DOI: 10.1515/9781501509247 Corpus ID: 130607958; Bacterially mediated mineral formation; insights into manganese(II) oxidation from molecular genetic and biochemical studies
WhatsApp: +86 18221755073
The first report in this recurring series on microbial processes in the minerals industries was published in 2003 (Olson et al. 2003), followed by an update after 10 years (Brierley and Brierley 2013) with bioleaching and biooxidation of sulfide minerals, primarily copper (in the case of bioleaching) and refractory gold ores (biooxidation) …
WhatsApp: +86 18221755073
The acid produced through the oxidation of sulfide minerals reactions can be neutralized along the groundwater flow path through reaction with gangue minerals incorporated in the mine wastes. Example gangue minerals which can contribute to acid neutralizing reactions include carbonate minerals and aluminosilicate mineral phases.
WhatsApp: +86 18221755073
The δ 34 S values of dissolved sulfate vary from −5.3‰ to +19.4‰, which are 3.0-26.4‰ higher than those of coexisting sulfide (Table 1).The Δ 33 S of dissolved sulfate vary from −0.40‰ to +0.50‰, which are either identical to or slightly lower (for up to 0.18%) than those of coexisting dissolved sulfide. In contrast, the CAS of the Malmani …
WhatsApp: +86 18221755073
Introduction. The oxidation of hydrogen sulfide is arguably one of the most important processes in the environment as the oceans have been suboxic or anoxic and euxinic (i.e., sulfidic) for long spans of geologic time (Canfield and Raiswell, 1999; Turchyn and Schrag, 2006).These are the oceans in which eukaryotes evolved and sulfur …
WhatsApp: +86 18221755073
In addition to common metals like copper, lead, zinc, and nickel, a number of other metals such as antimony, bismuth, cadmium, cobalt, mercury, and molybdenum occur as sulfide minerals. In the extraction of metals from sulfides, roasting is applied to achieve different objectives depending on the overall process flow sheet.
WhatsApp: +86 18221755073
Remember that the most common minerals in Earth's crust are the silicate minerals. Many silicate minerals form in igneous or metamorphic rocks. The minerals that form at the highest temperatures and pressures are the least stable at the surface. Clay is stable at the surface and chemical weathering converts many minerals to clay (figure 6).
WhatsApp: +86 18221755073
Reduced sulfur bonds as an anion with a significant range of metals (M) to form sulfide minerals of the general form M a S b, although two or more metals exist in many sulfide minerals.Sulfosalt minerals are a more complex subset of sulfide minerals of the general form M a X b S c, where X is typically one or more of the semimetals (As, …
WhatsApp: +86 18221755073
DOI: 10.1016/J.JCLEPRO.2018.04.172 Corpus ID: 158751437; Investigation of cleaner sulfide mineral oxidation technology: Simulation and evaluation of stirred bioreactors for gold-bioleaching process
WhatsApp: +86 18221755073
Results of recent experimental studies and modern theoretical concepts are combined in this volume to provide a comprehensive analysis of sulfide mineral oxidation processes. Introductory chapters discuss the properties of sulfide minerals and various investigative techniques, followed by chapters on oxidation mechanisms and the …
WhatsApp: +86 18221755073
The term bioleaching refers to the conversion of an insoluble metal (usually a metal sulfide, e.g., CuS, NiS, ZnS) into a soluble form (usually the metal sulfate, e.g., CuSO 4, NiSO 4, ZnSO 4).As the metal is extracted into water, this process is called bioleaching. Because this process involves oxidation, it may also be termed biooxidation.
WhatsApp: +86 18221755073
In addition, small amounts of gypsum and residual pyrite were observed in the SS sample (Fig. S5), confirming that gypsum is a relatively stable sulfate in weakly alkaline seawater and that pyrite is galvanically protected as a result of a high rest potential relative to other common sulfide minerals during the oxidation process (Fallon et al ...
WhatsApp: +86 18221755073
Selective oxidation of sulfide minerals occurs as one sulfide mineral is preferentially leached over another (Abraitis et al. 2004; Evangelou 1995; Evangelou and Zhang 1995; Hita et al. 2006; Kwong et al. 2003; Liu et al. 2008b; Nordstrom and Alpers 1999a; You et al. 2007). This galvanic protection process is the same as that for …
WhatsApp: +86 18221755073
Owing to the cycle of metal redox pairs mediated by S species, the iron sulfide minerals present more superior catalytic activity than iron oxide minerals towards H 2 O 2, ... To improve the efficiency of Fenton or Fenton-like oxidation process, photo-Fenton oxidation process introducing ultraviolet or visible light into the reaction system …
WhatsApp: +86 18221755073
Overall, these novel isotopic results demonstrate that geological processes can provide a steady long-term sulfate source in deep fracture fluids by in situ oxidation …
WhatsApp: +86 18221755073
The CESL process is a medium temperature pressure oxidation process taking place under an oxygen pressure of 1379 kPa (gauge) and temperature above the …
WhatsApp: +86 18221755073
The mechanism of the initial steps of pyrite (100) surface oxidation was investigated in detail by means of density functional theory/plane-wave calculations. Pyrite oxidation is related to many …
WhatsApp: +86 18221755073
Introduction. The oxidation of hydrogen sulfide is arguably one of the most important processes in the environment as the oceans have been suboxic or anoxic and euxinic (i.e., sulfidic) for long spans of geologic time (Canfield and Raiswell, 1999; Turchyn and Schrag, 2006).These are the oceans in which eukaryotes evolved and sulfur …
WhatsApp: +86 18221755073
In this Chapter, we will treated the use of ozone and advanced oxidation process, including microwave system, as methods to improve or to help the leaching of different sulphide …
WhatsApp: +86 18221755073
According to the model proposed by Rohwerer and Sand (2003) for the oxidation of elemental sulfur by acidophilic microorganisms (i.e. A. ferrooxidans, A. thiooxidans, and Acidiphilium acidophilum) the extracellular elemental sulfur is transported to the periplasm by the thiol group of the outer membrane protein as per sulfide sulfane …
WhatsApp: +86 18221755073
Oxidation is another very important chemical weathering process. The oxidation of the iron in a ferromagnesian silicate starts with the dissolution of the iron. ... A special type of oxidation takes place in areas where the rocks have elevated levels of sulfide minerals, especially pyrite (FeS 2). Pyrite reacts with water and oxygen to form ...
WhatsApp: +86 18221755073
Tracking the S oxidation pathway in sulfide-bearing mine waste-rock piles is complicated by variations in water content, O 2 and Fe 3+ concentrations, microbial diversity, mineralogy, the occurrence of a variety of S species associated with incomplete oxidation, and nonlinear coupling between physicochemical processes. Synchrotron …
WhatsApp: +86 18221755073
The Activox® process is essentially a low temperature (80–110°C), pressure oxidation process utilizing oxygen gas as the oxidant, whereby base metals are leached from the concentrate whilst sulfide is oxidized to elemental sulfur, thus reducing the oxygen requirement for leaching versus high temperature, high pressure oxidation …
WhatsApp: +86 18221755073
1. Properties of Sulfide Minerals Methods of Investigation of Sulfide Mineral Oxidation Processes 2. Electrode Kinetics and Oxidation Mechanism 3. Mutual Influence of Sulfide Minerals on Their Oxidation 4. Estimates of the Thermodynamic Stability of Sulfide Minerals Under Oxidizing Conditions 5. Oxidations of Sulfide …
WhatsApp: +86 18221755073
Coal pyrolysis desulfurization and the pretreatment of gold-bearing sulfide concentrates always involve the decomposition and oxidation of pyrite, which are complicated processes owing to the large number of …
WhatsApp: +86 18221755073
S can exist in different oxidation states, creating various reduced S compounds consisting of elemental S (S 0), sulfite (SO 3 2−), sulfide (S 2−), thiosulfate (S 2 O 3 2−), and tetrathionate (S 4 O 6 2−).SOB can oxidize reduced S compounds using diverse enzymatic systems (Fig. 2), which can be categorized into (1) sulfide oxidation …
WhatsApp: +86 18221755073
The process of arsenopyrite oxidation can occur via several mechanisms, depending on what one assumes is the oxidizing agent and what oxidation state one assumes the products are in. ... A key step in the reactions of all the sulfide minerals is that they release iron as ferrous ion (Fe 2+). Oxygen present in the water can then oxidize Fe 2 ...
WhatsApp: +86 18221755073
Sulfide-mineral oxidation is a complex hydrobiogeochemical process involving the oxidation of metal-sulfide minerals, catalyzed by numerous bacterial and archaeal …
WhatsApp: +86 18221755073
In addition to common metals like copper, lead, zinc, and nickel a number of other metals such as antimony, bismuth, cadmium, cobalt, mercury, and molybdenum occur as sulfide minerals. Sulfides are not reduced with the most widely used reducing agents, carbon and hydrogen, because the free energy change for the reactions 2MS + C = 2M + CS2 and …
WhatsApp: +86 18221755073
Bio-oxidation technology for leaching sulfide mineral of refractory gold concentrate is cleaner than conventional methods. Although liquid agitation can maintain cells and particles in suspension, thereby improving the mass transfer efficiency of oxygen, carbon dioxide, and nutrients, it also generates shear stress, which can reduce bio …
WhatsApp: +86 18221755073