(e) Effect of agitation
Agitation is often employed to enhance leaching process, and
the effect of agitation on the leaching of Al from WPBs is further
studied. As shown in Fig. 6, the recovery of Al increases with
increasing of agitation speed. The effect of agitation can be
explained by the fact that agitation increases the efficiency of
mass transfer to accelerate the Al dissolution. At fixed experimental
conditions, the recovery of Al is 34.0% without agitation,
becomes 82.0% at 800 r min1, and rises up to 100% at
800 r min1. Therefore, agitation is necessary in the leaching
process, and the agitation speed more than 500 r min1 is a
better choice.