Iron oxide pigments are the most often used colour pigments in the world. They are available in the primary colours yellow (FeOOH), black (Fe3O4) and red (Fe2O3), but also as a mixture in orange, beige and brown shades.
For more information, please visit CHENGYU.
Iron Oxides have been used since prehistoric times (mainly the red shades). They were first used by cavemen to leave testimony of their presence in cave dwellings including animal drawings to ensure bountiful hunting. The first cave drawing was found in the Saubia Mountains (Germany), Lascaux (France) and Altamira (Spain). They were painted between 40,000 and 10,000 BC. Iron Oxide rich mineral clays provided the colors used. Iron Oxide was later found in Neolithic ceramic, Renaissance or Impressionist paintings, bricks of early cities, etc. Natural Iron Oxides are still used nowadays. However, synthetic types are much more popular nowadays because of their higher pigment performance. Their widespread use is due to their natural shade and outstanding chemical, physical and technical properties, which make them essential in many applications.
Initially, the Laux process was exclusively used to manufacture aniline (C6H5NH2) from nitrobenzene (C6H5NO2). Only when in the chemist, Dr Laux, found out that the iron oxide, being a by-product of this reaction, could be used, subject to certain chemical conditions, as an iron oxide pigment with extremely high colour strength. This process is primarily used for black iron oxide (e.g. Black 330), however, the reaction to get iron oxide yellow (e.g. Yellow 420) is also possible. From black iron oxide, it is also possible to produce red iron oxide pigments (e.g. Red 110) in an additional reaction stage.
In the precipitation process, iron sulphate is oxidized to yellow iron oxide pigment (Bayferrox® Yellow 920) in an alkaline environment with atmospheric oxygen. In this case, similar to the Penniman process, a yellow nucleus pigment is necessary in order to obtain yellow pigments of a high quality.
In the Penniman process, iron scrap is oxidized to yellow iron oxide (Bayferrox® Yellow 920) in a sulphate acid medium in the presence of atmospheric oxygen. In this case, iron sulphate acts as a catalyst. As to obtain yellow pigments of a high quality, yellow nuclei are furthermore necessary.
Synthetic red, yellow, orange, brown and black iron oxides are non-toxic and made from 60% post-industrial recycled content processed .
Iron oxide Pigments are widely used as inexpensive, durable pigments with large number of benefits and application around wide range of industries and products
Iron oxides are chemical compounds composed of iron and oxygen. Several iron oxides are recognized. Often they are non-stoichiometric. Oxyhydroxides are a related class of compounds, perhaps the best known of which is rust.[1]
Iron oxides and oxyhydroxides are widespread in nature and play an important role in many geological and biological processes. They are used as iron ores, pigments, catalysts, and in thermite, and occur in hemoglobin. Iron oxides are inexpensive and durable pigments in paints, coatings and colored concretes. Colors commonly available are in the "earthy" end of the yellow/orange/red/brown/black range. When used as a food coloring, it has E number E172.
Stoichiometries
[
edit
]
Iron oxide pigment. The brown color indicates that iron is at the oxidation state +3. Green and reddish brown stains on a limestone core sample, respectively corresponding to oxides/hydroxides of Fe2+ and Fe3+.Iron oxides feature as ferrous (Fe(II)) or ferric (Fe(III)) or both. They adopt octahedral or tetrahedral coordination geometry. Only a few oxides are significant at the earth's surface, particularly wüstite, magnetite, and hematite.
Thermal expansion
[
edit
]
Iron oxide CTE (× 10&#;6 °C&#;1) Fe2O3 14.9[6] Fe3O4 >9.2[6] FeO 12.1[6]III
x
II
y
SO
2&#;
4
)Reactions
[
edit
If you want to learn more, please visit our website iron oxide pigments for paper.
]
In blast furnaces and related factories, iron oxides are converted to the metal. Typical reducing agents are various forms of carbon. A representative reaction starts with ferric oxide:[9]
2 Fe2O3 + 3 C &#; 4 Fe + 3 CO2
In nature
[
edit
]
Iron is stored in many organisms in the form of ferritin, which is a ferrous oxide encased in a solubilizing protein sheath.[10]
Species of bacteria, including Shewanella oneidensis, Geobacter sulfurreducens and Geobacter metallireducens, use iron oxides as terminal electron acceptors.[11]
Uses
[
edit
]
Almost all iron ores are oxides, so in that sense these materials are important precursors to iron metal and its many alloys.
Iron oxides are important pigments, coming in a variety of colors (black, red, yellow). Among their many advantages, they are inexpensive, strongly colored, and nontoxic.[12]
Magnetite is a component of magnetic recording tapes.
See also
[
edit
]
References
[
edit
]
Contact us to discuss your requirements of Iron Oxide Paint Colors. Our experienced sales team can help you identify the options that best suit your needs.