Major Minerals Research Articles

Mineralogy and Rock Response Analysis Approach to Mitigate Wellbore Stability issue in “B” Cluster of East Java Field

The instability of shales in drilled formations leads to serious operational problems with major economic consequences for petroleum exploration and production. It is generally has agreed that the nature of the clay minerals in shale formations is a primary causative factor leading to their instability, although the exact mechanism involved is more debatable. Currently, the principal cause of shale instability is considered to be volume expansion following the osmotic swelling of sodium smectite. However, illitic and Kaolinite shales may also be unstable, so that interlayer expansion cannot therefore be consider as a universal causative mechanism of shale instability. This review considers alternative scenarios of shale instability where the major clay minerals Kaolinite suspected to be a key success to mitigate the wellbore stability. It is found from the literature that the inhibited by the use of more concentrated Potassium-based fluids which is effectively shrink the thickness of the clay mineral surfaces in the pore walls but may differently responded by Kaolinite dominant clay. The use of soluble polymers would also encapsulate these clay mineral surfaces and so inhibit their hydration. In this scenario, the locus of action with respect to shale instability and its inhibition is moved from the interlamellar space of the smectitic clays to the charged external surfaces of the various clay minerals bounding the walls of the shale pores. Keywords: shale instability, smectitic shale, illitic shale, Kaolinitic shale.

26Al–26Mg chronology of high‐temperature condensate hibonite in a fine‐grained, Ca‐Al‐rich inclusion from reduced CV chondrite

AbstractAl–Mg mineral isochron studies using secondary ion mass spectrometry (SIMS) have revealed the initial 26Al/27Al ratios, (26Al/27Al)0, for individual Ca‐Al‐rich inclusions (CAIs) in meteorites. We find that the relative sensitivity factors of 27Al/24Mg ratio for SIMS analysis of hibonite, one of the major constituent minerals of CAIs, exhibit variations based on their chemical compositions. This underscores the critical need for using appropriate hibonite standards to obtain accurate Al−Mg data. We measured the Al−Mg mineral isochron for hibonite in a fine‐grained CAI (FGI) from the Northwest Africa 8613 reduced CV chondrite by SIMS using synthesized hibonite standards with 27Al/24Mg of ~30, ~100, and ~400. The obtained mineral isochron of hibonite in the FGI yields (26Al/27Al)0 of (4.73 ± 0.09) × 10−5, which is identical to that previously obtained from the mineral isochron of spinel and melilite in the same FGI (Kawasaki et al., 2020). The uncertainties of (26Al/27Al)0 indicate that the constituent minerals in the FGI formed within ~0.02 Myr in the earliest solar system. The disequilibrium O‐isotope distributions of the minerals in the FGI suggest that the O‐isotope compositions of the nebular gas from which they condensed underwent a transitional change from 16O‐rich to 16O‐poor within ~0.02 Myr in the earliest solar system. Once formed, the FGI may have been removed from the forming region within ~0.02 Myr and transported to the accretion region of the parent body.

Contrasting magmatic controls on the genesis of Fe-Ti-V oxide deposits in the Emeishan large igneous province using apatite Sr-Nd isotopes and apatite-zircon trace elements

We use Sr-Nd isotopes of apatite and trace element compositions of apatite-zircon pairs from a major ore layer in each of three selected magmatic Fe-Ti-V oxide ore deposits (Hongge, Panzhihua, and Taihe) in the Emeishan large igneous province (LIP) in southwestern China to contrast the magmatic controls on ore formation. The average contents of REEs in apatite from a representative ore zone/layer in each of these deposits are higher than the predicted values of apatite crystallizing from a melt with REE contents assumed to be the same as the average values of high-Ti basalts in the Emeishan LIP, confirming that the ore-forming magmas all experienced higher degrees of fractional crystallization by major silicate minerals than the average basalt. The apatites Sm/Yb and Sr/Y indicate that the Panzhihua magma was generated at a shallower depth and experienced higher degree of plagioclase fractional crystallization than Taihe and Hongge. The apatite Sr-Nd isotopes can be reproduced by ~ 8 wt% contamination with Precambrian gneiss-schist in the parental magma for Hongge and by ~ 10 wt% and ~ 25 wt% contamination with marbles in the parental magmas for Panzhihua and Taihe, respectively. A recycled, high-T altered oceanic gabbroic component in the mantle source is a viable alternative to the marble contamination model for Taihe. Coexisting zircon trace element compositions reveal that the parental magma for Taihe (ΔFMQ+4.0) is more oxidized than those for Hongge (ΔFMQ−0.4) and Panzhihua (ΔFMQ−0.7), questioning that magma oxidation played a critical role in the genesis of Fe-Ti-V oxide ore deposits in the Emeishan LIP.

An optimization of synthesis technique for Na-X zeolite from coal-fly ash using Taguchi experimental design

Na-X Zeolite was made from Class-F coal fly ash from a thermal power plant in the Indian state of Gujarat. The objective of this study is to maximize Na-X zeolite crystallization by using alkaline fusion hydrothermal treatment. The authors have also optimized the process variables using the L9 orthogonal Taguchi method. The operating parameters investigated are fusion temperature, fusion time, liquid/solid (L/S) ratio, and alkaline solution concentration. The XRF analysis of coal fly ash reveals that quartz (SiO2), mullite (Al2O3.SiO4), and a small fraction of hematite and magnetite are the major minerals. The highly crystalline zeolite (ZT-5) was synthesized in a 0.3 M NaOH solution at a fusion temperature of 550 °C for 12 h. with a 1.3 L/S ratio. Contrary to the CFA graph, the zeolite (ZT-5) XRD pattern displays prominent peaks between 20 and 40°. The SEM images illustrate the transition from a smooth spherical texture to a highly crystalline lattice structure in the morphology of zeolite. A sharp stretch around 440 and 460 cm−1 and weak bend around 660 and 694 cm−1 show the relative O-T-O deformation and the change in shape of the Al-O-H bonds, as measured by FT-IR absorption.

Determination of Minerals in Soft and Hard Cheese Varieties by ICP-OES: A Comparison of Digestion Methods.

For sample preparation prior to mineral analysis, microwave digestion (~2 h) is quicker and requires lower acid volume as compared to dry (6-8 h) and wet digestion (4-5 h). However, microwave digestion had not yet been compared systematically with dry and wet digestion for different cheese matrices. In this work, the three digestion methods were compared for measuring major (Ca, K, Mg, Na and P) and trace minerals (Cu, Fe, Mn and Zn) in cheese samples using inductively coupled plasma optical emission spectrometry (ICP-OES). The study involved nine different cheese samples with moisture content varying from 32 to 81% and a standard reference material (skim milk powder). For the standard reference material, the relative standard deviation was lowest for microwave digestion (0.2-3.7%) followed by dry (0.2-6.7%) and wet digestion (0.4-7.6%). Overall, for major minerals in cheese, strong correlation was observed between the microwave and the dry and wet digestion methods (R2 = 0.971-0.999), and Bland-Altman plots showed best method agreement (lowest bias), indicating the comparability of all three digestion methods. A lower correlation coefficient, higher limits of agreement and higher bias of minor minerals indicate possibilities of measurement error.

Preliminary Findings of Fe-Skarn Mineralization in Southeast Anatolian Orogenic Belt (Pertek, Tunceli)

The Southeast Anatolian Orogenic Belt (SAOB), one of the most important belts in Turkey, is located north of the Bitlis-Zagros Suture Zone. Major iron mineralizations are also observed along this belt. The Pertek (Tunceli) region is one of the dominant Fe-Skarn mineralizations. Keban Metamorphites of Permo-Carboniferous age forms the basement of the region. It is mainly represented by metacarbonates, marbles and schists, respectively. This unit is also cut by intrusive rocks from the Upper Cretaceous Elazığ Magmatic Complex (EMC). Tertiary volcanic rocks and sedimentary rocks also overlie both units with angular unconformity. Fe-Skarn was formed at the contact of carbonates belonging to Keban Metamorphites and diorites belonging to EMC. Macroscopically, magnetite crystals and garnet can be observed in the skarn formation, which is easily distinguished by its colour. Polarizing microscopy revealed quartz, calcite, garnet, pyroxene, chlorite and opaque minerals. X-ray diffraction (XRD) analysis revealed that the garnet is andraditic, and the ore minerals are magnetite and hematite. In the ore microscopy, it was determined that magnetite was first transformed into hematite and then hematite into goethite. Regarding the major oxide concentrations of the samples taken from the region, it was determined that the Fe2O3 value reached a maximum of 60% (average 21.94%), SiO2 (average 38.20%) and CaO (average 23.58%) concentrations were high, and Al2O3 concentration was generally low. Al2O3 concentration reaches 17.96 % in the sample where clayification is common. The findings of this study provide a baseline for identifying the origin of the Pertek Fe-Skarn formation.

Can Imaging Spectroscopy Divulge the Process Mechanism of Mineralization? Inferences from the Talc Mineralization, Jahazpur, India

Talc deposits of Jahazpur, Rajasthan, hosted by dolomite, are one of the largest high-quality talc deposits in India. In the present study, we use AVIRIS-NG datasets to study the link between the spatial pattern of talc mineralization, associated alteration minerals, and iron-oxide enrichment. It is noted that the majority of talc-bearing areas are characterized by the presence of clay minerals, such as an intimate mixture of kaolinite and muscovite, illite, dickite (indicative of phyllic and argillic alteration), and also enhanced iron enrichment. The talc-bearing zones are located adjacent to quartz-rich lithologies, and they are aligned along the Jahazpur thrust. Based on mineralogical and geological evidence, hydrothermal alteration of dolomites by silica and iron-rich fluid is proposed as major factorcontrolling talc mineralization. This study has implications for the identification of prospective zones of talc mineralization using imaging spectroscopy.

Nepheloid layer dynamics overview of the Portuguese continental shelf

As part of project AQUIMAR, intensive CTD (conductivity, temperature and depth), and turbidity/particulate matter concentration (PMC) data were collected in four cruises along the Portuguese continental shelf, over three consecutive years under contrasting seasonal scenarios. Two of the cruises were carried out during Fall (5-26 October 2018 and 10 - 31 October 2019), one in Spring (18 April to 12 May 2019), and another under Winter conditions (24 February to 19 March 2020). Water samples were collected at the surface nepheloid layer (SNL) and bottom nepheloid layer (BNL) for evaluation particulate matter concentration (PMC) and composition. Differences found between the 5 sampled areas (Viana do Castelo-Porto; Aveiro-Figueira da Foz; Peniche-Santa Cruz; Setúbal-Sines; Sagres-Tavira), are well visible in T-S (temperature vs. salinity) diagrams based on CTD casts. PMC found in the study samples for all cruises was in the range of 0.1-10.2 g/m3. Turbidity meter data, calibrated and converted into inferred PMC values, showed that the study areas were generally characterized by low values, with the exception of some sporadic maxima found during Winter in the northern areas (between Minho River and the Cape Mondego). Particulate matter sample composition, obtained via X-ray diffraction, identified illite > chlorite > kaolinite > calcite > quartz > feldspars as major minerals, with clay minerals dominating and taking up more than 83% in average of the total identified mineral content. This analysis revealed that, for the Fall and Spring cruises, particles in the SNL were mainly biogenic, and for the BNL, the lithogenic material (average mica content of 71%) and biogenic calcite (average content of 10%) were dominant in all cruises. Cruise data also indicate that upwelling/downwelling and internal waves affected and promoted a higher level of turbulence in the water column, resulting in generally higher turbidity values, found in both the SNL and BNL.

Peculiarities of the Extraterrestrial Basalts of the Solar System with Reference to the Exoplanet Science: a Brief Review

The formation of basalts is a global stage in the evolution of differentiated cosmic body (planet or asteroid) of the Solar System. The paper presents the main chemical and mineralogical features of basaltic meteorites of the SNC, HED group, angrites and lunar mare basalts based on literature data. Despite the differences in the products of basaltic volcanism on different cosmic bodies and significant compositional variations in major minerals of basaltic rocks, most of them belong to low-alkaline basalts, suggesting the prevalence of this type of rocks at least among small bodies of the Solar System. All of them are characterized by the presence of such rock-forming minerals as pyroxene, olivine, and plagioclase, and their spectral characteristics can be used to search for basalts on exoplanets. The main factors affecting the spectral characteristics of atmosphere-free bodies and larger planets with an atmosphere are shown, and the possibility of searching for products of basalt volcanism on exoplanets during future missions is considered.

Impact of International Mineral Price on Korea Composite Stock Price Index Market Capitalization

This study investigates market capitalization elasticity with respect to changes in mineral price by analyzing the relationship between the Korea Composite Stock Price Index market capitalization and the international prices of six major strategic minerals. Weekly data from the 1st week of 2009 to the 52nd week of 2022 were analyzed using the autoregressive distributed lag model. The model comprises market capitalization, mineral prices, exchange rate, money supply, and leading economic index variables with time lags. The results revealed that the changes in the prices of all six strategic minerals except bituminous coal had a positive effect on the market capitalization, while bituminous coal had no effect. The findings of this study support recent developments in the importance of strategic minerals in ensuring resource and economic security.

Contrasting global patterns and trait controls of major mineral elements in leaf

AbstractAimMultiple mineral elements in leaf are the foundation of plant life and regulate many ecosystem functions. However, whether a common mechanism governs the variations of all leaf mineral elements is still unknown.LocationGlobal.Time period1970–2020. 10.Major taxa studied: Plants.MethodsHere, we demonstrate the global‐scale biogeographic patterns of 12 major mineral elements (nitrogen, phosphorus, potassium, calcium, magnesium, sulphur, aluminium, iron, manganese, sodium, zinc and copper) by compiling a global data set including 2710 records of leaf mineral elements for 1073 species and of associated climate and soil indices.ResultsIn general, like nitrogen and phosphorus, elements including potassium, calcium, magnesium, sodium and copper in leaf declined towards the equator, which supported both plant physiological hypothesis and soil substrate age hypotheses developed on the basis of nitrogen and phosphorus. By contrast, other elements responded to latitude in a contrary manner as nitrogen and phosphorus, in line with a competing mechanism, temperature–biogeochemistry hypothesis. Besides, plant functional types intrinsically differed in mineral concentrations, and to a certain extent, shifts of their composition in turn exacerbated the latitudinal patterns of respective elements as predicted by the species composition hypothesis.Main conclusionsThe fundamentally different dynamics and control mechanisms of patterns of some elements compared with those of nitrogen and phosphorus challenge the idea that common hypotheses can predict biogeographic patterns across all mineral elements; thus, current paradigms of element biogeochemical models and ecological plant nutrition require revision.

The electrical conductivity of granite: The role of hydrous accessory minerals and the structure water in major minerals

The electrical conductivity of granitic rocks (granitoids) is crucial to understand the rock composition, physiochemical state and structure of the crust. However, it is not clear how the conductivity of granitoids is affected by the incorporated water in major minerals and hydrous accessory minerals. Here, we measured the electrical conductivity of two natural granites and two synthetic aggregates compositionally similar to the granites at temperatures of 573–1273 K and pressures of either ambient pressure or 1 GPa. No mineral preferred orientation was observed for the natural samples. The hydrous accessory minerals in the samples, including muscovite, biotite and amphibole, start to dehydrate at about 700 K at ambient pressure, but barely affect the bulk conductivity. The increase in conductivity of granite by more than half orders of magnitude at 1273 K and 1GPa indicated the onset of melting due to the dehydration of biotite. The conductivities of synthetic aggregates are higher than the granite samples, suggesting that the structural water in feldspars could influence, to a moderate degree, the conductivity of granite. We combined the effect of modal composition and structural water on the conductivity of granite and derived a maximal electrical conductivity of a granitoid at different geological settings. The maximal conductivity can be 0.004 ± 0.0001 S/m at 60 km under orogens, over one order of magnitude higher than a cratonic crust. The maximal conductivity provides an upper limit for interpreting the electrical anomalies in the crust.

Adsorption and characterization of exopolysaccharides from Rhizobium tropici on clay minerals

Exopolysaccharides (EPS) are extracellular macromolecular carbohydrate polymers secreted by microorganisms. EPS significantly improves soil structure, fertility and decreases erosion. Montmorillonite and kaolinite are two major clay minerals in soil. Interaction of EPS with clay minerals is important for understanding mechanisms of soil microaggregate and maintaining soil nutrients. The objectives of this study were to investigate mechanisms of EPS from Rhizobium tropici interaction with these clays and their adsorption capacity. Results show that EPS adsorption on clays were better described with Langmuir than Freundlich models, but kinetics followed the parabolic diffusion model. This suggested that EPS adsorption occurred on both surface and interlayers of montmorillonite as controlled by diffusion processes. The maximum adsorption capacity of EPS on montmorillonite and kaolinite were 236.4 mg/g and 168.6 mg/g, respectively. After initial adsorption of EPS on montmorillonite, the d-spacing was slightly increased, but further increase in EPS adsorption significantly decreased the d-spacing. This indicated the partial entrance of EPS into interlayers of montmorillonite, but high EPS presence possibly dehydrated metal ions within interlayers, shrinking montmorillonite. Thus, the current study provides an insight understanding of mechanisms of EPS from Rhizobium tropici interaction with clay minerals.

The occurrence and genesis of HREE-rich minerals from the giant Bayan Obo deposit, China

The carbonatite-related Bayan Obo deposit, China is the largest REE resource in the world. This deposit has long been a major light REE (LREE) producer, with heavy REE (HREE) rarely exploited. In order to better understand the occurrence of HREE in the deposit, this paper conducts a study of HREE-rich minerals at Bayan Obo. Overall, four types of HREE-rich minerals are identified, including fergusonite-group mineral [(Y, REE)(Nb, Ta, Ti)O4], samarskite-group mineral [(Y, REE, Fe)2(Nb, Ta, Ti)2O8], aeschynite-group mineral [(Y, REE, Ca, Th, U)(Nb, Ta, Ti)2O6], and a type of unknown Pb-rich mineral. These minerals have HREE contents varying from 3.4 wt% to 46.4 wt%, mostly between 19.7 wt% and 34.3 wt%. Yttrium, Dy and Gd are the major REE constitute. Textual relations indicate that the HREE-rich minerals were mainly precipitated from carbonatite-related fluids, with small amounts of grains crystallized from the carbonatitic magma or deposited from post-ore modification fluids. The HREE-rich minerals occur in close temporal and/or spatial association with LREE minerals (e.g., monazite and bastnäsite), so formation of these HREE-minerals does not mean strong LREE-HREE fractionation during the ore-formation or post-ore modification process. Given that certain niobium oxides strongly prefer HREE relative to LREE in the mineral structure, a local physiochemical environment that allowed for the deposition of niobium oxides may be significant for efficient HREE deposition. Although HREE-rich minerals are not widely present in the deposit, they tend to occur as clusters in places. To determine what proportions of HREE can be hosted in the HREE-rich minerals, the weight proportions and REE contents of major REE-bearing minerals were measured in three representative ore samples. The results show that ∼ 25–57 % HREE can be hosted in fergusonite, samarskite, and/or aeschynite. Therefore, the newly identified HREE-rich minerals are non-negligible targets for future exploitation of HREE in the Bayan Obo deposit.

First-principles calculations of equilibrium Ga isotope fractionations between several important Ga-bearing minerals and aqueous solutions

This study predicts the equilibrium isotope fractionation factors for some important Ga-bearing species, including major minerals, aqueous solutions and gas phase systems. Equilibrium isotope fractionations of Ga were investigated by using the first-principles quantum chemistry method at the B3LYP/6-311+G(d) level. The 103ln(RPFR) values of orthoclase, albite, quartz, kaolinite, forsterite, montmorillonite, gibbsite, cassiterite, aragonite, sphalerite and calcite were calculated with the volume variable cluster model. The 103ln(RPFR)s of these minerals decrease in the following order: orthoclase > albite > quartz > kaolinite > forsterite > montmorillonite > gibbsite > cassiterite > aragonite > sphalerite > calcite. The solvation effect of Ga3+-bearing aqueous species is modeled by the water-droplet method, and the 103ln(RPFR)s of Ga3+-bearing aqueous species decrease in the following order: [Ga(OH)4]− > [Ga(OH)3] > [Ga(OH)]2+ > [Ga(OH)2]+ > [Ga(H2O)6]3+. The calculation results show that equilibrium isotope fractionations of Ga between different minerals, solutions and gas phases are appreciable. Among minerals, Ga isotope fractionation exhibits the largest value between orthoclase and calcite. Ga isotopic fractionation factor between these two minerals can reach 3.18 per mil at 100 °C. Ga isotope fractionations between Ga-bearing aqueous species and minerals are important for obtaining information about the different geochemical processes, such as surficial geochemistry. This study has provided important Ga isotope fractionation factors.

Geochemical and Mineralogical Findings of Pertek (Tunceli) Fe-Skarn Mineralization: Preparation to Its Origin

The Southeast Anatolian Orogenic Belt (SAOB), one of the most important belts in Turkey, islocated north of the Bitlis-Zagros Suture Zone. Major iron mineralizations are also observed along this belt.The Pertek (Tunceli) region is one of the dominant Fe-Skarn mineralisations. Keban Metamorphites ofPermo-Carboniferous age forms the basement of the region. It is mainly represented by metacarbonates,marbles and schists, respectively. This unit is also cut by intrusive rocks from the Upper Cretaceous ElazığMagmatic Complex (EMC). Tertiary volcanic rocks and sedimentary rocks also overlie both units withangular unconformity. Fe-Skarn was formed at the contact of carbonates belonging to KebanMetamorphites and diorites belonging to EMC. Macroscopically, magnetite crystals and garnet can beobserved in the skarn formation, which is easily distinguished by its colour. Polarizing microscopy revealedquartz, calcite, garnet, pyroxene, chlorite and opaque minerals. X-ray diffraction (XRD) analysis revealedthat the garnet is andraditic, and the ore minerals are magnetite and hematite. In the ore microscopy, it wasdetermined that magnetite was first transformed into hematite and then hematite into goethite. Regardingthe major oxide concentrations of the samples taken from the region, it was determined that the Fe2O3 valuereached a maximum of 60% (average 21.94%), SiO2 (average 38.20%) and CaO (average 23.58%)concentrations were high, and Al2O3 concentration was generally low. Al2O3 concentration reaches 17.96% in the sample where clayification is common. The findings of this study provide a baseline foridentifying the origin of the Pertek Fe-Skarn formation.

Effect of clay on methane hydrate formation and dissociation in sediment: Implications for energy recovery from clayey-sandy hydrate reservoirs

Natural gas hydrate (NGH) is an unconventional energy source with high energy density, huge reserves and worldwide distribution. Sand-dominated hydrate-bearing sediments (HBS) are believed to be the most economically and technically feasible category of HBS for exploitation. Clay is one major mineral component of the natural HBS apart from sands. Due to the inhibition effect of clay on thermodynamics and kinetics of hydrate formation, it is challenging to synthesize representative clayey-sandy HBS samples in laboratory, and thus the corresponding fluid production behavior remains poorly understood. In this study, a sample synthesis method dedicated to clayey-sandy HBS (20 wt% clay) was developed. Two synergistic strategies including pre-wetting and multiple-site water injection were employed to enhance hydrate formation kinetics, increasing the final hydrate saturation from 0.285 to 0.473. Water-rich clayey-sandy HBS samples were formed with no dry sediment zones and improved hydrate distribution homogeneity. This optimized HBS synthesis method fills the gap between the conventional HBS synthesis methods and the need to form more representative clayey-sandy HBS samples. Energy recovery and fluid production from sandy and clayey-sandy HBS samples were investigated by depressurizing to 3.0 MPa at 6.0 °C. Unique features were observed for hydrate dissociation in clayey-sandy HBS: immediate hydrate decomposition upon depressurization and a great pressure difference (∼1.0 MPa) between sediment and wellbore during the production period. This pressure gradient, likely caused by the aggregation and clogging of clays near the wellbore, slowed hydrate decomposition compared to sandy HBS. Additionally, the gas recovery increased from 81.7% to 88.5%, whereas the water recovery substantially decreased from 25.3% to 8.1%. The significant difference in fluid production behavior between clayey-sandy HBS and sandy HBS calls for more thorough investigations into clay-containing HBS to develop specific production strategies for energy recovery from this type of HBS.

An experimental study of proton implantation in olivine

Implantation of ions in minerals by high energy radiation is an important process in planetary and materials sciences. For example, the solar wind is a multi-ion flux that progressively modifies the composition and structure of near-surface domains in solar objects, like asteroids. A bombardment of a target by different elements like hydrogen (H) at various energies causes, among other things, the implantation of these particles in crystalline and amorphous materials. It is important to understand the mechanisms and features of this process (e.g., how much is implanted and retained), to constrain its contribution to the chemical budget of solar objects or for planning various material-science applications. Yet, there has been no detailed study on H implantation into olivine (e.g., the quantification of maximum retainable H), a major mineral in this context. We performed experiments on H implantation in San Carlos olivine at 10 and 20 keV with increasing fluences (up to 3×1018 at/cm2). Nanoscale H profiles that result from implantation were analyzed using Nuclear Resonance Reaction Analysis after each implantation to observe the evolution of the H distribution as a function of fluence. We observed that after a systematic growth of the characteristic, approximately Gaussian shaped, H profiles with increasing fluences, a maximum concentration at H ~ 20 at% is attained. The maximum concentration is approximately independent of ion energy, but the maximum penetration depth is a function of beam energy and is greater at higher energies. The shapes of the profiles as well as the maximum concentrations deviate from those predicted by currently available models and point to the need for direct experimental measurements. We compared the depth profiles with predictions by SRIM. Based on observations from this study, we were able to constrain the maximum retainable H in olivine as a function of ion energy.

Sulfur Transformation and Metals Recovery During Co-Gasification of Municipal Solid Waste and Gypsum

AbstractThe fate of sulfur and conversion of metals during the co-gasification of municipal solid waste (MSW) and gypsum is examined here using aspen plus combined with Thermo-Calc for the process model development. The effect of air ratio, temperature, and MSW-to-gypsum feed mass ratio on the syngas evolution, sulfur transformation, and mineral speciation behavior is investigated. The results showed prevention of gypsum sulfur transformation to sulfur dioxide at temperatures below 1050 °C, air ratio < 0.4, and MSW-to-CaSO4 feed mass ratio < 33 wt%. Approximately 90 wt% of feed was transformed into gas products comprising 22% CO and 19% H2. At approximately 900 °C, major minerals formed were CaS (alabandite), melilite, anorthite, rankinite, nepheline, and wollastonite. Melilite, a calcium silicate of aluminum and magnesium, dominated over all other silicates. At temperatures >1000 °C, these minerals transformed into a more stable calcium orthosilicate (CaSiO4) and molten oxysulfide. At temperatures higher than 1200 °C, all metals in MSW were transformed into molten oxides. The results show that syngas and minerals can be recovered during the co-gasification of MSW and gypsum to directly reveal the synergetic benefits of co-processing MSW and gypsum low-value waste materials.

Mechanical and creep properties of granitic minerals of albite, biotite, and quartz at elevated temperature

Fundamental mechanical and creep behavior of minerals at elevated temperatures is relevant to many subsurface exploration and resource recovery processes, yet remains largely elusive. This study uses instrumented indentation to measure microscale deformation and nanoscale creep of biotite, albite, and quartz, which are the major mineral phases of granitic rocks, at temperatures up to 400 °C. The results show that the elastic modulus of biotite is not only the lowest at room temperature but also decays the most at elevated temperature (i.e., by 25% reduction at 400 °C) compared to that of albite and quartz. The creep deformation within 20 s doubles when the temperature increases from 20 °C to 400 °C for albite, quartz, and biotite, and biotite showed at least three times the overall creep deformation compared to quartz and albite under the same temperature. The indentation creep deformation can be well characterized using a logarithmic time model, showing both transient and constant-rate creep deformation. The secondary creep rate for biotite is about three times that of albite and quartz at the same temperature, and as the temperature increases from 20 °C to 400 °C, the rate of secondary creep becomes approximately 10 times faster for the three tested minerals. Both transient creep deformation and the rate of secondary creep can be empirically correlated to the elastic moduli, which allows quick estimates of the temperature-dependent creep behavior of granitic minerals using their elastic properties, especially when those creep constants are not readily available at elevated temperatures. These results enhance the understanding of temperature-dependent creep deformation at small scales and provide insight into mineral-level damage in granitic rocks due to temperature and long-term deformation.