Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Minerals marcasite

The mineral marcasite constitutes yellow rhombic crystals density 4.87g/cm3 transforms to more stable pyrite form when heated at 480°C insoluble in dilute acids. Both forms dissolve in concentrated nitric acid and are insoluble in water (4.9 mg/L at 20°C). [Pg.427]

Coal also contains inorganic components— mineral matter (Chapter 7)— which are determined as mineral ash (Chapter 8). The mineral matter includes minerals such as pyrite (FeS2) and the related mineral marcasite (FeSj), as well as other minerals formed from metals that accumulated in the living tissues of the ancient plants. Quartz, clay, and other minerals are also added to coal deposits by wind and groundwater. The mineral matter lowers the fixed carbon content of coal, decreasing its heating value (Chapter 8). [Pg.19]

Pyrite (FeS2) and the related mineral marcasite (FeS2) occur frequently in coal and are recognized as the major mineral constituents of many coals (Chapter 7). Thus, it is not surprising that there has... [Pg.366]

Huggins (1922) was the first investigator to assign structures to sphalerite, wurtzite, chalcopyrite, pyrite, marcasite, arsenopyrite, and other sulfide minerals in which each sulfur atom forms four tetrahedrally directed covalent bonds with surrounding atoms. These structures would be described as involving quadricovalent argononic S2+. [Pg.619]

From among the many other sulfide minerals that might be discussed I select pyrite and marcasite. [Pg.621]

Fig. 1.2 Crystal structures of the major sulfides (metal atoms are shown as smaller or black spheres) (A) galena (PbS) structure (rock salt) (B) sphalerite (ZnS) structure (zinc blende) (C) wurtzite (ZnS) strucmre (D) pyrite structure and the linkage of metal-sulfur octahedra along the c-axis direction in (/) pyrite (FeSa) and (//) marcasite (FeSa) (E) niccolite (NiAs) structure (F) coveUite (CuS) structure (layered). (Adapted from Vaughan DJ (2005) Sulphides. In Selley RC, Robin L, Cocks M, Plimer IR (eds.) Encyclopedia of Geology, MINERALS, Elsevier p 574 (doi 10.1016/B0-12-369396-9/00276-8))... Fig. 1.2 Crystal structures of the major sulfides (metal atoms are shown as smaller or black spheres) (A) galena (PbS) structure (rock salt) (B) sphalerite (ZnS) structure (zinc blende) (C) wurtzite (ZnS) strucmre (D) pyrite structure and the linkage of metal-sulfur octahedra along the c-axis direction in (/) pyrite (FeSa) and (//) marcasite (FeSa) (E) niccolite (NiAs) structure (F) coveUite (CuS) structure (layered). (Adapted from Vaughan DJ (2005) Sulphides. In Selley RC, Robin L, Cocks M, Plimer IR (eds.) Encyclopedia of Geology, MINERALS, Elsevier p 574 (doi 10.1016/B0-12-369396-9/00276-8))...
Opaque minerals include stibnite, jamesonite, cinnabar, gold, pyrite, pyrrhotite, arsenopyrite, marcasite, sphalerite, galena and chalcopyrite. [Pg.236]

From the mode of occurrence of opaque minerals it is considered that pyrrhotite and sphalerite were precipitated at an early-stage, gold, pyrite, marcasite, stibnite and cinnabar were precipitated at a late-stage, and arsenopyrite was precipitated throughout the mineralization period. [Pg.236]

Dominant sulfides and sulfate minerals in the Osorezan area are pyrite, marcasite, orpiment, realgar, stibnite, krennerite, coloradoite, jordanite, wurtzite, sphalerite, cinnabar, and barite (Aoki, 1992b). H2S concentration of the Osorezan hot spring is very high, compared with the other Japanese geothermal waters (Table 2.4). [Pg.312]

The iron sulphide in South African coals is a mixture of pyrite and marcasite (18). Although marcasite is known to transform into pyrite at elevated temperatures, separate spiking experiments were performed to see if pyrite or marcasite would show a preferential catalytic effect. The addition of pyrite and marcasite minerals (-200 mesh), to the coal showed equivalent total conversions, and yields of oil and asphaltene. [Pg.55]

The minerals that influence gold recovery in these ores are iron sulphides (i.e. pyrite, marcasite, etc.), in which gold is usually associated as minute inclusions. Thus, the iron sulphide content of the ore determines gold recovery in the final concentrate. Figure 17.3 shows the relationship between pyrite content of the ore and gold recovery in the copper concentrate for two different ore types. Most of the gold losses occur in the pyrite. [Pg.9]

In general, the run-of-mine ore is composed of quartz and silicates, 40-50%, and sulphides (pyrite, marcasite, pyrrhotite and arsenopyrite). The principal tin mineral is cassiterite, with minor amounts of stannite. Based on liberation studies, a large portion of the tin is liberated at 300-400 pm size. A portion of the tin is liberated at-12 pm size. The generalized gravity concentration flowsheet is shown in Figure 21.9. [Pg.103]

Magmatic Cu-Ni ore bodies are hosted in quartz schist and partially in gneiss. The ore averages 4.2% Ni, 3.0% Cu, and 0.01-0.2% Co and contains a small amount of platinum group elements. The main minerals comprise violarite, pyrite, marcasite, chalcopyrite, quartz and plagioclase. [Pg.45]

The fault-fill mineralization includes quartz, dolomite, ankerite, siderite, calcite, molybdenite, pyrrhotite, arsenopyrite, pyrite, chalcopyrite, sphalerite, galena, selenian galena, marcasite, ilmenite, and rutile (Maanijou 2007). [Pg.173]

The occurrence of non-carbonaceous material in coals has been the subject of much research, especially in relation to its effect on utilization and ash formation (4-14). In contrast to high rank coals in which minerals constitute almost all of the non-carbonaceous fraction, the low rank coals have two categories of non-carbonaceous material minerals which occur as discrete particles of quartz, marcasite, clays, etc. and inorganics which occur as w er soluble salts and exchangeable ions such as NaCl,... [Pg.21]

Minerals which are subsurface are therefore visible, however their brightness is diminished (e.g. subsurface marcasite can have a similar BSE image to clay on the surface). [Pg.27]

XRD allows the determination of the actual mineral species present. The bulk coal samples resulted in an x-ray pattern with a high background due to the coal matrix. The major mineral species were easily determined, however the minor species could not be detected. As with the SEM-BSE analysis, interpretation of results in a quantitative manner (in relation to the coal) is difficult. The major minerals detected were quartz, kaolinite, gypsum and marcasite. [Pg.27]

All of the samples analysed showed, as expected, that the major minerals are quartz, kaolinite, marcasite/pyrite and gypsum. In general the quartz is present in two distinct size ranges 500 ym and 50 ym. [Pg.28]

The size distribution of the kaolinite is quite variable and again the Kingston sample differed in that most of the kaolinite has sodium associated with it and could therefore be considered a smectite rather than kaolinite. Marcasite is commonly present as a replacement of original coal particles. The gypsum is present mainly in the -20 ym size range. Overall the mineral matter content of the lignites is of the order of 5%-10% (i.e. a medium distribution density). [Pg.28]

Fe sulfides - Marcasite, Commercial Pyrite, Mineral Pyrite,... [Pg.46]

Iron disulfide is obtained from its naturally occurring minerals, pyrite and marcasite. In the laboratory it may be prepared along with iron(II) sulfide by passing dry hydrogen sulfide through a suspension of hydrated iron (III) oxide or iron(III) hydroxide in alkaline medium. The unstable product formed decomposes to FeS2 and FeS. [Pg.427]

Figure 7.12. Examples of epitaxy observed in minerals, (a) lyrite on marcasite (b) quartz on calcite (c) albite on orthoclase. Figure 7.12. Examples of epitaxy observed in minerals, (a) lyrite on marcasite (b) quartz on calcite (c) albite on orthoclase.
The second book is devoted to what he calls the minor minerals, under which he includes mercury and its ores, sulphur, antimony, marcasites containing metals, vitriol, alum, arsenic, orpiment, and realgar, common salt and other salts, calamine, zaffre, ocher, Armenian bole, emery, borax, lapis lazuli, rock crystal and glass. [Pg.330]


See other pages where Minerals marcasite is mentioned: [Pg.66]    [Pg.5]    [Pg.66]    [Pg.5]    [Pg.438]    [Pg.617]    [Pg.621]    [Pg.622]    [Pg.622]    [Pg.66]    [Pg.89]    [Pg.161]    [Pg.162]    [Pg.163]    [Pg.186]    [Pg.187]    [Pg.241]    [Pg.337]    [Pg.368]    [Pg.352]    [Pg.318]    [Pg.170]    [Pg.435]    [Pg.427]    [Pg.123]    [Pg.153]    [Pg.124]    [Pg.212]    [Pg.232]   
See also in sourсe #XX -- [ Pg.156 ]




SEARCH



Marcasite

Marcasites

© 2024 chempedia.info