BS EN 12948-2010 pdf download.Liming materials Determination of size distribution by dry and wet sieving.
4.6 Oven, capable of being controlled at (105 ± 2) °C.
5 Sampling and sample preparation
Sampling is not part of the method specified in this document. A recommended sampling method is given in
EN 1482-1.
Sample preparation shall be carried out in accordance with EN 1482-2.
6 Procedure
6.1 Test portion
The whole laboratory sample shall be divided in equal test portions of at least 100 g. The size of the test portions will vary according to the coarseness of the laboratory sample and shall be in accordance with EN 1235:1995, Table 1. subject to a minimum of 100g.
6.2 Method A
6.2.1 Preparation of test portions
Dry wet samples if there is a possibility that blinding of the sieves could occur during the sieving.
Dry the wet sample in an oven (4.6) at (105 ± 2) °C for an appropriate period of time (see EN 12048).
Check whether agglomeration occurs after drying by carrying out a preliminary sieving test.
Use method B if agglomeration occurs.
6.2.2 Determination
WARNING — When sieving burnt or hydrated lime products, it is essential that precautions are taken to avoid Inhalation and skin contact with the product. It Is recommended that operations are carried out under a fume hood and appropriate gloves and eye protection are worn.
6.2.2.1 Carry out at least two single determinations on separate test portions prepared from the same laboratory sample.
6.2.2.2 Select a maximum of seven test sieves (4.3) from the range of principal sizes listed in ISO 565 to cover the range of particle size expected. For granular liming materials perforated plates according to ISO 3310-2 may be used.
Assemble the sieves in ascending order of aperture size on top of the receiver.
Weigh the test portion (6.1) to the nearest 0,01 g per 100 g of test portion, place it on the top sieve and fit the cover.
6.2.2.3 Place the sieve or the assembled nest of sieves on the mechanical shaker (4.2) and shake for exactly 10 mm (use a stopwatch (4.4)). Set the mechanical shaker to a medium vibration frequency throughout the sieving.
6.2.2.4 If a nest of sieves is used, remove the sieves from the nest and weigh the quantity retained on each sieve and in the receiver to the nearest 0,01 g. Remove particles caught in the mesh of the sieve by brushing the reverse side of the sieve.
6.2.2.5 If only one sieve is used, discard the undersize fraction that has passed through the sieve. Repeat the sieving process for exactly I mm. If more than 0,2 g passes through the sieve, repeat the procedure as many times as necessary. Remove particles caught in the mesh of the sieve by brushing the reverse side of the sieve. Weigh the oversize fraction.
6.3 Method B
6.3.1 General
Use an additional test portion to determine the moisture content in accordance with EN 12048.
Carry out at least two single determinations on separate test portions prepared from the same laboratory
sample.
6.3.2 Determination
6.3.2.1 Non-granulated and non-agglomerated products
6.3.2.1.1 Select a maximum of seven test sieves (4.3) 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.
Weigh the test portion (6.1) to the nearest 0,01 g per 100 g of test portion, place it on the top sieve and fit the lid with the intake for water.
6.3.2.1.2 Place the assembled nest of sieves on the mechanical shaker (4.2) and shake under a continuous water flow of 2,0 11mm to 2,5 1/mm for exactly 10 mm (use a stopwatch (4.4)).
Set the mechanical shaker to a medium vibration frequency throughout the sieving.
6.3.2.1.3 Remove the sieves from the mechanical shaker and rinse the residues of each sieve quantitatively into separate 250 ml pre-weighed beakers.
Decant or pipette most of the water on the top of the matenal, ensuring that no material is spilled.
Dry each of the oversize fractions in an oven (4.6) at (105 ± 2) °C and then weigh each fraction separately
(see EN 12048).
6.3.2.2 Granulated and agglomerated products
Weigh the test portion (6,1) to the nearest 0,01 g per 1009 of test portion and transfer it into a 800 ml beaker.
Add approximately 500 ml of water. Stir the granules for 10 mm by means of a mechanical stirrer with a rotational speed not exceeding 800 min’. Avoid grinding.
Rinse out the sample completely on to the top sieve and fit the lid with the intake for water. Continue according to 6.3.2.1.2 and 6.3.2.1.3.
If the sum of individual masses is less than 95 % of the original mass, it should be assumed that the sample contains water-soluble constituents.
7 Expression of results
7.1 Method A
7.1.1 Record the masses of the fractions retained on the sieves and the receiver (see 6.2.2.4 and 6.2.2.5).BS EN 12948-2010 pdf download.