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Industrial minerals
Published in Francis P. Gudyanga, Minerals in Africa, 2020
Ochre is a natural earth pigment containing hydrated iron oxide. Its colour ranges from yellow to deep orange or brown [883–885]. It is a family of earth pigments whose major ingredient is iron(III) oxide-hydroxide, limonite, responsible for the yellow colour. When natural sienna and umber pigments are heated, they are dehydrated and some of the limonite is transformed into haematite, giving them more reddish colours, called burnt sienna and burnt umber [1247]. Ochres are non-toxic and can be used to make an oil paint that dries quickly and covers surfaces thoroughly.
Textiles
Published in Jill L. Baker, Technology of the Ancient Near East, 2018
The Egyptians also made use of ochre and plant dyes. Ochre is a natural earthen pigment comprised of hydrated iron oxide and clay, and can be yellow, deep orange, or brown in color; however, yellow was the most commonly used color. Yellow ochre can be made red by heating dehydrated iron oxide and mixing the two. Red ochres come from anhydrous ferric oxide (Vogelsang-Eastwood 2000:278), or from ochre that contains a large quantity of hematite. The practice of dyeing linen with iron oxide dates to at least the Early Dynastic period and the Tarkhan textile. For example, textiles dyed with iron oxide have been found at the village of Amarna (Vogelsang-Eastwood 2000:278–279).
Killing death
Published in Sidney Dekker, The End of Heaven, 2017
And one of those myths would have been about the afterlife. Burial of the dead, and placing objects with them, pointed to a belief in an existence beyond the present: the goods would be useful to the deceased in the future. This, in turn, suggests much more than an awareness of death. One remarkable and widespread ritual during the Palaeolithic as well as Neolithic period was the liberal sprinkling of graves with ochre. This has been found in Europe, the Americas and Australia. Ochre is an earthy pigment containing iron oxide. This makes it red. One speculation is that it was meant to replace the blood of the dead, replenishing a fluid evidently critical for (continued) life.6
Mine-derived ochre precipitates: a potential selenium trap
Published in Applied Earth Science, 2019
L. A. Bullock, J. Parnell, J. G. T. Armstrong, M. Perez
In the last 10 years, attention has turned to the potential for ochres to be used as an ideal material for ground remediation projects. Ochres may act as a replacement for ferric sulphate in waste water treatment, and can be used as an iron oxide pigment due to its high iron oxide content. The Coal Authority has begun to find uses for thousands of tonnes of ochre to immobilise contaminants. Coal has been specifically identified as a promising source for future prospects by the UK Energy Research Centre, and pyrite has been noted as a potential source of economic interest for selenium. This is because selenium has a close chemical affinity to sulphur, found in pyrite and organic matter. As such, pyritic and organic-rich rocks may contain significant amounts of selenium. Conversely, high selenium coals can pose environmental threat to local soils, surface and groundwater systems, and has affected coal mining regions such as West Virginia, and Elk Valley, British Columbia. Therefore, understanding how selenium concentrates in ochre deposits is of great economic and environmental importance to UK conservation and resource authorities, and warrants further investigation.
Antibacterial, UV protection, flame retardancy and coloration properties of cotton fabrics coated with polyacrylate polymer containing various iron ores
Published in The Journal of The Textile Institute, 2018
Nurhan Onar Camlibel, Buket Arik, Ozan Avinc, Arzu Yavas
Iron(III) oxides make a pigment called ochre and iron ores are named differently according to the color of the ochre; for instance hematite, limonite, and goethite are known as red, yellow, and brown ochres and are crystalline iron minerals, respectively (Roelofs & Petillion, 2012; Xu, Xu, Li, & Deng, 2017). Among those, Hematite (Fe2O3) is the most known and the most commonly used iron ore. Goethite (α-FeOOH) is the second most common natural ore and generally contains approximately 80 to 90% Fe2O3. Limonite (α-FeOOH.n(H2O)) is one of principal iron ores and commonly composed from the hydration of hematite and magnetite. China, Australia, Brazil, India, and Russia are known to be leading countries in iron ore production (U.S. Geological Survey, 2015). In the case of Turkey, it is estimated that 82.5 million tons of iron ore reserves exist in Turkey (IBP, 2015). Iron ores capture great attention for many different application fields such as magnetic, catalytic, pigments, drug carriers, adsorption, waste water treatment recently due to their high availability, low cost, ease of application, and versatile properties. Moreover investigations regarding their potential usage have recently increased (Abbasi, Ghanbari, Salavati-Niasari, & Hamadanian, 2016; Ahmadi Golsefidi, Abbasi, Abrodi, & Abbasi, 2016; Kirwan, Fawell, & Van Bronswijk, 2003, 2004; Omoike & Chorover, 2006; Parikh & Chorover, 2006).
Enhancement of anti-corrosion and mechanical properties of alkyd-based protective paints for steel petroleum structures incorporating natural limonite pigment
Published in Cogent Engineering, 2018
M.I. Abdou, Hany El-Sayed Ahmed, M.A. Wahab Gaber, A.M. Fadl
Earthy pigments varying from dull yellow to red and brown are commonly called ochre’s in the economic geology, mining industry, and painting. Ochre’s are defined as clays used to make the earth colors; in pigment terminology, the word ochre is predominantly used as a synonym for yellow ochre (Hradil, Grygar, Hradilová, & Bezdička, 2003). Limonite is the significant colored mineral found in a natural state suitable for use as a pigment after being pulverized to the desired size. The name “limonite” was given to many of the yellowish to yellowish brown iron oxides produced during the weathering of iron-bearing rocks or deposited as bog, lake, and shallow marine sediments. The global production of iron oxide pigments in 2000 was estimated to be 1,500,000 Mt., and 87% of the total market is attributed to industrial applications (Will, 2004). Limonite is an iron ore consisting of a mixture of hydrated iron (III) oxide-hydroxides in varying composition. The generic formula is frequently written as FeO (OH)·nH2O, although this is not entirely accurate as the ratio of oxide to hydroxide can vary quite widely. Iron oxides pigments have the advantage of low cost, permanency, and non-toxicity. In the last century, the chemical industry improved on nature by developing a complete range of synthetic iron oxide pigments (IOPs) that surpass the pigments produced from natural iron ores in uniformity, color quality, and chemical purity. An important characteristic of a pigment is its color.