GB/T 5138-2021 English PDF (GBT5138-2021)

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GB/T 5138-2021: Liquid chlorine for industrial use
GB/T 5138-2021
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 71.060.10
CCS G 13
Replacing GB/T 5138-2006
Liquid Chlorine for Industrial Use
ISSUED ON: AUGUST 20, 2021
IMPLEMENTED ON: JULY 1, 2022
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 Technical Requirements ... 6 
5 Sampling ... 6 
6 Test Methods ... 6 
7 Inspection Rules ... 15 
8 Markings, Accompanying Documents, Packaging, Transportation and
Storage ... 16 
Liquid Chlorine for Industrial Use
WARNING---the personnel using this document shall have practical experience
in formal laboratory work. This Standard does not point out all possible safety
issues. The user is responsible for taking appropriate safety and health
measures and ensuring the compliance with the conditions stipulated by
relevant national laws and regulations.
1 Scope
This document specifies the technical requirements, sampling, test methods,
inspection rules, markings, accompanying documents, packaging, transportation and
storage of liquid chlorine for industrial use.
This document is applicable to liquid chlorine produced by electrolytic method-
generated chlorine through drying and liquefying.
2 Normative References
The contents of the following documents constitute indispensable clauses of this
document through 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 602 Chemical Reagent - Preparations of Standard Solutions for Impurity
GB/T 603 Chemical Reagent - Preparations of Reagent Solutions for Use in Test
Methods
GB/T 6682 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
GB 11984 Safety Regulation for Chlorine
GB 15258 General Rules for Preparation of Precautionary Label for Chemicals
HG/T 3941 Liquid Chlorine for Industrial Use - Determination of Water Content -
Electrolytic Method
A---gas burette, 100 mL, with 0.05 mL division value on the upper part;
B, C---rotary cock;
D---outlet of gas burette;
E---leveling bottle, 250 mL;
F---absorption bottle, 500 mL, filled with sodium hydroxide solution.
Figure 1 -- Schematic Diagram of Chlorine Content Determination Device
6.2.4 Analytical procedures
6.2.4.1 Connect the gas burette to the leveling bottle as shown in Figure 1. Rotate
Cock C of the gas burette, so that the gas burette is connected to the atmosphere.
Then, rotate Cock B; connect the gas burette to the leveling bottle; adjust the position
of the leveling bottle; make the liquid level of the potassium iodide solution in the
leveling bottle on a level with the “0” scale at the lower end of the gas burette; close
Cock B.
6.2.4.2 Connect the outlet D of the gas burette to the absorption bottle; rotate Cock B
to connect the gas burette to the sampler. Slowly open the valve of the sampler to let
chlorine flow into the gas burette for 2 min ~ 3 min; completely replace the air in the
gas burette. Close the valve of the sampler; quickly and successively close Cock C
and Cock B of the gas burette; remove the absorption bottle and the connecting pipe
that passes chlorine. Leave it for a while, so that the chlorine temperature in the gas
burette reaches equilibrium with the outside world. Quickly rotate Cock C of the gas
burette by one turn.
6.2.4.3 Gradually raise the leveling bottle; rotate Cock B, so that the potassium iodide
solution flows a little into the gas burette, and shake it; close Cock B, so that the
chlorine is absorbed by the potassium iodide solution. Repeat this operation, until no
chlorine is absorbed by the solution, then, let it stand and cool for 10 min ~ 15 min.
Adjust the position of the leveling bottle, make the gas burette on a level with the liquid
level of the leveling bottle; read the scale value of the absorption liquid level in the gas
burette.
6.2.5 Result calculation
The chlorine content is calculated by the volume fraction () of chlorine (Cl2) and in
accordance with Formula (1):
Where,
E---gas absorption tube;
H---air purification bottle (within 1 + 5 sulfuric acid solution inside);
I---electric heating device;
J---hydrochloric acid separation bottle;
K---sodium hydroxide solution absorption bottle;
L---conical flask (with color-changing silica gel inside);
M---conical flask (with calcium oxide inside).
Figure 4 -- Schematic Diagram of Hydrochloric Acid Separation Device
6.4.5 Analytical procedures
6.4.5.1 Draw a standard curve
6.4.5.1.1 Successively measure-take 0.0 mL, 0.4 mL, 0.8 mL, 1.2 mL, 1.6 mL and 2.0
mL of ammonium standard solution (6.4.3.8); place them in six 20 mL colorimetric
tubes with stopper. Use water to dilute them to the scale. Respectively add 1 mL of
Nessler’s reagent; shake them well; let them stand for 10 min.
6.4.5.1.2 Use an appropriate cuvette. At a wavelength of 420 nm, use water to adjust
the zero point of the spectrophotometer; determine the absorbance of the solution.
6.4.5.1.3 Subtract the absorbance of the blank solution from the absorbance of the
colorimetric solution. Take the ammonium content (μg) as the x-coordinate and the
corresponding absorbance as the y-coordinate; draw a standard curve.
6.4.5.2 Specimen
Use filter paper to wipe the sampling valve clean; carefully open the valve; let an
appropriate amount of chlorine into the unmetered sodium hydroxide solution
absorption bottle to clean the valve. In accordance with Figure 3, properly install the
sampling device; control the gauge pressure to sample at 0.02 MPa ~ 0.04 MPa for
about 10 min. The chlorine passes through a gas absorption tube (keep away from
light) containing 5 mL of hydrochloric acid solution and is absorbed by the metered
sodium hydroxide solution absorption bottle that is about 200 mL. In accordance with
the mass (accurate to 0.1 g) of the absorption bottle before and after the sampling,
calculate the sampling size.
6.4.5.3 Separation
Put the gas absorption tube into the pre-heated hydrochloric acid separation device
(see Figure 4) to remove hydrochloric acid.
6.4.5.4 Determination
6.4.5.4.1 Use water to rinse the inner wall of the gas inlet of the sampling gas
absorption tube after sample separation and the outer wall of the part immersed in the
hydrochloric acid absorption solution. Add 1 drop of potassium sodium tartrate solution;
use water to dilute to the scale. Then, add 1 mL of Nessler’s reagent; shake it well; let
it stand for 10 min.
6.4.5.4.2 At a wavelength of 420 nm, use the same cuvette as the cuvette used to draw
the standard curve; use water to adjust the zero point of the spectrophotometer;
determine the absorbance of the solution.
6.4.5.5 Blank test
DO NOT add the specimen. Add 5 mL of hydrochloric acid solution; use the same
reagents and dosage as the specimen. In accordance with 6.4.5.3 and 6.4.5.4, conduct
the blank test.
6.4.6 Result calculation
Nitrogen trichloride is calculated by the mass fraction (w1) of (NCl3) and in accordance