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Showing 1 to 20 of 33 for “"Mineral Dissolution"”.
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Atomic Force Microscopy Study of Clay Mineral Dissolution
… hectorite, and nontronite) with respect to acid dissolution using in situ atomic force microscopy (AFM). Three techniques are described which make it possible to fix these minerals and other small particles to a suitable substrate for examination in the fluid cell of the atomic force microscope. …
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Numerical Modeling and Simulation of Mineral Dissolution in Fractured Carbonate Formations
Mineral dissolution plays important role in many subsurface transport processes including waterflooding, geological CO2 sequestration (GCS), and matrix acidizing in carbonate formations. Such a dissolution process could form the preferential pathways to cause a failure of waterflooding and GCS due …
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Silicate Mineral Dissolution and Associated Carbonate Precipitation at Conditions Relevant to Geologic Carbon Sequestration
… from fossil fuel combustion on climate change. Mineral trapping, one of the trapping mechanisms of GCS, is of great importance because it has a potentially high sequestration capacity and provides very long-term sequestration. Forsterite: Mg2SiO4), a magnesium-rich silicate mineral, was studied …
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Effects of pore-scale fluid flow on fluid-solid reactions in porous and fractured media
Fluid-solid reactions, such as mineral dissolution and precipitation, are fundamental processes that govern various subsurface processes and engineering applications that are critical to addressing global water, climate, and energy issues. Recent studies have shown that fluid flow is one of the key …
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Aggressive water attack on carbonated cement materials
… OPC experiences significantly higher calcium mineral dissolution rates than both carbonated OPC and 30% fly ash OPC cement concretes. (ii) Once steady dissolution rates were attained, measurements indicated that 30% fly ash OPC and carbonated OPC concrete undergo closely the same calcium …
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Investigation of microbial metal-sulfide interfacial environments under mineral bioleach simulated conditions
… with particular reference to the copper sulfide mineral chalcopyrite (CuFeS2). While it is focused on heap bioleaching, it has applications to stirred tank bioleaching operations. In the context of bioleaching, microbial extra-cellular polymeric substance (EPS) components are thought to complex …
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Geomechanical impact of bio-competitive exclusion chemical on reservoir rocks.
… saturation test, the results showed there was mineral dissolution and precipitation response, which caused the separation of grain particles, and as a result, decreased the strength of the rock. The core flooding investigation was performed at increasing concentrations of 637.5 ppm, 850 ppm, …
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Characterisation of Schwertmannite - Geochemical Interactions with Arsenate and Chromate and Significance in Sediments of Lignite Opencast Lakes
… importance of schwertmannite, geochemical and mineralogical methods were applied in field- and laboratory-experiments. Thereby this thesis focussed on two consequential questions: The first (1) was if schwertmannite could enrich toxic compounds and therefore act as a sink in natural systems. By …
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An investigation into the feasibility of bioleaching copper sulphide ore of Nchanga mine, Chingola, Zambia
… marginal or low-grade ores where high-grade mineral reserves have been depleted. But the degree of microbial oxidation for different copper sulphides varies significantly partly because of different types and level of impurity minerals associated with copper sulphides from different sources. …
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Hydrogen Interactions in the Subsurface Geological Formations: Molecular and Biogeochemical Perspectives
… dynamic properties in representative geological minerals’ pores, including quartz, calcite, kaolinite, illite, and montmorillonite, under non-reactive conditions. These analyses consider coexisting fluids including hydrogen, carbon dioxide, methane, heavy alkanes, and brine with different …
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A spatial and temporal study of the carbon cycle; the role of carbonates in buffering Earth’s climate
… on investigating the impact carbonate rocks, and dissolution thereof, may have on buffering changes in Earth’s climate. The long term process of chemical weathering is of particular interest currently, as some suggest silicate mineral dissolution reactions provide a scalable escape route from …
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Geomycology: fungal bioweathering, bioleaching, bioprecipitation and biotransformation of metals and minerals
… and biogeochemical cycling, metal and mineral transformations, decomposition, bioweathering, and soil and sediment formation. Fungi can apply various mechanisms to effect changes in metal speciation, toxicity and mobility, mineral formation and/or mineral dissolution. This research has …
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Adsorption–Desorption Reactions in the Weathering Zone: Implications for Silicate Weathering & the Carbon Cycle
… acid-driven chemical weathering of silicate minerals removes carbon dioxide (CO2) from Earth's atmosphere. The tectonic processes of uplift, exhumation, and erosion modulate the negative feedback relationship between climate, silicate weathering rates, and atmospheric CO2 removal rates by …
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Microbial attachment to sulfide minerals in a bioleach environment
… with particular reference to the copper sulfide mineral chalcopyrite (CuFeS₂). While it is focused on heap bioleaching, it has applications to stirred tank bioleaching operations. Industrial heap bioleaching offers opportunities for processing of low grade ores but poses process operational …
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Forsterite Dissolution Kinetics: Applications and Implications for Chemical Weathering
Silicate minerals are the most common mineral group in the earth's crust so it is not surprising that their weathering reactions dominate the chemistry of many earth surface processes. This project used forsterite as a model system to identify the important factors that affect silicate mineral …
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Antibacterial calcite created with a multilayer polyelectrolyte coating method
… purposes. Calcite is a naturally occurring mineral in natural aqueous environments which mitigates the negative environmental impact of these materials versus previously used silver nanoparticles. Polycationic natural and synthetic polymers have been shown to interact electrostatically with …
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Characterising subaerial basaltic ‘a‘ā lava flows as potential geothermal reservoirs: Nordeste volcanic complex, Volcanic, São Miguel, Azores
… the sealing of vesicle and fluid networks due to mineral precipitation, although the alteration can also lead to mineral dissolution. Additionally, any secondary tectonic fracturing can form critical areas of high permeability and fluid pathways. <br/><br/>Since the porosity and permeability of …
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Impacts of Carbonate Mineral Weathering on Hydrochemistry of the Upper Green River Basin, Kentucky
… site is more strongly influenced by carbonate mineral dissolution, reflected in higher specific conductance (SpC) and pH. The SpC at Munfordville ranges from 0.9 to 4.8 times that at Greensburg, averaging 2.0 times higher. Although rainfall is impacted by sulfuric acid from coal burning, river …
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Geochemical modeling-based prediction of water-rock interaction during aquifer storage and recovery utilizing selected Colorado Front Range aquifers
… elements from bulk rock geochemical analysis and mineral identification from petrography are used to infer a generalized mineral suite to represent each of the formations of interest. Similarly, compositional analyses from domestic water well samples, including major anions and cations and …
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Capturing and Characterizing Soluble Organic Matter Dynamics in Soil Formation Processes
… several environmental processes such as organo-mineral complexation, nutrient bioavailability, and mineral dissolution. Because of these contributions of DOM to important ecosystem processes, it is often of interest to quantify the flux of DOM moving through different parts of ecosystems. …
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