South African chromite powder is mainly used for green, olive‑green and tea‑tint coloring of beer bottles and glass bottles. For South‑African‑origin chromite powder, the required Cr₂O₃ content shall be ≥46.0%.
Grade Classification
High‑grade stable emerald‑green (main grade for beer bottles) Typical Cr₂O₃: 46.3‑46.8 %, batch fluctuation controlled within ±0.8%; Cr/Fe ratio ≥1.55:1. It delivers stable color, low yellowing tendency and no black‑spot defects. Conventional particle size: 325 mesh (−45 μm) to ensure melting and dispersion without particle speckles.
Economical grade for yellow‑green and tea‑tint glass Cr₂O₃: 40‑42 %. Low‑cost with yellow‑green tint. Suitable for container glass with low requirements for green color saturation. Not recommended for high‑grade emerald‑green bottles.
Specifications of South African Iron Chromite flour Powder
| Item | Guarantee % | Typical % |
|---|---|---|
| Cr₂O₃ | ≥46.0 | 46.4 |
| Total Fe (FeO) | ≤26.5 | 26.0 |
| SiO₂ | ≤1.0 | 0.92 |
| Al₂O₃ | ≤15.5 | 13.5 |
| CaO | ≤0.30 | 0.11 |
| MgO | ≤10.0 | 8.5 |
| TiO₂ | ≤1.0 | 0.6 |
| P, S | ≤0.003 | trace |
| Cr/Fe ratio | ≥1.55:1 | 1.58:1 |
| Moisture | ≤0.1 | 0.08 |
| Size | 325 mesh | 95% pass 45 μm |
Key Impurity Notes
- SiO₂ ≤1.0%: Excessive silicon easily causes bubbles and stone defects.
- CaO ≤0.30%: High calcium content will generate black sand specks.
- 325‑mesh size is preferred. Over‑coarse particle size will result in tiny black particles on glass surfaces.