Glass Manufacturing
Glass batch chemistry with oolitic aragonite
The calcium carbonate values a batch calculation needs, the colourants and minor constituents a batch chemist reviews, and the status of each figure.
Summary
Calcium carbonate is the CaO source in a soda-lime batch. AragoCor oolitic aragonite analyses at 96.17% CaCO₃ (representative analysis, ASTM C 25, Bowser-Morner report 124914A) and is supplied for glass as GL-CAL, below 0.1 mm. Every value below carries its evidence status; none is a guaranteed minimum or maximum. No batch or furnace energy reduction is claimed against calcitic limestone.
Batch calculation
| Property | Value | Status | Use in the batch calculation |
|---|---|---|---|
| Calcium oxide (CaO) | 53.88% | Representative analysis | The CaO contribution to work the batch from. |
| Calcium carbonate (CaCO₃) | 96.17% | Representative analysis | Carbonate content of the tested sample; not a supplied minimum. |
| Loss on ignition | 43.50–45.00% | Published range | Mass lost on ignition, consistent with the carbonate content; use for batch yield. |
| Elemental calcium | 38.51% | Representative analysis | Same report and method as the composition. |
| Moisture, as received | 5–10% | Published range | Weigh as received; dried feed must be specified at order. |
| Specific gravity | 2.93 | Representative analysis | Silo, conveying and mixing calculations. |
Colourants and minor constituents
| Constituent | Value | Status | What a batch chemist does with it |
|---|---|---|---|
| Iron oxide (Fe₂O₃) | 0.01% | Representative analysis | One tested sample, not a supplied maximum. Agree an iron limit as a specification at order; confirm per lot on the certificate. |
| Silica (SiO₂) | < 0.01% | Representative analysis | Below detection in the tested sample. |
| Aluminium oxide (Al₂O₃) | 0.10% | Representative analysis | Enters the alumina balance. |
| Magnesium (MgCO₃ / MgO) | 0.24% / 0.12% | Representative analysis | Low magnesium; not a dolomite substitute. |
| Strontium carbonate (SrCO₃) | 1.43% | Representative analysis | The largest non-calcium carbonate present; disclose where a specification limits it. |
| Sulfur trioxide (SO₃) | 0.10–0.20% | Published range | Enters the sulfate balance with the fining agents. |
| Sodium chloride (NaCl) | 0.06–0.25% | Published range | Residual sea salt from a marine deposit; enters the chloride balance. |
| Sodium | 0.21% | Representative analysis | EPA 6010, Precision Enviro-Tech. |
Thermal behaviour
Calcium carbonate decomposes to calcium oxide and carbon dioxide at approximately 825 °C (published reference for the mineral species, not a test of AragoCor material). Aragonite is metastable and converts to calcite on heating before it decomposes, so the carbonate reaches decomposition as calcite whichever form was charged. For that reason no reduction in batch or furnace energy is claimed against calcitic limestone. Any thermal effect of the oolitic grain form is established in the buyer’s own batch trial, under the furnace conditions that apply.
Sizing and handling
Qualifying the material
| What to send | What comes back |
|---|---|
| Glass type and the batch specification, including iron and sulfur limits | A review of those limits against the analysis above, and which can be agreed as a specification. |
| Sizing required, or the standard batch sizing | Confirmation of GL-CAL or a custom classification within 100–325 mesh. |
| Annual volume, packaging and destination | A quotation against confirmed volume, packaging and destination, with freight to the named delivery point. |
| A sample request for the batch trial | Sample availability, quantity and how it ships, confirmed after review. |
Conclusion
Container, flat, solar, fibreglass and specialty batches each set their own chemistry and optical limits. The figures in this brief are the material as tested and published; the batch chemist sets the limits, and the batch trial, not the mineral data, establishes performance. The grade’s technical data sheet is TDS-GL-001; the full composition is in TDS-OA-001.