GB/T 7746-2023 English PDF (GBT7746-2023)

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GB/T 7746-2023: Anhydrous hydrogen fluoride for industrial use
GB/T 7746-2023
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 71.060.30
CCS G 11
Replacing GB/T 7746-2011
Anhydrous Hydrogen Fluoride for Industrial Use
工业无水氟化氢
ISSUED ON. NOVEMBER 27, 2023
IMPLEMENTED ON. JUNE 1, 2024
Issued by. State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword... 3
1 Scope... 5
2 Normative References... 5
3 Terms and Definitions... 6
4 Molecular Formula and Relative Molecular Mass... 6
5 Requirements... 6
6 Test Methods... 6
7 Inspection Rules... 17
8 Markings and Accompanying Documents... 18
9 Packaging, Transportation and Storage... 18
Appendix A (informative) Typical Values of Working Curve of Moisture Content... 19
Bibliography... 20
Anhydrous Hydrogen Fluoride for Industrial Use
WARNING. in accordance with the provisions of Chapter 6 in GB 12268-2012, this
product belongs to Category 8 corrosive substances, and the secondary hazard is Category
6 Item 6.1 toxic substances. Be careful during operation! If it splashes on your skin or eyes,
immediately rinse with water. In severe cases, immediately seek medical advice. Personnel
adopting this document shall have practical experience in formal laboratory work. This
document does not identify all possible safety issues. Users are responsible for taking
appropriate safety and health measures and ensuring the compliance with the conditions
stipulated in relevant national regulations.
1 Scope
This document specifies the requirements, test methods, inspection rules, markings,
accompanying documents, packaging, transportation and storage of anhydrous hydrogen
fluoride for industrial use.
This document is applicable to anhydrous hydrogen fluoride for industrial use.
NOTE. this product is mainly used as the raw material for preparing electronic grade hydrofluoric
acid, fluorinating agents, fluorohaloalkane, reagent hydrofluoric acid and other fluorine-
containing products, etc.
2 Normative References
The contents of the following documents constitute indispensable clauses of this document
through the normative references in the text. In terms of references with a specified date, only
versions with a specified date are applicable to this document. In terms of references without a
specified date, the latest version (including all the modifications) is applicable to this document.
GB 190 Packing Symbol of Dangerous Goods
GB/T 6682-2008 Water for Analytical Laboratory Use - Specification and Test Methods
GB/T 8170 Rules of Rounding off for Numerical Values and Expression and Judgement of
Limiting Values
HG/T 3696.1 Inorganic Chemicals for Industrial Use - Preparations of Standard and Reagent
Solutions for Chemical Analysis - Part 1.Preparations of Standard Volumetric Solutions
HG/T 3696.2 Inorganic Chemicals for Industrial Use - Preparations of Standard and Reagent
Solutions for Chemical Analysis - Part 2.Preparations of Standard Solutions for Impurity
HG/T 3696.3 Inorganic Chemicals for Industrial Use - Preparations of Standard and Reagent
Solutions for Chemical Analysis - Part 3.Preparations of Reagent Solutions
1---specimen entrance;
2---plastic welding support;
31, 32---plastic welding fixed platinum electrodes;
4---plastic welding specimen outlet capillary;
5---thermometer (or temperature sensor) equipped with polyethylene sleeve.
Figure 1 -- U-shaped Structure Conductivity Cell
6.5.3.2 Conductivity meter. measurement range. 0 s/cm ~ 100,000 s/cm.
6.5.3.3 Polyethylene bottle. with a volume of 500 mL, with gas-liquid phase pipe.
6.5.3.4 Thermometer or temperature sensor, which shall comply with the following
requirements.
a) Thermometer. with a division value of 0.1 C, and a measurement range of 0 C ~ 50
C. When in use, install it in the polyethylene sleeve.
b) Temperature sensor. with a display resolution of 0.1 C, a measurement range of 0 C
~ 60 C, a measurement accuracy of not lower than  1 C, and with automatic
temperature compensation function. When in use, install it in the polyethylene sleeve.
6.5.3.5 Injection needle. No.4 or No.5 medical needle.
6.5.4 Determination of conductivity cell constant
Use a dry hot air flow to blow the conductivity cell to make it completely dry, inject the
potassium chloride standard solution of the required concentration (rinse 2 ~ 3 times first), then,
connect the conductivity cell electrode to the conductivity meter, insert a thermometer (or
temperature sensor) into the upper port of the conductivity cell, and meanwhile, measure the
conductivity value and temperature of the solution in the conductivity cell. Repeat the
measurement for over 5 times and take the average value of the measurement as the
conductivity value and temperature of the potassium chloride standard solution. In addition,
from Table 2, obtain the conductivity of the potassium chloride standard solution at the above
temperature.
6, 7---determination wires;
8---waste acid collection bottle for pipeline system flushing;
9---conductivity meter;
10---thermometer with polyethylene sleeve.
Figure 2 -- Schematic Diagram of Moisture Determination Device by Conductivity
Method
Take the arithmetic mean of the parallel determination results as the determination result. The
absolute difference between the two parallel determination results shall not be greater than
0.0006% for superior products, not greater than 0.001% for first-class products, and not greater
than 0.0015% for qualified products.
6.6 Determination of Fluorosilicic Acid Content
6.6.1 Principle
Use sodium chloride to react with fluorosilicic acid in the specimen to generate non-volatile
salt and evaporate to remove the hydrogen fluoride. In a weakly acidic medium, add an
appropriate amount of boric acid to suppress the interference of fluorine, add ammonium
molybdate to react with silicate to generate silicon-molybdenum heteropoly acid (yellow), then,
add sulfuric acid solution and oxalic acid solution to eliminate the interference of phosphate.
Selectively reduce silicon-molybdenum heteropoly acid to silicon-molybdenum blue, at a
wavelength of 815 nm, measure the absorbance of the blue complex.
6.6.2 Reagents or materials
6.6.2.1 Sodium chloride solution. 10 g/L.
6.6.2.2 Sulfuric acid solution. 1 + 3.
6.6.2.3 Hydrochloric acid solution. 1 + 5.
6.6.2.4 Boric acid solution. 40 g/L.
6.6.2.5 Oxalic acid solution. 100 g/L.
6.6.2.6 Ammonium molybdate solution. 100 g/L (when the solution precipitates, re-preparation
is required).
6.6.2.7 Ascorbic acid solution. 10 g/L. The usage period is 10 days.
6.6.2.8 Fluorosilicic acid standard solution. 1 mL of solution contains 1.000 mg of fluorosilicic
acid (H2SiF6). Weigh-take 0.417 g of silica that has been burned at 1,000 C to a constant mass,
place it in a platinum crucible, add 5 g of anhydrous sodium carbonate, and thoroughly mix it.
Place it in a high-temperature furnace of 1,000 C to slowly melt it, then, leave it to cool. Add
hot water to dissolve it, after cooling, transfer it all into a 1,000 mL volumetric flask; use water
to dilute to the scale and shake it well. Immediately transfer it to a polyethylene bottle. The
usage period does not exceed 30 days.
6.6.2.9 Fluorosilicic acid standard working solution. 1 mL of solution contains 0.020 mg of
fluorosilicic acid (H2SiF6). Transfer-take 2 mL of fluorosilicic acid standard solution (see
6.6.2.8), place it in a 100 mL volumetric flas...