Figure6a, b show the variation of the porosity and
volume with the hold time at maximum compaction. All
pellets showed a decrease in the porosity and volume with
increasing hold time. Correspondingly, the strength of the
pellets during compaction increased with increasing hold
time (Fig. 6c). These changes appeared to reach a plateau
after a hold time of 60 s as no or near-zero porosities in the
pellets were reached.