Silicate minerals

About: Silicate minerals is a research topic. Over the lifetime, 1794 publications have been published within this topic receiving 67064 citations.

Flotation Research of a Fluorite Ore

Abstract: Separating fluorite from quartz and calcite by forth flotation can be both in weak-acidized (pH 6.0) condition and weak alkali (pH 9.0) condition. The experiment results have shown that ZnSO4 can decrease the depression that water glass works on the fluorite, and acidized water glass has a selective inhibition on the silicate minerals. The close flowsheet protocolled in the experiment can obtain the content of CaF2, SiO2 in the final concentrate are 97.89%, 0.91% respectively, and the recovery rate of CaF2 is 84.18%, which is reach the requirement of the plant.

Magnetic Ordering and Thermodynamics in Silicates

Abstract: An elementary account is given of the properties of the magnetic ions most commonly found in silicate minerals, Fe2+ and Fe3+, including the effect of the crystal field on the former. Collective magnetic behaviour is discussed, mainly in term of molecular field theory, and the influence of cation disorder is considered. There follows a survey of collective magnetic order of end-member iron minerals belonging to the garnet, pyroxene, amphibole, serpentine, mica and olivine families. They usually have complex antiferromangetic structures with Neel points in the range 1–100 K, but disorder may induce spin glass states. Finally, the thermodynamic consequences of magnetic order are considered, in relation to the enthalpy and entropy of iron minerals.

Magnesium-rich minerals in sediment and suspended particulates of South Florida water bodies : Implications for turbidity

Abstract: Fine sediments in shallow water bodies such as Lake Okeechobee are prone to resuspension. Predominantly inorganic "mud" sediment that covers approximately 670 km2 of the lake has been recognized as a persistent source of turbidity. The objective of this study was to determine if mineral components of sediments in Lake Okeechobee and water conveyances of the northern Everglades also occur as suspended sediment and hence constitute a potential abiotic contributor to turbidity. Sediment samples were collected from nine stations within the lake and eight locations north of Water Conservation Area 2A in the Everglades. Water samples were also collected at selected locations. The silt and clay mineralogy of sediment and suspended particles was determined using X-ray diffraction, thermogravimetry, scanning-electron microscopy, energy-dispersive X-ray elemental microanalysis, and high-resolution transmission-electron microscopy. Clay fractions of the lake sediment contained the Mg silicate minerals sepiolite and palygorskite, along with smectite, dolomite, calcite, and kaolinite. Sediment silt fractions were dominated by carbonates and/or quartz, with smaller amounts of Ca phosphates and sepiolite. Mineralogy of the mud sediment was similar to that reported for geologic phosphate deposits. This suggests that the mud sediment might have accumulated by stream transport of minerals from these deposits. Suspended solids and mud-sediment mineralogy were similar, except that smectite was more abundant in suspended solids. Everglade samples also contained Mg-rich minerals. The small size, low density, and fibrous or platy nature of the prevalent mud sediment minerals make them an abiotic, hydrodynamically sensitive source of persistent turbidity in a shallow lake. Mitigation efforts focused exclusively on P-induced biogeochemical processes do not address the origin or effects of these minerals. Ecological management issues such as turbidity control, P retention, geologic P input, and suitability of dredging are related to mud-sediment properties and provenance.

Hydrogen and oxygen isotope compositions of eclogites from the Dabie Mountains and geodynamic implications

Abstract: Heterogeneous δ18O values as low as - 2.6‰ to+7.0% are observed for ultrahigh pressure eclogites from the Dabie Mountains in East China. Oxygen isotope equilibrium has been approached between the eclogite minerals, suggesting that the rocks would have acquired the unusual δ18O values prior to ultrahigh pressure metamorphism by interaction with18O-depleted fluid. δD values of hydroxyl-bearing are between — 51% and - 83‰, precluding the possibility of paleoseawater involvement. The only likely fluid is ancient meteoric water that exchanged oxygen isotopes with the eclogite precursor (a kind of basaltic rocks) formerly resident on the continental crust. This suggests a crustal recycling process in the suture zone of late subduction. Because silicate minerals undergo rapid oxygen isotope exchange at mantle pressures, preservation of the isotopic signature of meteoric water in the eclogites indicates limited crust-mantle interaction and thus a short residence time (<20 Ma) when the plate containing the eclogite precursor was subducted to mantle depths. The agreement in oxygen isotope temperatures for different mineral pairs suggests a rapid cooling and ascent process for the eclogites subsequent to their formation at mantle depths.