Some standard content:
GB7746--1997 | | tt | Level, the equivalent test method for moisture measurement adopts ISO3700:1980 "Industrial Anhydrous Hydrogen Fluoride - Determination of Water Content Conductivity Method"; the equivalent determination of fluorosilicic acid content adopts ISO3701:1976 "Industrial Anhydrous Hydrogen Fluoride - Determination of Hexafluorosilicic Acid Content" Determination - Reduced silicate molybdate photometry"; the determination of sulfur dioxide content is equivalent to ISO3702:1976 "Industrial anhydrous hydrogen fluoride - Determination of sulfur dioxide content -
iodometric method"; the determination of non-volatile acid content is equivalent to adoption ISO3138: 1974 "Determination of acid content of industrial anhydrous hydrogen fluoride - titration method".
The main technical differences with the Russian national standards are as follows: The Russian national standard IOCT14022-88 has two levels. This standard has three levels based on the actual production and user needs, and adds a qualified product level.
The main technical differences between this standard and the original national standard are as follows: 1) The superior grade of the original national standard is changed to superior product, and the first grade is changed to first-class product, and the grade of qualified product is increased. 2) The technical indicators of high-quality products and first-class products are equivalent to Russian national standards, and the technical indicators of qualified products are determined based on actual production and user needs.
3) To measure the content of fluorosilicic acid, add sodium chloride and then evaporate to remove fluorine interference. The remaining measurement steps are the same as ISO3701:1976. This standard will replace GB7746-87 and GB/T7747.1~GB/T7747.4-87 from the date of entry into force. This standard is proposed by 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: Tianjin Chemical Industry Research Institute of the Ministry of Chemical Industry, Jinan Chemical Plant, Zhejiang Yingguang Chemical Co., Ltd., Zhejiang Yongkang Chemical Corporation, Jiangsu Sheyang Fluorine Chemical Plant, Baotou No. 1 Chemical Plant and Shanghai Chlor-Alkali Company Electrochemical plant. The main drafters of this standard: Su Peiji, Qi Enhui, Wang Da'e, Zhu Rongzhong, Yu Jiuju, Qiu Jian, Chen Rufeng. This standard was first published in May 1987.
This standard is entrusted to the inorganic salt product standardization technical unit of the Ministry of Chemical Industry to be responsible for interpretation. Scope
National Standard of the People's Republic of China
Industrial Anhydrous Hydrogen Fluoride
Anhydrous hydrogen
fluoride for industrial use
GB7746--1997
Replacement GB7746—87
GB/T 7747.1—7747.4—87
This standard specifies the requirements, test methods, inspection rules, marking, packaging, transportation, storage and safety of industrial anhydrous hydrogen fluoride. This standard applies to anhydrous hydrogen fluoride. Anhydrous hydrogen fluoride is mainly used to prepare fluorinating agents, fluorohaloalkane, reagent hydrofluoric acid and other fluorine-containing products. | |tt | The provisions contained in the standard constitute provisions of this standard through reference in this standard. At the time of publication, the editions indicated were valid. All standards are subject to revision and parties using this standard should explore the possibility of using the latest version of the standard listed below. GB190—-90
Dangerous goods packaging markings
GB/T 601-—88
GB/T 602-88
GB/T603—88||tt| |GB/T1250-89
Preparation of standard solutions for chemical reagent titration analysis (volume analysis) Preparation of standard solutions for chemical reagent impurity determination (neqISO6353-1:1982) Preparations and products used in chemical reagent test methods Preparation (neqISO6353-1:1982) Expression method and judgment method of limit values ??GB/T 6678--86
GB/T6682-92
3 requirements
General principles for sampling of chemical products| |tt||Analytical laboratory water specifications and test methods (eqvIS03696:1987) 3.1 Appearance: It is a colorless and transparent liquid at low temperature or under a certain pressure, with a strong pungent odor and smokes in the air. 3.2
Industrial anhydrous hydrogen fluoride should comply with the requirements of Table 1: Table 1
Requirements
Item
Hydrogen fluoride content
Moisture
Fluorosilicone Acid content
Sulfur dioxide content
Mesh
Superior product
99.95
0.03
0.010
0.007||tt| |Content of non-volatile acid (based on H.SO)
Approved by the State Bureau of Technical Supervision on 1997-06-24 0.005
Reference
Standard
Product||tt| |etc
99.90
0.06
0.020
0.015
0.020
quality
合
99.70
0.10
0.050
0.030
0.050
%
1998-01-01 Implementation
4 test methods
GB77461997
The reagents and water used in this standard, unless other requirements are specified, refer to analytically pure reagents and the third-grade water specified in GB/T6682. The standard titration solutions, impurity standard solutions, preparations and products required in the test shall be prepared in accordance with the provisions of GB/T601, GB/T602 and GB/T603 unless other requirements are specified. 4.1 Calculation of hydrogen fluoride content
The hydrogen fluoride content (X.) expressed as mass percentage is calculated according to formula (1): X. =100-(X+X,+X+X,)
Where: X
X
X.
Moisture content, %;
Fluorosilicic acid content, %;
Sulfur dioxide content, %;
Non-volatile acid (calculated as H, SO,) content, %. X
4.2 Determination of moisture
4.2.1 Method summary
(1)
Use a closed flow conductivity cell to measure the conductivity of anhydrous hydrogen fluoride, and then Find the corresponding moisture content from the working curve for measuring the moisture content of anhydrous hydrogen fluoride,
4.2.2 Reagents and materials
4.2.2.1 Potassium chloride standard solution: c(KCI)=0.1000mol/L . Weigh 7.455g of potassium chloride that has been burned to constant weight at 500-600C, dissolve it in water, transfer it to a 1000mL volumetric flask, and dilute it to the mark. 4.2.2.2 Potassium chloride standard solution: c(KCI)=0.0100mol/L. Pipette 100mL potassium chloride standard solution (4.2.2.1), place it in a 1000mL volumetric flask, dilute to the mark, and spread evenly. Prepare this solution just before use. 4.2.3 Instruments and equipment
4.2.3.1 Conductivity cell: Made of polyethylene tube or polytetrafluoroethylene tube with an inner diameter of 20mm. Two smooth rod-shaped gold or platinum electrodes are installed in the tube with a distance of 100mm. , diameter is 2.0mm (see Figure 1). Unit: mm | Outlet capillary; 5. Thermometer with polyethylene sleeve Figure 1 Conductivity cell
4.2.3.2 Conductivity meter: Measuring range 0~100ms/cm. GB7746—1997
Polyethylene bottle: volume 500mL, with gas-liquid phase tube 4.2.3.3
4.2.3.4 Thermometer: graduation value 0.1℃, measurement range room temperature, thermometer made of polytetrafluoroethylene Wrapped to prevent corrosion by hydrogen fluoride. Injection needle: No. 4 or No. 5 medical needle. 4.2.3.5
4.2.4 Determination of the conductivity cell constant
Dry the conductivity cell carefully in a dry hot air flow, then inject the potassium chloride standard solution of the required concentration (rinse 23 times first), and then put the conductivity cell electrode and Connect the conductivity meter, insert a mercury thermometer into the upper port of the conductivity cell, and measure the conductivity value and temperature of the solution in the conductivity cell at the same time. Repeat the measurement more than 5 times, and take the average value of the measurements as the conductivity value and temperature of the potassium fluoride standard solution, and use Table 2 Find the conductivity of the potassium chloride standard solution at the above temperature.
Table 2
Conductivity, S/cm
Temperature,
10
11
12
13| |tt||14
15
16
17
18
19
20
21||tt ||22
23
24
25
26
27
28
29
30
Concentration
Degree
The conductivity cell constant Q is calculated according to formula (2):
Where: K-
of potassium chloride standard solution Conductivity
c(KCI)=0. 100 0mol/L
0.00933
0.00956
0.009 79
0.010 02
0.01025
0.010 48
0.01072
0.01095
0.01119
0.01143
0.01167
0.01191
0.01215| |tt||0.01239
0. 012 64
0.01288
001313
0.01337
0.013 62
0.01387
0.01412
QK/G
The conductivity of the potassium nitride standard solution at a given temperature, S/cm; the measured conductivity value of the potassium chloride standard solution, S. G
The conductivity cell constant should be checked once every three months.
4.2.5 Analysis steps
4.2.5.1 Selection of background sample
Select bottled anhydrous hydrogen fluoride with low moisture and fewer impurities as the background sample. 4.2.5.2 Drawing of working curve
c(KCI)=0. 010 0mol/L
0.001020
0.001045
0.001070
0.001095||tt ||0.001121
0.001147
0.001173
0.001199
0.001225
0.001251
0.001278
0.001 305||tt| |0.001332
0.001359
0.001 386
0.001413
0.001 441
0.001468
0.001496
0.001524||tt| | 0.001552 | Measure the conductivity value at a certain temperature (10C recommended). Use extrapolation to estimate the percentage of water in the anhydrous hydrogen fluoride background sample. Draw the working curve with the total percentage of the background sample and each quantitative addition of water as the abscissa, and the corresponding conductivity as the ordinate. 4.2.5.3 Determination
GB7746--1997
Place the clean and dry conductivity cell on a fixed rack in a fume hood or a well-ventilated place, and use a nut joint with a polyethylene tube. Connect the liquid phase pipe of the cylinder or tank to the conductivity cell, and at the same time connect the thermometer to the conductivity cell. Then carefully and slowly open the liquid phase valve of the cylinder or tank, flush the sample to the measurement system until it is stable, and close the valve. The schematic diagram of the measuring device is shown in Figure 2. When the temperature rises to the same temperature as when the working curve was drawn (the error does not exceed ±0.5°C), measure the conductance value. The conductivity value multiplied by the conductivity cell constant is the conductivity of the sample. Find the moisture percentage (X) of the sample being tested from the working curve. !
1—Sample cylinder: 2—Nut joint: 3—Connect copper pipe: 4—Connect polyethylene pipe, 5—Conductivity cell; 6, 7—Measurement wires; 8—Waste acid flushing pipeline system Collection bottle: 9 - Conductivity meter: 10 - Thermometer with polyethylene sleeve Figure 2 Schematic flow chart of moisture determination by conductivity method
4.2.6 Allowable difference
Take the arithmetic mean of the parallel measurement results as the determination As a result, the absolute difference in parallel measurement results was not greater than 0.005%. 4.3 Determination of fluosilicic acid content
4.3.1 Method summary
Fluorosilicic acid and sodium chloride generate sodium fluosilicate, and evaporate to remove hydrogen fluoride. In a weakly acidic medium and in the presence of boric acid that can suppress fluorine interference, silicates react with ammonium molybdate to form silicomolybdate heteropoly acid (yellow). Add c(1/2H, SO4) about 9 mol/L sulfuric acid solution and oxalic acid solution to eliminate the interference of phosphate, and then selectively reduce the silicomolybdenum heteropoly acid. The absorbance of the blue complex was measured at a wavelength of 795 nm. 4.3.2 Reagents and materials
4.3.2.1.
4.3.2.2
4.3.2.3
4.3.2.4
4.3.2.5||tt ||4.3.2.6
4.3.2.7
Sodium chloride solution: 10g/L.
Sulfuric acid solution: c(1/2H.SO,) about 9mol/L. Hydrochloric acid solution: c (HCI) is about 2mol/L.
Boric acid solution 40g/L.
Oxalic acid solution: 100g/L.
Ammonium molybdate solution: 100g/L (re-preparation is required when the solution precipitates). Reducing solution
4.3.2.7.1
4.3.2.7.2
Dissolve 7g anhydrous sodium sulfite in 50mL water, add 1.5g 1-amino-2-teophyl-4-sulfonate Dissolve with acid; dissolve 90g of sodium metabisulfite in 900mL of water; mix the two solutions of 4.3.2.7.1 and 4.3.2.7.2 and dilute to 1000mL, filter if necessary, and place the solution in cold water. 4. 3.2.7.3||tt ||Dark place, avoid direct sunlight, use period does not exceed 20 days. Silica standard solution, 1mL is equivalent to 1.000mgH,SiF. . Weigh 0.417g of silica 4.3.2.8
that has been burned at 1000C to constant weight in platinum, add 5g of anhydrous sodium carbonate, stir thoroughly, and place it in a high temperature furnace of 1000°C to slowly melt it , leave to cool, add hot water to dissolve, transfer all to a 1000mL volumetric flask after cooling, dilute to volume, shake well. Transfer immediately to polyethylene bottles. This solution should be remade at least monthly.
4.3.2.9
Silica standard solution, 1mL is equivalent to 0.050mgH,SiF. Pipette 50ml of silica standard solution (4.3.2.8), place it in a 1000mL volumetric flask, dilute to the mark, and shake well. Prepare this solution just before use. 4.3.3 Instruments and equipment
4.3.3.1 Spectrophotometer;
4.3.3.2 Platinum blood, with a volume of about 100mL.
4.3.4 Analysis steps
4.3.4.1 Drawing of working curve
GB7746-1997
In a series of 100mL volumetric flasks, add 0, 2.00 respectively , 4.00, 6.00, 8.00mL and 10.00mL silica standard solution (4.3.2.9), add water to 10mL, add 10mL sodium fluoride solution, add 4mL hydrochloric acid solution and 35mL boric acid solution while stirring, leave for 5 minutes, add 10mL ammonium molybdate solution, shake well, leave for 15min, add 5mL of oxalic acid solution respectively while stirring , 20mL sulfuric acid solution, shake well, add 2ml reducing solution, dilute to the mark with water, sow, leave for 20min, adjust the wavelength of the spectrophotometer to 795nm, use a 2cm absorption cell, use water as a reference, measure each standard solution The absorbance of the zero ml solution was subtracted from the absorbance of each standard solution. Taking the fluorosilicic acid content as the abscissa and the corresponding absorbance as the ordinate, draw a working curve. 4.3.4.2 Determination
4.3.4.2.1 Preparation of blank test solution
Add 5mL water and 10mL sodium chloride solution to the platinum dish and shake well. 4.3.4.2.2 Determination
Put 10ml sodium chloride solution in a platinum dish, weigh it to the nearest 0.01g, and add 4~5g of diluted sample (5.4.2) (including about 1g of sample) , weigh again, accurate to 0.01g: in order to calculate the mass of the diluted sample taken. At the same time, handle it in the same way as the blank test solution as follows. Place it on a water bath and evaporate it to dryness, add 10 mL water and 35 mL boric acid solution, leave it for 5 minutes, add 4 mL hydrochloric acid solution and 10 mL ammonium molybdate solution, mix, and transfer all the solutions to a 100 ml volumetric flask. Follow the steps for drawing a working curve, starting from "After leaving it for 15 minutes,...".
According to the measured absorbance, find out the fluorosilicic acid content from the standard curve. 4.3.5
Explanation of analysis results
The fluorosilicic acid content (X2) expressed as mass percentage is calculated according to formula (3); mi-mz
0.1×(mmg)| |tt||Xxx,1:00×100
x, The amount of fluorosilicic acid in the blank test solution found on the working curve, mg; m
X
mass concentration of the sample in the diluted sample, %; mass of the diluted sample, g.
4.3.6
Allowable difference
Take the arithmetic mean of the parallel measurement results as the measurement result, and the absolute difference of the parallel measurement results shall not be greater than 0.002%. 4.4 Determination of sulfur dioxide content
4.4.1 Method summary
(3)
Add an excess of known volume of iodine standard titration solution to the sample, and use sodium thiosulfate standard titration solution The excess iodine is back-dropped, and then the sulfur dioxide content is calculated based on the amount of iodine used. 4.4.2
2 Reagents and materials
4.4.2.1
Iodine standard titration solution: c(1/212) is about 0.01mol/L. Take 100ml of c(1/2I.) about 0.1mol/L standard titration solution prepared according to GB/T601, dilute to 1000mL, prepare this solution before use; 4.4.2.2 Sodium thiosulfate standard titration solution: c(NazS,O ) about 0.01mol/L. Take 100mL of c(NazS.O,) about 0.1mol/L standard titration solution prepared according to GB/T601, dilute to 1000mL, prepare this solution before use; potassium iodide solution: 100g/L
4.4.2.3|| tt||4.4.2.4
Starch indicator liquid: 10g/L.
4.4.3
3 Instruments and equipment
GB 7746—1997
4.4.3.1 Microburette: graduation value 0.02mL, volume 5mL or 10mL; 4.4. 3.2 Polyethylene beaker with lid: volume is about 250mL. 4.4.4 Analysis steps
Take 100ml of water and place it in a polyethylene beaker with a lid, accurately add 5.00mL of iodine standard titration solution, add 1mL of potassium iodide solution, weigh to the nearest 0.1g, add about 25ml, and dilute the sample (5.4.2), weigh again to the nearest 0.1g in order to calculate the mass of the diluted sample taken. Let it stand for several minutes, titrate with sodium thiosulfate standard titration solution until it turns light yellow, add 1mL of starch indicator solution, and continue titrating until the blue color disappears. At the same time, conduct a blank test under the same conditions and the same reagent amount, but without adding diluted samples. 4.4.5 Expression of analysis results
The sulfur dioxide content (X,) expressed as mass percentage is calculated according to formula (4): X-VxeX0.032
X, . -V)XciX3.2
X,Xm
In the formula: V.---
V.---The volume of the sodium thiosulfate standard titration solution consumed by the titration test solution, mL; the actual concentration of the sodium thiosulfate standard titration solution, mol/L; 0.032
The mass of sulfur dioxide in grams equivalent to 1.00mL sodium thiosulfate standard titration solution [c(Na,S,O;)=1.000mol/L];
X||tt ||The mass concentration of the sample in the diluted sample, %; the mass of the diluted sample·g.
m
4.4.6 Allowable difference
Take the arithmetic mean of the parallel measurement results as the measurement result, and the absolute difference of the parallel measurement results shall not be greater than 0.002%. 4.5 Determination of non-volatile acid content
4.5.1 Method summary
After removing the volatile acid by evaporation, use phenolphthalein as the indicator and titrate the non-volatile acid with sodium hydroxide standard titration solution. 4.5.2 Reagents and materials
4.5.2.1 Sodium hydroxide standard titration solution: c (NaOH) is about 0.01mol/L. Take 100mlL of c(NaOH) approximately 0.1mol/L standard titration solution prepared according to GB601, dilute it with carbon dioxide-free water to 1000mL, and prepare this solution before use. 4.5.2.2 Phenolic acid indicator solution: 10g/L. Dissolve 1g of phenol in 100mL of 95% ethanol, and add sodium hydroxide standard titration solution dropwise until light pink appears.
4.5.3 Instruments and equipment
4.5.3.1 Platinum III: the volume is about 150mL,
4.5.3.2 Polyethylene dropper: the volume is 2mL. 4.5.4 Determination steps
Weigh 50g of the diluted sample (5.4.2), accurate to 0.1g, place it in a platinum dish, evaporate to nearly dryness on a boiling water bath in the fume hood, add 5mL of water to evaporate (repeat Second time), add about 10ml of carbon dioxide-free water to the platinum dish, add 3 drops of phenolphthalein indicator solution, and titrate with sodium hydroxide standard titration solution until it turns light pink.
4.5.5 Expression of analysis results
The non-volatile acid (calculated as H, SO,) content expressed as mass percentage (X,) is calculated according to formula (5): yXGX0.049×100 =
X,=
X.Xm
VXcX4.9
Volume of titration solution, mL; actual concentration of sodium hydroxide standard titration solution, mol/L; (5)
is equivalent to 1.00ml sodium hydroxide standard titration solution [c(NaOH)=1.000mol/L] The mass of non-volatile acid 0.049
(in H, SO,) expressed in grams:
GB7746-1997
X. The mass concentration of the sample in the diluted sample, %; m--the mass of the diluted sample, g.
4.5.6 Allowable difference
Take the arithmetic mean of the parallel measurement results as the measurement result, and the absolute difference of the parallel measurement results shall not be greater than 0.002%. 5 Inspection Rules
5.1 Industrial anhydrous hydrogen fluoride shall be inspected by the quality supervision and inspection department of the manufacturer in accordance with the provisions of this standard. The manufacturer should ensure that each batch of products shipped meets the requirements of this standard. Each batch of products leaving the factory should be accompanied by a quality certificate, which includes: manufacturer name, factory address, product name, trademark, grade, net weight, batch number or production date, proof that product quality complies with this standard, and this standard number. 5.2 The user has the right to inspect and accept the industrial anhydrous hydrogen fluoride received within one month in accordance with the provisions of this standard. 5.3 Each batch of industrial anhydrous hydrogen fluoride shall not exceed 50t. 5.4 Sampling
5.4.1 Sampling ratio
Determine the number of sampling units for sampling according to the provisions of 6.6 of GB/T6678-86. When filling tanks, each tank is a batch and one sample is taken. .
5.4.2
Preparation of diluted sample
Connect the joint with the plastic nut to the liquid phase pipe of the cylinder or tank, open the liquid phase valve of the cylinder or tank, and allow liquid hydrogen fluoride to flush the pipe 1 ~2 minutes, close the liquid phase valve of the cylinder or tank, then insert the plastic tube into the plastic bottle of the ice-water mixture of known weight, open the liquid phase valve of the cylinder or tank, and slowly pass the liquid hydrogen fluoride into the ice water ( Shake while passing through), do not let the hydrogen fluoride gas escape. When the sample content reaches 20% or 25% (take no less than 50g of sample from each bottle), close the liquid phase valve of the cylinder or tank, and then weigh and sample the plastic bottles. Total mass, accurate to 0.1g. The diluted samples from the same batch were mixed and measured. The mass percent concentration (Xs) of the sample in the diluted sample is calculated according to formula (6): where: n—the total mass of the sample introduced + g; ml—the total mass of ice water in g.
Xm,+m
Samples are taken from twice the amount of packaging units for verification. If even one indicator of the verification result does not meet the requirements of this standard, the entire batch of products is unqualified. 5.6 Rounding value comparison method according to 5.2 of GB/T1250-89 Determine whether the inspection results meet the standards. 6 Marking, packaging, transportation, storagewww.bzxz.net
6.1 Industrial anhydrous hydrogen fluoride packaging containers should have firm and clear markings, including: manufacturer name, factory address, product name, trademark, grade, net weight, batch number or production date , this standard number and the mark 14 "drugs" mark and mark 20 "corrosives" mark in GB190-90. And should comply with the provisions of the "Gas Cylinder Safety Supervision Regulations". 6.2 Industrial anhydrous hydrogen fluoride is packaged in clean, dry special tankers or cylinders. The packaging container has a gas-liquid phase inlet and outlet, and the filling factor is 0.83kg/L. The cylinder is painted with gray paint and has black characters and a safety helmet. and anti-shock rubber rings. 6.3 When shipping industrial anhydrous hydrogen fluoride, it should comply with the provisions of the "Gas Cylinder Safety Supervision Regulations" and "Railway Dangerous Goods Transportation Management Rules". 6.4 Industrial anhydrous hydrogen fluoride cylinders should be stored in a covered warehouse. Exposure to the sun and easy contact with other products is strictly prohibited. 7 Safety when mixing flammable and explosive items
7.1 Anhydrous hydrogen fluoride is a highly corrosive liquid that is irritating and toxic. It has a strong corrosive effect on skin and eyes, and can produce severe and painful burns, and the treatment is effective. Slower,
GB77461997
It must be taken in a well-ventilated place or in a fume hood. Wear fluorine-resistant gloves, boots and protective clothing of appropriate size. 7.2 |
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