Iron oxide powder is one of the most widely used industrial minerals. It colours concrete and paint, goes into magnets and welding fluxes, and is used for polishing and as a catalyst. Most buyers need one of two forms: red iron oxide or black iron oxide. They come from the same element, but they are different compounds and they are not interchangeable.
Red iron oxide (Fe₂O₃, hematite)
Red iron oxide is ferric oxide, the same compound as the mineral hematite. It is stable, non-magnetic in ordinary use, and gives a strong red-brown colour.
Where it is used:
- Pigments: colouring paints, coatings, concrete, paving blocks, tiles, plastics and rubber.
- Ferrites: as a raw material for soft and hard ferrite magnets.
- Polishing: fine red oxide, sometimes called jeweller’s rouge, polishes glass and metals.
- Catalysts and chemicals: as a catalyst or catalyst support, and as an iron source in chemical processes.
- Welding and ceramics: in electrode coatings and in ceramic bodies and glazes.
Black iron oxide (Fe₃O₄, magnetite)
Black iron oxide is magnetite, which contains iron in two oxidation states. Its two most useful properties are its deep black colour and its strong magnetism.
Where it is used:
- Pigments: black colour for concrete, coatings and plastics.
- Magnetic applications: toners, magnetic inks, and some ferrite and magnetic-separation uses.
- Welding: in electrode coatings and fluxes.
- Heavy media and other uses: where its density and magnetism are an advantage.
How to tell them apart
| Property | Red iron oxide | Black iron oxide |
|---|---|---|
| Chemical formula | Fe₂O₃ | Fe₃O₄ |
| Mineral name | Hematite | Magnetite |
| Colour | Red to red-brown | Black |
| Magnetism | Weak / non-magnetic | Strongly magnetic |
| Main uses | Pigments, ferrites, polishing, catalysts | Black pigment, magnetic uses, welding |
A quick check is a magnet: black iron oxide is drawn to it, and red iron oxide is not.
What to specify when buying iron oxide powder
- Form: red (Fe₂O₃) or black (Fe₃O₄).
- Purity: the Fe₂O₃ or Fe₃O₄ content, and limits on moisture and water-soluble salts.
- Particle size: mesh or micron range. Pigment and polishing uses need fine powder.
- Colour and tint strength: important for pigment buyers. Ask for a sample to match against your standard.
- End use: tell the supplier what the powder is for, so they can recommend the right grade.
Iron oxide powder from Powdrox
Powdrox supplies red, black and yellow iron oxide powder to your specification, for buyers across India and for export. Each supply comes with a Certificate of Analysis and MSDS on request, and trial quantities are available. Send us your requirement and we will quote a matching grade.