Magnetite, 856 table

Minerals. Iron-bearing minerals are numerous and are present in most soils and rocks. However only a few minerals are important sources of iron and thus called ores. Table 2 shows the principle iron-bearing minerals. Hematite is the most plentiful iron mineral mined, followed by magnetite, goethite, siderite, ilmenite, and pyrite. Siderite is unimportant in the United States, but is an important source of iron in Europe. Tlmenite is normally mined for titania with iron as a by-product. Pyrite is roasted to recover sulfur in the form of sulfur dioxide, leaving iron oxide as a by-product. 

Custom-ground natural magnetite is available in many size ranges. Table 19-13 gives atypical specification sheet. Cost is based on truckload quantities in 45.4-kg (100-lb) paper bags, FOB Frazer, Pennsylvania. 

TABLE 19-13 Typical Size Distribution of Ground Natural Magnetite ... 

NOTE For any boiler, the maximum recommended tolerance for deposit thickness can be related to a weight of deposit per unit area clearly, the weight will vary dependent on the density of the deposit. Typically, deposit densities vary between 2.3 and 5.7 g/cm3. The densities of calcite and magnetite (which are two common mineral components of deposits) are 2.71 and 5.17 g/cm3, respectively. Table 4.2 assumes an average deposit density of 3.5 g/cm3. 

In Figure 2, the MCssbauer spectrum of sample 2 (Table I) and a matching computer-simulated model spectrum are shown. This spectrum was recorded over a period of 30 hours while sample 2 was under a flowing CO/CO2 (15 85) gas mixture at 613 K. Following the completion of the experiment, the average magnetite particle... 

Weighting agents (Table 10-10) are added to increase the density of the cement. They are typically used to combat high bottom-hole pressures. Common additives are powdered iron, ferromat, powdered magnetite, and barite. Hematite ean be used to increase the density of a mixture up to 2200 kg/m (19 Ib/gal). Hematite requires the addition of some water. 

Table 7.1 Comparison of the yields of carbon-containing compounds obtained from an atmosphere of CH4, NH3, H2O and H2 using spark discharges with those obtained under hydrothermal conditions from a mixture of HCN, HCHO and NH3 at 423 K and 10 atm in the presence of pyrite-pyrrhotite-magnetite redox buffer (Holm and Andersson, 1995)...

Figure 19. Iron isotope fractionations between magnetite and Fe carbonates from adjacent bands in Banded Iron Formations (Johnson et al. 2004a), compared to Fe(II)aq sources and Fe pathways inferred from the Fe isotope fractionations given in Table 3. values are as measured, and the scales for...

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