In an enclosed blast room with a recovery system, abrasive stops being a consumable and becomes an asset that depreciates. That shift is what makes garnet economics work in workshops where copper slag wins on open sites.

How recovery changes the numbers

Each blasting pass fractures some grains and leaves others intact. A recovery system collects the used abrasive, screens out fines and contamination, and returns serviceable material to the pot. Tough angular garnet survives multiple cycles, so purchase volume falls to a top up rate replacing what was lost as fines and carry out, rather than the full consumption of a single use abrasive.

The real comparison therefore involves three numbers: top up rate per hour of blasting, labour and energy for the recovery and screening system, and disposal cost for spent material and dust.

Disposal is the forgotten line

Spent abrasive plus removed coating is waste that must be handled and disposed of, and where the removed coating contains hazardous material such as old lead or chromate pigments, disposal cost rises sharply. A single use abrasive generates several times the waste volume of a recycled one for the same area prepared. On projects removing old industrial coatings, this line frequently exceeds the abrasive purchase itself.

Maintaining the working mix

Recycled abrasive is a graded mix, not fresh material. As cycles accumulate, the particle size distribution shifts finer, which reduces cutting rate and changes the achieved surface profile. Two controls keep it in specification: effective screening to remove undersize particles and dust, and disciplined top up with fresh abrasive to maintain the coarse fraction.

Monitor achieved profile periodically rather than assuming, since a drifting mix produces a profile that gradually falls below the coating specification. The consequences are covered in our surface preparation guide.

Contamination control

Recycled abrasive accumulates whatever comes off the work: oil, chlorides, coating residues. Where the next job is immersion service with soluble salt limits, contaminated recycled abrasive undermines the whole preparation. Segregating abrasive by job type, or using fresh material for critical work, is standard practice in shops handling mixed work.

MENA Industrial Supplies supplies washed garnet 30/60 for blast rooms and recovery systems across the UAE.