The most highly recommend abrasive recovery type that offers the superior cost proficiency of the available options.
The abrasive classifier unit is used in conjunction with a bucket elevator and an underfloor recovery system. The bucket elevator and recovery system brings the abrasive up to the abrasive classifier which then utilizes a 'winnowing' principle to remove all the dust and waste.
The winnowing is a constant metered flow of air which passes through a curtain or ‘waterfall’ of abrasive under gravity, this carries the dust out to the dust collector and the fines are separated into another drum/skip. The good abrasive falls back into the storage hopper over the blast pot, ready to be used again. It is hard to think of any disadvantages with this system; wear is low because of low air velocities, fines are not loading up the dust collector, they are falling into a separate drum; the best thing is that you can achieve a high class of separation. Very little dust will find its way back into the blast pot, reducing dust levels within the blast room, and you will not be disposing good abrasive.
You can adjust it simply so that you can keep abrasive which has broken up but is still useful, or increase the airflow a little and it will return only larger particles to the blast pot.