Some standard content:
Chemical Industry Standard of the People's Republic of China
Industrial Sodium Metasilicate
Subject Content and Scope of Application
HG/T 2568—94
This standard specifies the technical requirements, test methods, inspection rules and marking, packaging, transportation and storage of industrial sodium metasilicate. This standard applies to industrial sodium metasilicate. This product is mainly used as an additive for detergents and metal cleaning agents, and is also used in artificial zeolite, paper bleaching, cotton yarn cooking, etc.
Referenced standards
GB 191
Packaging, storage and transportation pictorial symbols
GB/T 601
GB/T 602
GB/T603
Chemical reagents-Preparation of standard solutions for titration analysis (volume analysis) Chemical reagents
Preparation of standard solutions for impurity determination
Chemical reagent meters
Preparation of preparations and products used in test methods-Expression and determination methods of limit values GB 1250
GB/T 3049
General method for determination of iron content in chemical products-O-phenanthroline spectrophotometry GB/T 5950
General rules for whiteness test methods for building materials and non-metallic mineral products-General rules for sampling of chemical products
GB/T 6678
Specifications and test methods for water used in analytical laboratories GB/T 6682
GB 8946
Plastic woven bags
GB 8947
3Product classification
Composite plastic woven bags
Industrial sodium metasilicate is divided into two categories:
Class I: Sodium metasilicate pentahydrate
Molecular formula NazSiO,·5H,0
Relative molecular mass: 212.14 (according to the 1989 international relative atomic mass) [Class: Sodium metasilicate nonahydrate
Molecular formula: Na2SiO,·9H,0
Relative molecular mass: 284.20 (according to the 1989 international relative atomic mass) 4 Technical requirements
4.1 Appearance: white crystalline particles or powder. 4.2 Industrial sodium metasilicate should meet the requirements of the following table. Approved by the Ministry of Chemical Industry of the People's Republic of China on February 9, 1994 5.14
Implemented on July 1, 1994
Total base (in Naz))
Silicon dioxide (in SiO2) content
Iron (Fo) content
Water-insoluble matter content
5 Test method
HG/T 2568--94
Superior product
28. 5~~30. 0
27. 3~~29. 2
Qualified product
28.0~30.5
27.0~29.0
% (m/m)
20.0~~22.0
19.0~~22.0
The reagents and water used in this standard, unless otherwise specified, refer to analytically pure reagents and grade 3 water specified in GB/T6682. The standard solutions, impurity standard solutions, preparations and products required in the test, unless otherwise specified, shall be prepared in accordance with the provisions of GB/T601, GB/T602 and GB/T603.
5.1 Determination of total alkali content
5.1.1 Summary of the method
Use methyl red as an indicator and titrate the total alkali content with hydrochloric acid standard titration solution. 5.1.2 Reagents and materials
5.1.2.1 Hydrochloric acid (GB/T622) standard titration solution: c(HCI) is about 0.2 mol/L. 5.1.2.1.1 Preparation: Measure 18mL of hydrochloric acid, inject it into 1000mL of water, and shake well. 5.1.2.1.2 Calibration: Weigh about 0.4g of standard anhydrous sodium carbonate (GB/T1255) burned to constant weight at 270-300C, weigh to 0.0001g. Dissolve in 50mL of water, add 10 drops of bromocresol green-methyl red mixed indicator solution, and titrate with the prepared hydrochloric acid standard titration solution until the solution changes from green to dark red, boil for 2 minutes, and continue to titrate until the solution turns dark red again after cooling. Perform a blank test at the same time. 5.1.2.1.3 Calculation
Concentration c of standard hydrochloric acid titration solution is calculated according to formula (1): m
C= (V,-V,)×0. 052 99
Wherein: c—actual concentration of standard hydrochloric acid titration solution, mol/L; m mass of anhydrous sodium carbonate, g;
V, volume of standard hydrochloric acid titration solution consumed in titration, ml; V. volume of standard hydrochloric acid titration solution consumed in blank test, mL; (1)
0.05299—mass of anhydrous sodium carbonate in grams equivalent to 1.00mL standard hydrochloric acid titration solution Cc(HCI)=1.000mol/L).
5.1.2.2 Methyl red (HG/T3-958) ethanol solution: 1 g/L. 5.1.3 Analysis steps
5.1.3.1 Preparation of test solution
Weigh about 5g of test sample (Class 1 product) or about 8g of test sample (Class I product), (accurate to 0.0002g). Place in a 250mL beaker and dissolve in 200mL of water. Transfer all to a 500mL volumetric flask, dilute to scale with water, and shake well. This solution is test solution A. 5.1.3.2 Determination
Use a pipette to transfer 50mL of test solution A, place in a 250mL conical flask, and add 8 to 12 drops of methyl red indicator solution. Titrate with hydrochloric acid standard titration solution until the solution changes from yellow to slightly red, which is the end point. Keep this solution as test solution B for the determination of silica content. 515
5.1.4 Expression of analysis results
HG/T 2568-94
The total alkali content (in terms of Na2O) X expressed as a percentage by mass is calculated according to formula (2): X = cV×0.030 99×100
Wherein: c
actual concentration of hydrochloric acid standard titration solution, mol/L; volume of hydrochloric acid standard titration solution consumed in titration, mL; m-mass of the sample, g;
(2)
0.03099--mass of sodium oxide in grams equivalent to 1.00mL hydrochloric acid standard titration solution Ec(HCI)=1.000mol/L). 5.1.5 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 0.1%. 5.2 Determination of silicon dioxide content
5.2.1 Method summary
Add excess sodium fluoride to the solution after the total alkali content has been determined to generate a certain amount of sodium hydroxide. Add excess hydrochloric acid solution and then back-titrate with sodium hydroxide standard titration solution.
5.2.2 Reagents and materials
5.2.2.1 Hydrochloric acid (GB/T622) standard titration solution: c(HCI) about 0.5mol/L; 5.2.2.2 Sodium hydroxide (GB/T629) standard titration solution: c(NaOH) about 0.5mol/L, 5.2.2.3 Sodium fluoride (GB/T1264);
5.2.2.4 Methyl red (HG/T3-958) ethanol solution: 1g/L. 5.2.3 Analysis steps
After the total alkali content is determined, add 1.5±0.1g sodium fluoride to the test solution B, shake it to dissolve, and the solution turns yellow again. Immediately titrate with hydrochloric acid standard titration solution until the reddish color remains unchanged, then add 2~3mL in excess, accurately record the total volume of the hydrochloric acid standard titration solution, and then titrate with sodium hydroxide standard titration solution until the yellow color is the end point. At the same time, do a blank test. In a 250mL conical flask, add about 50mL of water, 8~12 drops of methyl red indicator solution, add 1.5±0.1g sodium fluoride, shake it to dissolve, and immediately titrate with hydrochloric acid standard titration solution until the reddish color remains unchanged, then add 2~3mL in excess, accurately record the total volume of the hydrochloric acid standard titration solution. Then titrate with sodium hydroxide standard titration solution until the yellow color is the end point. 5.2.4 Expression of analysis results
The silicon dioxide (SiO) content X expressed as mass percentage is calculated according to formula (3): [(cV.-cV,)-(cVcV.)]×0. 015 02×100X2=
m×500
15. 02[(G,Vi-c,V2) -(cV,-c,V,)]m
Wu Zhong: cr
actual concentration of hydrochloric acid standard titration solution, mol/L; actual concentration of sodium hydroxide standard titration solution, mol/L; V1-—volume of hydrochloric acid standard titration solution consumed in titration, mL; V2—volume of sodium hydroxide standard titration solution consumed in titration, mL; V.-volume of hydrochloric acid standard titration solution consumed in blank test, mL; V,---—Volume of standard sodium hydroxide solution consumed in blank test, mL; m-—Mass of sample for determination of total alkali content in Article 5.1.3.2, g, 0.015 02
（3）
Mass of silicon dioxide in grams equivalent to 1.00mL standard hydrochloric acid solution (c(HCl)-1.000mol/LJ).
5.2.5 Allowable difference
HG/T 2568—94
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 0.2%. 5.3 Determination of iron content
5.3.1 Summary of the method
Same as Article 2 of GB/T3049.
5.3.2 Reagents and materials
Same as Article 3 of GB/T3049.
5.3.3 Instruments and equipment
Same as Article 4 of GB/T3049.
5.3.4 Analysis steps
5.3.4.1 Drawing of working curve
According to Article 5.3 of GB/T3049, use a 3cm absorption cell and the corresponding amount of iron standard solution to draw the working curve. 5.3.4.2 Test solution Preparation of solution
Weigh about 5g of sample (accurate to 0.01g). Place in a 400mL beaker, add 150mL of water to dissolve, add 15ml of 1+1 hydrochloric acid solution, boil for 3~5min, cool, and filter if necessary. Transfer all to a 250mL volumetric flask, dilute to the mark with water, and shake well. 5.3.4.3 Preparation of blank test solution
Add 200mL of water and 15mL of 1+1 hydrochloric acid solution to a 250ml volumetric flask, dilute to the mark with water, and shake well. 5.3.4.4 Determination
Use a pipette to transfer 10mL of test solution and 10mL of blank test solution respectively, place them in 100mL volumetric flasks respectively, and adjust the pH value to close to 2 with 1+9 ammonia water (check with precision pH test paper). Add 2. 5mL ascorbic acid solution, 10ml buffer solution, 5mL o-phenanthroline solution, dilute to the scale with water and shake well. Use a 3cm absorption cell to measure the absorbance according to the provisions of Article 5.4.2 of GB/T3049. 5.3.5 Expression of analysis results
Iron (Fe) content X expressed as mass percentage: calculated according to formula (4): (mlm2)×103
(4)
Where: m is the mass of iron found from the working curve based on the measured absorbance of the test solution, mg; m2 is the mass of iron found from the working curve based on the measured absorbance of the blank test solution, mg; m----sample mass, g.
5.3.6 Allowable difference
Take the arithmetic mean of the parallel determination results as the determination As a result, the absolute difference of the parallel determination results is not greater than 0.005%. 5.4 Determination of water-insoluble content
5.4.1 Reagents and materials
5.4.1.1 Hydrochloric acid (GB/T622) solution: 1+3; 5.4.1.2 Sodium hydroxide (GB/T629) solution: 50g/L; 5.4.1.3 Phenolic acid (GB/T10729) ethanol solution: 10g/L; 5.4.1.4 Acid-washed asbestos (HG/T3-1062): Take an appropriate amount of acid-washed right cotton, soak it in 1+3 hydrochloric acid solution, boil it for 20 minutes, filter it with a Buchner funnel and wash it with water until it is neutral, then soak it with 50g/L sodium hydroxide solution and boil it for 20 minutes, filter it with a Buchner funnel and wash it with water until it is neutral (check with phenol indicator solution). Use water 5-17
to make a thin paste and set aside.
5.4.2 Instruments and equipment
German crucible: volume 30mL.
HG/T 2568-94
Place the Gooch crucible on the filtration bottle, evenly spread about 2mm thick acid-washed asbestos on the upper and lower sieve plates, and wash with hot water until the filtrate does not contain cotton wool. Remove the crucible and dry it at 110±5℃, weigh it after cooling; wash it with hot water again, dry it at 110±5℃, weigh it after cooling: repeat this process until the weight is constant. 5.4.3 Analysis steps
Weigh about 5g of sample (accurate to 0.01g), put it in a 500mL beaker, and add 300mL of hot water to dissolve it. Filter it with a Gooch crucible with acid-washed asbestos that has been dried at 110±5℃, and wash it with hot water until it is neutral (check with phenolphthalein indicator solution). Dry it at 110±5℃ to constant weight.
5.4.4 Expression of analysis results
The water-insoluble content X expressed as a percentage of mass is calculated according to formula (5): X,-m2-m
1×100
Where: m--the mass of the Gooch crucible·g;
m.-the mass of the water-insoluble matter and Gooch crucible, g;
m-the mass of the sample, g.
5.4.5 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 0.02%. 5.5 Determination of degree
5.5.1 Instruments and equipment
5.5.1.1 Autometer: Same as the provisions of Article 3 of GB/T5950; 5.5.1.2 Standard white board: Magnesium oxide standard white board specified in Article 4 of GB/T5950; 5.5.1.3 Working white board: Same as the provisions of Article 5 of GB/T5950. 5.5.2 Analysis steps
Perform in accordance with the provisions of Article 6 of GB/T5950.
5.5.3 Expression of analysis results
Perform in accordance with the provisions of Article 7 of GB/T5950.
5.5.4 Allowable difference
Take the arithmetic mean of the results of the row determination as the determination result, and the absolute difference of the parallel determination results shall not exceed 1%. 6 Inspection rules
(5)
6.1 Industrial sodium metasilicate 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. The content shall include the manufacturer's name, address, product name, category, grade, net weight, batch number or production date, proof that the product quality meets this standard and the standard number. 6.2 The user has the right to inspect and accept the industrial sodium metasilicate 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
6.3 Each batch of products shall not exceed 100t.||tt ||6.4 Determine the number of sampling units in accordance with the provisions of Article 6.6 of (B/T6678). When sampling, insert the sampler vertically from the center line of the packaging bag to 3/4 of the depth of the material layer, mix the sample thoroughly, reduce it to about 500g by quartering, and immediately put it into two clean, dry bottles and seal them. Stick labels on the bottles, indicating the manufacturer name, product name, category, grade, batch number, sampling date and name of the sampler. One bottle is used for inspection, and the other bottle is kept for one month for future reference. 6.5 If one of the test results does not meet the requirements of this standard, re-sample from twice the amount of packaging for verification. Even if the verification result is 518
HG/T 2568—94
If only one indicator does not meet the requirements of this standard, the entire batch of products cannot be accepted. 6.6 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". 6.7 The rounded comparison method specified in GB1250 shall be used to determine whether the inspection results meet the standards. 7 Marking, packaging, transportation, storage
7.1 The packaging bag of sodium metasilicate should have firm and clear markings, including the manufacturer's name, address, product name, trademark, category, grade, net weight, batch number or production date, this standard number and the "moisture-afraid" mark specified in GB191. 7.2 Sodium metasilicate is double-layer packaged, the inner packaging is a polyethylene plastic film bag with a thickness of not less than 0.07mm, and the inner bag packaging area should be larger than the outer bag: the outer packaging is a plastic woven bag or a composite plastic woven bag, and its performance and inspection methods shall comply with GB8946 and GB8947. The net weight of each bag is 25, 40, and 50 kg. The inner bag of the package is tied with a vinyl rope or other rope of equivalent quality, and the outer package is sewn with a bag sewing machine. The stitches should be neat, the stitch length is evenly distributed, and there is no leakage or jumper.
7.3 Industrial sodium metasilicate should be protected from rain, moisture and exposure during transportation. 7.4 Industrial sodium metasilicate should be stored in a ventilated and dry warehouse. 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 is drafted by Tianjin Chemical Research Institute of the Ministry of Chemical Industry, Tianjin Alkali Factory, Qingdao Soda Factory, and Tianjin Dongfanghong Chemical Factory. The main drafters of this standard are Jiang Junhua, Wu Hongfa, Wang Benmao, Liu Zongchang, and Su Kaiying. This standard refers to the British standard BS3984-1982 "Sodium Metasilicate Pentahydrate" and the Japanese standard JISK1408--1985 "Solid Sodium Silicate".015 02
（3）
The mass of silicon dioxide in grams equivalent to 1.00 mL of standard hydrochloric acid titration solution (c(HCl)-1.000 mol/LJ).
5.2.5 Tolerance
HG/T 2568—94
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 0.2%. 5.3 Determination of iron content
5.3.1 Summary of the method
Same as Article 2 of GB/T3049.
5.3.2 Reagents and materials
Same as Article 3 of GB/T3049.
5.3.3 Instruments and equipment
Same as Article 4 of GB/T3049.
5.3.4 Analysis steps
5.3.4.1 Drawing of working curve
According to Article 5.3 of GB/T3049, use a 3cm absorption cell and the corresponding amount of iron standard solution to draw the working curve. 5.3.4.2 Test solution Preparation of solution
Weigh about 5g of sample (accurate to 0.01g). Place in a 400mL beaker, add 150mL of water to dissolve, add 15ml of 1+1 hydrochloric acid solution, boil for 3~5min, cool, and filter if necessary. Transfer all to a 250mL volumetric flask, dilute to the mark with water, and shake well. 5.3.4.3 Preparation of blank test solution
Add 200mL of water and 15mL of 1+1 hydrochloric acid solution to a 250ml volumetric flask, dilute to the mark with water, and shake well. 5.3.4.4 DeterminationwwW.bzxz.Net
Use a pipette to transfer 10mL of test solution and 10mL of blank test solution respectively, place them in 100mL volumetric flasks respectively, and adjust the pH value to close to 2 with 1+9 ammonia water (check with precision pH test paper). Add 2. 5mL ascorbic acid solution, 10ml buffer solution, 5mL o-phenanthroline solution, dilute to the scale with water and shake well. Use a 3cm absorption cell to measure the absorbance according to the provisions of Article 5.4.2 of GB/T3049. 5.3.5 Expression of analysis results
Iron (Fe) content X expressed as mass percentage: calculated according to formula (4): (mlm2)×103
(4)
Where: m—the mass of iron found from the working curve based on the measured absorbance of the test solution, mg; m2—the mass of iron found from the working curve based on the measured absorbance of the blank test solution, mg; m----the mass of the sample, g.
5.3.6 Allowable difference
Take the arithmetic mean of the parallel determination results as the determination As a result, the absolute difference of the parallel determination results is not greater than 0.005%. 5.4 Determination of water-insoluble content
5.4.1 Reagents and materials
5.4.1.1 Hydrochloric acid (GB/T622) solution: 1+3; 5.4.1.2 Sodium hydroxide (GB/T629) solution: 50g/L; 5.4.1.3 Phenolic acid (GB/T10729) ethanol solution: 10g/L; 5.4.1.4 Acid-washed asbestos (HG/T3-1062): Take an appropriate amount of acid-washed right cotton, soak it in 1+3 hydrochloric acid solution, boil it for 20 minutes, filter it with a Buchner funnel and wash it with water until it is neutral, then soak it with 50g/L sodium hydroxide solution and boil it for 20 minutes, filter it with a Buchner funnel and wash it with water until it is neutral (check with phenol indicator solution). Use water 5-17
to make a thin paste and set aside.
5.4.2 Instruments and equipment
German crucible: volume 30mL.
HG/T 2568-94
Place the Gooch crucible on the filtration bottle, evenly spread about 2mm thick acid-washed asbestos on the upper and lower sieve plates, and wash with hot water until the filtrate does not contain cotton wool. Remove the crucible and dry it at 110±5℃, weigh it after cooling; wash it with hot water again, dry it at 110±5℃, weigh it after cooling: repeat this process until the weight is constant. 5.4.3 Analysis steps
Weigh about 5g of sample (accurate to 0.01g), put it in a 500mL beaker, and add 300mL of hot water to dissolve it. Filter it with a Gooch crucible with acid-washed asbestos that has been dried at 110±5℃, and wash it with hot water until it is neutral (check with phenolphthalein indicator solution). Dry it at 110±5℃ to constant weight.
5.4.4 Expression of analysis results
The water-insoluble content X expressed as a percentage of mass is calculated according to formula (5): X,-m2-m
1×100
Where: m--the mass of the Gooch crucible·g;
m.-the mass of the water-insoluble matter and Gooch crucible, g;
m-the mass of the sample, g.
5.4.5 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 0.02%. 5.5 Determination of degree
5.5.1 Instruments and equipment
5.5.1.1 Autometer: Same as the provisions of Article 3 of GB/T5950; 5.5.1.2 Standard white board: Magnesium oxide standard white board specified in Article 4 of GB/T5950; 5.5.1.3 Working white board: Same as the provisions of Article 5 of GB/T5950. 5.5.2 Analysis steps
Perform in accordance with the provisions of Article 6 of GB/T5950.
5.5.3 Expression of analysis results
Perform in accordance with the provisions of Article 7 of GB/T5950.
5.5.4 Allowable difference
Take the arithmetic mean of the results of the row determination as the determination result, and the absolute difference of the parallel determination results shall not exceed 1%. 6 Inspection rules
(5)
6.1 Industrial sodium metasilicate 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. The content shall include the manufacturer's name, address, product name, category, grade, net weight, batch number or production date, proof that the product quality meets this standard and the standard number. 6.2 The user has the right to inspect and accept the industrial sodium metasilicate 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
6.3 Each batch of products shall not exceed 100t.||tt ||6.4 Determine the number of sampling units in accordance with the provisions of Article 6.6 of (B/T6678). When sampling, insert the sampler vertically from the center line of the packaging bag to 3/4 of the depth of the material layer, mix the sample thoroughly, reduce it to about 500g by quartering, and immediately put it into two clean, dry bottles and seal them. Stick labels on the bottles, indicating the manufacturer name, product name, category, grade, batch number, sampling date and name of the sampler. One bottle is used for inspection, and the other bottle is kept for one month for future reference. 6.5 If one of the test results does not meet the requirements of this standard, re-sample from twice the amount of packaging for verification. Even if the verification result is 518
HG/T 2568—94
If only one indicator does not meet the requirements of this standard, the entire batch of products cannot be accepted. 6.6 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". 6.7 The rounded comparison method specified in GB1250 shall be used to determine whether the inspection results meet the standards. 7 Marking, packaging, transportation, storage
7.1 The packaging bag of sodium metasilicate should have firm and clear markings, including the manufacturer's name, address, product name, trademark, category, grade, net weight, batch number or production date, this standard number and the "moisture-afraid" mark specified in GB191. 7.2 Sodium metasilicate is double-layer packaged, the inner packaging is a polyethylene plastic film bag with a thickness of not less than 0.07mm, and the inner bag packaging area should be larger than the outer bag: the outer packaging is a plastic woven bag or a composite plastic woven bag, and its performance and inspection methods shall comply with GB8946 and GB8947. The net weight of each bag is 25, 40, and 50 kg. The inner bag of the package is tied with a vinyl rope or other rope of equivalent quality, and the outer package is sewn with a bag sewing machine. The stitches should be neat, the stitch length is evenly distributed, and there is no leakage or jumper.
7.3 Industrial sodium metasilicate should be protected from rain, moisture and exposure during transportation. 7.4 Industrial sodium metasilicate should be stored in a ventilated and dry warehouse. 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 is drafted by Tianjin Chemical Research Institute of the Ministry of Chemical Industry, Tianjin Alkali Factory, Qingdao Soda Factory, and Tianjin Dongfanghong Chemical Factory. The main drafters of this standard are Jiang Junhua, Wu Hongfa, Wang Benmao, Liu Zongchang, and Su Kaiying. This standard refers to the British standard BS3984-1982 "Sodium Metasilicate Pentahydrate" and the Japanese standard JISK1408--1985 "Solid Sodium Silicate".015 02
（3）
The mass of silicon dioxide in grams equivalent to 1.00 mL of standard hydrochloric acid titration solution (c(HCl)-1.000 mol/LJ).
5.2.5 Tolerance
HG/T 2568—94
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 0.2%. 5.3 Determination of iron content
5.3.1 Summary of the method
Same as Article 2 of GB/T3049.
5.3.2 Reagents and materials
Same as Article 3 of GB/T3049.
5.3.3 Instruments and equipment
Same as Article 4 of GB/T3049.
5.3.4 Analysis steps
5.3.4.1 Drawing of working curve
According to Article 5.3 of GB/T3049, use a 3cm absorption cell and the corresponding amount of iron standard solution to draw the working curve. 5.3.4.2 Test solution Preparation of solution
Weigh about 5g of sample (accurate to 0.01g). Place in a 400mL beaker, add 150mL of water to dissolve, add 15ml of 1+1 hydrochloric acid solution, boil for 3~5min, cool, and filter if necessary. Transfer all to a 250mL volumetric flask, dilute to the mark with water, and shake well. 5.3.4.3 Preparation of blank test solution
Add 200mL of water and 15mL of 1+1 hydrochloric acid solution to a 250ml volumetric flask, dilute to the mark with water, and shake well. 5.3.4.4 Determination
Use a pipette to transfer 10mL of test solution and 10mL of blank test solution respectively, place them in 100mL volumetric flasks respectively, and adjust the pH value to close to 2 with 1+9 ammonia water (check with precision pH test paper). Add 2. 5mL ascorbic acid solution, 10ml buffer solution, 5mL o-phenanthroline solution, dilute to the scale with water and shake well. Use a 3cm absorption cell to measure the absorbance according to the provisions of Article 5.4.2 of GB/T3049. 5.3.5 Expression of analysis results
Iron (Fe) content X expressed as mass percentage: calculated according to formula (4): (mlm2)×103
(4)
Where: m—the mass of iron found from the working curve based on the measured absorbance of the test solution, mg; m2—the mass of iron found from the working curve based on the measured absorbance of the blank test solution, mg; m----the mass of the sample, g.
5.3.6 Allowable difference
Take the arithmetic mean of the parallel determination results as the determination As a result, the absolute difference of the parallel determination results is not greater than 0.005%. 5.4 Determination of water-insoluble content
5.4.1 Reagents and materials
5.4.1.1 Hydrochloric acid (GB/T622) solution: 1+3; 5.4.1.2 Sodium hydroxide (GB/T629) solution: 50g/L; 5.4.1.3 Phenolic acid (GB/T10729) ethanol solution: 10g/L; 5.4.1.4 Acid-washed asbestos (HG/T3-1062): Take an appropriate amount of acid-washed right cotton, soak it in 1+3 hydrochloric acid solution, boil it for 20 minutes, filter it with a Buchner funnel and wash it with water until it is neutral, then soak it with 50g/L sodium hydroxide solution and boil it for 20 minutes, filter it with a Buchner funnel and wash it with water until it is neutral (check with phenol indicator solution). Use water 5-17
to make a thin paste and set aside.
5.4.2 Instruments and equipment
German crucible: volume 30mL.
HG/T 2568-94
Place the Gooch crucible on the filtration bottle, evenly spread about 2mm thick acid-washed asbestos on the upper and lower sieve plates, and wash with hot water until the filtrate does not contain cotton wool. Remove the crucible and dry it at 110±5℃, weigh it after cooling; wash it with hot water again, dry it at 110±5℃, weigh it after cooling: repeat this process until the weight is constant. 5.4.3 Analysis steps
Weigh about 5g of sample (accurate to 0.01g), put it in a 500mL beaker, and add 300mL of hot water to dissolve it. Filter it with a Gooch crucible with acid-washed asbestos that has been dried at 110±5℃, and wash it with hot water until it is neutral (check with phenolphthalein indicator solution). Dry it at 110±5℃ to constant weight.
5.4.4 Expression of analysis results
The water-insoluble content X expressed as a percentage of mass is calculated according to formula (5): X,-m2-m
1×100
Where: m--the mass of the Gooch crucible·g;
m.-the mass of the water-insoluble matter and Gooch crucible, g;
m-the mass of the sample, g.
5.4.5 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 0.02%. 5.5 Determination of degree
5.5.1 Instruments and equipment
5.5.1.1 Autometer: Same as the provisions of Article 3 of GB/T5950; 5.5.1.2 Standard white board: Magnesium oxide standard white board specified in Article 4 of GB/T5950; 5.5.1.3 Working white board: Same as the provisions of Article 5 of GB/T5950. 5.5.2 Analysis steps
Perform in accordance with the provisions of Article 6 of GB/T5950.
5.5.3 Expression of analysis results
Perform in accordance with the provisions of Article 7 of GB/T5950.
5.5.4 Allowable difference
Take the arithmetic mean of the results of the row determination as the determination result, and the absolute difference of the parallel determination results shall not exceed 1%. 6 Inspection rules
(5)
6.1 Industrial sodium metasilicate 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. The content shall include the manufacturer's name, address, product name, category, grade, net weight, batch number or production date, proof that the product quality meets this standard and the standard number. 6.2 The user has the right to inspect and accept the industrial sodium metasilicate 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
6.3 Each batch of products shall not exceed 100t.||tt ||6.4 Determine the number of sampling units in accordance with the provisions of Article 6.6 of (B/T6678). When sampling, insert the sampler vertically from the center line of the packaging bag to 3/4 of the depth of the material layer, mix the sample thoroughly, reduce it to about 500g by quartering, and immediately put it into two clean, dry bottles and seal them. Stick labels on the bottles, indicating the manufacturer name, product name, category, grade, batch number, sampling date and name of the sampler. One bottle is used for inspection, and the other bottle is kept for one month for future reference. 6.5 If one of the test results does not meet the requirements of this standard, re-sample from twice the amount of packaging for verification. Even if the verification result is 518
HG/T 2568—94
If only one indicator does not meet the requirements of this standard, the entire batch of products cannot be accepted. 6.6 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". 6.7 The rounded comparison method specified in GB1250 shall be used to determine whether the inspection results meet the standards. 7 Marking, packaging, transportation, storage
7.1 The packaging bag of sodium metasilicate should have firm and clear markings, including the manufacturer's name, address, product name, trademark, category, grade, net weight, batch number or production date, this standard number and the "moisture-afraid" mark specified in GB191. 7.2 Sodium metasilicate is double-layer packaged, the inner packaging is a polyethylene plastic film bag with a thickness of not less than 0.07mm, and the inner bag packaging area should be larger than the outer bag: the outer packaging is a plastic woven bag or a composite plastic woven bag, and its performance and inspection methods shall comply with GB8946 and GB8947. The net weight of each bag is 25, 40, and 50 kg. The inner bag of the package is tied with a vinyl rope or other rope of equivalent quality, and the outer package is sewn with a bag sewing machine. The stitches should be neat, the stitch length is evenly distributed, and there is no leakage or jumper.
7.3 Industrial sodium metasilicate should be protected from rain, moisture and exposure during transportation. 7.4 Industrial sodium metasilicate should be stored in a ventilated and dry warehouse. 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 is drafted by Tianjin Chemical Research Institute of the Ministry of Chemical Industry, Tianjin Alkali Factory, Qingdao Soda Factory, and Tianjin Dongfanghong Chemical Factory. The main drafters of this standard are Jiang Junhua, Wu Hongfa, Wang Benmao, Liu Zongchang, and Su Kaiying. This standard refers to the British standard BS3984-1982 "Sodium Metasilicate Pentahydrate" and the Japanese standard JISK1408--1985 "Solid Sodium Silicate".2.5 Allowable difference
HG/T 2568—94
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 0.2%. 5.3 Determination of iron content
5.3.1 Summary of method
Same as Article 2 of GB/T3049.
5.3.2 Reagents and materials
Same as Article 3 of GB/T3049.
5.3.3 Instruments and equipment
Same as Article 4 of GB/T3049.
5.3.4 Analysis steps
5.3.4.1 Drawing of working curve
Draw the working curve using a 3 cm absorption cell and the corresponding amount of iron standard solution according to Article 5.3 of GB/T3049. 5.3.4.2 Preparation of test solution
Weigh about 5g of sample (accurate to 0.01g). Place in a 400mL beaker, add 150mL of water to dissolve, add 15ml of 1+1 hydrochloric acid solution, boil for 3~5min, cool, and filter if necessary. Transfer all to a 250mL volumetric flask, dilute to scale with water, and shake well. 5.3.4.3 Preparation of blank test solution
Add 200mL of water and 15mL of 1+1 hydrochloric acid solution to a 250mL volumetric flask, dilute to scale with water, and shake well. 5.3.4.4 Determination
Use a pipette to transfer 10mL of test solution and 10mL of blank test solution respectively, place them in 100mL volumetric flasks respectively, and adjust the pH value to close to 2 with 1+9 ammonia water (check with precision pH test paper). Add 2.5mL ascorbic acid solution, 10mL buffer solution, 5mL o-phenanthroline solution, dilute to the mark with water, and shake well. Use a 3cm absorption cell to measure the absorbance according to the provisions of Article 5.4.2 of GB/T3049. 5.3.5 Expression of analysis results
Iron (Fe) content X expressed as mass percentage: Calculate according to formula (4): (mlm2)×103
(4)
Where: m is the mass of iron found from the working curve based on the measured absorbance of the test solution, mg; m2 is the mass of iron found from the working curve based on the measured absorbance of the blank test solution, mg; m----sample mass, g.
5.3.6 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 0.005%. 5.4 Determination of water-insoluble matter content
5.4.1 Reagents and materials
5.4.1.1 Hydrochloric acid (GB/T622) solution: 1+3; 5.4.1.2 Sodium hydroxide (GB/T629) solution: 50g/L; 5.4.1.3 Phenolic acid (GB/T10729) ethanol solution: 10g/L; 5.4.1.4 Acid-washed asbestos (HG/T3-1062): Take an appropriate amount of acid-washed right cotton, soak it in 1+3 hydrochloric acid solution, boil it for 20 minutes, filter it with a Buchner funnel and wash it with water until it is neutral, then soak it with 50g/L sodium hydroxide solution and boil it for 20 minutes, filter it with a Buchner funnel and wash it with water until it is neutral (check with phenol indicator solution). Use water 5-17
to make a thin paste and set aside.
5.4.2 Instruments and equipment
German crucible: volume 30mL.
HG/T 2568-94
Place the Gooch crucible on the filtration bottle, evenly spread about 2mm thick acid-washed asbestos on the upper and lower sieve plates, and wash with hot water until the filtrate does not contain cotton wool. Remove the crucible and dry it at 110±5℃, weigh it after cooling; wash it with hot water again, dry it at 110±5℃, weigh it after cooling: repeat this process until the weight is constant. 5.4.3 Analysis steps
Weigh about 5g of sample (accurate to 0.01g), put it in a 500mL beaker, and add 300mL of hot water to dissolve it. Filter it with a Gooch crucible with acid-washed asbestos that has been dried at 110±5℃, and wash it with hot water until it is neutral (check with phenolphthalein indicator solution). Dry it at 110±5℃ to constant weight.
5.4.4 Expression of analysis results
The water-insoluble content X expressed as a percentage of mass is calculated according to formula (5): X,-m2-m
1×100
Where: m--the mass of the Gooch crucible·g;
m.-the mass of the water-insoluble matter and Gooch crucible, g;
m-the mass of the sample, g.
5.4.5 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 0.02%. 5.5 Determination of degree
5.5.1 Instruments and equipment
5.5.1.1 Autometer: Same as the provisions of Article 3 of GB/T5950; 5.5.1.2 Standard white board: Magnesium oxide standard white board specified in Article 4 of GB/T5950; 5.5.1.3 Working white board: Same as the provisions of Article 5 of GB/T5950. 5.5.2 Analysis steps
Perform in accordance with the provisions of Article 6 of GB/T5950.
5.5.3 Expression of analysis results
Perform in accordance with the provisions of Article 7 of GB/T5950.
5.5.4 Allowable difference
Take the arithmetic mean of the results of the row determination as the determination result, and the absolute difference of the parallel determination results shall not exceed 1%. 6 Inspection rules
(5)
6.1 Industrial sodium metasilicate 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. The content shall include the manufacturer's name, address, product name, category, grade, net weight, batch number or production date, proof that the product quality meets this standard and the standard number. 6.2 The user has the right to inspect and accept the industrial sodium metasilicate 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
6.3 Each batch of products shall not exceed 100t.||tt ||6.4 Determine the number of sampling units in accordance with the provisions of Article 6.6 of (B/T6678). When sampling, insert the sampler vertically from the center line of the packaging bag to 3/4 of the depth of the material layer, mix the sample thoroughly, reduce it to about 500g by quartering, and immediately put it into two clean, dry bottles and seal them. Stick labels on the bottles, indicating the manufacturer name, product name, category, grade, batch number, sampling date and name of the sampler. One bottle is used for inspection, and the other bottle is kept for one month for future reference. 6.5 If one of the test results does not meet the requirements of this standard, re-sample from twice the amount of packaging for verification. Even if the verification result is 518
HG/T 2568—94
If only one indicator does not meet the requirements of this standard, the entire batch of products cannot be accepted. 6.6 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". 6.7 The rounded comparison method specified in GB1250 shall be used to determine whether the inspection results meet the standards. 7 Marking, packaging, transportation, storage
7.1 The packaging bag of sodium metasilicate should have firm and clear markings, including the manufacturer's name, address, product name, trademark, category, grade, net weight, batch number or production date, this standard number and the "moisture-afraid" mark specified in GB191. 7.2 Sodium metasilicate is double-layer packaged, the inner packaging is a polyethylene plastic film bag with a thickness of not less than 0.07mm, and the inner bag packaging area should be larger than the outer bag: the outer packaging is a plastic woven bag or a composite plastic woven bag, and its performance and inspection methods shall comply with GB8946 and GB8947. The net weight of each bag is 25, 40, and 50 kg. The inner bag of the package is tied with a vinyl rope or other rope of equivalent quality, and the outer package is sewn with a bag sewing machine. The stitches should be neat, the stitch length is evenly distributed, and there is no leakage or jumper.
7.3 Industrial sodium metasilicate should be protected from rain, moisture and exposure during transportation. 7.4 Industrial sodium metasilicate should be stored in a ventilated and dry warehouse. 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 is drafted by Tianjin Chemical Research Institute of the Ministry of Chemical Industry, Tianjin Alkali Factory, Qingdao Soda Factory, and Tianjin Dongfanghong Chemical Factory. The main drafters of this standard are Jiang Junhua, Wu Hongfa, Wang Benmao, Liu Zongchang, and Su Kaiying. This standard refers to the British standard BS3984-1982 "Sodium Metasilicate Pentahydrate" and the Japanese standard JISK1408--1985 "Solid Sodium Silicate".2.5 Allowable difference
HG/T 2568—94
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 0.2%. 5.3 Determination of iron content
5.3.1 Summary of method
Same as Article 2 of GB/T3049.
5.3.2 Reagents and materials
Same as Article 3 of GB/T3049.
5.3.3 Instruments and equipment
Same as Article 4 of GB/T3049.
5.3.4 Analysis steps
5.3.4.1 Drawing of working curve
Draw the working curve using a 3 cm absorption cell and the corresponding amount of iron standard solution according to Article 5.3 of GB/T3049. 5.3.4.2 Preparation of test solution
Weigh about 5g of sample (accurate to 0.01g). Place in a 400mL beaker, add 150mL of water to dissolve, add 15ml of 1+1 hydrochloric acid solution, boil for 3~5min, cool, and filter if necessary. Transfer all to a 250mL volumetric flask, dilute to scale with water, and shake well. 5.3.4.3 Preparation of blank test solution
Add 200mL of water and 15mL of 1+1 hydrochloric acid solution to a 250mL volumetric flask, dilute to scale with water, and shake well. 5.3.4.4 Determination
Use a pipette to transfer 10mL of test solution and 10mL of blank test solution respectively, place them in 100mL volumetric flasks respectively, and adjust the pH value to close to 2 with 1+9 ammonia water (check with precision pH test paper). Add 2.5mL ascorbic acid solution, 10mL buffer solution, 5mL o-phenanthroline solution, dilute to the mark with water, and shake well. Use a 3cm absorption cell to measure the absorbance according to the provisions of Article 5.4.2 of GB/T3049. 5.3.5 Expression of analysis results
Iron (Fe) content X expressed as mass percentage: Calculate according to formula (4): (mlm2)×103
(4)
Where: m is the mass of iron found from the working curve based on the measured absorbance of the test solution, mg; m2 is the mass of iron found from the working curve based on the measured absorbance of the blank test solution, mg; m----sample mass, g.
5.3.6 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 0.005%. 5.4 Determination of water-insoluble matter content
5.4.1 Reagents and materials
5.4.1.1 Hydrochloric acid (GB/T622) solution: 1+3; 5.4.1.2 Sodium hydroxide (GB/T629) solution: 50g/L; 5.4.1.3 Phenolic acid (GB/T10729) ethanol solution: 10g/L; 5.4.1.4 Acid-washed asbestos (HG/T3-1062): Take an appropriate amount of acid-washed right cotton, soak it in 1+3 hydrochloric acid solution, boil it for 20 minutes, filter it with a Buchner funnel and wash it with water until it is neutral, then soak it with 50g/L sodium hydroxide solution and boil it for 20 minutes, filter it with a Buchner funnel and wash it with water until it is neutral (check with phenol indicator solution). Use water 5-17
to make a thin paste and set aside.
5.4.2 Instruments and equipment
German crucible: volume 30mL.
HG/T 2568-94
Place the Gooch crucible on the filtration bottle, evenly spread about 2mm thick acid-washed asbestos on the upper and lower sieve plates, and wash with hot water until the filtrate does not contain cotton wool. Remove the crucible and dry it at 110±5℃, weigh it after cooling; wash it with hot water again, dry it at 110±5℃, weigh it after cooling: repeat this process until the weight is constant. 5.4.3 Analysis steps
Weigh about 5g of sample (accurate to 0.01g), put it in a 500mL beaker, and add 300mL of hot water to dissolve it. Filter it with a Gooch crucible with acid-washed asbestos that has been dried at 110±5℃, and wash it with hot water until it is neutral (check with phenolphthalein indicator solution). Dry it at 110±5℃ to constant weight.
5.4.4 Expression of analysis results
The water-insoluble content X expressed as a percentage of mass is calculated according to formula (5): X,-m2-m
1×100
Where: m--the mass of the Gooch crucible·g;
m.-the mass of the water-insoluble matter and Gooch crucible, g;
m-the mass of the sample, g.
5.4.5 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 0.02%. 5.5 Determination of degree
5.5.1 Instruments and equipment
5.5.1.1 Autometer: Same as the provisions of Article 3 of GB/T5950; 5.5.1.2 Standard white board: Magnesium oxide standard white board specified in Article 4 of GB/T5950; 5.5.1.3 Working white board: Same as the provisions of Article 5 of GB/T5950. 5.5.2 Analysis steps
Perform in accordance with the provisions of Article 6 of GB/T5950.
5.5.3 Expression of analysis results
Perform in accordance with the provisions of Article 7 of GB/T5950.
5.5.4 Allowable difference
Take the arithmetic mean of the results of the row determination as the determination result, and the absolute difference of the parallel determination results shall not exceed 1%. 6 Inspection rules
(5)
6.1 Industrial sodium metasilicate 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. The content shall include the manufacturer's name, address, product name, category, grade, net weight, batch number or production date, proof that the product quality meets this standard and the standard number. 6.2 The user has the right to inspect and accept the industrial sodium metasilicate 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
6.3 Each batch of products shall not exceed 100t.||tt ||6.4 Determine the number of sampling units in accordance with the provisions of Article 6.6 of (B/T6678). When sampling, insert the sampler vertically from the center line of the packaging bag to 3/4 of the depth of the material layer, mix the sample thoroughly, reduce it to about 500g by quartering, and immediately put it into two clean, dry bottles and seal them. Stick labels on the bottles, indicating the manufacturer name, product name, category, grade, batch number, sampling date and name of the sampler. One bottle is used for inspection, and the other bottle is kept for one month for future reference. 6.5 If one of the test results does not meet the requirements of this standard, re-sample from twice the amount of packaging for verification. Even if the verification result is 518
HG/T 2568—94
If only one indicator does not meet the requirements of this standard, the entire batch of products cannot be accepted. 6.6 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". 6.7 The rounded comparison method specified in GB1250 shall be used to determine whether the inspection results meet the standards. 7 Marking, packaging, transportation, storage
7.1 The packaging bag of sodium metasilicate should have firm and clear markings, including the manufacturer's name, address, product name, trademark, category, grade, net weight, batch number or production date, this standard number and the "moisture-afraid" mark specified in GB191. 7.2 Sodium metasilicate is double-layer packaged, the inner packaging is a polyethylene plastic film bag with a thickness of not less than 0.07mm, and the inner bag packaging area should be larger than the outer bag: the outer packaging is a plastic woven bag or a composite plastic woven bag, and its performance and inspection methods shall comply with GB8946 and GB8947. The net weight of each bag is 25, 40, and 50 kg. The inner bag of the package is tied with a vinyl rope or other rope of equivalent quality, and the outer package is sewn with a bag sewing machine. The stitches should be neat, the stitch length is evenly distributed, and there is no leakage or jumper.
7.3 Industrial sodium metasilicate should be protected from rain, moisture and exposure during transportation. 7.4 Industrial sodium metasilicate should be stored in a ventilated and dry warehouse. 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 is drafted by Tianjin Chemical Research Institute of the Ministry of Chemical Industry, Tianjin Alkali Factory, Qingdao Soda Factory, and Tianjin Dongfanghong Chemical Factory. The main drafters of this standard are Jiang Junhua, Wu Hongfa, Wang Benmao, Liu Zongchang, and Su Kaiying. This standard refers to the British standard BS3984-1982 "Sodium Metasilicate Pentahydrate" and the Japanese standard JISK1408--1985 "Solid Sodium Silicate".3 Instruments and equipment
Conform to Article 4 of GB/T3049.
5.3.4 Analysis steps
5.3.4.1 Drawing of working curve
According to Article 5.3 of GB/T3049, use a 3cm absorption cell and the corresponding amount of iron standard solution to draw a working curve. 5.3.4.2 Preparation of test solution
Weigh about 5g of sample (accurate to 0.01g). Place in a 400mL beaker, add 150mL of water to dissolve, add 15ml of 1+1 hydrochloric acid solution, boil for 3~5min, cool, and filter if necessary. Transfer all to a 250mL volumetric flask, dilute to the mark with water, and shake well. 5.3.4.3 Preparation of blank test solution
Add 200mL of water and 15mL of 1+1 hydrochloric acid solution to a 250mL volumetric flask, dilute to the mark with water, and shake well. 5.3.4.4 Determination
Use a pipette to transfer 10mL of the test solution and 10mL of the blank test solution respectively, and place them in 100mL volumetric flasks respectively. Use 1+9 ammonia water to adjust the pH value to close to 2 (check with precision pH test paper). Add 2.5mL of ascorbic acid solution, 10mL of buffer solution, and 5mL of o-phenanthroline solution, dilute to the scale with water, and shake well. Use a 3cm absorption cell to measure the absorbance according to the provisions of Article 5.4.2 of GB/T3049. 5.3.5 Expression of analysis results
Iron (Fe) content X expressed as mass percentage: Calculate according to formula (4): (mlm2)×103
(4)
Where: m is the mass of iron found from the working curve based on the measured absorbance of the test solution, mg; m2 is the mass of iron found from the working curve based on the measured absorbance of the blank test solution, mg; m----the mass of the sample, g.
5.3.6 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 0.005%. 5.4 Determination of water-insoluble matter content
5.4.1 Reagents and materials
5.4.1.1 Hydrochloric acid (GB/T622) solution: 1+3; 5.4.1.2 Sodium hydroxide (GB/T629) solution: 50g/L; 5.4.1.3 Phenolic acid (GB/T10729) ethanol solution: 10g/L; 5.4.1.4 Acid-washed asbestos (HG/T3-1062): Take an appropriate amount of acid-washed right cotton, soak it in 1+3 hydrochloric acid solution, boil it for 20 minutes, filter it with a Buchner funnel and wash it with water until it is neutral, then soak it with 50g/L sodium hydroxide solution and boil it for 20 minutes, filter it with a Buchner funnel and wash it with water until it is neutral (check with phenol indicator solution). Mix it with water 5-17
to make a thin paste and set aside.
5.4.2 Instruments and equipment
German crucible: volume 30mL.
HG/T 2568-94
Place the Gooch crucible on the filtration bottle, evenly spread about 2mm thick acid-washed asbestos on the upper and lower sieve plates, and wash with hot water until the filtrate does not contain cotton wool. Remove the crucible and dry it at 110±5℃, weigh it after cooling; wash it with hot water again, dry it at 110±5℃, weigh it after cooling: repeat this process until the weight is constant. 5.4.3 Analysis steps
Weigh about 5g of sample (accurate to 0.01g), put it in a 500mL beaker, and add 300mL of hot water to dissolve it. Filter it with a Gooch crucible with acid-washed asbestos that has been dried at 110±5℃, and wash it with hot water until it is neutral (check with phenolphthalein indicator solution). Dry it at 110±5℃ to constant weight.
5.4.4 Expression of analysis results
The water-insoluble content X expressed as a percentage of mass is calculated according to formula (5): X,-m2-m
1×100
Where: m--the mass of the Gooch crucible·g;
m.-the mass of the water-insoluble matter and Gooch crucible, g;
m-the mass of the sample, g.
5.4.5 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 0.02%. 5.5 Determination of degree
5.5.1 Instruments and equipment
5.5.1.1 Autometer: Same as the provisions of Article 3 of GB/T5950; 5.5.1.2 Standard white board: Magnesium oxide standard white board specified in Article 4 of GB/T5950; 5.5.1.3 Working white board: Same as the provisions of Article 5 of GB/T5950. 5.5.2 Analysis steps
Perform in accordance with the provisions of Article 6 of GB/T5950.
5.5.3 Expression of analysis results
Perform in accordance with the provisions of Article 7 of GB/T5950.
5.5.4 Allowable difference
Take the arithmetic mean of the results of the row determination as the determination result, and the absolute difference of the parallel determination results shall not exceed 1%. 6 Inspection rules
(5)
6.1 Industrial sodium metasilicate 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. The content shall include the manufacturer's name, address, product name, category, grade, net weight, batch number or production date, proof that the product quality meets this standard and the standard number. 6.2 The user has the right to inspect and accept the industrial sodium metasilicate 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
6.3 Each batch of products shall not exceed 100t.||tt ||6.4 Determine the number of sampling units in accordance with the provisions of Article 6.6 of (B/T6678). When sampling, insert the sampler vertically from the center line of the packaging bag to 3/4 of the depth of the material layer, mix the sample thoroughly, reduce it to about 500g by quartering, and immediately put it into two clean, dry bottles and seal them. Stick labels on the bottles, indicating the manufacturer name, product name, category, grade, batch number, sampling date and name of the sampler. One bottle is used for inspection, and the other bottle is kept for one month for future reference. 6.5 If one of the test results does not meet the requirements of this standard, re-sample from twice the amount of packaging for verification. Even if the verification result is 518
HG/T 2568—94
If only one indicator does not meet the requirements of this standard, the entire batch of products cannot be accepted. 6.6 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". 6.7 The rounded comparison method specified in GB1250 shall be used to determine whether the inspection results meet the standards. 7 Marking, packaging, transportation, storage
7.1 The packaging bag of sodium metasilicate should have firm and clear markings, including the manufacturer's name, address, product name, trademark, category, grade, net weight, batch number or production date, this standard number and the "moisture-afraid" mark specified in GB191. 7.2 Sodium metasilicate is double-layer packaged, the inner packaging is a polyethylene plastic film bag with a thickness of not less than 0.07mm, and the inner bag packaging area should be larger than the outer bag: the outer packaging is a plastic woven bag or a composite plastic woven bag, and its performance and inspection methods shall comply with GB8946 and GB8947. The net weight of each bag is 25, 40, and 50 kg. The inner bag of the package is tied with a vinyl rope or other rope of equivalent quality, and the outer package is sewn with a bag sewing machine. The stitches should be neat, the stitch length is evenly distributed, and there is no leakage or jumper.
7.3 Industrial sodium metasilicate should be protected from rain, moisture and exposure during transportation. 7.4 Industrial sodium metasilicate should be stored in a ventilated and dry warehouse. 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 is drafted by Tianjin Chemical Research Institute of the Ministry of Chemical Industry, Tianjin Alkali Factory, Qingdao Soda Factory, and Tianjin Dongfanghong Chemical Factory. The main drafters of this standard are Jiang Junhua, Wu Hongfa, Wang Benmao, Liu Zongchang, and Su Kaiying. This standard refers to the British standard BS3984-1982 "Sodium Metasilicate Pentahydrate" and the Japanese standard JISK1408--1985 "Solid Sodium Silicate".3 Instruments and equipment
Conform to Article 4 of GB/T3049.
5.3.4 Analysis steps
5.3.4.1 Drawing of working curve
According to Article 5.3 of GB/T3049, use a 3cm absorption cell and the corresponding amount of iron standard solution to draw a working curve. 5.3.4.2 Preparation of test solution
Weigh about 5g of sample
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