ISO 17322:2015
(Main)Fertilizers and soil conditioners — Analytical methods for Sulfur Coated Urea (SCU)
Fertilizers and soil conditioners — Analytical methods for Sulfur Coated Urea (SCU)
ISO 17322:2015 specifies analytical methods for the determination of mass fraction of total nitrogen, one-day dissolution rate (1DDR), seven-day dissolution rate (7DDR), mass fraction of sulfur, mass fraction of biuret, mass fraction of water (H2O), and particle size of SCU. These methods are applicable to SCU.
Matières fertilisantes — Méthodes analytiques pour l'urée enrobée de soufre (SCU)
General Information
Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 17322
First edition
2015-06-01
Fertilizers and soil conditioners —
Analytical methods for Sulfur Coated
Urea (SCU)
Matières fertilisantes — Méthodes analytiques pour l’urée enrobée
de soufre (SCU)
Reference number
©
ISO 2015
© ISO 2015, Published in Switzerland
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ii © ISO 2015 – All rights reserved
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Sampling and sample preparation . 1
4 Determination of the appearance . 1
5 Determination of the mass fraction of total nitrogen . 1
6 Determination of 1DDR and 7DDR . 1
6.1 Titrimetric method after distillation . 1
6.1.1 Principle . 1
6.1.2 Reagents . 1
6.1.3 Apparatus . 2
6.1.4 Procedure . 2
6.1.5 Calculation . 2
6.2 Refractometer method . 3
6.2.1 Principle . 3
6.2.2 Reagents . 3
6.2.3 Apparatus . 3
6.2.4 Procedure . 4
6.2.5 Calculation . 5
7 Determination of the mass fraction of sulfur . 6
7.1 Principle . 6
7.2 Reagents. 6
7.3 Apparatus . 6
7.4 Procedure . 6
7.4.1 Determination of the sulfur content . 6
7.4.2 Blank test . 7
7.5 Calculation . 7
8 Determination of the mass fraction of biuret . 7
8.1 Principle . 7
8.2 Reagents. 8
8.3 Apparatus . 8
8.4 Procedure . 8
8.4.1 Preparation of the calibration curve. 8
8.4.2 Preparation of the solution to be analysed . 9
8.5 Calculation . 9
9 Determination of the water content .10
9.1 Principle .10
9.2 Reagents.10
9.3 Apparatus .10
9.4 Installation and test of the Karl Fischer titrator .10
9.5 Procedure .11
9.5.1 Standardization of the Karl Fischer reagent .11
9.5.2 Determination .11
9.6 Calculation .11
9.6.1 Water equivalent of the Karl Fischer reagent .11
9.6.2 Water content of the sample .12
10 Determination of particle size.12
11 Precision .12
11.1 Ring test .12
11.2 Repeatability .12
11.3 Reproducibility .13
12 Test report .13
Annex A (informative) Interlaboratory testing .14
Bibliography .48
iv © ISO 2015 – All rights reserved
Foreword
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bodies (ISO member bodies). The work of preparing International Standards is normally carried out
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electrotechnical standardization.
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described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
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Any trade name used in this document is information given for the convenience of users and does not
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assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT), see the following URL: Foreword — Supplementary information.
The committee responsible for this document is ISO/TC 134, Fertilizers and soil conditioners.
Introduction
Sulfur Coated Urea (SCU) is a coated, slow release fertilizer consisting of urea particles coated with sulfur,
which was first developed by the Tennessee Valley Authority’s National Fertilizer Development Center
(TVA/NFDC), Alabama in 1961, and produced commercially in 1967. SCU is made by coating urea with
sulfur and sealant. It contains 30 % to 40 % nitrogen and 10 % to 30 % sulfur. The main coating material of
SCU is sulfur. Sulfur is insoluble in water and its chemical properties are stable, thus, it is an impermeable
coating material. In addition, sulfur itself is a secondary nutrient and it does not pollute the soil.
This International Standard specifies analytical methods, including mass fraction of total nitrogen, one-
day dissolution rate (1DDR), seven-day dissolution ra
...
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