EN 1235-1995 pdf download.Solid fertilizers – Test sieving.
This International Standard specifies a method for the determination of the particle size distribution of solid fertilizers by test sieving. J
NOTE The applicability of the method has been tested with sieves of nominal sizes of openings between 100 jim and 5.60 mm.
E Annex ZA gives E) guidance on the interpretation of sieving test data J.
Annex ZB lists the bibliography. J
2 References
I ISO 565:1990, Test sieves — Woven metal wire cloth, perforated plate and elect roformed sheet — Nominal sizes of openings.
ISO 2395:1990, Test sieves and test sieving — Vocabulary.
ISO 2591:1988, Test sieving.
ISO 3310-1:1990, Test sieves — Technical requirements and testing— Part 1: Test sieves of metal wire cloth.
ISO 3944:1992, Fertilisers — Determination of bulk density (loose)’).
3 Definitions
For the purpose of this International Standard, the definitions of ISO 2395 apply.
4 Principle
Dry sieving of a fertilizer sample with one or more test sieves using a mechanical sieving machine.
5 Apparatus
5.1 Balance, capable of weighing to the nearest 0,1 g.
5.2 Stainless steel woven wire test sieves, 200 mm diameter, complying with ISO 33 10-1, with a lid and receiver for the sieves.
5.3 Mechanical shaker (sieving machine), capable of imparting both horizontal and vertical motion to material inside a nest of sieves.
5.4 Stopwatch.
5.5 Soft brush.
6 Sampling
ED Carry out sampling by an appropriate method. J
7 Preparation of the test portion
Reduce the sample (a method will form the subject of a future International Standard) to the quantity required for the sieving test. This quantity should be approximately that indicated in column 2 of Table 1 for the sieve corresponding to the dominant size fraction of the sample, provided that the size distribution does not cause excess volume on any of the sieves in the set as indicated in column 3 of Table 1.
8 Procedure
8.1 Select a maximum of seven test sieves from the range of principal sizes listed in ISO 565 to cover the range of particle size expected. Assemble the sieves in ascending order of aperture size on top of the receiver.
NOTE Normally the principal sizes (R 2013) should be used. In special cases, however, it may be necessary to use supplementary sizes (R 20).
8.2 Weigh the test portion to the nearest 0,1 g, place it on the top sieve and fit the cover.
8.3 Place the assembled nest of sieves on the mechanical shaker and shake for 10 mm.
8.4 Remove the sieves from the nest and weigh the quantity retained on each sieve and in the receiver to the nearest 0,1 g. Particles caught in the mesh of the sieve may be removed by brushing the reverse side of the sieve.
8.5 Carry out at least two tests on separate test portions prepared from the same laboratory sample.
9 Expression of results
9.1 Sum the masses of the fractions retained on the sieves and in the receiver.
NOTE The sum of these masses should not differ by more than 1 % from the original mass of the test portion.
9.2 Calculate each fraction mass as a percentage of the sum of these masses.
10 Precision
The statistical information given here is only intended as a guideline to what can be expected. The values are based on the evaluation of collaborative studies which have been carried out using sieves of nominal sizes of openings between 100 .im and 5,60 mm.
10.1 Repeatability, r
The difference I x1 — x2 I between two single results (x1 and x2) found on identical test material by one operator using the same apparatus within the shortest feasible time interval will exceed the repeatability value r, expressed as a percentage, given by equation (1) and with a maximum value of 2,5 %, on average not more than once in 20 cases in the normal and correct operation of the method. Both results should be considered suspect if the repeatability value r is exceeded.
r = 0,5ft . . (1)
where is the mean value of the two results, expressed as a percentage by mass, of the fractions.
10.2 Reproducibility, R
Single results (x1 and x2) on identical test material reported by two laboratories will differ by more than the reproducibility value R, expressed as a percentage, given by equation (2) and with a maximum value of 12,5%, on average not more than once in 20 cases in the normal and correct operation of the method. Both results should be considered suspect if the reproducibility value R is exceeded.EN 1235-1995 pdf download.