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Final Technical Report Reactivity Of Iron Bearing Minerals And Co2 Sequestration And Surface Chemistry Of Pyrite An Interdisciplinary Approach
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Book Synopsis Final Technical Report. Reactivity of Iron-Bearing Minerals and CO2 Sequestration and Surface Chemistry of Pyrite. An Interdisciplinary Approach by :
Download or read book Final Technical Report. Reactivity of Iron-Bearing Minerals and CO2 Sequestration and Surface Chemistry of Pyrite. An Interdisciplinary Approach written by and published by . This book was released on 2014 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the course of the scientific program, two areas of research were pursued: reactions of iron oxides with supercritical CO2 and sulfide and surface reactivity of pyrite. The latter area of interest was to understand the chemistry that results when supercritical CO2 (scCO2) with H2 S and/or SO2 in deep saline formations (DFS) contacts iron bearing minerals. Understanding the complexities the sulfur co-injectants introduce is a critical step in developing CO2 sequestration as a climate-mitigating strategy. The research strategy was to understand macroscopic observations of this chemistry with an atomic/molecular level view using surface analytical techniques. Research showed that the exposure of iron (oxyhdr)oxides (which included ferrihydrite, goethite, and hematite) to scCO2 in the presence of sulfide led to reactions that formed siderite (FeCO3). The results have important implications for the sequestration of CO2 via carbonation reactions in the Earth's subsurface. An earlier area of focus in the project was to understand pyrite oxidation in microscopic detail. This understanding was used to understand macroscopic observations of pyrite reactivity. Results obtained from this research led to a better understanding how pyrite reacts in a range of chemical environments. Geochemical and modern surface science techniques were used to understand the chemistry of pyrite in important environmental conditions. The program relied on a strong integration the results of these techniques to provide a fundamental understanding to the macroscopic chemistry exhibited by pyrite in the environment. Major achievements during these studies included developing an understanding of the surface sites on pyrite that controlled its reactivity under oxidizing conditions. In particular sulfur anion vacancies and/or ferric sites were sites of reactivity. Studies also showed that the adsorption of phospholipid on the surface to selectively suppress the reactivity of these sites could of potential importance for suppressing acid mine drainage in the environment (a problem common to coal-mining sites). Biotic studies showed that microbial activity that promotes the oxidation of pyrite to produce AMD could also be suppressed by the adsorption of phospholipid.
Book Synopsis Reactivity of Iron-bearing Minerals and CO2 Sequestration by :
Download or read book Reactivity of Iron-bearing Minerals and CO2 Sequestration written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The reactivity of sandstones was studied under conditions relevant to the injection of supercritical carbon dioxide in the context of carbon geosequestration. The emphasis of the study was on the reactivity of iron-bearing minerals when exposed to supercritical CO2 (scCO2) and scCO2 with commingled aqueous solutions containing H2S and/or SO2. Flow through and batch experiments were conducted. Results indicate that sandstones, irrespective of their mineralogy, are not reactive when exposed to pure scCO2 or scCO2 with commingled aqueous solutions containing H2S and/or SO2 under conditions simulating the environment near the injection point (flow through experiments). However, sandstones are reactive under conditions simulating the edge of the injected CO2 plume or ahead of the plume (batch experiments). Sandstones containing hematite (red sandstone) are particularly reactive. The composition of the reaction products is strongly dependent on the composition of the aqueous phase. The presence of dissolved sulfide leads to the conversion of hematite into pyrite and siderite. The relative amount of the pyrite and siderite is influenced by the ionic strength of the solution. Little reactivity is observed when sulfite is present in the aqueous phase. Sandstones without hematite (grey sandstones) show little reactivity regardless of the solution composition.
Book Synopsis Pyrite Oxidation and Its Control by : V. P. Evangelou
Download or read book Pyrite Oxidation and Its Control written by V. P. Evangelou and published by CRC Press. This book was released on 2018-04-27 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pyrite Oxidation and its Control is the single available text on the market that presents the latest findings on pyrite oxidation and acid mine drainage (AMD). This new information is an indispensable reference for generating new concepts and technologies for controlling pyrite oxidation. This book focuses on pyrite oxidation theory, experimental findings on oxidation mechanisms, as well as applications and limitations of amelioration technologies. The text also includes discussions on the theory and potential application of novel pyrite microencapsulation technologies for controlling pyrite oxidation currently under investigation in the author's laboratory.
Book Synopsis Implications of Pyrite Oxidation for Engineering Works by : A. Brian Hawkins
Download or read book Implications of Pyrite Oxidation for Engineering Works written by A. Brian Hawkins and published by Springer Science & Business Media. This book was released on 2013-07-30 with total page 311 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book highlights and analyses the distress to buildings caused by sulphate-induced heave, with particular reference to the recent problems in the Dublin area of Ireland. It describes the formation of pyrite, the processes involved in its oxidation and the various ways in which consequential expansion takes place. For the first time in the literature it discusses the way that buildings can be raised above their supporting foundation walls by the expansion of pyritiferous fill which has been used beneath ground-bearing floor slabs in Ireland. The significance of fractures through the iron sulphide microcrystals for the rate and extent of oxidation is discussed. Photographs and profiles of sulphate ingress into concrete/concrete blocks are presented. Case histories from the UK, North America and Ireland are discussed.
Download or read book Final Report written by and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This project addresses key issues of importance in the geochemical behavior of iron oxides and in the geochemical cycling of carbon and iron. For Fe, we are specifically studying the influence of carbonate on electron transfer reactions, solid phase transformations, and the binding of carbonate to reactive sites on the edges of particles. The emphasis on carbonate arises because it is widely present in the natural environment, is known to bind strongly to oxide surfaces, is reactive on the time scales of interest, and has a speciation driven by acid-base reactions. The geochemical behavior of carbonate strongly influences global climate change and CO2 sequestration technologies. Our goal is to answer key questions with regards to specific site binding, electron transfer reactions, and crystallization reactions of iron oxides that impact both the geochemical cycling of iron and CO2 species. Our work is focused on the molecular level description of carbonate chemistry in solution including the prediction of isotope fractionation factors. We have also done work on critical atmospheric species.
Book Synopsis Control of Pyrite Surface Chemistry in Physical Coal Cleaning by : G. H. Luttrell
Download or read book Control of Pyrite Surface Chemistry in Physical Coal Cleaning written by G. H. Luttrell and published by . This book was released on 1994 with total page 63 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Pyrite Surface Characterization and Control for Advanced Fine Coal Desulfurization Technologies by :
Download or read book Pyrite Surface Characterization and Control for Advanced Fine Coal Desulfurization Technologies written by and published by . This book was released on 1992 with total page 29 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the 9th quarterly technical progress report for the project entitled Pyrite surface characterization and control for advanced fine coal desulfurization technologies'', DE-FG22-90PC90295. The work presented in this report was performed from September 1, 1992 to November 31, 1992. The objective of the project is to conduct extensive fundamental studies on the surface chemistry of pyrite oxidation and flotation and to understand how the alteration of the coal-pyrite surface affects the efficiency of pyrite rejection in coal flotation. During this reporting period, the surface oxidation of pyrite in various electrolytes was investigated. It has been demonstrated, for the first time, that borate, a pH buffer and electrolyte used by many previous investigators in studying sulfide mineral oxidation, actively participates in the surface oxidation of pyrite. In borate solutions, the surface oxidation of pyrite is tronly enhanced. The anodic oxidation potential of pyrite is lowered by more than 0.4 volts. The initial reaction of the borate enhanced pyrite oxidation can be described by:FeS[sub 2] + B(OH)[sub 4][sup =] --> [S[sub 2]Fe-B(OH)[sub 4]][sub surf] + e. This reaction is irreversible and is controlled by the mass-transfer of borate species from the solution to the surface. It has been shown that the above reaction inhibits the adsorption of xanthate on pyrite. Comparative studies have been made with other sulfide minerals. The solution chemistry of the iron-borate systems have been studied to understand the electrochemical results.
Book Synopsis Acidic Leaching and Flotation Studies of Pyrite by : Anand P. Chandra
Download or read book Acidic Leaching and Flotation Studies of Pyrite written by Anand P. Chandra and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The aim of the thesis was to advance the understanding of the surface chemistry and reactivity of the most abundant and important sulfide mineral, pyrite (FeS2), relevant to the mineral processing industry and environmental remediation. The research primarily involved the use of state-of-art synchrotron radiation methodologies to provide spatially resolved analyses of the nature of the fresh pyrite surface, oxidation of the pyrite surface, and the effects of leaching and certain flotation treatments. Surface chemical variations at the nanometre to micron scale were identified which were correlated to the surface topography. Combined with solution based analysis a spatially resolved oxidation mechanism of pyrite was developed. Copper activation and collector (xanthate) adsorption mechanisms were also proposed.
Book Synopsis Chemistry of Aluminum and Iron Minerals in Oil Shales Containing Pyrite by : Katta Jayaram Reddy
Download or read book Chemistry of Aluminum and Iron Minerals in Oil Shales Containing Pyrite written by Katta Jayaram Reddy and published by . This book was released on 1988 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Oxidation of Coal and Coal Pyrite Mechanisms and Influence on Surface Characteristics. Technical Progress Report by :
Download or read book Oxidation of Coal and Coal Pyrite Mechanisms and Influence on Surface Characteristics. Technical Progress Report written by and published by . This book was released on 1995 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this research is to develop a mechanistic understanding of the oxidation of coal and coal pyrite, and to correlate the intrinsic physical and chemical properties of these minerals, along with changes resulting from oxidation, with those surface properties that influence the behavior in physical cleaning processes. Work during the nineteenth quarter has concluded studies of the surface functional groups produced on coal by severe thermal and chemical oxidation, and on investigating the partition of metal ions between such strongly oxidized coal samples and aqueous solutions. This partitioning behavior was being followed to obtain further information on the chemistry of the coal surfaces after different oxidation treatments. Adsorption isotherms for the uptake of Cd{sup 2+} on coal oxidized by different methods were obtained, and these and the Cu{sup 2+} adsorption isotherms reported in the last report have been scrutinized, and interpreted more exhaustively. The apparent discrepancies noted in the last report for the analysis of surface functional groups have been investigated further. The adsorption behavior has been related to the surface chemistry of Upper Freeport coal oxidized by different methods.
Book Synopsis Control of Pyrite Surface Chemistry in Physical Coal Cleaning. Technical Progress Report for the Ninth Quarter, September 1--November 30, 1991 by :
Download or read book Control of Pyrite Surface Chemistry in Physical Coal Cleaning. Technical Progress Report for the Ninth Quarter, September 1--November 30, 1991 written by and published by . This book was released on 1992 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: The separation of pyrite from coal by flotation is based on exploiting the wettability difference between coal and pyrite. There is evidence that the wettability of coal pyrite changes upon superficial oxidation. Therefore, the oxidation of coal pyrite has been studied under carefully controlled electrochemical conditions. In order to identify the species responsible for the changes in wettability, the surface products formed during oxidation have been identified by means of various surface analysis techniques, including X-ray photoelectron spectroscopy (XPS) and ion scattering spectroscopy (ISS). It has been found that pyrite oxidation creates a sulfur-rich surface along with iron oxides/hydroxides. The ratio between these hydrophobic and hydrophilic species correlates well with the results of the wettability measurements.
Book Synopsis Surface Chemistry of the Oxidation Mechanisms on Pyrite and Mineral Inoculated with Chemolithotrophic Bacteria by : Mankata Inkumsah
Download or read book Surface Chemistry of the Oxidation Mechanisms on Pyrite and Mineral Inoculated with Chemolithotrophic Bacteria written by Mankata Inkumsah and published by . This book was released on 2006 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The goal of the work is to apply conventional X-ray Photoelectron Spectroscopy (XPS) as a probe to characterize the composition of pyrite in lieu of a synchrotron source.", (4)
Book Synopsis Control of Pyrite Surface Chemistry in Physical Coal Cleaning. Tenth Quarterly Progress Report, December 1, 1991--February 29, 1992 by :
Download or read book Control of Pyrite Surface Chemistry in Physical Coal Cleaning. Tenth Quarterly Progress Report, December 1, 1991--February 29, 1992 written by and published by . This book was released on 1992 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the most difficult separations in minerals processing involves the differential flotation of pyrite and coal. Under practical flotation conditions, they are both hydrophobic and no cost-effective method has been developed to efficiently reject the pyrite. The problem arises from inherent floatability of coal and pyrite. Coal is naturally hydrophobic and remains so under practical flotation. Although pyrite is believed to be naturally hydrophilic under practical flotation conditions it undergoes a relatively rapid incipient oxidation reaction that causes ''self-induced'' flotation. The oxidation product responsible for ''self-induced'' flotation is believed to be a metal polysulfide, excess sulfur in the lattice, or in some cases elemental sulfur. It is believed that if incipient oxidation of pyrite could be prevented, good pyrite rejection could be obtained. In order to gain a better understanding of how pyrite oxidizes, a new method of preparing fresh, unoxidized pyrite surfaces and a new method of studying pyrite oxidation have been developed this reporting period.
Book Synopsis Control of Pyrite Surface Chemistry in Physical Coal Cleaning. Second Quarterly Progress Report, December 1, 1989--February 28, 1990 by :
Download or read book Control of Pyrite Surface Chemistry in Physical Coal Cleaning. Second Quarterly Progress Report, December 1, 1989--February 28, 1990 written by and published by . This book was released on 1992 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: To better understand the surface chemical properties of coal and mineral pyrite, studies on the effect of flotation surfactants (frother and kerosene) on the degree of hydrophobicity have been conducted. The presence of either frother or kerosene enhanced the flotability of coal and mineral pyrite with a corresponding decrease in induction time over the pH range examined. Scanning electron microscopy (SEM) results indicate a correlation exists between the sample surface morphology and crystal structure and the observed hydrophobicity. As a result of the data obtained from the surface characterization studies, controlled surface oxidation was investigated as a possible pyrite rejection scheme in microbubble column flotation.
Book Synopsis Control of Pyrite Surface Chemistry in Physical Coal Cleaning by :
Download or read book Control of Pyrite Surface Chemistry in Physical Coal Cleaning written by and published by . This book was released on 1992 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past 10 years, much research has provided convincing evidence that one major difficulty in using froth flotation to separate pyrite from coal is the self-induced'' flotation of pyrite. Numerous studies have attempted to identify reactions that occur under moderate oxidizing conditions, which lead to self-induced flotation, and to identify the oxidization products. During the past two report periods, it was established that: (1) freshly fractured pyrite surfaces immediately assume, at fracture, an electrode potential several hundred millivolts more negative than the usual steady state mixed potentials. Within minutes after fracture, the electrodes oxidize and reach higher steady state potentials. It was also shown, by photocurrent measurements, that a negative surface charge (upward band bending) already exists on freshly fractured pyrite, and (2) particle bed electrodes can be used to control the oxidation of pyrite and to precisely determine the electrochemical conditions where flotation occurs, or is depressed. By circulating the solution phase to an ultraviolet spectrometer, soluble products produced on pyrite by oxidation and reduction can be determined, e.g., HS[sup [minus]] was identified as a soluble cathodic reduction product. These and other studies have provided considerable information concerning the anodic oxidation of pyrite. Much less is known about the mechanism and kinetics of oxygen reduction, the other half of the mixed potential reaction. To better understand pyrite oxidation kinetics and determine if oxygen reduction is rate determining, studies have been conducted during this report period on the oxygen reduction reaction with pyrite. In addition, to provide further support that the potential of particle bed electrodes can be controlled, the electro-adsorption and desorption of an organic surfactant was studied.
Book Synopsis A Novel Approach to Experimental Studies of Mineral Dissolution Kinetics by :
Download or read book A Novel Approach to Experimental Studies of Mineral Dissolution Kinetics written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Currently, DOE is conducting pilot CO2 injection tests to evaluate the concept of geological sequestration. One strategy that potentially enhances CO2 solubility and reduces the risk of CO2 leak back to the surface is dissolution of indigenous minerals in the geological formation and precipitation of secondary carbonate phases, which increases the brine pH and immobilizes CO2. Clearly, the rates at which these dissolution and precipitation reactions occur directly determine the efficiency of this strategy. However, one of the fundamental problems in modern geochemistry is the persistent two to five orders of magnitude discrepancy between laboratory measured and field derived feldspar dissolution rates. To date, there is no real guidance as to how to predict silicate reaction rates for use in quantitative models. Current models for assessment of geological carbon sequestration have generally opted to use laboratory rates, in spite of the dearth of such data for compositionally complex systems, and the persistent disconnect between laboratory and field applications. Therefore, a firm scientific basis for predicting silicate reaction kinetics in CO2 injected geological formations is urgently needed to assure the reliability of the geochemical models used for the assessments of carbon sequestration strategies. The funded experimental and theoretical study attempts to resolve this outstanding scientific issue by novel experimental design and theoretical interpretation to measure silicate dissolution rates and iron carbonate precipitation rates at conditions pertinent to geological carbon sequestration. In the second year of the project, we completed CO2-Navajo sandstone interaction batch and flow-through experiments and a Navajo sandstone dissolution experiment without the presence of CO2 at 200 C and 250-300 bars, and initiated dawsonite dissolution and solubility experiments. We also performed additional 5-day experiments at the same conditions as alkali-feldspar dissolution experiments with and without the presence of CO2 performed in the first year to check the validation of the experiments and analysis. The changes of solution chemistry as dissolution experiments progressed were monitored with on-line sampling of the aqueous phase at the constant temperature and pressure. These data allow calculating overall apparent mineral (feldspars and sandstones) dissolution rates and secondary mineral precipitation rates as a function of saturation states. State-of-the-art atomic resolution transmission electron microscopy (TEM), scanning electron microscopy (SEM), and electron microprobe was used to characterize the products and reactants. Reaction-path geochemical modeling was used to interpret the experimental results of alkali-feldspar dissolution experiments without the presence of CO2. Two manuscripts are near completion. Also during the second year, our education goal of graduate student training has been advanced. A Ph. D. student at Indiana University is progressing well in the degree program and has taken geochemical modeling, SEM, and TEM courses, which will facilitate research in the third year. A Ph. D. student at University of Minnesota had graduated. With the success of training of graduate students and excellent experimental data in the second year, we anticipate a more fruitful year in the third year.
Book Synopsis Environmental Mineralogy by : J. D. Cotter-Howells
Download or read book Environmental Mineralogy written by J. D. Cotter-Howells and published by . This book was released on 2000 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt:
