Glass Green Material (Chromite Powder / Chrome Flour)，It is a natural mineral green colorant for glass, refined from high-grade South African chromite ore. Cr₂O₃ ≥46%, standard 325 mesh. It is the preferred olive green / beer green colorant for soda-lime-silica beer bottles, fruit wine bottles and olive oil bottles. It replaces high-priced synthetic chromium oxide green and is suitable for mass production in continuous container glass furnaces. It provides both coloration and UV shielding to protect wine and beverages from oxidation degradation caused by ultraviolet rays.
Specifications: Green Glass Chromite flour-46% Cr₂O₃ 325 Mesh Colorant for Beer Bottles
| Item | Specification |
|---|---|
| Cr₂O₃ | ≥44–47% (core color-forming component) |
| SiO₂ | ≤3.0% (strictly controlled to avoid glass stones and cords) |
| Total Iron (FeO+Fe₂O₃) | 26–28% |
| Al₂O₃ | ≤15.5% |
| MgO | ≤10.0% |
| CaO | ≤0.3% |
| Particle Size | 325 mesh, ≥95% passing sieve |
| Moisture | ≤0.5%, free-flowing without caking, low magnetic impurities |
| Appearance | Dark black-brown fine mineral powder |
Coloration Mechanism of Chromite Powder as Glass Colorant
The main mineral of South African chromite powder is ferrous chromite (FeCr₂O₄). During glass melting at 1400–1550 °C, it releases stable Cr³⁺ ions, which selectively absorb ultraviolet light and transmit uniform olive green / classic beer green. It contains inherent natural iron for a soft and stable hue, so large additional iron colorants are generally not required. It features excellent high-temperature stability, good color fastness and controllable batch-to-batch color deviation. Compared with chromium oxide green, it greatly cuts the coloring cost for container glass and adapts to long continuous furnace production.
Types of Glass Bottles Suitable for Coloring with Chromite Powder
- Beer bottles, wine / fruit wine, olive oil and sauce green packaging glass bottles (main market)
- Light-proof oral liquid, essential oil and aromatherapy green vials
- Decorative art green glass and daily-use colored soda-lime-silica glass; can be compounded with cobalt, copper and manganese to formulate dark green and blue-green color systems
Glass Green Material – Chromite Powder | Green Glass Colorant for Beer Bottles, 46% Cr₂O₃ – Standard Grades
| Mesh Size | Guaranteed Value | Typical Test Result |
|---|---|---|
| 200# | ≥90% passing 200# sieve | 95–100% |
| 270# | ≥90% passing 270# sieve | 95–100% |
| 325# | ≥90% passing 325# sieve | 95–100% |
| 400# | ≥90% passing 400# sieve | 95–100% |
| 500# | ≥90% passing 500# sieve | 95–100% |
| 600# | ≥90% passing 600# sieve | 95–100% |
| 800# | ≥90% passing 800# sieve | 95–100% |
| 1000# | ≥90% passing 1000# sieve | 95–100% |
| 1200# | ≥90% passing 1200# sieve | 95–100% |
| 1500# | ≥90% passing 1500# sieve | 95–100% |
| 2000# | ≥90% passing 2000# sieve | 95–100% |
| 2500# | ≥90% passing 2500# sieve | 95–100% |
