Some standard content:
Chemical Industry Standard of the People's Republic of China
HG/T2497—93
Published on September 8, 1993
Implemented on October 1, 1994
Ministry of Chemical Industry of the People's Republic of China
WChemical Industry Standard of the People's Republic of China
Subject Content and Scope of Application
HG/T2497-—93
This standard specifies the technical requirements, test methods, inspection rules and marking, packaging, transportation and storage of bleaching liquid. This standard applies to bleaching liquid obtained by the reaction of lime milk or calcium carbide slag slurry with chlorine. The active ingredient of bleaching liquid is Ca(CIO). It is mainly used for bleaching of pulp and fiber and disinfection of environmental sanitation. 2 Reference standards
GB/T601
GB/T603
Preparation of standard solutions for titration analysis (volume analysis) of chemical reagents Preparation of preparations and products used in chemical reagent test methods Specifications and test methods for water in analytical laboratories GB/T6682
Numerical rounding rules
GB/T8170
3 Technical requirements
3.1 Appearance: light green or slightly red liquid, slightly turbid is allowed. 3.2 The technical indicators of bleaching liquid shall comply with the provisions of the following table. Item
Available chlorine (in terms of CI) (m/m), %
Residue (V/V), %
Note: The residue content is a negotiated indicator and can be left uncontrolled if the user does not require it. 4 Test method
4.1 Determination of effective chlorine content
4.1.1 Principle
Qualified products
In an acidic medium, the hypochlorite of the bleaching solution reacts with potassium iodide to precipitate iodine. Starch is used as an indicator and titrated with sodium thiosulfate standard titration solution. The end point is the disappearance of the blue color. The reaction formula is as follows: CIO-+2I-+2H+H20+CI-+I2
I2+2S0-S0+21
4.1.2 Reagents and solutions
The reagents used are analytically pure reagents and laboratory water that meets the third-grade water specifications in GB/T6682. 4.1.2.1 Potassium iodide (GB/T1272) solution: 100g/L; H2SO4=1mol/L, prepared according to GB/T601; 4.1.2.2 Sulfuric acid (GB/T625) solution: c() 4.1.2.3 Sodium thiosulfate (GB/T637) standard titration solution: c(NazS2O:)=0.1mol/L, prepared and calibrated according to GB/T601; approved by the Ministry of Chemical Industry of the People's Republic of China on September 8, 1993 and implemented on October 1, 1994
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4.1.2.4 Starch (HGB3095) indicator solution: 10g/L, prepared according to GB/T603. 4.1.3 Instruments
General laboratory instruments.
4.1.4 Sample and its preparation
Mix the sample collected according to Article 5.7 of this standard and take about 15mL. After weighing (accurate to 0.01g), quickly transfer all of it into a 250mL volumetric flask, dilute with water to the scale, and shake well. 4.1.5 Analysis steps
Pipette 25.0mL of the mixed sample (4.1.4), place it in a 250mL iodine volumetric flask, add 10mL of potassium iodide solution (4.1.2.1) and 10mL of sulfuric acid solution (4.1.2.2), and cover it. After placing it in the dark for 5 minutes, titrate it with sodium thiosulfate standard titration solution (4.1.2.3) until it turns light yellow, add 1mL of starch indicator solution (4.1.2.4), and the solution turns blue. Continue titrating until the blue disappears, which is the end point. 4.1.6 Calculation of analysis results
The mass percentage of available chlorine (X,) is calculated according to formula (1): X1 =0V×0 03545×100= 9
m×250
Wherein: c——actual concentration of sodium thiosulfate standard titration solution, mol/L; V——volume of sodium thiosulfate standard titration solution consumed, mL; m——mass of sample, g;
C·VX35.45
0.03545——mass of chlorine in grams equivalent to 1.00mL sodium thiosulfate standard titration solution [c(NazS203=1.000mol/L)].
Take the arithmetic mean of the results of two parallel determinations as the reported result. 4.1.7 Allowable difference
The absolute difference between the results of two parallel determinations should not exceed 0.1%. 4.2 Determination of residue content
4.2.1 Principle
Particle impurities (residues) in the bleaching solution sink to the bottom of the centrifuge tube under the action of centrifugal force and are separated from the clear liquid. 4.2.2 ApparatuswwW.bzxz.Net
4.2.2.1 Laboratory right-angle centrifuge; 4.2.2.2 10mL graduated centrifuge tube.
4.2.3 Analysis steps
Take 4 centrifuge tubes (4.2.2.2) and fill them with 10.0mL of the mixed sample collected according to Article 5.7 of this standard respectively, and centrifuge and settle until the volume of the sediment remains unchanged. Record the volume of the sediment in each centrifuge tube. 4.2.4 Calculation of analysis results
The volume percentage of the residue (X2) is calculated according to formula (2): Vi+V,+Vs+V.
X100=(V+V2+V+V) X2.5 ..
........... (2)
Where: Vi-——the volume of sediment in each centrifuge tube, mL; 10-the volume of the sample taken, mL.
5 Inspection rules
5.1 The inspection results of this standard are determined by the rounded value comparison method, and the data processing is carried out in accordance with GB8170. 5.2 The factory inspection item of bleaching liquid products is the effective chlorine content, and its value shall be based on the test results at the time of leaving the factory. 2
WHG/T2497-93
5.3 The products leaving the factory shall be inspected by the quality inspection department of the manufacturer. Each batch of products must meet the requirements of this standard and be accompanied by a quality certificate in a certain format.
5.4 The user has the right to inspect and accept the bleaching liquid products received on the same day according to the inspection rules and test methods specified in this standard. 5.5 If the inspection results do not meet the requirements of this standard, double sampling should be carried out for re-inspection. If the re-inspection results still do not meet the requirements, the batch of products will be unqualified.
5.6 The bleaching liquid products are batched into each finished product storage tank. Each batch of barrels shall not exceed 800 barrels (plastic barrels), and the tank truck shall not exceed 5 tanks. 5.7 Sampling method
Mixed samples shall be collected from the upper, middle and lower layers of the finished product storage tank and tank truck at different depths. For barrels, random sampling shall be carried out according to the number of barrels. Take 2 barrels for barrels below 15, 3 barrels for barrels between 16 and 50, 5 barrels for barrels between 51 and 150, 8 barrels for barrels between 151 and 500, and 10 barrels for barrels between 501 and 800. The total amount of the sample shall not be less than 500mL, and it shall be quickly put into a clean, dry, stoppered ground-mouth bottle and mixed. The sample bottle should be marked with the manufacturer's name, product name, batch number, quantity, sampling date and the name of the sampler.
6 Marking, packaging, transportation, storage
6.1 Marking
The tank truck containing bleach should have a mark that complies with the transportation regulations. For bleach packaged in barrels, each barrel must be affixed with a product label, indicating the product name, manufacturer's name, production date and batch. 6.2 Packaging
The user unit can prepare its own packaging container, but it should be a special can or barrel with a lid. Containers that have been used to transport other substances (such as acid or organic matter) must be strictly checked. If there is sediment, it must be cleaned before packaging, otherwise packaging is not allowed. 6.3 Transportation
The container for transporting bleach must be corrosion-resistant, pressure-resistant, and covered. It should be protected from sunlight during transportation. 6.4 Storage
Bleach should be stored in a cool place away from heat sources and direct sunlight, and should not be stored loose. Additional Notes:
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 technical supervision of Jinxi Chemical Research Institute of the Ministry of Chemical Industry. This standard was drafted by Jinxi Chemical Research Institute of the Ministry of Chemical Industry. The main drafters of this standard were Xu Zengyi, Tang Shijie and Guo Fengxia. This standard refers to the Japanese standard JIS K1207-1964 (confirmed in 1985) "Bleaching Liquid". 3
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