neutral. Place in an electric constant temperature drying oven and dry at 105℃～110℃ to constant weight. 4.3.3 Expression of analysis results
The water-insoluble content (X:) expressed as mass percentage is calculated according to formula (3): Xs =m2=ml×100
Where: ni——mass of glass sand crucible, g; m2——mass of water-insoluble matter and glass sand crucible, g; m——mass of sample, g.
4.3.4 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 0.001%. 928
·（3）
4.4 Determination of free alkali content
4.4.1 Summary of the method
HG/T 2967—2000
Add hydrogen peroxide to the sample to oxidize the sulfite, and titrate the free alkali in the sample with a standard hydrochloric acid titration solution. 4.4.2 Reagents and materials
4.4.2.1 Hydrogen peroxide solution: 20%.
Use methyl red as the indicator solution and neutralize with sodium hydroxide solution [NaOH] (about 0.1 mol/L]. 4.4.2.2 Standard hydrochloric acid titration solution: c (HCl) about 0.1 mol/L. 4.4.2.3 Methyl red indicator solution: 1 g/L. www.bzxz.net
4.4.3 Instruments and equipment
Microburette: the graduation value is 0.02 mL. 4.4.4 Analysis steps
Weigh about 2g of sample (accurate to 0.01g), place in a 250mL conical flask, dissolve with 20mL of water, add 5mL of hydrogen peroxide solution, shake well, evaporate the solution on a water bath to about 1/2 of the original volume. Cool, add 10mL of water and 1 drop of methyl red indicator solution, use a microburette, and titrate with hydrochloric acid standard titration solution until the solution changes from yellow to red, which is the end point. 4.4.5 Expression of analysis results
The free alkali content (in terms of Na2CO3) expressed as a mass percentage (X4) is calculated according to formula (4): X4 = cVX0.05299 ×100 = 5.299 ×cYm
Wherein: c-
actual concentration of hydrochloric acid standard titration solution, mol/L; volume of hydrochloric acid standard titration solution consumed by the titration test solution, mL; V
mass of the sample, g;
(4)
0.05299-mass of free alkali (in terms of Na2CO3) equivalent to 1.00mL hydrochloric acid standard titration solution [c(HC1)=1.000mol/L] expressed in grams.
4.4.6 Allowable difference
Take the arithmetic mean of the parallel determination results as the determination result. The absolute difference of the parallel determination results shall not exceed 0.01% for superior products, and not exceed 0.02% for first-class products and qualified products.
4.5 Determination of sodium sulfate content
4.5.1 Summary of the method
In the hydrochloric acid medium, barium chloride reacts with sulfate in the sample to form barium sulfate precipitate. After filtering, washing, drying and weighing, the sodium sulfate content is obtained.
4.5.2 Reagents and materials
4.5.2.1 Hydrochloric acid.
4.5.2.2 Barium chloride solution: 100g/L.
4.5.2.3 Silver nitrate solution: 10g/L.
4.5.3 Analysis steps
Weigh about 1g of sample (accurate to 0.001g), place it in a 500mL beaker, add 15mL of hydrochloric acid, and evaporate to dryness in a boiling water bath. Dissolve the residue with 3ml hydrochloric acid and 50ml water. Filter if necessary and wash with water. Dilute the solution to 300ml and heat to boiling. Add 20ml hot barium chloride solution under stirring, keep warm in a boiling water bath for 1h, and cool. Filter with slow quantitative filter paper. Wash with water until there is no chloride ion (check with silver nitrate solution). Transfer the filter paper and the precipitate into a constant weight porcelain crucible, tilt the crucible to allow air to flow, and ash. Burn at about 700℃ for 30min. After cooling in a desiccator, weigh the mass of barium sulfate. 4.5.4 Expression of analysis results
The sodium sulfate (NazSO4) content (Xs) expressed as mass percentage is calculated according to formula (5): X = m X0.608 6×100 = 6
· (5)
Wherein: ml—mass of barium sulfate precipitate, g; m—mass of sample, g;
HG/T 2967—2000
0.6086—coefficient for converting barium sulfate (BaS4) to sodium sulfate (NazSO4). 4.5.5 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 0.1%. 4.6 Determination of sodium chloride content
4.6.1 Summary of the method
In nitric acid medium, chloride reacts with silver nitrate to form a turbid silver chloride precipitation solution, which is compared with the standard turbidity solution. 4.6.2 Reagents and Materials
4.6.2.1 30% hydrogen peroxide.
4.6.2.2 Nitric acid: 1+2.
4.6.2.3 Dextrin solution: 20g/1.
4.6.2.4 Silver nitrate solution: 20g/L.
4.6.2.5 Sodium chloride standard solution: 1mL solution contains 0.1mgNaCl. Weigh 0.100g of sodium chloride burned to constant weight at 500℃~600℃, dissolve in water, transfer to a 1000ml volumetric flask, dilute to scale with water, and shake well.
4.6.2.6 Sodium chloride standard solution: 1ml solution contains 0.01mgNaCl. Use a pipette to transfer 10mL of sodium chloride standard solution (4.6.2.5) into a 100mL volumetric flask, dilute to the mark with water, and shake well. 4.6.3 Instruments and equipment
Colorimetric tube: 50mL.
4.6.4 Analysis steps
Weigh (0.5±0.001)g of sample, place in a 200mL beaker, dissolve with 10mL of water, add 5mL of 30% hydrogen peroxide, place for 5min, and evaporate to dryness on a water bath. After adding a small amount of water to dissolve the residue, transfer all of it to a 100mL volumetric flask, dilute to the mark with water, and shake well.
Use a pipette to transfer 10ml of the above test solution into a colorimetric tube, dilute to 20mL with water. Add 5mL of nitric acid solution, 0.2mL of dextrin solution, and 1mL of silver nitrate solution, and shake well. The turbidity presented shall not be greater than that of the standard turbidity solution. The standard is to take a portion of 0.5mL hydrogen peroxide, evaporate it to dryness on a water bath, dissolve it with a small amount of water, transfer it to a colorimetric tube, add 5.00mL sodium chloride standard solution (4.6.2.6), dilute it to 20mL with water, and treat it in the same way as the sample solution that has been treated and diluted to 20mL.
5 Inspection rules
5.1 All items specified in this standard are factory inspection items. 5.2 Each batch of products shall not exceed 10t.
5.3 Determine the number of sampling units according to the provisions of GB/T6678. When sampling, insert the sampler obliquely from the top of the packaging bag to 3/4 of the depth of the material layer to take a sample. After mixing the collected samples, reduce them to no less than 500g by the quartering method, and pack them in two clean and dry plastic bottles and seal them. Paste labels on the bottles, indicating: manufacturer name, product name, grade, batch number, sampling date and name of the sampler. One bottle is used as a laboratory sample, and the other bottle is kept for three months for reference.
5.4 Industrial anhydrous sodium sulfite shall be inspected by the quality supervision and inspection department of the manufacturer in accordance with the provisions of this standard. The manufacturer shall ensure that each batch of products leaving the factory meets the requirements of this standard. 5.5 The user has the right to accept the industrial anhydrous sodium sulfite received in accordance with the provisions of this standard, and the acceptance shall be carried out within one month from the date of arrival of the goods.
5.6 If one of the indicators in the test results does not meet the requirements of this standard, samples should be taken from twice the amount of packaging for re-testing. Even if only one indicator does not meet the requirements of this standard in the re-test results, the entire batch of products shall be unqualified. 930
HG/T2967-2000
5.7 Determine whether the test results meet the standards according to the rounded value comparison method specified in GB/T1250. 6 Marking and labeling
6.1 The packaging of industrial anhydrous sodium sulfite should have firm and clear markings, including: manufacturer name, factory address, product name, trademark, grade, net content, batch number or production date, storage period and this standard number. 6.2 Each batch of industrial anhydrous sodium sulfite shipped out of 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, storage period, proof that the product quality meets this standard and this standard number. 7 Packaging, transportation and storage
7.1 Industrial anhydrous sodium sulfite is double-packed. The inner packaging is a polyethylene plastic film bag with a thickness of not less than 0.05mm; the outer packaging is a plastic woven bag. The net content of each bag is 25kg or 50kg. 7.2 For the packaging of industrial anhydrous sodium sulfite, the inner bag is tied manually with vinyl rope or other ropes of equivalent quality, or sealed with other equivalent methods; the outer bag is folded at a distance of not less than 30mm from the edge of the bag, and the opening is sewn with vinyl thread or other thread of equivalent quality at a distance of not less than 15mm from the edge of the bag. The stitches are neat and the stitch length is uniform. There are no leaks or skipped stitches. 7.3 Industrial anhydrous sodium sulfite should be covered during transportation to prevent sun exposure, rain and moisture. 7.4 Industrial anhydrous sodium sulfite should be stored in a ventilated and dry place to avoid contact with strong acids and oxidants. 7.5 The storage period of this product shall not exceed half a year from the date of leaving the factory. 931
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