Effect Of Mineralogy Research Articles

Engineering properties of fine-grained red mud

ABSTRACT Basic engineering parameters of fine-grained red mud tailings were evaluated via laboratory tests; the coupled effect of mineralogy and microstructure was investigated by appraising the stress-deformation characteristics; and the static and seismic liquefaction susceptibilities were evaluated via critical state soil mechanics and empirical equations, respectively. Results indicated the presence of cementitious minerals without swollen clay minerals. The textural and compression properties were similar to those of clays, whereas the strength parameters were similar to those of sand. The stress-deformation curves show overall strain softening with a temporary strain-hardening curve at the beginning, which can be qualitatively explained by the coupled effect of the microstructure and mineral components. Hydroxysodalite precipitated at the contact points among the particles afforded microstructural cementation bonds, allowing the aggregates to resist external loads at the initial loading stage. Red mud presented strong resistance to static liquefaction but was potentially seismically liquefiable.

Microstructure, tensile strength and shear strength of aggregate-mortar interface: Effect of aggregate mineralogy

This work aims to study the mechanical properties of the interfacial transition zone (ITZ) through both experimental tests and microstructural observations. The study considers a mortar with water-cement ratio of 0.58 and four types of aggregates: sandstone, granite, and two different types of limestone with varying water absorption coefficients. Chemical compositions, physical characteristics, and surface micromorphology of the four aggregates were evaluated using X-ray diffraction (XRD), thermogravimetric analysis (TGA), and water absorption measurements as well as SEM observations. Experimental setups were developed to investigate the bonding behavior of the aggregate-mortar interface. The bonding strength between granite and mortar through direct tensile test varied from 51% to 69% of tensile strength of mortar from young age to mature, while 61% to 74% for sandstone, 48% to greater than 90% and 81% to greater than 102% averagely for black and white limestone respectively. The fact of failure in the bulk mortar indicates ITZ adhesion for limestones may equal or exceed the mortar tensile strength generally from 28-day age. This conclusion is consistent with the results obtained by slant shear test. The significant difference of adhesion behavior of ITZ between two limestones due to their water absorption capability. High-water absorption turns out to be beneficial in forming a strong chemical bond at early age, however, the mineralogy remains the pivot under same surface condition. This chemical bond is evidenced by the failure pattern and morphology of the aggregate surface after failure and the presence of a dense accumulation of portlandite and C-S-H under SEM.

Impact of clay mineralogy on the petrophysical properties of tight sandstones

A full petrographic and petrophysical characterization of tight sandstones has been conducted as part of ongoing study of Carbon Dioxide Enhanced Oil and Gas Recovery (CO2-EOR/EGR) and CO2sequestration. The main purpose of this study is to give novel perception into the interplay of the rock characteristics and fluid flow in tight formations, which are candidates for EOR/EGR processes (macroscopic sweep vs. microscopic displacement efficiency). To achieve this, several experimental techniques, including routine core analysis, X-ray diffraction (XRD), X-ray fluorescence (XRF), thin sections petrography, Scanning Electron Microscopy (SEM) and capillarity/pore size distributions by using Mercury Injection Capillary Pressure (MICP), Nuclear Magnetic Resonance (NMR), and Micro-Computed Tomography (Micro-CT), were conducted. Three tight sandstone rock samples (Bandera, Kentucky, and Scioto) were used in this work and particular attention was paid to the impact of clay content on rock's pore system and other petrophysical characteristics and hence fluids flow during production process.Results indicate that the presence of fibrous illite clay acting as pore bridging in Bandera and Kentucky samples have blocked the overall micro-pore system causing a significant reduction in the micro-pore throat system to 36% in Bandera sand and 50.9% in Kentucky sample. On the other hand, absence of fibrous illite and the presence of illite platelets in the Scioto sandstone led to a clear preservation of the sample's micro-pore throat attributing to a total of 59.1% of the total pore throat system.A new dimensionless number (dimensionless micro-pore throat modality) was established, defined as the ratio of micro-to macro-pore sizes. This shows that Scioto has the highest value of 1.44 implying that both macro- and micro-pore systems contribute to flow. Therefore, the mitigation of oil bypass from smaller pores should be a key criterion in selecting the proper recovery methods. Results show the effect of clay mineralogy on pore system considering a part of the physical and spatial properties the pore/grain framework of the tight sandstones.

The Effect of Soil Mineralogy and Particle Breakage on the Impulse Generated from Shallow Buried Charges

Historically, most testing with shallow buried charges has focussed on soils which are predominantly quartz (silica)-based. Particle size, moisture content and density have previously been investigated to ascertain their importance, along with other geotechnical parameters, in governing the magnitude of an impulsive output. This has shown that, in order of importance, moisture content, density and particle size drive the total impulse imparted. The work in this paper presents the results of blast testing carried out with carbonate sands to investigate the difference that particle mineralogy (and hence, propensity for breakage) has on both the localised loading and the total impulse using an array of 17 Hopkinson pressure bars known as the Characterisation of Blast Loading (CoBL) apparatus. Carbonate sands are thought to have more friable particles due to their plate-like morphology, as opposed to the rounded morphology of quartz-based sands. Testing was conducted with low moisture content samples and compared with the well-established Leighton Buzzard uniform sand to isolate the effect of particle mineralogy/morphology on the loadings measured. The results show that, despite attaining a 23% lower bulk density, carbonate soils deliver almost identical total impulses (0.7–3.0% higher) when compared with quartz soils for nominally identical moisture contents.

The effects of clay mineralogy and crack properties on elastic properties of dry and water-saturated transversely isotropic rocks

The causes of the intrinsic elastic anisotropy of shales are very complicated, and clay mineralogy and crack properties are critical for rock-physics models and geomechanics applications in shales, but they are still poorly understood. Further, it is difficult to directly measure the elastic properties of single-crystal clays due to their small particle size. To reduce the multiparametric influence factors caused by complex components in natural shales, two sets of artificial rocks with different clay minerals are fabricated, and their porosity, permeability, and ultrasonic velocities are measured under different pressure conditions. The results suggest that clay mineralogy can significantly affect physical and elastic properties and their pressure sensitivity, and the permeabilities of the sample composed of kaolinite are much higher than those of the sample composed of smectite due to the larger particle size of kaolinite compared with smectite. Further, the type of clay can cause a difference in “intrinsic” velocity and anisotropy. The microcrack can enhance the velocity anisotropy on the basis of intrinsic anisotropy, and crack properties such as maximum dip angle and normal-to-tangential compliance ratio are obtained by a theoretical model, which is also affected by clay type, causing the difference in the pressure sensitivity of elastic properties. Water has a significant influence on the elastic properties and anisotropy of artificial clay samples, which can reduce the S-wave velocity and increase the P-wave velocity driven by multiple competing factors. Water reduces the velocity anisotropy because the presence of water narrows the difference between the velocity parallel and perpendicular to the axis of symmetry. The normal-to-tangential compliance ratio of cracks is also affected by water as a stiffer fluid can reduce the normal compliance of cracks at the grain scale.

Kinetic Response of Industrial Flotation Banks: Effect of Particle Size and Mineralogy

One of the main problems in current flotation plants and new projects is the significant decrease in feed grades and changes in the mineral composition, which has an important effect on the mineral liberation and associations. Additionally, flotation plants usually operate with a feed throughput higher than the original design, which has a significant impact on the feed particle size. All these conditions affect the metallurgical performance, and they must be evaluated and addressed by improving the control strategies for the optimization of banks. For this purpose, the flotation of valuable minerals along the circuits requires better understanding, considering the compromise between performance and selectivity in flotation circuits. This paper presents a characterization of the different minerals recovered along industrial flotation circuits. Plant sampling campaigns, performed in a copper industrial concentrator in Chile, provided the data for the study. Two rougher flotation banks consisting of cells of 130 m3 and 300 m3, were evaluated. All the samples from the industrial surveys were analysed by screening and mineralogy, and the mineral recovery along the circuits was evaluated per particle size class, liberation class, type of associations, and others. Additionally, operating data on froth depth profiles complemented the evaluation of the mineral composition of concentrate streams along the circuit. The results allowed for identifying and quantifying the main factors that affect the copper recovery and concentrate grade along the flotation banks. We found that minerals with liberation lower than 50% have a significant impact on the recovery. On the other hand, the decrease in the Cu grade in concentrates along the flotation circuits is mainly due to the relative increase of middling minerals (less liberated), non-valuable floatable minerals, such as free pyrite, and gangue entrainment. The characterization of the gangue entrainment flowrate along the flotation banks showed a strong relationship with froth depth, which becomes more critical towards the last cells of the banks.

Insights into the Effect of Micropore Structure and Mineralogy on Adsorbed Tight Oil in the Huaqing Area, Ordos Basin, China

There is great potential for tight oil as an alternative to conventional fossil fuels throughout the world. Adsorption, mineralogy, and pore structure of tight sandstone are very important factors for the efficient development of adsorbed tight oil from tight sandstone oil reservoirs. In this study, the occurrence morphology of tight oil adsorbed to varying pore structures was examined, as well as the relationship between adsorption content and occurrence morphology. X-ray energy dispersive spectra, environmental scanning electron microscope observations, and thin fluorescence sections were used to describe the occurrence morphology of adsorbed tight oil in tight sandstone reservoirs. It was found that adsorbed tight oil can be classified into five types: emulsion, cluster, throat, thin-film, and isolation, with average contents of 34.9%, 14.5%, 3.1%, 42.7%, and 4.7%, respectively. In addition, a Soxhlet extraction was developed with four pore structures to describe the geological effects of adsorbed tight oil in reservoirs. The adsorption content of tight oil ranges from 4.015 mg/g to 16.987 mg/g, with an average of 10.115 mg/g. The order of adsorption content for different occurrence morphologies is as follows: emulsion form > throat form > cluster form > isolation form > thin-film form. It is the size and connectivity of the porous throat that determines the desorption efficiency of tight oil. An important outcome of this study can be the introduction of rational development plans and the improvement of oil recovery efficiency for tight oil reservoirs.

Effect of mineralogy on grindability -A case study of copper ores

The effect of mineralogy on the grindability was investigated using three copper ores - two sulphides and one oxide. The dominant copper minerals were identified by optical microscopy and mineral chemistry derived from SEM-EDS analysis. The sample designated sulphide 1 was bornite-rich, sulphide 2 ore was mainly chalcopyrite, and the oxide ore was predominantly malachite and minor azurite. The gangue minerals were identified using semi-qualitative XRD analysis. Sulphide 1 contained more than 80% (w/w) of quartz compared to about 70% in the other two ores. The Bond work indices were 13.8, 21.6, and 17.3 kWh/t for sulphide 1, sulphide 2, and oxide ore respectively. This suggested that the chalcopyrite-rich ore is the hardest, while the malachite-rich ore has intermediate hardness, and the bornite-rich ore is the softest. The brittleness indices of the ores were calculated using the chemical composition of the gangue, and a good correlation between brittleness indices and Bond work indices was observed, which highlights the importance of the gangue composition in determining the fracture behaviour of the ores. There is scope for further investigation into the relationship between ore mineralogy and comminution behaviour using other breakage characterization techniques.

Spectral and mineralogical effects of heating on CM chondrite and related asteroids

Several carbonaceous chondrites (CCs) display evidence of aqueous and thermal alteration. However, the process of thermal alteration is not fully understood. To investigate the spectral variations caused by thermal alteration, we heated powders of CM2 CCs Murchison and Jbilet Winselwan, as well as a simulant Murchison mixture (WMM) and its end members. Heating was conducted up to 1200 °C, in 100 °C increments under a purified nitrogen environment. We also compared the findings of our study with results of previous heating experiments conducted on CCs to better understand the effect differing conditions have on the spectral properties observed. Formation of Fe3+ oxyhydroxides and the decomposition of serpentine due to heating are confirmed by both reflectance and X-ray diffraction (XRD) data. Fe3+ oxyhydroxides features such as a steep slope in between 350 to ∼700 nm, and an ∼850 nm feature can be seen starting at ∼300 and 400 °C, respectively. The serpentine-associated features start to decompose at ∼700 °C and disappear by ∼900 °C. Spectra >1000 °C are generally dark and featureless and above this temperature, mafic silicate absorption bands begin to appear. Our results show that heating-induced spectral variations are evident, and the nature of these changes depends on various parameters including temperature, experimental conditions, duration of heating, sample grain size, as well as mineralogical changes accompanying heating, and heterogeneity between CCs.

Role of Clay Mineralogy in the Estimation of Permeability Coefficient in Compacted Fine-grained Soils

The foundations constructed upon the soils are depending upon the three major criteria i.e., strength, stiffness, and stability. In all three cases, the subsoil is expected to be in a compacted state. In coarse-grained soils, the result of compaction is a problem of substantiality, whereas physicochemical sort of response for fine soils. There is comparatively limited research known about the effects of clay mineralogy on the permeability properties of fine-grained soils, as well as different placement conditions and energy levels. In this study, consolidation behavior will be estimated for the six field soils and one artificial soil having different liquid limits, the Mineralogical composition of clay, and its plasticity properties under placement conditions like 95% of the γd max on dry and wet sides, and at OMC. The permeability behavior of these soils under study is computed by calculating the IS Light and Heavy Compaction energy levels' corresponding consolidation properties (Cv and Mv) using five practical approaches that have been described in the literature. The coefficient of permeability (K) of soils is calculated accurately with a fair degree of accuracy by 1-D consolidation test data like Cv and Mv. The estimated values of K were compared with the K values obtained from experimental studies under various stages of loading, and it was observed that there was good agreement between the two. These results were validated using Abaqus software through Finite Element Modelling analysis.

Effects of Blast Furnace Representative Temperatures and Gas Compositions on Coke Reactivity

The effects of coke mineralogy on coke reactivity under conditions representative of the blast furnace were studied. Coke samples were reacted under coke reactivity index (CRI) like conditions (1100°C, 100% CO2) and at higher temperatures and atmospheres designed to replicate conditions lower in the blast furnace.

Effect of mineralogy on elastic properties of the Bakken formation: A lab scale rock physics modelling

The Bakken formation in the Williston Basin, is one of the largest tight oil reserves in the U.S.A. and is currently the second largest oil producer in the nation. The Bakken formation is divided into the upper and lower shale members which comprise the source rocks, while the middle Bakken, which is a fractured silicious-carbonate formation, is the main producer. The Bakken has a complex mineralogy, composed of mainly quartz and clay in the two shale members and quartz, calcite, dolomite, and anhydrite in the middle member, along with several other minerals with lower volume fractions. Past studies have reported the importance of mineral composition in development, completion, and production from shales.In this study, the effect of mineral composition of the three Bakken members on rock elastic and velocity properties are investigated. Rock physics models were developed at macro (core) scales from data in Dunn and Mountrail Counties. The minerals' volume fractions from core XRD data were used for estimation of rock stiffness and velocities. The calculations were performed for the upper and lower Bakken (UB, LB) shales as well as the clastic and carbonate intervals of the middle Bakken (MB). Hill averaging was used to mix the non-clay members. Clays were added using both Kuster-Toksoz (K-T) model and differential effective medium (DEM) theory. The effect of fluid phase (assuming both homogeneous and patchy fluids) was applied using K-T (Kuster and Toksöz, 1974) and Gassmann equations (Gassmann, 1951) for frequency-dependent velocity estimation. For shales, Backus averaging (Backus, 1962) captured the upper and lower bounds of the data, whereas the K-T model developed for parallel and perpendicular to the laminations, allowed accurate curve fits to the lab data by changing the pore's aspect ratios to capture the pores heterogeneity exhibited in Bakken. The results showed that, In overall, the UB and LB shales, due to the presence of clay minerals, show lower properties than the MB and composed mainly of microfracures (pores). The MB is shown to have more intraparticle pores with stiffer properties. The estimated stiffness and velocity properties are valuable input data for the development, completion and production planning from future wells.

A 13 million-year record of Li isotope compositions in island carbonates: Constraints on bulk inorganic carbonate as a global seawater Li isotope archive

Lithium isotope (δ7Li) variations in marine carbonate sediments and rocks have been widely used to reconstruct global seawater Li isotope compositions and then trace the paleo-weathering processes. However, there are still debates on whether ancient carbonates can faithfully document original seawater δ7Li signals, as δ7Li values of shallow-water carbonates are tightly related to carbonate mineralogy and diagenetic alteration. In this study, we present high-resolution δ7Li, trace element and carbonate mineralogy data of shallow-water carbonate deposits from two shallow drillcores (Jiuzhang A and B) and a deep drillcore (XK-1) in the South China Sea. We compare these new δ7Li data to the ca. 13 Myr history of seawater δ7Li evolution from the middle Miocene to Pleistocene, in order to better constrain the effects of carbonate mineralogy and early diagenesis on δ7Li values of bulk inorganic carbonates. We observe that the δ7Li values of primary carbonate deposits in Jiuzhang A, B and the uppermost XK-1 drillcores (24.6% ± 1.6%, n = 37, 1σ) are significantly lower than modern seawater δ7Li values (Δ7Liprimary-seawater = ∼–6.0%). In contrast, marine diagenetic carbonates in the XK-1 drillcore exhibit δ7Li values of 28.7% ± 0.7% (n = 54, 1σ), approaching coeval seawater values (Δ7Limarine diagenetic-seawater = ∼–2.0%) and much higher than those of primary carbonate deposits. Meteoric diagenetic carbonates in the XK-1 drillcore show δ7Li values of 22.4% ± 1.6% (n = 46, 1σ), close to that of primary carbonate deposits in Jiuzhang A, B and the uppermost XK-1 drillcores, but significantly lower than coeval seawater δ7Li values (Δ7Limeteoric diagenetic-seawater = –5.0% to –9‰ for modern and Miocene seawater). Such δ7Li variations in shallow-water carbonates are attributed to variations in carbonate mineralogy (i.e., aragonite, high-Mg calcite and low-Mg calcite) and diagenetic regimes (fluid- or sediment-buffered conditions of marine and meteoric diagenesis). By comparing δ7Li data from the South China Sea to those from the Bahamas, we suggest strongly fluid-buffered conditions for Li isotopes during marine diagenesis, resulting in δ7Li values of marine limestones and dolostones approaching ambient seawater δ7Li signals. In contrast, meteoric diagenetic carbonates, likely marked by sediment-buffered conditions, may inherit the original δ7Li signals of primary carbonate deposits. Hence, full considerations of the carbonate mineralogy and diagenesis facilitate a better use of bulk inorganic carbonate-archived δ7Li to reconstruct paleo-weathering evolution in deep time lacking the skeletal fossil records.

Log scale rock physics modelling to study the effect of mineralogy on elastic properties of the Bakken Formation

The Bakken Formation is a geographically extensive, organic-rich, tight formation in the Williston Basin and currently serves as the second largest producer of oil in the USA. With respect to stratigraphy, the Devonian–Mississippian-age Bakken Formation typically comprises three members: the Upper (UB), Middle (MB), and Lower Bakken (LB). Lithologically, the upper and lower members of the Bakken are dominated by shales rich in organic-carbon, which act as the source rock for oil reservoirs in the Middle Bakken. The lithology of the Middle Bakken varies widely from siliciclastic to carbonates, with multiple distinct lithofacies typically being identified in the North Dakota portion of the Williston Basin. Good knowledge of the rock properties of the various Bakken members and lithofacies are a key component of their production potential.This study is a continuation of earlier rock physics modelling, which was done at core scale. Data from one well in Mountrail County was used for estimation of rock stiffness and velocities. Rock physics models were developed at log scale to obtain knowledge of formations' elastic properties across the Bakken members, as a function of porosity and pores' fluid type and geometry. Furthermore, the effect of frequency on fluid mixing type was investigated using both homogeneous and patchy models, then fluids were incorporated into the inclusion system using K-T, DEM, or Gassmann's equations. Kerogen was added to the system as a part of the inclusion in a way that fluid was embedded into the organic-matter. Critical porosity of 30% was also applied during DEM modeling to investigate the effects of kerogen being the load-bearing and rock matrix being suspended into it for case of high kerogen content in thermally immature source-rocks. The UB and LB shales, due to the presence of clay minerals, showed lower properties than MB and composed mainly of microfracture pores. Furthermore, the conversion of kerogen into hydrocarbons lowers the overall rock properties of the Bakken shales. The MB siliciclastic intervals showed to have more of intraparticle pores (primary porosity) with stiffer properties, whereas carbonate zones exhibited fracturing (secondary porosity). The rock physics models at macro and log scale complement each other and present a full picture of formations' elastic properties. The estimated stiffness and velocity properties are valuable input data for the development of and production from future wells.

Weathering rates of Ca and Mg related to granitic and gabbro mineralogy in boreal forest soils and the effect of mechanical soil disturbance on weathering release

This study’s aim was to calculate the weathering rates of Ca and Mg for five boreal forest soils in southern Finland on granitic and gabbro containing bedrock. The effect of mineralogy on the total concentrations of Ca and Mg in soil and weathering rates was evaluated. The aim was also to estimate the effect of mechanical soil disturbance related to ploughing on the weathering in the gabbro area. The total concentrations of SiO2, CaO, MgO, and Zr were determined by XRF, and weathering rates of Ca and Mg were determined based on the changes in the CaO, MgO, and Zr concentrations. The weathering rates of Ca+Mg varied 5–38 mmolc m–2 year–1 in the E+B/BC horizons among the plots. Soil disturbance related to ploughing increased the weathering of Ca and Mg largely in the disturbed part of the topmost mineral soil as indicated by the decreasing concentrations of Ca and Mg after mechanical soil disturbance. The weathering input of Ca in the undisturbed soil did not fully replace the Ca output in final whole-tree cutting. The weathering input of Mg in the undisturbed soil was sufficient to replace the lost Mg in stemwood harvesting but not on all the plots the lost Mg in whole-tree harvesting. Weathering rates were higher in the gabbro than the granitic areas.

Reconstructing the lithium isotopic composition (δ7Li) of seawater from shallow marine carbonate sediments

Records of the lithium isotopic composition of seawater (δ7Lisw), preserved in the lithium isotopic composition of shallow-marine carbonate sediments (δ7Licarb), provide information about the links between silicate weathering and clay formation, the global carbon cycle, and Earth’s climate on geologic timescales. However, the record of δ7Lisw values in shallow marine carbonates is complicated by the effects of mineralogy (e.g., calcite vs aragonite) and diagenesis. Here we present measurements of bulk carbonate δ7Li values paired with a suite of stable isotope systems (δ44/40Ca, δ26Mg) and element abundance ratios (Li/(Ca + Mg), Sr/(Ca + Mg), Mg/(Ca + Mg)) in Neogene shallow-marine carbonates from sites in the Bahamas and southwest Australia. The studied sites span a range of depositional and diagenetic settings and exhibit large stratigraphic trends in δ7Li values that correlate with mineralogy, δ44/40Ca values, and/or element abundances. These trends differ from coeval planktonic foraminifera records of δ7Lisw and instead predominantly reflect local processes. We show, using a suite of geochemical analyses and a numerical model of early marine diagenesis, that the observed variability in bulk sediment δ7Li values can be quantitatively explained by the effects of mineralogy and diagenetic alteration under both fluid-buffered and sediment-buffered conditions. Using this framework, we show that it is possible to produce robust and accurate ‘snapshots’ of the δ7Li value of seawater in the geologic past from shallow-water marine carbonate sediments.

Direct laser sintering for lunar dust control: An experimental study of the effect of simulant mineralogy and process parameters on product strength and scalability

Dust is a hazard for lunar surface operations, and controlling lunar dust is critical to the operation of a permanent lunar base. The cost of importing materials from earth necessitates methods of dust control which use only in-situ materials. One such method is direct sintering, a process by which areas of the lunar surface are melted or sintered to seal the surface. Previous trials of solar, microwave and radiant direct sintering have produced mixed results, but direct laser sintering (DLS) offers a viable alternative. Lasers can be focussed to very high intensities, so a system power of a few hundred watts would be sufficient for DLS. In this study, almost 900 trials of DLS using a CO2 laser were conducted to investigate the influence of processing parameters and lunar dust simulant type on the physical and mechanical properties of DLS crusts formed on compacted simulants. A process parameter tuning method was implemented to maximise product mass, density, flexural strength and production rates while minimising energy requirements. Thereafter, strategies were developed by which a sintered crust of unlimited dimensions could be produced. The potential advantages of screening regolith prior to DLS were considered, and the impact of simulant type on the process was investigated. From the study, it was concluded that DLS was a viable method of dust control for un-trafficked or lightly trafficked areas and could be implemented by a small robot that could be accommodated within the payload of proposed Commercial Lunar Payload Services. Therefore, DLS has the potential to be the first ISRU dust control measure to be implemented on the moon.

Localized equilibrium and mineralogic effects on trace element distribution and mobility in highly metamorphosed Eucrite Elephant Moraine (EET) 90020

Eucrites exhibit a range of igneous and metamorphic textures and geochemistries that can be used to study the evolution of early planetary differentiation and crust formation in the solar system. We integrated petrologic/textural observations, in-situ geochemical analyses, and thermodynamic modeling to explore the petrogenesis of Elephant Moraine (EET) 90020, an unbrecciated meteorite. We identified microdomains that record relatively high metamorphic temperatures and concluded that diffusion processes likely modified EET 90020 during and/or after peak thermal conditions. There is little evidence that partial melting caused the distribution of minor and trace elements within or among the microdomains. Trace element linear transect measurements within the microdomains imply that phosphate minerals strongly controlled trace element distributions throughout the sample. The discrepancy between the observed metamorphic textures, major element chemistry, and the trace element distributions is a consequence of differing chemical mobility. Multiple processes are influencing geochemistry within a single sample which has implications for the development of petrogenetic models that seek to reconcile the differences observed between eucrite geochemical groups.

The effect of paste composition, aggregate mineralogy and temperature on the pore solution composition and the extent of ASR expansion

The reaction kinetics of the alkali silica reaction depends on the composition of the pore solution. The evolution of the pore solution composition in different cement pastes and concretes was studied. Pastes containing silica fume or metakaolin had the lowest amount of alkalis in the pore solution. In addition, metakaolin increased the aluminium concentrations. The lowest expansion was measured for the concretes made of blended cement pastes with low alkali and hydroxide content in their pore solution, for the duration of the present study, no additional aluminium effect was observed due to the already low pH. Addition of 400 mM of Li slowed down expansion rate of concrete prisms at 40 and 60 °C, however, similar expansion was observed for samples with and without Li at 60 °C after 1 year. Temperature, alkali concentration and pH of pore solution all have a major effect on ASR expansion.

Effect of Mineralogy on the Physicochemical Properties of a Heavy Crude Oil in Hybrid Steam Injection Technologies Using 1H NMR

Effect of Mineralogy on the Physicochemical Properties of a Heavy Crude Oil in Hybrid Steam Injection Technologies Using 1H NMR