The chrome oxide green that becomes metallic chromium. Engineered for aluminothermic reduction: controlled particle gradation, low carbon and silicon — so your metal comes out clean and your yield stays predictable.
Aluminothermic (Goldschmidt) reduction — one of the oldest and still the cleanest routes from oxide to metal.
Cr₂O₃ + 2 Al → 2 Cr + Al₂O₃. A self-sustaining exothermic reaction reaching well above the melting point of both chromium (1907 °C) and alumina slag — the metal settles, the slag floats.
Metallic yield is set by oxide purity and particle contact with aluminium powder. Our smelting grade is screened to a controlled window — fine enough for fast, complete reaction, coarse enough to stay mixed before ignition.
Low carbon and low silicon in the oxide translate directly into low carbon and silicon in the metal — critical for the aerospace-grade and ferroalloy markets that specify 99%+ chromium.
The aluminothermic (Goldschmidt) process in numbers — one reaction, self-sustaining, no external fuel.
Density does the separating: liquid chromium (6.3 g/cm³) sinks below molten alumina (2.7 g/cm³) — no stirring, no tapping, just gravity and a clean slag line.
Cr₂O₃ + 2 Al → 2 Cr + Al₂O₃. The oxide hands its oxygen to aluminium; molten chromium sinks, alumina slag floats, and the two separate cleanly.
Reaction enthalpy ≈ −536 kJ per mole of Cr₂O₃ — enough to drive the charge to roughly 2400–2700 °C adiabatically, far above the melting points of chromium (1907 °C) and the alumina slag.
Density does the work: liquid chromium (≈6.3 g/cm³) settles below the molten alumina slag (≈2.7 g/cm³). A clean slag line means a clean metal block on solidification.
Typical chromium-metal targets that our smelting-grade oxide is engineered to support (reference grades per GB/T 3211; confirm final specs with your smelter).
| Element | Typical target | Where the limit comes from |
|---|---|---|
| Chromium | ≥ 99.0 % | Oxide purity — every impurity in the oxide reports to the metal |
| Carbon | ≤ 0.03 % | Low-C oxide feedstock; aerospace-grade alloys demand it |
| Silicon | ≤ 0.25 % | Controlled by charge stoichiometry and oxide cleanliness |
| Iron | ≤ 0.35 % | Oxide Fe content plus aluminium-powder purity |
| Aluminium | ≤ 0.30 % | Excess reductant — tuned by your charge recipe |
| Sulphur | ≤ 0.02 % | Low-S oxide lot selection |
Values verified per batch with full traceability from Cr ore (HS 261000) to pallet.
| Parameter | Typical value | Parameter | Typical value |
|---|---|---|---|
| Cr₂O₃ content | ≥ 99.0 % | Particle gradation | Controlled window (custom) |
| Carbon | Low | Bulk density | High (sintered) |
| Silicon | Low | Moisture | ≤ 0.3 % |
| Packaging | 25 kg bags · 1 t big bags | Traceability | Blockchain QR per lot |
Metallurgy articles written around the smelting-grade oxide — chemistry, quality and process notes.
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