Magnetite colour

Franklinite, (Mn, Zn)0.Fe203, is a magnetite in which the ferrous oxide is more or less replaced by zinc oxide and manganous oxide, which latter imparts a red colour to the ore. It is found in New Jersey, U.S.A., in large black octahedra, and in recognition of its zinc content is frequently called zincite. It is slightly magnetic. Hardness 5 5 to 6 5. Density 5 07 to 5 2. It is infusible in the blowpipe soluble in concentrated hydrochloric acid.2... 

The separates obtained from the bulk had a reddish-brown colour, while the clays of the LAR and TAR were yellowish brown, and remained so after a treatment with NaClO. The NH4-oxalate-treated clays gave similar amounts of extracted Fe-oxyhydroxides (Table 4), even though possible differences could have been hidden by the presence of magnetite, which is slightly soluble in acid oxalate (Schwertmann and Taylor, 1989). The Fe extracted by CBD (Table 4) was lower than that extracted by acid oxalate, as CBD fails to dissolve magnetite completely (Jackson et al., 1986). The HAHC solution, which is able to extract... 

Fes04 Magnetite 8.396 — Inverse spinel/ Octahedra 5.18 -1014.2 Black colour, mill scale... 

The Sirofloc process removes turbidity (algae, bacteria, colloidal matter) and dissolved coloured material from contaminated underground and surface waters or waste waters by flocculation with reusable magnetite particles (a waste product of some iron processing plants). The magnetite particles from 1 to 10 microns in size have great adsorptive powers and important magnetic... 

Anderson, N. J. et al, Colour and turbidity removal with reusable magnetite particles, VI Pilot plan operation . Water Res., 17 (10), 1235-1243 (1983)... 

Iron group Iron oxides and lydroxides group Zinc group Iron zinc oxide Calcite Jacobsite Magnetite Zincite Zinc oxide Colour Index (1971) 77496,77950 Rutley (1988) 282-283... 

Schweppe (1992) describes iron oxide black as a very deep colour of black produced, in ancient Mesopotamia and Minoan Crete, by heating iron oxide derived from clays and ochres to 800-1100°C. It is unclear as to whether this was used in this context as anything other than a fired glaze on ceramics. According to Mayer (1991), black oxide of iron is a synonym for a black synthetic iron oxide pigment if so, then probably this would be magnetite. An iron black is also referred to by the Colour Index (1971) however, this is described in that source as being a form of precipitated antimony. 

Iron oxides, which were undoubtedly components of these prehistoric paints, still find application today as low-cost, low-toxicity pigments in paint, plastics, rubbers and cosmetics. The three main colours available are red (haematite-, Fe203), yellow (goethite FeO.OH) and black (magnetite-, Fe304), and other colours can be produced by blending these three. The oxides are generally prepared by precipitation from aqueous solution ... 

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