Some standard content:
Chemical Industry Standard of the People's Republic of China
Industrial Heavy Magnesium Oxide
Topic Content and Scope of Application
HG/T 2679-95
This standard specifies the technical requirements, test methods, inspection rules, and marking, packaging, transportation, and storage of industrial heavy magnesium oxide. This standard applies to heavy magnesium oxide produced by calcining magnesia. This product is mainly used in the chemical, rubber and plastic, grain processing, and building materials industries.
Fractional formula: MgO
Relative molecular mass: 40.03 (according to the international relative atomic mass in 1991) 2 Reference standards
Packaging, storage and transportation pictorial symbols
Preparation of standard solutions for titration analysis (volume analysis) of chemical reagents GB/T 601
GB/T 602
Preparation of standard solutions for determination of impurities in chemical reagents Preparation of preparations and products used in test methods for chemical reagents GB/T 603
Methods for expressing and determining limit values GB 1250
GB/T 3049
General method for determination of iron content in chemical products General rules for determination of density and relative density of chemical products GB/T 4472
GB/T 6678
GB/T 6682
General rules for sampling of chemical products
Specifications and test methods for water used in analytical laboratories GB 8946
Plastic woven bag
HG/T2573Industrial magnesium oxide
3Product classification
Industrial heavy magnesium oxide is divided into two categories:
O-phenanthroline spectrophotometry
Class I is mainly used in chemical, rubber, plastic, building materials industry and steel ball polishing industry: Class II is mainly used in grain processing industry, machinery industry and building materials industry 4Technical requirements
4.1Appearance: beige, gray or earthy red powder. 4.2T.Industrial heavy magnesium oxide should meet the requirements of the following table: Ministry of Chemical Industry of the People's Republic of China 1995-0 4-05 Approved for implementation on January 1, 1996
Magnesium oxide (Mg(0)), %
Calcium oxide (Ca0) %
Hydrochloric acid insoluble matter, %
Iron oxide (Fe20,), %bzxZ.net
Ignition loss, %
Sieve residue (125um sieve), %
Density·g/cm
Initial setting time, min
Setting time
Final setting time.h
Flexural strength, MPa
Test method
HG/T 2679—95
First-class product
Qualified product
First-class product
3.30~3.43
Qualified product
The reagents and water used in this standard, unless otherwise specified, refer to analytical pure reagents and grade 3 water specified in GB/T6682. The standard titration solutions, impurity standard solutions, preparations and products used in the test, unless otherwise specified, When required, they are prepared according to the provisions of GB/T601, GB/T602 and GB/T603. 5.1 Determination of magnesium oxide content
HG/T2573 Article 4.1.
5.2 Determination of calcium oxide content
Same as HG/T2573 Article 4.2.
5.3 Determination of hydrochloric acid insoluble matter content
Same as HGT2573 Article 4.3.
5.4. Determination of ferric oxide content
5.4.1 Summary of method
Same as GB/T3049 Article 2.
5.4.2 Reagents and materials
Same as GB/T3049 Article 3.
5.4.3 Instruments and equipment
Spectrophotometer: with an absorption cell with a thickness of 0.5 cm 5.4.4 Analysis steps
5.4.4.1T. Plotting of the curve
According to Article 5.3 of GB/T3049, select an absorption cell with a thickness of 0.5 cm and the corresponding amount of iron standard solution, and plot the working foot line.
5.4.4.2 Determination
Use a pipette to transfer 2 mL of the test solution prepared in Article 5.1 into a 100 mL volumetric flask, and transfer 1 mL of 1+1 hydrochloric acid solution (reagent blank solution) into another 100 mL volumetric flask, and add water to each until about 40 mL. The following operations are in accordance with Article 5.4 of GB/T3049, starting from "adjust the pH to about 2 with ammonia or hydrochloric acid solution." 5.4.5 Expression of analysis results
The content of ferric oxide (Fe2Os) X expressed as mass percentage is calculated according to formula (1): 226
HG/T 2679-95
Xx=(mlmo)×1. 430×100=
35.75(ml-mo)
m×1 000X
Wherein: m—the amount of iron found from the working curve based on the measured absorbance of the test solution, mg; m—the amount of iron found from the working curve based on the measured absorbance of the blank test solution, mg; - mass of the sample, g;
1.430-the coefficient for converting ferric oxide to ferric oxide. 5.4.6 Allowable difference
The arithmetic mean of the parallel determination results is taken as the determination result. The absolute difference of the parallel determination results shall not exceed 0.1%. 5.5 Determination of loss on ignition
Same as Article 4.9 of HG/T2573.
5.6 Determination of sieve residue
Use R40/3 series, Φ200mm×50mm/125μm test sieve, according to Article 4.5 of HG/T2573. (1)
5.7 Determination of density
Use a 25ml. pycnometer to weigh about 25g of sample (accurate to 0.01g), use kerosene as the measuring medium, and measure according to Article 2.2.2 of GB/T4472.
5.8 Determination of setting time
5.8.1 Reagents and materials
Magnesium chloride (GB/T672) solution: relative density is 1.24. 5.8.2 Instruments and equipment
Cement setting tester.
5.8.3 Analysis steps
Place the sample mold on the glass plate and adjust the instrument so that when the test needle touches the glass, the pointer is aligned with the zero point of the scale. Weigh about 15g of the sample and place it in a porcelain stirrer. Use a mixing shovel to make a small pit on the sample, gently pour in 4.5mL of magnesium chloride solution, cover the pit with the sample, gently stir first, then turn and squeeze in different directions to mix evenly. From the time the magnesium chloride solution is poured in, stir for 5 minutes, immediately load the sample mold once, vibrate several times and then scrape it flat, and store it at 28±3℃. When measuring, place the sample mold under the test needle so that the test needle contacts the clean slurry surface, tighten the screw, and then suddenly release it, the test needle sinks freely into the clean slurry, and observe the pointer reading.
Measure once every 5 minutes when it is close to initial setting, and once every 15 minutes when it is close to final setting. The time required from pouring the magnesium chloride solution to the time when the test needle sinks into the clean slurry to a distance of 0.5~~1.0mm from the bottom plate is the initial setting time; the time required until the test needle sinks into the clean slurry no more than 1.0mm is the final setting time.
The test needle must be wiped clean after each measurement. The test needle must not fall into the previous pinhole in each measurement, and the sample mold should not be vibrated during the measurement.
During the initial measurement, in order to prevent the test needle from hitting the bottom plate and being bent, the metal rod can be gently supported to make it fall slowly. 5.8.4 Allowable difference
The arithmetic mean of the parallel measurement results is taken as the measurement result, and the absolute difference of the parallel measurement results shall not exceed 5min. 5.9 Determination of flexural strength.
5.9.1 Instruments and equipment
5.9.1.1 Sample mold bar: 1cm×1cm×6cm; 5.9.1.2 Ceramic flexural strength tester.
5.9.2 Analysis steps
Weigh about 15g of the sample and place it in a porcelain stirrer. Use a mixing shovel to make a small pit on the sample, gently pour in 4.5ml of magnesium chloride solution, cover the pit with the sample, gently stir first, then turn and squeeze in different directions to mix evenly. Then put it into the sample mold, vibrate it several times and then scrape it flat. 227
HG/T 2679—95
Make a sample mold bar and place it at 28±3℃ for 24h. Place the test bar between the fixed support and the movable pull frame of the testing machine, adjust the pull frame nut so that the pull frame contacts the working surface of the mobile frame. At this time, the end of the lever can be slightly lifted up, turn on the button switch, and the red light is on. The motor has started to rotate. Pull out the pull handle, and the motor drives the floating code through the gear box to start loading until the test bar breaks and stops. Read the breaking force reading on the ruler. 5.9.3 Expression of analysis results
The flexural strength X2 expressed in MPa is calculated according to formula (2): 3XN×5
X2=2XIX1X100=
Where: N——the reading of the breaking force on the ruler, N. 5.9.4 Allowable difference
The arithmetic mean of the parallel determination results shall be taken as the determination result, and the absolute difference of the parallel determination results shall not exceed 1MPa. 6 Inspection rules
·(2)
6.1 Industrial heavy magnesium oxide 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 contents shall include: manufacturer name, factory address, product name, category, grade, net weight, batch number or production date, proof that the product quality meets this standard and the number of this standard. 6.2 The user has the right to accept the industrial heavy magnesium oxide received in accordance with the provisions of this standard. 6.3 Each batch of products shall not exceed 2t.
6.4 Determine the number of sampling units in accordance with the provisions of Article 6.6 of GB/T6678. When sampling, insert the sampler from the vertical line of the center of the packaging bag to 3/4 of the depth of the material layer to take a sample. After mixing the sample, divide it into about 500g according to the quartering method, and pack it into two clean, dry wide-mouth bottles with stoppers and seal them. Paste labels on the bottles, indicating: manufacturer name, product name, category, batch number, sampling date and name of the sampler. ...-bottle is used for inspection, and the other bottle is kept for three months for reference. 6.5 If one indicator of the inspection result does not meet the requirements of this standard, re-sample from twice the amount of packaging for verification. Even if only one indicator of the verification result 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 value comparison method specified in GB1250 shall be used to determine whether the inspection result meets the standard. 7. Marking, packaging, transportation and storage
7.1 The packaging bags of industrial heavy magnesium oxide should be firmly and clearly marked, including: manufacturer name, address, product name, trademark, category, grade, net weight, batch number or production date, this standard number and GB/T191 "moisture-averse" mark. 7.2 Industrial heavy magnesium oxide is packed in double layers: the inner packaging is made of polyethylene plastic film bags, with specifications and dimensions: 20kg: 850mm×550mm, 40kg: 1000mm×600mm, thickness: 0.1mm; the outer packaging is made of plastic woven bags, with specifications and dimensions: 20kg: 800mm×500mm, its performance and inspection methods shall comply with the provisions of GB8946A; 40kg: 950mm×550mm, its performance and inspection methods shall comply with the provisions of GB8946B. The net weight of each bag of this product is 20kg or 40kg. 7.3 For industrial heavy magnesium oxide packaging, the inner bag is tied with vinyl rope or other ropes of equivalent quality, or with other equivalent methods. Sealing: The outer bag should be folded at a distance of not less than 30mm from the edge of the bag, and the edge should be sewn with vinyl thread or other thread of equivalent quality at a distance of not less than 15mm from the edge of the bag. The stitch length should not exceed 10mm. The stitches should be neat and the stitch length should be uniform. There should be no leakage or skipping of stitches. 7.4 Industrial heavy magnesium oxide should be covered during transportation to prevent rain and moisture. 7.5 Industrial heavy magnesium oxide should be stored in a cool and dry place to prevent rain and moisture. Additional instructions:
This standard was 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 the Tianjin Chemical Industry Research Institute of the Ministry of Chemical Industry. This standard was drafted by the Tianjin Chemical Industry Research Institute of the Ministry of Chemical Industry and Xingtai Chemical Plant No. 1. The main drafters of this standard are Wang Qi, Zhao Jimin and Wang Aigui. 228
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