GB/T 23948-2023Inorganic chemicals for industrial use—General method for the determination of water insoluble matter (English PDF)

Foreword

This document was drafted in accordance with the rules given in GB/T 1.1-2020 "Directives for standardization - Part 1: Rules for the structure and drafting of standardizing documents".

This document replaces GB/T 23948-2009 "Inorganic chemicals for industrial use -- General method for the determination of water insoluble matter". Compared with GB/T 23948-2009, in addition to structural adjustments and editorial changes, the main technical changes are as follows:

a) Changed the scope of application (see Chapter 1 of this Edition; Chapter 1 of Edition 2009);

b) Added the specimen sampling weight (see 7.1 of this Edition);

c) Changed the method for determining whether the glass crucible method and the Gooch crucible method are clean (see 7.2 and 7.3 of this Edition; 6.1 and 6.2 of Edition 2009);

d) Added the microporous membrane method (see 7.4 of this Edition);

e) Added the mass constant operation step (see 7.5 of this Edition).

1 Scope

This document describes the principles, reagents or materials, instruments and equipment, test procedures and test data processing of the general method for the determination of water-insoluble matter in inorganic chemical products.

This document is applicable to the determination of water-insoluble matter in inorganic chemical products. The glass sand crucible method specified in this document is applicable to the determination of water-insoluble matter in non-alkaline products. The microporous membrane filter method (made of polytetrafluoroethylene) is applicable to the determination of water-insoluble matter in products with a pH value of 2~13 in aqueous solution. The Gooch crucible method is applicable to the determination of water-insoluble matter in all products.

2 Normative references

The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

GB/T 6682-2008, Water for analytical laboratory use - Specification and test methods

3 Terms and definitions

There are no terms or definitions that require definition in this document.

4 Principle

Dissolve the specimen with water. Use appropriate filtering equipment (glass crucible, Gooch crucible or microporous filter membrane) to filter out the insoluble matter in the sample. Wash the filter residue with water to completely separate it from the main body of the sample. After drying, weigh the mass of the insoluble matter with an electronic balance.

5 Reagents or materials

5.1 Hydrochloric acid solution: 1+1.

5.2 Silver nitrate solution: 17 g/L.

5.3 Water: Unless otherwise specified, water shall comply with the grade three water specified in Table 1 of GB/T 6682-2008.

5.4 Acid-washed asbestos: Take an appropriate amount of acid-washed asbestos and soak it in hydrochloric acid solution (1+3). Boil for 20 min. Filter with a Buchner funnel and wash with water until neutral. Soak with sodium hydroxide solution (50 g/L) and boil for 20 min. Filter with a Buchner funnel and wash with water until nearly neutral (check with a wide range pH test paper). Mix with water to make a thin paste and set aside.

6 Instruments and equipment

6.1 Glass crucible: the filter plate pore size is 5 µm~15 µm, or other pore sizes can be selected according to product properties.

6.2 Gooch crucible: the capacity is 30 mL, or other capacity can be selected according to the properties of the product.

6.3 Microporous filter membrane: the pore size is 0.45 µm; the material is polytetrafluoroethylene (PTFE).

6.4 Vacuum filtration device.

6.5 Membrane filtration device: the capacity is 1000 mL, see Figure 1.

7 Test steps