The problem you’re solving
Glass batch houses need a consistent CaO source with tightly controlled iron so colour and redox stay predictable. GL-CAL supplies calcium carbonate at fine sizing with iron oxide at ≤ 0.04% representative.
Why this material fits
- CaO source in container and flat glass batches
- Low iron supports colour and redox control
- Fine sizing supports batch-free time
- Consistent marine-origin feedstock rather than blended quarry lots
Verified specifications
Representative values, technical data sheet Rev 2026.1. Lot-specific values are given on the certificate of analysis for the shipment supplied.
| Property | Value | Method |
|---|---|---|
| Calcium carbonate (CaCO₃) | 97.8% representative | — |
| Magnesium carbonate (MgCO₃) | ≤ 0.9% | — |
| Silica (SiO₂) | ≤ 0.6% | — |
| Iron oxide (Fe₂O₃) | ≤ 0.04% | — |
| Alumina (Al₂O₃) | ≤ 0.10% | — |
| Alkalis (Na₂O + K₂O) | ≤ 0.30% | — |
| Loss on ignition | ~ 43% | — |
| Crystal system | Orthorhombic (aragonite) | — |
| Specific gravity | 2.93 | — |
| Whiteness | 92–94 | ISO |
| Hardness | 3.5–4.0 Mohs | — |
| Surface area | 1.0–2.5 m²/g | — |
| Particle morphology | Rounded oolitic | — |
| CAS number | 471-34-1 | — |
Available particle sizes
- < 0.1 mm fine
- Custom distribution to your specification
Packaging options
- Bulk
Technical documents
- Technical data sheet (Rev 2026.1)
- Glass batch chemistry with aragonite (PDF)
- Safety data sheet (SDS) — sent by our team
- Certificate of analysis, current lot
No kiln. No calcination. Less processing than conventional calcined lime.
Frequently asked questions
What iron level should we design the batch around?
Iron oxide (Fe₂O₃) is ≤ 0.04% on the representative analysis in the Rev 2026.1 technical data sheet. Lot-specific values are given on the certificate of analysis for the shipment supplied.
Can you hit a specific particle size distribution?
Custom-sized material to a target distribution is available. Send the target distribution with your enquiry and our technical team will confirm feasibility.
Where GL-CAL is used
Ready to evaluate GL-CAL?
Send your specification, tonnage and delivery point and our team comes back with numbers, usually within one business day.