BS ISO 556:2020 pdf download.Coke (greater than 20 mm in size) — Determination of mechanical strength.
For each of the determinations to be made, prepare a test portion from the amount given in Table 4 and charge it into the clean and empty drum, taking care to avoid breakage of the coke during charging. Secure the cover to the opening on the drum. Rotate the drum at a constant rotational frequency of (25 ± 1) min1 for the number of revolutions as given for the chosen test in Table .4. Allow the dust to settle for 1 mm, remove the opening and empty all the contents of the drum into the tray.
Use the same set of test sieves as for the preparation of the sample, so that a full-size analysis from all contents of the tray will be obtained. In all cases, use at least the sieves of aperture diameter 10 mm, 20 mm and 40 mm. Cumulatively weigh the size fractions of 10 mm and above, noting the mass of each individual size fraction. Weigh separately the fraction of size less than 10 mm and add this fraction also to the cumulatively weighed fractions.
Micum and Irsid tests may be performed on the same coke sample. In this case the sample which is taken out after 100 revolutions, sieved into fractions and weighed shall be retained completely in the drum and treated with an additional 400 revolutions. Check the loss of the test portion after the Micum test is carried out. If it is larger than specified in &1, stop further testing. If this combined test (Micum and Irsid test) is executed, it shall he specified in the test report.
8 Expression of results
8.1 Calculation
Calculate the percent mass fraction for each cumulative mass (determined as specified in 7.1) in relation to the initial test portion mass Li.e. of (50 ± 05) kg, or of (25 ± 0,25) kg, as per specifications in Table 4].
Add the loss of mass to the weighed mass of the fraction of size less than 10 mm, provided that the following conditions apply:
a) If the procedure specified in 2.1 starting with 50 kg of coke has been followed, the difference between the total of the masses of the individual fractions and the mass of the original test portion does not indicate a loss of more than 0,35 kg.
h) If the procedure specified in 71 starting with 25 kg of coke has been followed, the difference between the total of the masses of the individual fractions and the mass of the original test portion does not indicate a loss of more than 0,15 kg.
Round off each percentage to the first decimal place.
8.2 Micum indices
If Micum tests are carried out on coke of a lower size limit different from 20 mm, report the lower size limit of the test portion.
Express the results of Micum indices as follows:
a) Index M40 is the percentage of the test portion remaining on the 40 mm aperture test sieve after 100 drum revolutions.BS ISO 556 pdf download.