BS ISO 719:2020 pdf download.Glass — Hydrolytic resistance of glass grains at 98 °C — Method of test and classification.
7 Preparation of sample
7.1 Crushing
Check that the articles as received have been annealed to a commercially acceptable quality.
If an article is not annealed to a commercially acceptable quality, this fact should be noted because the results can he affected. Such articles, if very badly annealed, might also break very easily and extra care should be taken when handling them. Further annealing should not he carried out before the test.
Wrap the glass articles in clear paper and crush to produce two 100 g samples of pieces not more than 30 mm across.
7.2 Manual preparation
Place 30 g to 40 g ol’ pieces (see Li) between 10 mm and 30 mm across iii the mortar (611), insert the pestle (6.11), and strike it sharply, once only, with the hammer (6.1).
If more than one hammer blow is used in crushing the glass, the very fine particles produced may he compacted into aggregates which may or may not he subsequently broken down and which can, therefore, introduce further variables into the test.
Transfer the glass from the mortar to the upper sieve 0 of the assembled set of sieves (6.13) and shake the set of sieves briefly to separate the finer particles. Return the glass remaining on sieves A and 0 to the mortar. Repeat crushing and sieving until only about 10 g of glass remain on sieve 0. Discard the glass from sieve A and 0 and from the receiving pan. Shake the set of sieves by hand for 5 mm. Reserve for the test those grains that pass through sieve A and that are retained on sieve B.
At least 10 g of sample are required for the test. If it is necessary to crush and sieve more sample, the sample already obtained shall be removed from sieve B and stored in a weighing bottle (6.8).
After completion of all crushing and sieving, combine the samples, spread the grains on clean glazed paper and remove any iron particles using the magnet (6.12). Transfer the grains into a beaker (61) for cleaning.
7.3 Mechanical preparation
Transfer about 50 g of the coarsely broken glass (see Li) into the mill-beaker ñ.14). add the balls and crush thin-walled glass (wall thickness 1.5 mm) for 2 mm, thick-walled glass (>1,5 mm) for 5 mm.
Transfer the grains to the upper sieve 0 of the assembled set (6113) of the sieving-machine (6.15), sieve for about 30 s and collect the grains retained on sieve B in the beaker (62), which shall he kept in the desiccator 69). Transfer the glass from sieves 0 and A back into the hall-mill and crush again for the time given above. Repeat sieving and crushing until about 10 of grains have been collected from sieve B. Continue as specified in 2.3. last paragraph.BS ISO 719 pdf download.