Pyrite distribution

In addition, the TRW samples were analyzed by the SEM-AIA technique described previously (13). The SEM-AIA data on the mineral phase identification and distribution between the size fractions are presented in Table VI for all three samples of raw and treated coal. The SEM-AIA data show the nearly complete removal of many minerals and a reduction of more than 90X in the overall content of the coal as a result of treatment by the TRW Gravimelt Process. No major changes in particle size distribution were observed, although the pyrite distribution shifted somewhat towards the coarse fraction after processing. 

Figure 3. Pyrite distribution in raw and cleaned Illinois No. 6 coal (200 X 0 mesh).

Figure 4.10 Measured oxygen and pyrite distribution in approx. 43 years old pyrite bearing dump body modelled oxygen distribution, current oxidation zone and depyritization depth.

Sulfur occurs native in the vicinity of volcanos and hot springs. It is widely distributed in nature as iron pyrites, galena, sphalerite, cinnabar, stibnite, gypsum, epsom salts, celestite, barite, etc. 

Sanskrit Jval Anglo-Saxon gold L. aurum, gold) Known and highly valued from earliest times, gold is found in nature as the free metal and in tellurides it is very widely distributed and is almost always associated with quartz or pyrite. 

Pyrite is the most abundant of the metal sulfides. Eor many years, until the Erasch process was developed, pyrite was the main source of sulfur and, for much of the first half of the twentieth century, comprised over 50% of world sulfur production. Pyrite reserves are distributed throughout the world and known deposits have been mined in about 30 countries. Possibly the largest pyrite reserves in the world are located in southern Spain, Portugal, and the CIS. Large deposits are also in Canada, Cypms, Einland, Italy, Japan, Norway, South Africa, Sweden, Turkey, the United States, and Yugoslavia. However, the three main regional producers of pyrites continue to be Western Europe Eastern Europe, including the CIS and China. 

Figure 7 shows an example of a space-resolved microwave conductivity measurement of the semiconducting surface of a natural pyrite (FeS2) sample (from Murgul, Turkey). The overflow of the PMC signal (white color) was adjusted to a level that shows the patterns of distribution of low photoeffects (dark areas). Figure 8 shows a similar image in which,... 

Figure 7. Example of space-resolved photoinduced microwave conductivity mapping of semiconductor interface distribution of photoconductivity in natural pyrite (from Murgul, Turkey, surface etched in acid solution). The overflow was adjusted to show patterns of low photoactivity. For color version please see color plates opposite p. 452.

Sulfur is widely distributed as sulfide ores, which include galena, PbS cinnabar, HgS iron pyrite, FeS, and sphalerite, ZnS (Fig. 15.11). Because these ores are so common, sulfur is a by-product of the extraction of a number of metals, especially copper. Sulfur is also found as deposits of the native element (called brimstone), which are formed by bacterial action on H,S. The low melting point of sulfur (115°C) is utilized in the Frasch process, in which superheated water is used to melt solid sulfur underground and compressed air pushes the resulting slurry to the surface. Sulfur is also commonly found in petroleum, and extracting it chemically has been made inexpensive and safe by the use of heterogeneous catalysts, particularly zeolites (see Section 13.14). One method used to remove sulfur in the form of H2S from petroleum and natural gas is the Claus process, in which some of the H2S is first oxidized to sulfur dioxide ... 

ABSTRACT This study forms part of a larger multidisciplinary environmental study of the Lower Guadiana River basin carried out by a joint Portuguese-Spanish research team. It describes the mobility of lead in soil profiles taken over varied lithologies of the Iberian Pyrite Belt and the distribution of this metal with the root, stems and leaves of three plant species native to the area (Cistus ladanifer L., Lavandula luisieri and Thymus vulgaris). Results indicate that at all sample sites the mobility of lead is very low. 

Airborne particles collected with filters distributed across Vitoria, Brazil were analyzed by MB spectroscopy, whereby certain Fe-bearing minerals indicated different pollution sources. For example, hematite comes mostly from iron ore pellet plants, pyrite from handling and storing coal in the industrial area, and magnetite is related to steelwork plants (de Souza et al. 2001). 

In order to prepare standard mineral mixtures, pyrite (Py), pyrrhotite (Po), chalcopyrite (Cp), sphalerite (Sp), siderite (Sid), dolomite (Dol), calcite (Cal) and quartz (Qz) were acquired as pure mineral samples through a specialized distributor (Minerobec, Canada). These 8 pure minerals were further cleaned under a binocular microscope and separately crushed to reach 95% under 150pm (typical tailings grain size distribution e.g. Aubertin et al. 2002). Each pure mineral powder was characterized thereafter with a series of chemical and mineralogical techniques. More details can be found in Bouzahzah et al. (2008). The relative density of each mineral specimen were measured with an He pycnometer and are... 

Paktunc, D. Kingston, D., Pratt, A., Mcmullen, J. 2006. Distribution of gold in pyrite and in products of its transformation resulting from roasting of refractory gold ore. Canadian Mineralogist, 44, 213-227. 

GGA property calculation on optimized bulk pyrite has been performed. The calculated band structure and frontier orbital distribution are presented in Fig. 9.3 and Fig. 9.4. The calculated band gap of FeS2 is 0.97 eV, and it is in good line... 

Detailed mineralogical studies have shown that pyrite of different generations is the main form containing siderophile elements, and their zonal distribution is connected both to the position of wall rock pyritization zones and to the concentration changes of these elements within the pyrites. 

This deposit is located in the north-east of Russia and belongs to a gold-arsenic type of low-sulphide formation (Abramson et al, 1980). It lies within a carbonaceous terrigenous rock of Triassic age and is associated with a dome-shaped uplift in a node of intersecting faults of various directions. The ore bodies consist of zones of silicification and kaolinization with veinlet-disseminated sulphide mineralisation. Gold is present in the form of finely-dispersed dissemination in arsenopyrite and pyrite. As an example. Figure 1 illustrates the distribution of Au and Mn in connection with commercial ore... 

Fig.1. Distribution of Au and Mn in haloes of commercial ore bodies (A) and in a zone of barren disseminated mineraiisation (B). Mayskoe deposit. Russia. 1. Black shale. 2. Ore body. 3. Zone of mineralisation. 4. Zone of pyritization...

An investigation of minerai fractions in ores and ore-adjacent areas carried out jointiy with i.M. Shuigina (Abramson et al. 1993) has shown that pyrite of various generations is the main concentrator of Co, Ni and Mn (Tabie 1). The distribution of these eiements is iinked mainiy with the quantity of pyrite concentration in ores and... 

This investigation relied on petrographic analysis of polished sections using reflected light and the scanning electron microscopy (SEM) and electron microprobe (EPMA) analyses to identify minerals and to document the distribution of gold. The mineralized zone is coincident with a distinct bleached alteration zone that contains fine- to coarse-grained, subhedral arsenopyrite and pyrite in quartz-carbonate veins. 

Evidence from drill core and microstructure studies indicate that euhedral, zoned arsenopyrite grains tend to be clustered, and mantled by pyrite (Fig. 4), and their distribution is structurally controlled. These textures are interpreted to represent pressure solution as the main deformation mechanism during Di. This interpretation is supported by serrated pyrite boundaries (Fig. 4) and pyrite-bearing veins. However, locally unstrained euhedral pyrite porphyroblasts overprint Di and D2 structures, implying a late-stage post-D2 growth (Fig. 4). 

The first method chosen to express the coal-mineral association results is in terms of the weight fraction of mineral matter in the individual particles, as determined from their cross section. The resulting distribution is comparable to the so-called "grade distributions" used in the mineral industry [8,9]. Such a distribution is included in Table II for the Upper Freeport coal. The data in the table indicate that pyrite is preferentially liberated as compared to quartz or kaolinite. About 78% of the pyrite is in particles containing more than 80% mineral matter, which should be easily removed by density-based separations. 

However, Figure 5 illustrates that the general distribution of mineral matter is not the same as that of the pyrite which is liberated to a larger degree. 

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