Glass Cullet

Every glass plant wants more cullet in the batch, and every glass plant pays for it in wear and sorting.

Wear is different here

Sharp glass edges cut belt covers and chute liners rather than polishing them.

• Thick, replaceable liners and belt covers specified for cut resistance.
• Low drop heights to limit both further breakage and impact damage.
• Chute design that keeps material sliding on a bed of its own kind.

Contamination control

Ceramics, stones and porcelain do not melt at furnace temperature and appear as inclusions in the product.

Optical sorting, magnets, eddy current separators and screening together determine whether the cullet is usable at high substitution rates.

Organic residues from the collection stream burn off, but they also create odour and sticky deposits in storage.

Fines and dust

Crushing produces a fine fraction that is respirable and contains crystalline silica.

Extraction at transfer points and enclosed conveying protect both the operators and the plant environment.

Storage and feeding

Cullet silos need steep, lined walls and outlets sized for the largest fragment, and vibrating feeders are preferred over screws for abrasion reasons.

What to establish before buying equipment

• Size distribution and the largest fragment that will arrive.
• Contamination profile of the supply stream.
• Required substitution rate, which sets the sorting investment.
• Wear part strategy and inspection interval.

Cullet is cheap material that destroys expensive equipment, and storage is where the contamination problem starts.

Recovered cullet arrives with whatever came through the collection system: ceramics, stones, metal and organics. A single ceramic fragment that reaches the furnace becomes an inclusion in the finished glass, so the store is also the last place to catch it.

• Keep streams separated by colour and by source; mixing them cannot be undone.
• Keep the store dry, because wet cullet carries fines and organics into the next step.
• Design the store so that the sorting and detection equipment sits upstream of it, not after.

Sharpness and impact dominate the equipment choice.

Cullet cuts belts, liners and skirting, and the damage concentrates where material lands. Chutes with impact zones, replaceable liners and generous radii are worth more here than a faster line.

• Impact beds and replaceable wear plates at every drop.
• Heavy-duty belts with rated cover thickness, and a maintained belt cleaner.
• Screening and separation designed as a process step, not as a filter.

The hazards are mechanical and respiratory.

• Cut protection for anyone working near open cullet.
• Dust capture at crushing and transfer; the fines contain crystalline silica.
• Guarding and lockout at screens and crushers, which are the pinch points.