The geochemistry of sulfide-mineral oxidation and its effect on surface-water quality can vary substantially depending on the composition and grain size of the sulfide
The oxidation of sulfide minerals from the exposure to atmospheric O2 results in the generation and release of acid, Fe(II) and potentially toxic metals. Oxidation products transported from the mine site can discharge to streams and lakes having a negative impact on the water quality.
Bio-oxidation has proved to be a viable process for the oxidative pretreatment of refractory gold-bearing sulfides. Generally, the oxidation rate is maximal at 20%
The rate of sulfide mineral oxidation in mine rock is proportional to the oxygen consumption rate (Elberling et al, 1994), so the rate of sulfide mineral oxidation in wall rock is proportional to the flux rate of oxygen into mine surfaces through advection and diffusion.
spite of the importance of mineral weathering behaviour, little is known about the acid generation characteristics of common sulfide minerals. The aim of this work
water coupled to oxidation of sulfide minerals, such as pyrite (Lefticariu et al., 2006b, c, d). The process produces e1emental hydrogen and partially to fully oxidized sulfur species in suitable proportions for maintenance and cell division of microbes (Chivian et al., 2008).
The surface oxidation of sulfides was studied in relation to the nature and concentration of the dissolved gas. The influence of sulfide surface inhomogeneities and mineral concretion on the electrochemical oxidation was investigated. The oxidation rate of minerals was found to be increased by impurities with higher electropositive potentials.
Supergene processes include the predominance of meteoric water circulation with concomitant oxidation and chemical weathering. The descending meteoric waters oxidize the primary ( hypogene ) sulfide ore minerals and redistribute the metallic ore elements.
The sulfide minerals represent higher temperatures and a slightly deeper setting than the sulfate minerals, which reflect the oxygen-rich environment near the Earth's surface. Sulfides occur as primary accessory minerals in many different igneous rocks and in deep hydrothermal deposits that are
Sulfide surface chemistry is particularly important because of its relevance to the oxidation and breakdown of sulfide minerals and to the processing of mined ores using froth flotation or leaching. Investigations using spectroscopic and imaging studies of pristine surfaces in ultra-high vacuum (UHV) conditions have provided information on structure and reactivity at an atomic resolution.
Introductory chapters discuss the properties of sulfide minerals and various investigative techniques, followed by chapters on oxidation mechanisms and the behavior of minerals under these various oxidizing conditions.
Apr 09, 2011· The linear plot of sulfide with time indicates that the reaction is zeroth order in sulfide and that sulfide oxidation depends on light as the external stimulus and not the concentration of sulfide as a reactant.
A versatile numerical model that couples oxygen diffusion and sulfidemineral oxidation (PYROX) has been developed to simulate the oxidation of pyrite in the vadose zone of mine tailings. A shrinkingcore oxidation model and a finite element numerical scheme are used to simulate the transport of oxygen and oxidation of pyrite grains.
The most common sulfide mineral is pyrite; other important sulfide ore minerals include chalcopyrite (copper ore), molybdenite (molybdenum ore), sphalerite
Oxidation of sulfide minerals near the Earths surface in the presence of water and oxygen frequently results in production of highly acidic, sulfate-rich solutions known as acid drainage (AD). Acid drainage is commonly associated with the extraction and processing of sulfide-bearing metalliferous ore deposits, sulfide-rich coal, and weathering of metalliferous black shales.
sulfide minerals. The oxidation of pyrite, chal-copyrite and pyrrhotite at 52oC and, 687o of. relative humidity (RH) has already been in-vestigated (Steger & Desjardins 1978). This re-potr summarizes the results of the study 9f tle bxidation of galena, sphalerite and chalcocite under the same conditions.
isotopic composition of sulfi de minerals and related compounds such as sulfate minerals or aqueous sulfur species, caused by preferential partitioning of isotopes among sulfur-bearing phases, known as fractionation. These variations arise from differences in temperature, or more importantly, oxidation and reduction reactions acting upon the sulfur.
Sulfur Isotope Geochemistry of Sulfide Minerals Robert R. Seal II U.S. Geological Survey, 954 National Seal, Robert R. II, "Sulfur Isotope Geochemistry of Sulfide Minerals" (2006).USGS Staff -- Published more importantly, oxidation and reduction reactions acting upon the sulfur. The oxidation and reduction reactions can occur at high
Table of ContentsOxidation of Sulfide in the Absence of Collectors or DepressantsPyriteGalenaChalcociteChalcopyriteDepression of Sulfide MineralsDepression of Cooper MineralsDepression of PyriteDepression of GalenaSummary Discussion Although a variety of inorganic and some organic reagents are used as depressants in the flotation recovery of sulfide minerals, a
The adsorptionof xanthate on sulfide minerals is a mixed -potential mechanism, i.e., the anodic oxidation of xanthate requires a cathodic counterpart. Normally, the cathodic reaction is
The oxidation of sulfide ores by ozone can occur by dissolution of sulfide species and the formation sulfate ion, as suggested by Elorza et al. Then, the global reaction of the pyrite
Oxidation and collector adsorption in sulfide mineral flotation 555 highly variable, and the presence of small, oxidized particles and particle interactions must be considered.
The rate of sulfide oxidation observed in batch reactors was a function of available sulfide surface area, dissolved oxygen concentration, and to a much lesser extent pH (equation 1). The dependence on surface area and dissolved oxygen indicates that the oxidation was
Samples of pyrite, chalcopyrite and pyrrhotite were subjected to 52°C and 68% Relative Humidity in air for periods of up to four weeks. The resultant oxidation products were analyzed for metal and the various possible surface-bearing products such as sulfate, etc.
destruction of sulfides, oxides, and silicate minerals (Titley, 1982; Titley and Marozas, 1995). Importantly, the relative susceptibility to oxidation of sulfide minerals determines the sequence of sulfide mineral destruction, the consequent availability of metals for supergene transport, and the nature and zoning of resulting minerals (Bladh, 1982).
Samples of pyrite, chalcopyrite and pyrrhotite were subjected to 52°C and 68% Relative Humidity in air for periods of up to four weeks. The resultant oxidation products were analyzed for metal
sulfide mineral oxidation, 645 sulfur and oxygen isotope geochemistry in western United States, 481-511 Wales chemistry of acid lake water, 264,267-269 chemistry of mine water, 264,266* experimental procedure, 264 history, 261-262 ochre chemistry, 270 pH vs. water type, 269
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