Some standard content:
HG/T2775--1996
In this standard, the superior products are equivalent to the Russian standard TOCT2912:1979 (1995) Technical Conditions for Industrial Chromium Oxide. The main differences between this standard and TOCT2912:1979 (1995) are as follows: 1. TOCT2912:1979 (1995) is divided into three categories: pigment, abrasive, and metallurgical. Pigment and abrasive are divided into two levels, and metallurgical is divided into three levels. This standard is divided into two categories according to use: pigment and abrasive. Since there is no production and use in China at present, metallurgical use is not set. Each category is divided into three levels: superior products, medium products, and qualified products. 2. TOCT2912:1979 (1995) has 8 indicators for pigments and 5 indicators for abrasives. According to user requirements, this standard also has 8 indicators for pigments, among which hiding power is not set but oil absorption is added. There are 5 indicators for abrasives, among which polishing ability and surface roughness after polishing are not set, but oil absorption and sieve residue indicators required by users are added. 3 The determination of chromium trioxide content in the test method refers to IOCT2912:1979 (1995) using the ammonium ferrous sulfate method. The oxidation of trivalent chromium is based on the Russian standard using hydrogen peroxide oxidation, and this standard uses enhanced oxidant oxidation. The determination methods of other items are based on relevant Chinese standards.
This standard is proposed by the Technical Supervision Department of the Ministry of Chemical Industry of the People's Republic of my country. This standard is under the jurisdiction of the Tianjin Chemical Research Institute of the Ministry of Chemical Industry. The drafting units of this standard are: Tianjin Chemical Research Institute of the Ministry of Chemical Industry, Hunan Changsha Chromium Salt Factory, Hebei Chromium Salt Factory, Tianjin Tongsheng Chemical Factory, Chongqing Dongfeng Chemical Factory, Inner Mongolia Yellow River Leather Chemical General Factory, Shanghai Chemical Application Research Institute. The main drafters of this standard are: Liu Shuying, Shao Zhenqiu, Ni Benyun, Han Guizhen, Xiao Naiping, Du Jian, Liang Qunhuan. 264
1 Scope
Chemical Industry Standard of the People's Republic of China
Industrial Chromium Trioxide
HG/T 2775--1996
This standard specifies the requirements, sampling, test methods, marking, packaging, transportation and storage of industrial chromium trioxide. This standard applies to industrial chromium trioxide (also known as chromium oxide green) produced by thermal decomposition and reduction methods. This product is mainly used as a colorant for ceramics, pond porcelain and glass, and is also used to make polishing pastes, paints, pigments and chromium catalysts for organic synthesis. Molecular formula: Cr20
Relative molecular mass: 151.99 (according to the 1991 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 is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB191—1990 Pictorial markings for packaging, storage and transportation
GB/T 601--1988
Preparation of standard solutions for titration analysis (volume analysis) of chemical reagentsGB/T 602--1988
GB/T 603-1988
GB/T 1250—1989
GB/T 1717--1986
GB/T 1864 ---1980
Preparation of standard solutions for determination of impurities in chemical reagents (neqISO6353-1:1982) Preparation of preparations and products used in test methods for chemical reagents (neqISO6353-1:1982) Methods for expressing and determining limit values Determination of pH of aqueous pigment suspensions (eqvISO787-9:1981) Determination of pigment color (eqvISO787-1:1982) Determination of water-soluble matter in pigments by hot extraction method (neqISO787-3:1979) GB/T 5211.2-
GB/T 5211.3—85
Determination of volatile matter of pigments at 105°C (eqvISO787-2:1981) GB/T 5211.15—1988
GB/T 5211.18-
GB/T 5211. 19-
GB/T 6003---1985
GB/T 6678 --1986
GB/T 6682—1992
GB/T 8946—1988
GB/T 8947—1988
3 Product classification
Determination of oil absorption of pigments (eqvISO787-5:1980) Determination of pigment sieve residue Water method manual operation (neqISO787-7:1981) Determination of relative tinting strength and dilution color of coloring pigments Visual comparison method (eqvISO787-16:1986)
Test sieve
General rules for sampling of chemical products
Specifications and test methods for water in analytical laboratories (eqvISO3696:1987) Plastic woven bags
Composite plastic woven bags
Industrial chromium trioxide is divided into two categories according to its use: Class I products are used for pigments, and Class II products are used for abrasives. 4 Requirements
4.1 Appearance: Emerald green or dark green powder. Approved by the Ministry of Chemical Industry of the People's Republic of China on January 24, 1996 and implemented on January 1, 1997
4.2 Industrial chromium trioxide shall meet the requirements of Table 1: Item
Chromium trioxide (Cr2O3) content, %
Water, %
Water-soluble matter content, %
pH of aqueous solution
Oil absorption, g/100g
Relative tinting strength, %
Sieve residue 45μm, %
HG/T 2775--1996
Table 1 Requirements
Pigment
Superior quality
Note: The color light standard and relative tinting strength standard shall be negotiated between the manufacturer and the user. 5 Sampling
Each batch of products shall not exceed 10 t.
Qualified products" Superior products
Meet the requirements
Meet the requirements
For abrasives
Qualified products
Not specified
Not specified
Not specified
5.2 Determine the number of sampling units in accordance with the provisions of 6.6 of GB/T6678. Each plastic woven bag or iron drum is a packaging unit. When sampling, insert the sampler obliquely to 3/4 of the depth of the material layer to take samples. From each selected packaging unit, take out no less than 50g of sample, mix the sampled samples and reduce them to about 500g by quartering method, and immediately put them into two clean and dry wide-mouth bottles with ground stoppers and seal them. Paste labels on the bottles, indicating: manufacturer name, product name, category, 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.
5.3 If one of the test results does not meet the requirements of this standard, re-sampling should be carried out from twice the number of sampling units. If only one of the test results does not meet the requirements of this standard, the entire batch of products will be unqualified. 6 Test method
6.1 The rounded value comparison method specified in 5.2 of GB/T1250 is used to determine whether the test results meet the standards. 6.2 The reagents and water used in this standard refer to analytical pure reagents and grade 3 water specified in GB/T6682 unless otherwise specified. The standard titration solutions, impurity standard solutions, preparations and products used in the test are prepared in accordance with the provisions of GB/T601, GB/T602 and GB/T603 unless otherwise specified. 6.3 Determination of chromium trioxide content
6.3.1 Summary of method
The trivalent chromium in the sample is oxidized to hexavalent chromium. The divalent iron ions and hexavalent chromium ions undergo redox reaction in an acidic medium. The chromium trioxide content is determined based on the consumption of the standard titration solution of ammonium ferrous sulfate. 6.3.2 Reagents and materials
Mixed sulfuric acid solution: phosphoric acid + sulfuric acid: 6+4; 6.3.2.1
Mixed sulfuric acid aqueous solution: phosphoric acid + sulfuric acid + water: 1+1+4; 6.3.2.2
Perchloric acid;
Silver nitrate solution: 25g/L;
Ammonium persulfate;
6.3.2.6 o-phenylaminobenzoic acid solution: 1g/L; HG/T 2775—1996
Preparation: Weigh 0.1g of o-phenylaminobenzoic acid and dissolve it in 100mL (2g/L) sodium carbonate solution. 6.3.2.7 Potassium dichromate standard solution: c(1/6K,Cr2O,) is about 0.15mol/L; Preparation: Weigh about 7.5g of standard potassium dichromate (accurate to 0.0002g) dried at 105℃~110℃ to constant weight, dissolve it in a 1000mL volumetric flask with water, dilute to scale, and shake well. The concentration ci of potassium dichromate standard solution is calculated according to formula (1): K,Cr2O,=
Where: m-
Weigh the mass of the standard potassium dichromate, g;
(一K,Cr2O,) molar mass, g/mol. Potassium dichromate
6.3.2.8 Standard titration solution of ammonium ferrous sulfate: cCFe(NH)2(SO,)2) is about 0.2mol/L. (1)
Preparation: Weigh about 80g of ammonium ferrous sulfate [Fe(NH)2(SO.)2·6H,O), dissolve it in 300mL (1+8) sulfuric acid solution, add 700ml water, and shake well. The solution is calibrated before use. Calibration: Use a pipette to transfer 25mL of potassium dichromate standard solution into a 500mL conical flask, add 150mL of water and 20mL of sulfuric acid and phosphoric acid mixed aqueous solution (6.3.2.2), and titrate with ammonium ferrous sulfate standard titration solution until it turns yellow-green, then add 1ml of o-phenylaminobenzoic acid indicator solution, and continue titrating until the purple-red color changes to bright green as the end point. The concentration c of ammonium ferrous sulfate standard titration solution is calculated according to formula (2): Vici
volume of potassium dichromate standard solution, mL; where: Vi—
actual concentration of potassium dichromate standard solution, mol/L; -volume of ammonium ferrous sulfate standard titration solution consumed in titration, mL. 6.3.3 Analysis steps
·(2)
Weigh about 0.2g of sample (accurate to 0.0002g), place in a 500mL conical flask, add 20mL sulfuric acid and phosphoric acid mixed solution (6.3.2.1), 2mL perchloric acid and heat on an electric stove until the solution is transparent and there are no green particles at the bottom. Remove and cool to room temperature, add 150mL water, 5mL silver nitrate solution, 4g~5g ammonium persulfate, shake to dissolve, let stand for 5min, continue heating until small bubbles turn into large bubbles (destroy excess oxidant), keep for 10min. Remove and cool to room temperature, add water to dilute to 200mL, titrate with ammonium ferrous sulfate standard titration solution until the solution turns yellow-green, add 1mL o-phenylaminobenzoic acid indicator solution, continue titrating until the solution turns bright green as the end point, and perform a blank test at the same time. 6.3.4 Expression of analysis results
The content of chromium trioxide (Cr2O3) expressed as mass percentage X is calculated according to formula (3): Xi = (V-Vo)c× 0.025 33 ×
Wherein: V-
The volume of ammonium ferrous sulfate standard titration solution consumed by titrating the test solution, mL; The volume of ammonium ferrous sulfate standard titration solution consumed by titrating the blank, mL; ---The actual concentration of ammonium ferrous sulfate standard titration solution, mol/L; (3)
The mass of sample, g;
The mass of chromium trioxide equivalent to 1.00mL of ammonium ferrous sulfate standard titration solution (cCFe(NH4), (SO4)2] = 1.000mol/L) expressed in grams.
6.3.5 Allowable difference
The arithmetic mean of the parallel determination results is taken as the determination result. The absolute difference of parallel determination results shall not exceed 0.3%. 6.4 Determination of moisture
Perform according to the provisions of GB/T5211.3.
6.5 Determination of water-soluble content
Perform according to the provisions of GB/T5211.2.
6.6 Determination of pH of aqueous solution
Perform according to the provisions of GB/T1717.
6.7 Determination of oil absorption
Perform according to the provisions of GB/T5211.15.
6.8 Determination of color light
Perform according to the provisions of GB/T1864.
6.9 Determination of relative tinting strength
Perform according to the provisions of GB/T5211.19.
6.10 Determination of sieve residue
6.10.1 Summary of the method
HG/T 2775—1996
The percentage of the mass of the residue to the mass of the sample after the sample passes through a sieve with a certain aperture. 6.10.2 Instruments and equipment
Test sieve (GB/T6003): R40/3 series, $70mmX40mm/45μm. $70mm×40mm/75μm. Others shall be in accordance with Chapter 3 of GB/T5211.18.
6.10.3 Analysis steps
Weigh about 10g of sample (accurate to 0.01g), place it in a constant weight sieve moistened with 95% (V/V) ethanol, then moisten the sample with ethanol, hold the upper end of the sieve, immerse the sieve in water, and gently scrub it with a wool brush on the middle finger until there are no pigment particles in the water. Rinse it twice with water and once with ethanol, and dry it in an oven at 105℃～110℃ for 2h. After cooling, weigh it until constant weight. 6.10.4 Expression of analysis results
The sieve residue content X expressed as mass percentage is calculated according to formula (4): m - m2 × 100
Mass of the sample, g;
Where: m----
-Mass of the test sieve and residue, g;
Mass of the test sieve, g.
6.10.5 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 0.05%. 7 Marking, packaging, transportation and storage
·(4)
7.1 The packaging bags or iron drums of industrial chromium trioxide shall be firmly and clearly marked, including: the manufacturer's name, address, product name, trademark, category, grade, net weight, batch number or production date and the number of this standard, as well as the "upward" mark (iron drum packaging) and "wet-afraid" mark specified in GB191.
7.2 Each batch of industrial chromium trioxide shipped from the factory shall be accompanied by a quality certificate. The contents include: the manufacturer's name, address, product name, trademark, category, grade, net weight, batch number or production date, proof that the product quality complies with this standard and the number of this standard. 7.3 Industrial chromium trioxide can be packaged in polypropylene woven bags lined with plastic bags, or in iron drums lined with plastic bags. When using woven bags for packaging: the inner packaging is a polyethylene plastic film bag with a thickness of not less than 0.08mm, and the outer packaging is a polypropylene woven bag. Its performance and inspection methods should comply with the relevant provisions of GB/T8946B. The net weight of each bag of this product is 25kg or 50kg. When using iron drums for packaging: the inner packaging is a polyethylene plastic film bag with a thickness of 0.05mm, and the outer packaging is a special sealed, fully open iron drum with a wall thickness of not less than 0.5mm. The net weight of each drum is 50kg.
When using woven bags for packaging, put the industrial chromium trioxide into a polypropylene woven bag lined with a polyethylene plastic film bag, and discharge the remaining gas in the bag. The inner bag is tied twice with a string and tied tightly. The outer bag is sewn with a bag sewing machine at a distance of not less than 17mm from the upper end of the bag, with a stitch length of 6mm to 7mm. The stitches are neat and evenly hooked, without leaking seams or skipped stitches. 268
HG/T 2775—1996
When using iron barrels for packaging, industrial chromium trioxide is placed in an iron barrel lined with a polyethylene plastic film bag, and the remaining air in the bag is discharged. The inner bag is tied twice with a string and tied tightly, and the barrel lid is covered and sealed. 7.4 Industrial chromium trioxide should be covered during transportation to prevent sun exposure, rain, and packaging damage, and should not be inverted. 7.5 Industrial chromium trioxide should be stored in a ventilated and dry warehouse to prevent sun exposure and moisture. 2691) Heat 2mL perchloric acid on an electric stove until the solution is transparent and there are no green particles at the bottom. Remove and cool to room temperature, add 150mL water, 5mL silver nitrate solution, 4g-5g ammonium persulfate, shake to dissolve, let stand for 5 minutes, continue to heat until small bubbles turn into large bubbles (destroy excess oxidant), keep for 10 minutes. Remove and cool to room temperature, dilute to 200mL with water, titrate with ammonium ferrous sulfate standard titration solution until the solution turns yellow-green, add 1mL o-phenylaminobenzoic acid indicator solution, continue to titrate until the solution turns bright green as the end point, and perform a blank test at the same time. 6.3.4 Expression of analysis results
The content of chromium trioxide (Cr2O3) expressed as mass percentage X is calculated according to formula (3): Xi = (V-Vo)c× 0.025 33 ×
Wherein: V-
The volume of ammonium ferrous sulfate standard titration solution consumed by titrating the test solution, mL; The volume of ammonium ferrous sulfate standard titration solution consumed by titrating the blank, mL; ---The actual concentration of ammonium ferrous sulfate standard titration solution, mol/L; (3) bZxz.net
The mass of sample, g;
The mass of chromium trioxide equivalent to 1.00mL of ammonium ferrous sulfate standard titration solution (cCFe(NH4), (SO4)2] = 1.000mol/L) expressed in grams.
6.3.5 Allowable difference
The arithmetic mean of the parallel determination results is taken as the determination result. The absolute difference of parallel determination results shall not exceed 0.3%. 6.4 Determination of moisture
Perform according to the provisions of GB/T5211.3.
6.5 Determination of water-soluble content
Perform according to the provisions of GB/T5211.2.
6.6 Determination of pH of aqueous solution
Perform according to the provisions of GB/T1717.
6.7 Determination of oil absorption
Perform according to the provisions of GB/T5211.15.
6.8 Determination of color light
Perform according to the provisions of GB/T1864.
6.9 Determination of relative tinting strength
Perform according to the provisions of GB/T5211.19.
6.10 Determination of sieve residue
6.10.1 Summary of the method
HG/T 2775—1996
The percentage of the mass of the residue to the mass of the sample after the sample passes through a sieve with a certain aperture. 6.10.2 Instruments and equipment
Test sieve (GB/T6003): R40/3 series, $70mmX40mm/45μm. $70mm×40mm/75μm. Others shall be in accordance with Chapter 3 of GB/T5211.18.
6.10.3 Analysis steps
Weigh about 10g of sample (accurate to 0.01g), place it in a constant weight sieve moistened with 95% (V/V) ethanol, then moisten the sample with ethanol, hold the upper end of the sieve, immerse the sieve in water, and gently scrub it with a wool brush on the middle finger until there are no pigment particles in the water. Rinse it twice with water and once with ethanol, and dry it in an oven at 105℃～110℃ for 2h. After cooling, weigh it until constant weight. 6.10.4 Expression of analysis results
The sieve residue content X expressed as mass percentage is calculated according to formula (4): m - m2 × 100
Mass of the sample, g;
Where: m----
-Mass of the test sieve and residue, g;
Mass of the test sieve, g.
6.10.5 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 0.05%. 7 Marking, packaging, transportation and storage
·(4)
7.1 The packaging bags or iron drums of industrial chromium trioxide shall be firmly and clearly marked, including: the manufacturer's name, address, product name, trademark, category, grade, net weight, batch number or production date and the number of this standard, as well as the "upward" mark (iron drum packaging) and "wet-afraid" mark specified in GB191.
7.2 Each batch of industrial chromium trioxide shipped from the factory shall be accompanied by a quality certificate. The contents include: the manufacturer's name, address, product name, trademark, category, grade, net weight, batch number or production date, proof that the product quality complies with this standard and the number of this standard. 7.3 Industrial chromium trioxide can be packaged in polypropylene woven bags lined with plastic bags, or in iron drums lined with plastic bags. When using woven bags for packaging: the inner packaging is a polyethylene plastic film bag with a thickness of not less than 0.08mm, and the outer packaging is a polypropylene woven bag. Its performance and inspection methods should comply with the relevant provisions of GB/T8946B. The net weight of each bag of this product is 25kg or 50kg. When using iron drums for packaging: the inner packaging is a polyethylene plastic film bag with a thickness of 0.05mm, and the outer packaging is a special sealed, fully open iron drum with a wall thickness of not less than 0.5mm. The net weight of each drum is 50kg.
When using woven bags for packaging, put the industrial chromium trioxide into a polypropylene woven bag lined with a polyethylene plastic film bag, and discharge the remaining gas in the bag. The inner bag is tied twice with a string and tied tightly. The outer bag is sewn with a bag sewing machine at a distance of not less than 17mm from the upper end of the bag, with a stitch length of 6mm to 7mm. The stitches are neat and evenly hooked, without leaking seams or skipped stitches. 268
HG/T 2775—1996
When using iron barrels for packaging, industrial chromium trioxide is placed in an iron barrel lined with a polyethylene plastic film bag, and the remaining air in the bag is discharged. The inner bag is tied twice with a string and tied tightly, and the barrel lid is covered and sealed. 7.4 Industrial chromium trioxide should be covered during transportation to prevent sun exposure, rain, and packaging damage, and should not be inverted. 7.5 Industrial chromium trioxide should be stored in a ventilated and dry warehouse to prevent sun exposure and moisture. 2691) Heat 2mL perchloric acid on an electric stove until the solution is transparent and there are no green particles at the bottom. Remove and cool to room temperature, add 150mL water, 5mL silver nitrate solution, 4g-5g ammonium persulfate, shake to dissolve, let stand for 5 minutes, continue to heat until small bubbles turn into large bubbles (destroy excess oxidant), keep for 10 minutes. Remove and cool to room temperature, dilute to 200mL with water, titrate with ammonium ferrous sulfate standard titration solution until the solution turns yellow-green, add 1mL o-phenylaminobenzoic acid indicator solution, continue to titrate until the solution turns bright green as the end point, and perform a blank test at the same time. 6.3.4 Expression of analysis results
The content of chromium trioxide (Cr2O3) expressed as mass percentage X is calculated according to formula (3): Xi = (V-Vo)c× 0.025 33 ×
Wherein: V-
The volume of ammonium ferrous sulfate standard titration solution consumed by titrating the test solution, mL; The volume of ammonium ferrous sulfate standard titration solution consumed by titrating the blank, mL; ---The actual concentration of ammonium ferrous sulfate standard titration solution, mol/L; (3)
The mass of sample, g;
The mass of chromium trioxide equivalent to 1.00mL of ammonium ferrous sulfate standard titration solution (cCFe(NH4), (SO4)2] = 1.000mol/L) expressed in grams.
6.3.5 Allowable difference
The arithmetic mean of the parallel determination results is taken as the determination result. The absolute difference of parallel determination results shall not exceed 0.3%. 6.4 Determination of moisture
Perform according to the provisions of GB/T5211.3.
6.5 Determination of water-soluble content
Perform according to the provisions of GB/T5211.2.
6.6 Determination of pH of aqueous solution
Perform according to the provisions of GB/T1717.
6.7 Determination of oil absorption
Perform according to the provisions of GB/T5211.15.
6.8 Determination of color light
Perform according to the provisions of GB/T1864.
6.9 Determination of relative tinting strength
Perform according to the provisions of GB/T5211.19.
6.10 Determination of sieve residue
6.10.1 Summary of the method
HG/T 2775—1996
The percentage of the mass of the residue to the mass of the sample after the sample passes through a sieve with a certain aperture. 6.10.2 Instruments and equipment
Test sieve (GB/T6003): R40/3 series, $70mmX40mm/45μm. $70mm×40mm/75μm. Others shall be in accordance with Chapter 3 of GB/T5211.18.
6.10.3 Analysis steps
Weigh about 10g of sample (accurate to 0.01g), place it in a constant weight sieve moistened with 95% (V/V) ethanol, then moisten the sample with ethanol, hold the upper end of the sieve, immerse the sieve in water, and gently scrub it with a wool brush on the middle finger until there are no pigment particles in the water. Rinse it twice with water and once with ethanol, and dry it in an oven at 105℃～110℃ for 2h. After cooling, weigh it until constant weight. 6.10.4 Expression of analysis results
The sieve residue content X expressed as mass percentage is calculated according to formula (4): m - m2 × 100
Mass of the sample, g;
Where: m----
-Mass of the test sieve and residue, g;
Mass of the test sieve, g.
6.10.5 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 0.05%. 7 Marking, packaging, transportation and storage
·(4)
7.1 The packaging bags or iron drums of industrial chromium trioxide shall be firmly and clearly marked, including: the manufacturer's name, address, product name, trademark, category, grade, net weight, batch number or production date and the number of this standard, as well as the "upward" mark (iron drum packaging) and "wet-afraid" mark specified in GB191.
7.2 Each batch of industrial chromium trioxide shipped from the factory shall be accompanied by a quality certificate. The contents include: the manufacturer's name, address, product name, trademark, category, grade, net weight, batch number or production date, proof that the product quality complies with this standard and the number of this standard. 7.3 Industrial chromium trioxide can be packaged in polypropylene woven bags lined with plastic bags, or in iron drums lined with plastic bags. When using woven bags for packaging: the inner packaging is a polyethylene plastic film bag with a thickness of not less than 0.08mm, and the outer packaging is a polypropylene woven bag. Its performance and inspection methods should comply with the relevant provisions of GB/T8946B. The net weight of each bag of this product is 25kg or 50kg. When using iron drums for packaging: the inner packaging is a polyethylene plastic film bag with a thickness of 0.05mm, and the outer packaging is a special sealed, fully open iron drum with a wall thickness of not less than 0.5mm. The net weight of each drum is 50kg.
When using woven bags for packaging, put the industrial chromium trioxide into a polypropylene woven bag lined with a polyethylene plastic film bag, and discharge the remaining gas in the bag. The inner bag is tied twice with a string and tied tightly. The outer bag is sewn with a bag sewing machine at a distance of not less than 17mm from the upper end of the bag, with a stitch length of 6mm to 7mm. The stitches are neat and evenly hooked, without leaking seams or skipped stitches. 268
HG/T 2775—1996
When using iron barrels for packaging, industrial chromium trioxide is placed in an iron barrel lined with a polyethylene plastic film bag, and the remaining air in the bag is discharged. The inner bag is tied twice with a string and tied tightly, and the barrel lid is covered and sealed. 7.4 Industrial chromium trioxide should be covered during transportation to prevent sun exposure, rain, and packaging damage, and should not be inverted. 7.5 Industrial chromium trioxide should be stored in a ventilated and dry warehouse to prevent sun exposure and moisture. 2694 Expression of analysis results
The content of sieve residue X expressed as a mass percentage shall be calculated according to formula (4): m - m2 × 100
Mass of the test material, g;
Wherein: m----
-Mass of the test sieve and residue, g;
Mass of the test sieve, g.
6.10.5 Permissible 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 0.05%. 7 Marking, packaging, transportation and storage
·(4)
7.1 The packaging bags or iron drums of industrial chromium trioxide shall be firmly and clearly marked, including: manufacturer name, address, product name, trademark, category, grade, net weight, batch number or production date and the number of this standard, as well as the "upward" mark (iron drum packaging) and "wet-afraid" mark specified in GB191.
7.2 Each batch of industrial chromium trioxide shipped out of the factory should be accompanied by a quality certificate. The content includes: manufacturer name, factory address, product name, trademark, category, grade, net weight, batch number or production date, proof that the product quality complies with this standard and the number of this standard. 7.3 Industrial chromium trioxide can be packaged in polypropylene woven bags lined with plastic bags, or in iron drums lined with plastic bags. Woven bag packaging: the inner packaging uses polyethylene plastic film bags with a thickness of not less than 0.08mm, and the outer packaging uses polypropylene woven bags. Its performance and inspection methods should comply with the relevant provisions of GB/T8946B. The net weight of each bag of this product is 25kg or 50kg. Iron drum packaging: the inner packaging uses polyethylene plastic film bags with a thickness of 0.05mm, and the outer packaging uses special sealed, fully open iron drums with a wall thickness of not less than 0.5mm. The net weight of each drum is 50kg.
When using woven bags for packaging, industrial chromium trioxide shall be placed in a polypropylene woven bag lined with a polyethylene plastic film bag, and the remaining air in the bag shall be discharged. The bag mouth of the inner bag shall be tied twice with a string and tied tightly. The outer bag shall be sewn with a bag sewing machine at a distance of not less than 17mm from the upper end of the bag, with a stitch length of 6mm to 7mm, neat stitches, even stitch lengths, and no leaking or skipping stitches. 268
HG/T 2775—1996
When using iron barrels for packaging, industrial chromium trioxide shall be placed in an iron barrel lined with a polyethylene plastic film bag, and the remaining air in the bag shall be discharged. The bag mouth of the inner bag shall be tied twice with a string and tied tightly, and the barrel cover shall be covered and sealed. 7.4 Industrial chromium trioxide shall be covered during transportation to prevent sun exposure, rain, and packaging damage, and shall not be inverted. 7.5 Industrial chromium trioxide shall be stored in a ventilated and dry warehouse to prevent sun exposure and moisture. 2694 Expression of analysis results
The content of sieve residue X expressed as a mass percentage shall be calculated according to formula (4): m - m2 × 100
Mass of the test material, g;
Wherein: m----
-Mass of the test sieve and residue, g;
Mass of the test sieve, g.
6.10.5 Permissible 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 0.05%. 7 Marking, packaging, transportation and storage
·(4)
7.1 The packaging bags or iron drums of industrial chromium trioxide shall be firmly and clearly marked, including: manufacturer name, address, product name, trademark, category, grade, net weight, batch number or production date and the number of this standard, as well as the "upward" mark (iron drum packaging) and "wet-afraid" mark specified in GB191.
7.2 Each batch of industrial chromium trioxide shipped out of the factory should be accompanied by a quality certificate. The content includes: manufacturer name, factory address, product name, trademark, category, grade, net weight, batch number or production date, proof that the product quality complies with this standard and the number of this standard. 7.3 Industrial chromium trioxide can be packaged in polypropylene woven bags lined with plastic bags, or in iron drums lined with plastic bags. Woven bag packaging: the inner packaging uses polyethylene plastic film bags with a thickness of not less than 0.08mm, and the outer packaging uses polypropylene woven bags. Its performance and inspection methods should comply with the relevant provisions of GB/T8946B. The net weight of each bag of this product is 25kg or 50kg. Iron drum packaging: the inner packaging uses polyethylene plastic film bags with a thickness of 0.05mm, and the outer packaging uses special sealed, fully open iron drums with a wall thickness of not less than 0.5mm. The net weight of each drum is 50kg.
When using woven bags for packaging, industrial chromium trioxide shall be placed in a polypropylene woven bag lined with a polyethylene plastic film bag, and the remaining air in the bag shall be discharged. The bag mouth of the inner bag shall be tied twice with a string and tied tightly. The outer bag shall be sewn with a bag sewing machine at a distance of not less than 17mm from the upper end of the bag, with a stitch length of 6mm to 7mm, neat stitches, even stitch lengths, and no leaking or skipping stitches. 268
HG/T 2775—1996
When using iron barrels for packaging, industrial chromium trioxide shall be placed in an iron barrel lined with a polyethylene plastic film bag, and the remaining air in the bag shall be discharged. The bag mouth of the inner bag shall be tied twice with a string and tied tightly, and the barrel cover shall be covered and sealed. 7.4 Industrial chromium trioxide shall be covered during transportation to prevent sun exposure, rain, and packaging damage, and shall not be inverted. 7.5 Industrial chromium trioxide shall be stored in a ventilated and dry warehouse to prevent sun exposure and moisture. 269
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