Foreword
Codeofchina Inc. is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard replaces GB/T 4348.3-2002 Sodium hydroxide for industrial use - Determination of iron content – 1, 10-phenanthroline photometric method, and the following main technical changes have been made with respect to GB/T 4348.3-2002 (previous edition):
——The normative references are modified (see clause 2, clause 2 of Edition 2002);
——The reducing agent reducing Fe3+ to Fe2+ is modified (see 3, 6.1.1 and 6.4; 3, 6.1.1 and 6.3.3 of Edition 2002);
——The reagents are partially modified (see clause 4; clause 4 of Edition 2002);
——The preparation of standard colorimetric solution is modified (see 6.1.1; 6.1.1 of Edition 2002);
——The solution for adjusting the zero point of the spectrophotometer is modified (see 6.1.2 and 6.5; 6.1.2 and 6.3.4 of Edition 2002);
——The sampling volume is modified (see 6.2; 6.2 in Edition 2002);
——The result calculation formula is modified (see clause 7; clause 7 of Edition 2002);
——The clause of test report is added (see clause 9);
This standard was proposed by the China Petroleum and Chemical Industry Association.
This standard is under the jurisdiction of SAC/TC 63/SC 6 Subcommittee on Chlor Alkali of National Technical Committee on Chemical of Standardization Administration of China.
The previous editions replaced by this standard are as follows:
——GB/T 4348.3-1984 and GB/T 4348.3-2002.
Foreword i
1 Scope
2 Normative references
3 Principle
4 Reagents and materials
5 Apparatus
6 Analytical procedures
7 Result calculation
8 Allowable deviation
9 Test report
