BS ISO 17322:2015 pdf download

BS ISO 17322:2015 pdf download.Fertilizers and soil conditioners — Analytical methods for Sulfur Coated Urea (SCU)
1 Scope
This International Standard 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 (H 2 O), and particle size of SCU.
These methods are applicable to SCU.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 760, Determination of water — Karl Fischer method (General method)
ISO 3310-1, Test sieves — Technical requirements and testing — Part 1: Test sieves of metal wire cloth
ISO 5315, Fertilizers — Determination of total nitrogen content — Titrimetric method after distillation
ISO 17323, Fertilizers and soil conditioners — Sulfur Coated Urea — General requirements
3 Sampling and sample preparation
Sampling and sample preparation shall be carried out in accordance with ISO 17323.
4 Determination of the appearance
It shall be determined by visual method.
5 Determination of the mass fraction of total nitrogen
It shall be determined in accordance with ISO 5315.
6 Determination of 1DDR and 7DDR
6.1 Titrimetric method after distillation
6.1.1 Principle
Digest the testing sample in static water at a constant temperature (38,0 ± 0,5) °C. Within a certain period, the nitrogen component in the testing sample will dissolve into the water through the coatings,and then the released nitrogen can be determined by titrimetric method after distillation. The percentage of released nitrogen to the total nitrogen is defined as 1DDR or 7DDR.
6.1.3 Apparatus
6.1.3.1 Common laboratory apparatus.
6.1.3.2 The apparatus listed in ISO 5315.
6.1.3.3 Balance, capable of weighing to the nearest 0, 01 g.
6.1.3.4 Constant temperature incubator, capable of being controlled at (38,0 ± 0,5) °C.
6.1.4 Procedure
The replicate experiments shall be done for the determination.
6.1.4.1 Place 20 g uncrushed test sample (accurate to 0,01 g) into a small bag made of 100 meshes nylon yarn nets. Then, seal the bag and place it into a 250 ml Erlenmeyer flask with a plug.
6.1.4.2 Add 200 ml of water into the flask precisely before the flask sealed with the plug.
6.1.4.3 Shake the glass flask gently to disperse the particle of test portion. Then, place the glass flask into a constant temperature incubator with temperature set at (38,0 ± 0,5) °C and keep for 24 h and 7 d,respectively.
6.1.4.4 After a set period, take out the flask from the incubator and reverse it gently three times to ensure the uniformity of solution concentration throughout the flask.
6.1.4.5 Then, cool the flask down to room temperature, and the solution should be filtrated with dry filter paper with a pore size of 30 µm to 50 µm.