Some standard content:
Chemical Industry Standard of the People's Republic of China
Industrial Magnesium Sulfate Heptahydrate
Subject Content and Scope of Application
HG/T 2680--95
This standard specifies the technical requirements, test methods, inspection rules, marking, packaging, transportation and storage of industrial magnesium sulfate heptahydrate. This standard applies to industrial magnesium sulfate heptahydrate. This product is mainly used in fertilizers, leather making, printing and dyeing, catalysts, papermaking, plastics, etc. Molecular formula: MgSO.·7H,0
Relative molecular mass: 246.48 (according to the international relative atomic mass in 1991) 2 Reference standards
GB 191
Pictorial symbols for packaging, storage and transportation
GB/T 601
GB/T602
GB/T 603
GB1250
Chemical reagents
Preparation of standard solutions for titration analysis (volume analysis) Chemical reagents
Preparation of standard solutions for impurity determination
Chemical reagents
Preparation of preparations and products used in test methods Methods for expressing and determining limit values GB/T 3049
GB/T 3051
GB/T 6678
GB/T 6682
General method for determination of iron content in chemical products-Phenanthroline spectrophotometry
General method for determination of chloride content in inorganic chemical products-Mercury titration General rules for sampling of chemical products
Specifications and test methods for water used in analytical laboratories GB8946
Plastic woven bags
3 Technical requirements
3.1 Appearance: white or colorless crystalline particles or powder. 3.2 Industrial magnesium sulfate heptahydrate shall meet the requirements of Table 1: Table 1
Main content (calculated as MgSO·7H0)
Iron (Fe) content
Murine (CI) content
Water-insoluble matter content
4 Test method
%(m/m)
Qualified products
The reagents and water used in this standard, unless otherwise specified, refer to analytical pure reagents and the standard titration solutions, impurity standard solutions, preparations and products required for the third-level water test specified in GB/T6682. Unless otherwise specified, they shall be prepared in accordance with the provisions of GB/T601, the Ministry of Chemical Industry of the People's Republic of China approved on April 5, 1995 and implemented on January 1, 1996
GB/T602 and GB/T603. 4.1 Determination of main content
4.1.1 Summary of method
HG/T2680--95
Use ethanolamine to mask a small amount of trivalent iron, aluminum and other ions, add ammonia-ammonium chloride buffer solution A with a pH of about 10, use chrome black T as an indicator, and titrate with disodium ethylenediaminetetraacetic acid (EDTA) standard titration solution. 4.1.2 Reagents and materials
4.1.2.1 Ammonia water (GB/T631): 1+2 solution; 4.1.2.2
Triethanolamine: 1+3 solution;
4.1.2.3 Ammonia-ammonium chloride buffer solution A: pH~10; 4.1.2.4 Disodium ethylenediaminetetraacetic acid (EDTA) (GB/T1401) standard titration solution: c(EDTA) is about 0.05 mol/L; 4.1.2.5 Eriochrome black T: 1% (m/m) solid indicator. Grind riochrome black T and sodium chloride in a mortar in a ratio of 1+99, mix thoroughly, and store in a bottle with a ground stopper.
4.1.3 Analysis steps
4.1.3.1 Preparation of test solution
Weigh about 20g of sample (accurate to 0.01g), place in a 250mL beaker, add 100mL of water to dissolve. Transfer all to a 500ml volumetric flask, dilute to scale with water, and shake well. Dry filter if necessary. This solution is solution A, and keep this solution for the determination of chloride content. 4.1.3.2 Determination
Use a pipette to transfer 10mL of solution A (4.1.3.1), place in a 250mL conical flask, add 40mL of water and 5mL of triethanolamine solution, adjust the pH to 7-8 with ammonia water, add 10ml of ammonia-ammonium chloride buffer solution A and a small amount of chrome black T indicator, and titrate with disodium ethylenediaminetetraacetic acid standard titration solution until the solution changes from purple-red to pure blue as the end point. 4.1.4 Expression of analytical results
The main content expressed as mass percentage (calculated as MgSO4·7H2O) X is calculated according to formula (1): cX0.246 5×100
m×500
1232.5×Vc
Formula 4: V is the volume of the standard titration solution of disodium ethylenediaminetetraacetic acid (EDTA) consumed in the titration, mL; V is the actual concentration of the standard titration solution of disodium ethylenediaminetetraacetic acid, mol/L; mass of the sample, g;
(1)
is the mass of magnesium sulfate (MgSO4·7H2O) in grams equivalent to 1.00 mL of the standard titration solution of disodium ethylenediaminetetraacetic acid (c(EDTA)-1.000 mol/L). 4.1.5 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 0.2%. 4.2 Determination of iron content
4.2.1 Summary of method
Same as Article 2 of GB/T3049.
4.2.2 Reagents and materials
Same as Article 3 of GB/T3049.
4.2.3 Instruments and equipment
Same as Article 4 of GB/T3049.
4.2.4 Drawing of working curve
Draw the working curve according to Article 5.3 of GB/T3049 using a 3 cm absorption cell and the corresponding amount of iron standard solution. 4.2.5 Analysis steps
4.2.5.1 Preparation of test solution
HG/T 2680—95
Weigh about 10g of sample (accurate to 0.01g), place in a 400ml beaker, add 150mL of water and 5mL of 1+1 hydrochloric acid solution, boil for 3-5min, and cool. Transfer all to a 250ml volumetric flask, dilute to the mark with water, and shake well. Filter if necessary. 4.2.5.2 Preparation of empty test solution
In a 250ml volumetric flask, add 200mL of water and 5mL of 1+1 hydrochloric acid solution, dilute to the mark with water, and shake well. 4.2.5.3 Determination
Use a pipette to transfer 10mL (for inferior products) or 5mL (for qualified products) of the test solution (4.2.5.1) into a 100mL volumetric flask; transfer the same volume of blank test solution (4.2.5.2) as the test solution into another 100mL volumetric flask, add water to about 60mL respectively, and adjust the pH to about 2 with 1+9 ammonia water (check with precision pH test paper). According to Article 5.3.2 of GB/T3049, start the operation by adding 2.5 ml of ascorbic acid solution.
Use a 3 cm absorption cell and measure the absorbance according to Article 5.4.2 of GB/T3049. 4.2.6 Expression of analysis results
The iron (Fe) content X expressed as mass percentage is calculated according to formula (2): (mm.)
m×1000×250
25(ml-mo)
Where: m
The mass of iron obtained from the working curve based on the measured absorbance of the test solution, mg; The mass of iron obtained from the working curve based on the measured absorbance of the blank test solution, mg. The mass of iron obtained above, mg; the mass of the test sample,;
The volume of the test solution transferred, mL. wwW.bzxz.Net
4.2.7 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 0.002%. 4.3 Determination of chloride content
4.3.1 Summary of method
(2)
In a solution with a pH of 2.5~～~3.0, use diphenylazocarbonyl hydrazide as an indicator and use mercuric nitrate standard titration solution to titrate chloride ions. 4.3.2 Reagents and materials
4.3.2.1 Nitric acid (GB/T626): 1+15 solution; 4. 3.2.2 95% ethanol (GB/T 679);
4.3.2.3 Standard titration solution of mercuric nitrate: c［1/2Hg（NO.）2J about 0.05mol/L, prepared and calibrated according to Article 4.9 of GB/T3051; 4.3.2.4 Bromophenol blue ethanol solution: 1g/L; 4.3.2.5 Diphenylazocarbonylhydrazide ethanol solution: 5g/L. 4.3.3 Instruments and equipment
Microburette: nominal graduation value is 0.01 or 0.02mL. 4.3.4 Analysis steps
4.3.4.1 Blank test: Add 100 mL of water and 3 drops of bromophenol blue indicator solution to a 250 mL conical flask, add nitric acid solution until the color just changes from blue to yellow, and then add 5 drops in excess. Add 1 mL of diphenylazocarbonylhydrazide indicator solution, use a microburette, and titrate with standard mercuric nitrate titration solution until the solution turns purple-red. Record the volume used. 4.3.4.2 Determination
Use a pipette to transfer 100 mL of solution A (4.1.3.1), place it in a 250 mL conical flask, add 3 drops of bromophenol blue indicator solution, add nitric acid solution until the color just changes from yellow to yellow, and then add 5 drops in excess. Add 1 mL of diphenylazocarbonylhydrazide indicator solution, use a microburette, and titrate with standard mercuric nitrate titration solution until the solution turns from yellow to the same purple-red as the blank test, which is the end point. Save the waste liquid after titration and handle it according to the provisions of Appendix D of GB/T3501. 575
4.3.5 Expression of analysis results
HG/T 2680—95
Nitrides (in terms of CI) content X expressed as mass percentage: calculated according to formula (3): (VV).cX0.03545×100
m×500
_17.725×(VV.)
Wuzhong--The volume of standard mercuric nitrate solution consumed by titrating the test solution, mL; ---The volume of standard mercuric nitrate solution consumed by titrating the blank test solution, mL, the actual concentration of standard mercuric nitrate solution, mol/L; m——-The mass of the sample, g;
(3)
(0.(03545—The mass of chlorine in grams equivalent to 1.00mL standard mercuric nitrate solution (cE1/2Hg(NO)2)=1.000mol/L.
4.3.6 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 0.01%. 4.4 Determination of water-insoluble matter content
4.4.1 Summary of method
Dissolve the sample in water and filter it with a crucible filter. Wash, dry, weigh, and calculate the insoluble matter. Soluble matter content. 4.4.2 Reagents and materials
Barium chloride (GB/T652) solution: 10 g/L. 4.4.3 Instruments and equipment
Crucible filter: filter plate pore size 5-15 μm. 4.4.4 Analysis steps
Weigh about 20 g of sample (accurate to 0.01 g), place in a 400 mL beaker, add 200 mL of water to dissolve. Use a formula that has been dried to constant weight at 105-110°C Filter and wash the residue with water until the filtrate does not contain SO2 (check with barium chloride solution). Dry at 105-110℃ to constant weight.
4.4.5 Expression of analysis results
The water-insoluble content X expressed as a mass percentage is calculated according to formula (4): X,=m2-m,
Where: m,—-the mass of the crucible filter, g; n2—-the mass of the crucible filter and water-insoluble matter, g; m —Test material mass, g.
4.4.6 Allowable difference
The arithmetic mean of the results of the parallel determinations shall be taken as the determination result, and the absolute difference of the parallel determination results shall not exceed 0.01%. 5 Inspection rules
(4)
5.1 Industrial magnesium sulfate heptahydrate 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 all products leaving the factory meet the requirements of this standard. Each batch of products leaving the factory shall be accompanied by a quality certificate, which shall include: manufacturer name, factory address, product name, grade, net weight, batch number or production date, product quality certificate that meets this standard and this standard number. 5.2 The user has the right to inspect and accept the industrial magnesium sulfate heptahydrate received in accordance with the provisions of this standard. The inspection and acceptance shall be carried out within one month from the date of arrival of the goods.
5.3 Each batch of products shall not exceed 50t.
5.4 Determine the number of sampling units in accordance with the provisions of Article 6.6 of GB/T6678. When sampling, insert the sampler vertically along the center line of the packaging bag to two-quarters of the material layer depth, mix the sample thoroughly, and use the quartering method to reduce it to about 500g. Immediately put it in two clean, dry, stoppered wide-mouth bottles and seal them. Paste labels on the bottles, indicating: manufacturer name, product name, grade, batch number, sampling date and name of the sampler. ...-bottle is used for inspection, and the other bottle is kept for months for reference. 5.5 If one of the indicators of the inspection results does not meet the requirements of this standard, re-sample from twice the amount of packaging for verification. The verification results show that only ---indicators do not meet the requirements of this standard, and 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 "Product Quality Law of the People's Republic of China". 5.7 The rounded value comparison method specified in GB1250 is used to determine whether the inspection results meet the standards. 6 Marking, packaging, transportation and storage
6.1 The packaging of industrial magnesium sulfate heptahydrate should be firmly and clearly marked, including: manufacturer name, factory address, product name, trademark, grade, net weight, batch number or production date, this standard number and the "heat-afraid" and "moisture-afraid" marks specified in GB191. 6.2 Industrial magnesium sulfate heptahydrate is double-packed, the inner packaging is a polyethylene plastic film bag, the inner bag packaging volume should be larger than the outer bag; the outer packaging is a plastic woven bag, and its performance and inspection method should comply with the provisions of GB8946. The net weight of the bag is 25, 40 or 50kg.
The inner bag of the packaging is tied with vinyl rope or other ropes of equivalent quality, and the outer packaging is sewn with a sewing machine. The stitches should be neat, the stitch length is uniform, and there should be no leaking or skipping
6.3 Industrial magnesium sulfate heptahydrate should be protected from rain, moisture and exposure during transportation. 6.4 Industrial magnesium sulfate heptahydrate should be stored in a ventilated and dry warehouse. The temperature shall not exceed 48℃. Additional remarks:
This standard is proposed by the Technical Supervision Department of the Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of Tianjin Chemical Research Institute of the Ministry of Chemical Industry. This standard was drafted by Tianjin Chemical Research Institute of the Ministry of Chemical Industry and Shanxi Yuncheng Salt Chemical Bureau. The main drafters of this standard are Jiang Junhua, Hao Baoyu and Lv Hongxia. 577—-Mass of crucible filter, g; n2 —Mass of crucible filter and water insoluble matter, g; m —Mass of sample, g.
4.4.6 Allowable difference
The arithmetic mean of the results of the parallel determinations shall be taken as the determination result, and the absolute difference of the parallel determination results shall not exceed 0.01%. 5 Inspection rules
(4)
5.1 Industrial magnesium sulfate heptahydrate 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 all products leaving the factory meet the requirements of this standard. Each batch of products leaving the factory shall be accompanied by a quality certificate, including: manufacturer name, factory address, product name, grade, net weight, batch number or production date, product quality certificate of compliance with this standard and this standard number. 5.2 The user has the right to inspect and accept the industrial magnesium sulfate heptahydrate received in accordance with the provisions of this standard. The inspection and acceptance shall be carried out within one month from the date of arrival of the goods.
5.3 Each batch of products shall not exceed 50t.
5.4 Determine the number of sampling units in accordance with the provisions of Article 6.6 of GB/T6678. When sampling, insert the sampler vertically along the center line of the packaging bag to two-quarters of the depth of the material layer to take samples. Mix the collected samples thoroughly, reduce them to about 500g by quartering method, and immediately put them into two clean, dry, stoppered wide-mouth bottles and seal them. Paste labels on the bottles, indicating: manufacturer name, product name, grade, batch number, sampling date and name of the sampler. ...-bottle is used for inspection, and the other bottle is kept for months for reference. 5.5 If one of the indicators does not meet the requirements of this standard, re-sample from twice the amount of packaging for verification. The verification results show that only ---indicators do not meet the requirements of this standard, and 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 "Product Quality Law of the People's Republic of China". 5.7 The rounded value comparison method specified in GB1250 shall be used to determine whether the test results meet the standard. 6 Marking, packaging, transportation and storage
6.1 The packaging of industrial magnesium sulfate heptahydrate shall be firmly and clearly marked, including: manufacturer name, factory address, product name, trademark, grade, net weight, batch number or production date, this standard number and the "heat-afraid" and "wet-afraid" marks specified in GB191. 6.2 Industrial magnesium sulfate heptahydrate shall be double-layered, with the inner packaging made of polyethylene plastic film bags, the inner bag packaging volume shall be larger than the outer bag; the outer packaging shall be made of plastic woven bags, the performance and inspection methods of which shall comply with the provisions of GB8946. The net weight of the bag is 25, 40 or 50kg.
The inner bag of the packaging shall be tied with vinyl rope or other ropes of equivalent quality, and the outer packaging shall be sewn with a bag sewing machine. The stitches shall be neat, the stitch length shall be uniform, and there shall be no leaking seams or skipping seams
6.3 Industrial magnesium sulfate heptahydrate shall be protected from rain, moisture and exposure during transportation. 6.4 Industrial magnesium sulfate heptahydrate should be stored in a ventilated and dry warehouse. The temperature should not exceed 48℃. Additional remarks:
This standard is proposed by the Technical Supervision Department of the Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of Tianjin Chemical Research Institute of the Ministry of Chemical Industry. This standard was drafted by Tianjin Chemical Research Institute of the Ministry of Chemical Industry and Shanxi Yuncheng Salt Chemical Bureau. The main drafters of this standard are Jiang Junhua, Hao Baoyu and Lv Hongxia. 577—-Mass of crucible filter, g; n2 —Mass of crucible filter and water insoluble matter, g; m —Mass of sample, g.
4.4.6 Allowable difference
The arithmetic mean of the results of the parallel determinations shall be taken as the determination result, and the absolute difference of the parallel determination results shall not exceed 0.01%. 5 Inspection rules
(4)
5.1 Industrial magnesium sulfate heptahydrate 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 all products leaving the factory meet the requirements of this standard. Each batch of products leaving the factory shall be accompanied by a quality certificate, including: manufacturer name, factory address, product name, grade, net weight, batch number or production date, product quality certificate of compliance with this standard and this standard number. 5.2 The user has the right to inspect and accept the industrial magnesium sulfate heptahydrate received in accordance with the provisions of this standard. The inspection and acceptance shall be carried out within one month from the date of arrival of the goods.
5.3 Each batch of products shall not exceed 50t.
5.4 Determine the number of sampling units in accordance with the provisions of Article 6.6 of GB/T6678. When sampling, insert the sampler vertically along the center line of the packaging bag to two-quarters of the depth of the material layer to take samples. Mix the collected samples thoroughly, reduce them to about 500g by quartering method, and immediately put them into two clean, dry, stoppered wide-mouth bottles and seal them. Paste labels on the bottles, indicating: manufacturer name, product name, grade, batch number, sampling date and name of the sampler. ...-bottle is used for inspection, and the other bottle is kept for months for reference. 5.5 If one of the indicators does not meet the requirements of this standard, re-sample from twice the amount of packaging for verification. The verification results show that only ---indicators do not meet the requirements of this standard, and 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 "Product Quality Law of the People's Republic of China". 5.7 The rounded value comparison method specified in GB1250 shall be used to determine whether the test results meet the standard. 6 Marking, packaging, transportation and storage
6.1 The packaging of industrial magnesium sulfate heptahydrate shall be firmly and clearly marked, including: manufacturer name, factory address, product name, trademark, grade, net weight, batch number or production date, this standard number and the "heat-afraid" and "wet-afraid" marks specified in GB191. 6.2 Industrial magnesium sulfate heptahydrate shall be double-layered, with the inner packaging made of polyethylene plastic film bags, the inner bag packaging volume shall be larger than the outer bag; the outer packaging shall be made of plastic woven bags, the performance and inspection methods of which shall comply with the provisions of GB8946. The net weight of the bag is 25, 40 or 50kg.
The inner bag of the packaging shall be tied with vinyl rope or other ropes of equivalent quality, and the outer packaging shall be sewn with a bag sewing machine. The stitches shall be neat, the stitch length shall be uniform, and there shall be no leaking seams or skipping seams
6.3 Industrial magnesium sulfate heptahydrate shall be protected from rain, moisture and exposure during transportation. 6.4 Industrial magnesium sulfate heptahydrate should be stored in a ventilated and dry warehouse. The temperature should not exceed 48℃. Additional remarks:
This standard is proposed by the Technical Supervision Department of the Ministry of Chemical Industry of the People's Republic of China. This standard is under the jurisdiction of Tianjin Chemical Research Institute of the Ministry of Chemical Industry. This standard was drafted by Tianjin Chemical Research Institute of the Ministry of Chemical Industry and Shanxi Yuncheng Salt Chemical Bureau. The main drafters of this standard are Jiang Junhua, Hao Baoyu and Lv Hongxia. 577
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