GB/T 1918-2021 English PDF (GBT1918-2021)

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GB/T 1918-2021: Potassium nitrate for industrial use
GB/T 1918-2021
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 71.060.50
CCS G 12
Replacing GB/T 1918-2011
Potassium Nitrate for Industrial Use
工业硝酸钾
ISSUED ON: AUGUST 20, 2021
IMPLEMENTED ON: MARCH 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 Molecular Formula and Relative Molecular Mass ... 6
5 Classification ... 6
6 Requirements ... 6
7 Test Methods ... 7
8 Inspection Rules ... 22
9 Marking and Labeling ... 23
10 Packaging, Transportation and Storage ... 24
Appendix A (informative) Commonly Used ICP-OES Spectral Lines and Detection
Limits ... 25
Bibliography ... 26
Potassium Nitrate for Industrial Use
WARNING: in accordance with the provisions of Chapter 6 in GB 12268-2012, this
product belongs to Category 5, Item 5.1 oxidizing substances, and caution shall be
exercised when handling it. Personnel using this document shall have practical experience
in formal laboratory work. This document does not point out 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 classification, requirements, test methods, inspection rules,
marking, labeling, packaging, transportation and storage of potassium nitrate for industrial use.
This document is applicable to potassium nitrate for industrial use.
NOTE: this product is mainly used in molten salt, black powder, fuses, pharmaceutical
intermediates, optical glass, ammonia catalyst, metal heat treatment, enamel and other
industries.
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/T 191-2008 Packaging - Pictorial Marking for Handling of Goods
GB/T 3051-2000 Inorganic Chemical Products for Industrial Use - General Method for
Determination of Chloride Content - Mercurimetric Method
GB/T 3600-2000 Fertilizers - Determination of Ammoniacal Nitrogen Content - Formaldehyde
Method
GB/T 6678 General Principles for Sampling Chemical Products
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
GB/T 23945-2009 Inorganic Chemicals for Industrial Use - General Method for the
Determination of Chloride Content - Visible Turbidimetric Method
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
JT/T 617 (all parts) Regulations Concerning Road Transportation of Dangerous Goods
3 Terms and Definitions
This document does not have terms or definitions that need to be defined.
4 Molecular Formula and Relative Molecular Mass
Molecular formula: KNO3
Relative molecular mass: 101.10 (in accordance with the international relative atomic mass in
2018)
5 Classification
Potassium nitrate for industrial use is classified into three categories. The main purposes are as
follows:
---Category I products are mainly used for molten salt manufacturing;
---Category II products are divided into two types. Type I products are mainly used for the
manufacturing of black powder, fuses, pharmaceutical intermediates and glass clarifiers,
etc. Type II products are mainly used for metal heat treatment and the manufacturing
of enamel paint, etc.;
---Category III products are products added inorganic salts as anti-caking agents and are
mainly used as fluxes for glass and ceramics.
6 Requirements
6.1 Appearance: potassium nitrate for industrial use is white crystal or spherical particles.
6.2 Potassium nitrate for industrial use shall be tested in accordance with the test methods
specified in this document and shall comply with the stipulations of Table 1.
3696.1, HG/T 3696.2 and HG/T 3696.3.
7.2 Appearance Inspection
Under natural light, adopt the method of visual inspection for determination.
7.3 Determination of Potassium Nitrate Content
7.3.1 Principle
In neutral medium, potassium ions react with sodium tetraphenylborate to generate potassium
tetraphenylborate precipitate. If ammonium ions are present, formaldehyde solution can be
added to eliminate the interference of ammonium ions. In accordance with the mass of the
generated potassium tetraphenylborate, determine the potassium nitrate content. Its main
reaction formula is as follows:
7.3.2 Reagents or materials
7.3.2.1 Absolute ethanol.
7.3.2.2 Formaldehyde solution: filter before use.
7.3.2.3 Acetic acid solution: 1 + 100.
7.3.2.4 Sodium hydroxide solution: 4 g/L.
7.3.2.5 Sodium tetraphenylborate ethanol solution.
7.3.2.6 Saturated ethanol solution of potassium tetraphenylborate.
7.3.2.7 Methyl orange indicator solution: 1 g/L.
7.3.2.8 Phenolphthalein indicator solution: 10 g/L.
7.3.3 Instruments and equipment
7.3.3.1 Electric thermostatic drying oven: the temperature can be controlled at 120 C  2 C.
7.3.3.2 Glass sand crucible: with a filter plate pore size of 5 m ~ 15 m.
7.3.4 Test steps
7.3.4.1 Preparation of test solution
Weigh-take 1.0 g ~ 1.2 g of sample, accurate to 0.0002 g, place it in a 100 mL beaker. Add water
to dissolve it, transfer the solution to a 500 mL volumetric flask, use water to dilute to the scale
and shake it well.
7.3.4.2 Test
Use a pipette to transfer 25 mL of the test solution, place it in a 150 mL beaker, add 20 mL of
water and 2 drops of methyl orange indicator solution, and use acetic acid solution to adjust the
solution to just turn red. If it contains ammonium salt, add 1 ~ 2 drops of phenolphthalein
indicator solution and 2 mL of formaldehyde solution, and use sodium hydroxide solution to
adjust it to turn reddish. Use a constant-temperature water bath to heat the solution to 45 C
(continue to keep the solution in reddish, and if there is any precipitate, filter and thoroughly
wash it), while stirring, dropwise add 8 mL of sodium tetraphenylborate ethanol solution (the
dropping time is about 5 minutes) and continue stirring for 1 minute. After letting it stand for
30 minutes, use a glass sand crucible that has been dried to a constant mass in an electric
thermostatic drying oven at 120 C  2 C to suction filter it, use 20 mL of saturated ethanol
solution of potassium tetraphenylborate to transfer the precipitate, and use 15 mL of saturated
ethanol solution of potassium tetraphenylborate to wash the precipitate in 3 ~ 4 times (it shall
be drained each time). Then, use 2 mL of absolute ethanol to wash once along the inner wall of
th...