Raw material: South‑African chromite ore powder (Glass‑Grade Chromite Flour). The mainstream industry grade: Cr₂O₃ ≥46%, 325 mesh (-325#).
Standard Specifications (Commonly Adopted by Glass Plants)
Chemical Indexes (Glass‑coloring Grade)
Chemical Indexes (Glass‑coloring Grade)
| Item | Specification |
|---|---|
| Cr₂O₃ | ≥46.0% |
| SiO₂ | ≤1.0% (Excessive silica causes devitrification and spots) |
| CaO | ≤0.30% (CaO shall be strictly controlled) |
| P, S | ≤0.003% (Trace impurities to prevent bubble formation) |
| Cr/Fe Ratio | 1.55:1 |
Particle Size Selection
- 325 mesh (45 μm, 98% passing) [Most Popular]: First‑choice for olive‑green beer bottles. It achieves complete melting without black spots or color mottling, delivering uniform and stable color.
- 200 mesh: Used in some old production lines. Larger particles tend to trigger black spots, and this grade is gradually replaced by 325 mesh.
- 400‑600 mesh: For high‑grade emerald‑green glass bottles with better dispersion at higher cost.
