GB/T 2440-2017 (GB/T2440-2017, GBT 2440-2017, GBT2440-2017) & related versions
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GB/T 2440-2017
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 65.080
G 21
Replacing GB/T 2440-2001
Urea
尿素
ISSUED ON. DECEMBER 29, 2017
IMPLEMENTED ON. JULY 01, 2018
Issued by. General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Terms and definitions ... 5
4 Requirements ... 5
5 Test methods ... 6
6 Inspection rules ... 8
7 Marking ... 10
8 Packaging, transportation and storage ... 10
Appendix A (Informative) Calculation method of size guide number (SGN) and
uniformity index (UI) ... 12
Urea
1 Scope
This standard specifies the terms and definitions, requirements, test methods,
inspection rules, marking, packaging, transportation and storage of urea.
This standard applies to agricultural (fertilizer) urea and industrial urea which
are produced by the synthesis of ammonia and carbon dioxide. For the sulfur-
coated urea, urea for AUS32, urea for raw materials with national standards or
industry standards, it shall implement the corresponding standards.
Note. Urea formula. CO(NH2)2.
Relative molecular mass. 60.055 (according to the 2013 International Relative
Atomic Mass Table).
2 Normative references
The following documents are essential to the application of this document. For
the dated documents, only the versions with the dates indicated are applicable
to this document; for the undated documents, only the latest version (including
all the amendments) are applicable to this standard.
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 judgement 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
The following terms and definitions apply to this document.
3.1
Size guide number; SGN
Average particle size of the materials between the two sieves according to
the mass fraction more than 50%, which reflects the size of the dominant
particle size.
3.2
Uniformity index; UI
The uniformity index, which reflects the uniformity of the particle size.
3.3
Trace additive
An additive which has a mass fraction of not more than 1.0% in the urea
product.
4 Requirements
4.1 Appearance. Granular or crystalline, without mechanical impurities.
4.2 Agricultural (fertilizer) urea shall meet the requirements of Table 1,
meanwhile it shall also meet the indicated values.
requirements of this standard, the batch of products is judged to be qualified.
6.5.3 When performing the exit-factory inspection, if one indicator of the
inspection results does not meet the requirements of this standard, it shall
retake the samples from double number of packaging bags for inspection. In
the re-inspection results, even though there is one indicator failing to comply
with this standard, this batch of products is judged to be disqualified.
6.5.4 Each batch of qualified exit-factory products shall be accompanied by a
quality certificate, which includes. name and address (residence) of
manufacturer, name of product, batch number or date of manufacture, net
product content, total nitrogen content, biuret content, this standard number,
other contents to be marked as required by laws and regulations. For
agricultural (fertilizer) urea which has trace additives and industrial urea which
has formaldehyde and other additives, it shall indicate the composition of
additive in the quality certificate.
7 Marking
7.1 For the agricultural (fertilizer) urea, it shall be marked on the packaging
container with the name and address (residence) of manufacturer, name of
product, net content, grade, range of particle size (or SGN and UI), this standard
number, other contents to be marked as required by laws and regulations. The
net content of each bag shall be marked with a single value, such as 50 kg. The
rest executes GB 18382.
7.2 For agricultural (fertilizer) urea products, it shall be marked on the packaging
container with the following warning. “Biuret-containing urea, improper use can
cause damage to crops”.
7.3 For the industrial urea, it shall be marked on the packaging container with
the name and address (residence) of manufacturer, name of product, batch
number or date of manufacture, net product content, grade, this standard
number, other contents to be marked as required by laws and regulations.
7.4 For bulk products and products with container bags as packaging
containers, if the attached quality certificate has already indicated all the
marking contents, it may follow the requirements of the agreement to simplify
the marking contents.
8 Packaging, transportation and storage
8.1 Agricultural (fertilizer) urea products are packaged by the materials in
accordance with the provisions of GB/T 8569, the packaging specifications are
50.0 kg, 40.0 kg, 25.0 kg, 10.0 kg. The allowable range of net content per bag
Appendix A
(Informative)
Calculation method of size guide number (SGN) and uniformity index
(UI)
SGN is the abbreviation of SIZE GUIDE NUMBER, which is the size guide
number. It refers to the average particle size of the material between the two
sieves based on the mass fraction more than 50%. It reflects the size of the size
guide number. The SGN value of different raw materials is generally 280 ~ 340,
the closer it is, the more suitable it is to match.
UI is the abbreviation of UNIFORMITY INDEX, which is the uniformity index,
which reflects the uniformity of particle size. The larger the value, the better the
uniformity. It is acceptable when it is at least exceeding 40. When mixing
different materials, the difference in UI value shall not exceed 15%.
When selecting raw materials, SGN values and UI values shall be fully
considered, all raw materials shall be closer in both aspects. If necessary, use
the sieving pretreatment for selection.
The calculation method of SGN is to weigh a certain mass of raw material
sample for sieving, weigh it separately, calculate the ratio of the mass of the
material above-sieve to the total amount of the sample as well as the difference
between the pore sizes of the two adjacent sieves, make calculation according
to the pore size of the two sieves on which more than 50% materials above-
sieve is located as well as the proportion of the materials above-sieve.
SGN = Inter-sieve pore-size difference x 100 x [(Proportion of small-pore-size
material above-sieve - 50)/(Proportion of small-pore-size material above-sieve
- proportion of large-pore-size material above-sieve)] + small-pore-size x 100
Example of calculation method of SGN value.
Taylor sieve system mesh +4 +5 +6 +7 +8 +9 +10 +12 +14 +16 -16
Standard sieve system mm 4.75 4.00 3.35 2.80 2.36 2.00 1.70 1.40 1.18 1.00
under-sieve
Inter-sieve pore-size difference 0.75 0.65 0.55 0.44 0.36 0.30 0.30 0.22 0.18 -
Proportion of material above-sieve, % 0 3.5 25.3 71.0 94.2 98.4 99.7 99.91
99.95 99.96 0.04
Calculation of SGN.
......
| Standard ID | GB/T 2440-2017 (GB/T2440-2017) | | Description (Translated English) | Urea | | Sector / Industry | National Standard (Recommended) | | Classification of Chinese Standard | G21 | | Classification of International Standard | 65.080 | | Word Count Estimation | 10,199 | | Date of Issue | 2017-12-29 | | Date of Implementation | 2018-07-01 | | Older Standard (superseded by this standard) | GB/T 2440-2001 | | Drafting Organization | Shanghai Chemical Research Institute | | Administrative Organization | National fertilizer and soil conditioner standardization Technical Committee | | Regulation (derived from) | National Standards Bulletin 2017 No. 32 | | Proposing organization | China Petroleum and Chemical Industry Federation | | Issuing agency(ies) | People's Republic of China General Administration of Quality Supervision, Inspection and Quarantine, China National Standardization Administration |
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