Iron oxide symbol

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Fe2O3.H2O, FeO(OH), Goethite

Formula: FeO.OH or Fe2O3.H2O
Alternate Names: Iron(III) oxide, hydrated iron oxide, iron(III) hydroxide, yellow iron oxide

Oxide Analysis Formula 88.00% 1.000 12.00 Oxide Weight 160.00 Formula Weight 181.82 Enter the formula and formula weight directly into the Insight MDT dialog (since it records materials as formulas).
Enter the analysis into an Insight recipe and enter the LOI using Override Calculated LOI (in the Calc menu). It will calculate the formula. 3.5-7

This is one of the many colors of iron oxide. Yellow ochre clay contains yellow iron oxide. In ceramics red iron oxide is most commonly used in glazes and clay bodies, but black is also used. Yellow is the least color-stable form. Yellow iron oxide is a synthetic material of very fine particle size (but not as fine as black or red).

Actual yellow iron oxides are around 85% Fe2O3 and about 12% LOI with some impurities (e.g. SiO2, CaO).

Theoretically, any form of iron could be used to source Fe in the fired ceramic product (of course they lose different amounts of volatiles on firing so they cannot be substituted gram-for-gram). However in practice this is not the case. Yellow iron, in our tests, for example, does not stain a glaze but it does stain a clay body. The reason is not apparent to us yet.

Yellow irons can be used where raw color or other raw properties are important to the manufacturing process or color of the unfired product and where a less messy material is desired. Yellow iron is not as fluffy and light as black, but more than red. It does not agglomerate as badly as red, but more than black. It is coarser in particle size and does leave some lighter colored residue on a 325 mesh screen (up to 8% in one specimen we tested whereas the others left zero).

Yellow iron is also used in paints, enamels, concrete colorants, plastics, rubber, and paper where permanent yellow is required. It has excellent hiding power, absorbs ultraviolet light, is compatible with a broad range of vehicles, disperses well in aqueous and solvent systems, does not contain heavy metals.

One process of manufacture involves precipitation of ferric oxyhydroxide followed by purification through washing, drying and milling.

Pictures

Example of three different colors of iron oxide pigments

Out Bound Links

In Bound Links

• (Materials - Related) Iron Oxide Red - Fe2O3 - Synthetic Hematite

  Ferric Oxide, Red Iron Oxide, RIO, Iron(III) oxide, Fe2O3, Hematite

• (Materials - Related) Iron Phosphate - (FePO4)2 H2O - Ferric Phosphate

  Iron(III) phosphate, Ferric orthophosphate