Search results
Results From The WOW.Com Content Network
In ore deposit geology, supergene processes or enrichment are those that occur relatively near the surface as opposed to deep hypogene processes. Supergene processes include the predominance of meteoric water circulation (i.e. water derived from precipitation) with concomitant oxidation and chemical weathering.
This ore is so rich in limonite (generally grading 47% to 59% iron, 0.8 to 1.5% nickel and trace cobalt) that it is essentially similar to low-grade iron ore. As such, certain steel smelters in China have developed a process for blending nickel limonite ore with conventional iron ore to produce stainless steel feed products like nickel pig iron.
Limonite (/ ˈ l aɪ m ə ˌ n aɪ t /) 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)· n H 2 O , although this is not entirely accurate as the ratio of oxide to hydroxide can vary quite widely.
Limonite, a mixture of various hydrates and polymorphs of ferric oxyhydroxide, is one of the three major iron ores, having been used since at least 2500 BC. [ 8 ] [ 9 ] Yellow iron oxide, or Pigment Yellow 42, is Food and Drug Administration (FDA) approved for use in cosmetics and is used in some tattoo inks.
The changes between these levels are called "transitions" and are plotted on the Jablonski diagram. Radiative transitions involve either the absorption or emission of a photon. As mentioned above, these transitions are denoted with solid arrows with their tails at the initial energy level and their tips at the final energy level.
Iron production sites in central Sweden are dated to the late Bronze Age and the innovation might have been transmitted from both the south and the east. The ore used was limonite in the form of red soil and bog ore. From 200 CE ore from limonite-deposits in lakes was used. The ore was reduced in bloomeries.
Transition metal sulfates form a variety of hydrates, each of which crystallizes in only one form. The sulfate group often binds to the metal, especially for those salts with fewer than six aquo ligands. The heptahydrates, which are often the most common salts, crystallize as monoclinic and the less common orthorhombic forms.
Silica pseudomorph after gypsum crystals and silicified serpulid polychaete tubes Pseudomorph of goethite after pyrite. In mineralogy, a pseudomorph is a mineral or mineral compound that appears in an atypical form (crystal system), resulting from a substitution process in which the appearance and dimensions remain constant, but the original mineral is replaced by another due to alteration, or ...