GB/T 2440-2017 Urea
1 Scope
This standard specifies the terms and definitions, requirements, test methods, inspection rules, marking, packaging, transportation and storage of urea.
This standard is applicable to agricultural (fertilizer) urea and industrial urea synthesized from ammonia and carbon dioxide. Sulfur coated urea, AUS32 special urea, and pharmaceutical-grade urea for which national or professional standards exist shall comply with the respective standards.
Note: The molecular formula of urea is CO(NH2)2.
Relative molecular mass: 60.055 (as per the international relative atomic mass in 2013).
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 2441.1 Determination of urea - Part 1: Total nitrogen content
GB/T 2441.2 Determination of urea - Part 2: Biuret content - Spectrophotometric method
GB/T 2441.3 Determination of urea - Part 3: Water content - Karl Fischer method
GB/T 2441.4 Determination of urea - Part 4: Iron content - 1,10-Phenanthroline spectrophotometric method
GB/T 2441.5 Determination of urea - Part 5: Alkalinity - Titrimetric method
GB/T 2441.6 Determination of urea - Part 6: Water insoluble matter content - Weight method
GB/T 2441.7 Determination of urea - Part 7: Particle size - Sieve method
GB/T 2441.8 Determination of urea - Part 8: Sulphate content - Visible turbidimetric method
GB/T 2441.9 Determination of urea - Part 9: Methylenediurea content - Spectrophotometric method
GB/T 6679 General rules for sampling solid chemical products
GB/T 8170-2008 Rules of rounding off for numerical values & expression and judgment of limiting values
GB/T 8569 Packing of solid chemical fertilizers
GB/T 10454 Flexible freight container
GB 18382 Fertilizer marking - Presentation and declaration
HG/T 4365-2012 Water soluble fertilizer
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
size guide number; SGN
average particle size of the material between two sieves where the mass fraction exceeds 50%, which reflects the dominant particle size
3.2
uniformity index; UI
uniformity index, which reflects the uniformity of particle size
3.3
trace additive
additives in urea products with a mass fraction not exceeding 1.0%
4 Requirements
4.1 Appearance: Granular or crystalline, free of mechanical impurities.
4.2 Agricultural (fertilizer) urea shall meet those specified in Table 1 and also conform to the indicated values.
Contents
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Requirements
5 Test methods
6 Inspection rules
7 Marking
8 Packaging, transportation and storage
Annex A (Informative) Calculation methods of size guide number (SGN) and uniformity index (UI)
GB/T 2440-2017 Urea
1 Scope
This standard specifies the terms and definitions, requirements, test methods, inspection rules, marking, packaging, transportation and storage of urea.
This standard is applicable to agricultural (fertilizer) urea and industrial urea synthesized from ammonia and carbon dioxide. Sulfur coated urea, AUS32 special urea, and pharmaceutical-grade urea for which national or professional standards exist shall comply with the respective standards.
Note: The molecular formula of urea is CO(NH2)2.
Relative molecular mass: 60.055 (as per the international relative atomic mass in 2013).
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 2441.1 Determination of urea - Part 1: Total nitrogen content
GB/T 2441.2 Determination of urea - Part 2: Biuret content - Spectrophotometric method
GB/T 2441.3 Determination of urea - Part 3: Water content - Karl Fischer method
GB/T 2441.4 Determination of urea - Part 4: Iron content - 1,10-Phenanthroline spectrophotometric method
GB/T 2441.5 Determination of urea - Part 5: Alkalinity - Titrimetric method
GB/T 2441.6 Determination of urea - Part 6: Water insoluble matter content - Weight method
GB/T 2441.7 Determination of urea - Part 7: Particle size - Sieve method
GB/T 2441.8 Determination of urea - Part 8: Sulphate content - Visible turbidimetric method
GB/T 2441.9 Determination of urea - Part 9: Methylenediurea content - Spectrophotometric method
GB/T 6679 General rules for sampling solid chemical products
GB/T 8170-2008 Rules of rounding off for numerical values & expression and judgment of limiting values
GB/T 8569 Packing of solid chemical fertilizers
GB/T 10454 Flexible freight container
GB 18382 Fertilizer marking - Presentation and declaration
HG/T 4365-2012 Water soluble fertilizer
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
size guide number; SGN
average particle size of the material between two sieves where the mass fraction exceeds 50%, which reflects the dominant particle size
3.2
uniformity index; UI
uniformity index, which reflects the uniformity of particle size
3.3
trace additive
additives in urea products with a mass fraction not exceeding 1.0%
4 Requirements
4.1 Appearance: Granular or crystalline, free of mechanical impurities.
4.2 Agricultural (fertilizer) urea shall meet those specified in Table 1 and also conform to the indicated values.
Contents of GB/T 2440-2017
Contents
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Requirements
5 Test methods
6 Inspection rules
7 Marking
8 Packaging, transportation and storage
Annex A (Informative) Calculation methods of size guide number (SGN) and uniformity index (UI)
