Two synthesis routes of the zircon-hafnon solid solution series were carried out. The high-temperature route uses the growth of single crystals via a flux mixture that has been cooled down slowly from 1400 °C over 4 weeks. The reaction products were colorless and idiomorphic without byproducts. The hydrothermal tetraethoxysilane (TEOS)-based route represents the low-temperature method at 200 °C for approximately 7 days. The hydrothermal route yielded a white powder and scanning electron microscopy analysis thereof did not reveal any specific idiomorphic properties. However, the synthesis also featured some byproducts besides the zircon-hafnon solid solutions. Thermogravimetric analysis coupled with differential scanning calorimetry, and mass spectroscopy indicated, that hydrothermal reaction products feature the presence of organic residues originating from the starting materials. However, a specific dependency on the hafnium content could not be observed due to the data scatter. Infrared (IR) analysis revealed the presence of Zr/Hf-oxides. The structural characterization demonstrated that properties change constantly with the hafnium amount, however, gradual variations of some properties related to the composition of the solid solution series depend in part on the synthesis route, considering the c/a ratio and IR modes. Furthermore, analyses of the single crystals by Raman spectroscopy and μXRF suggested a nonequilibrated crystal growth based on the starting composition.

The synthesis of highly reactive dicalcium silicate phases by the alternative method flame spray pyrolysis (FSP) was investigated. Five main conditions of the synthesis process were varied and analyzed by applying a two-level fractional factorial design 25-2 resolution III, with a replica of a chemical system defined by a mixture of Ca (O2CCH2CH3)2/Si(C2H5O))4 dissolved in ethanol/water/triethanolamine to evaluate the formation of poly-morphs and their reactivity. For this, a physical and mineralogical characterization was carried out that included X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET) specific surface area analysis, thermogravimetric analysis (TGA-DSC), and transmission electron microscopy (TEM). The investigation reveals that the process parameters have a remarkable importance on the final properties of the samples, favoring the formation of belite phases with high reproducibility. The hydraulic samples present a complete hydration reaction after 24 h of contact with water, giving a clear image of the potential of this technique for the development of highly reactive materials that can be part of sustainable construction in the future.

Construction and demolition waste recycling is mandatory in the context of circular economy. Specifically, applications for the cementitious waste fines are less discussed in scientific literature and barely implemented. Apart from the use of cementitious waste fines as raw materials for clinker production, thermal treatment by the decomposition of fines at temperatures lower than 600 ? has been explored to produce an alternative binder implying under this limit in low CO2 emissions during production. However, there are doubts if its reactivity results from the hydration from residual calcium silicates, and quicklime (CaO) eventually formed after the thermal treatment. This paper investigated quantitively the contributions of calcium silicates and quicklime by thermogravimetry (TG) and quantitative X-ray diffraction (QXRD) on the reactivity of the rehydrated cements. After hydration of the high initial strength Portland cement, only 5% (g/g) of calcium silicates remained, mostly larnite. After dehydration at 500 ?, only 6% (g/g) of quicklime was formed due to the decomposition of portlandite. Intermediate silicates increased in function of temperature of dehydration until 500 ?, but the contents were lower than 18%-g/g. Those phases can explain partially the heat released during rehydration. The heat seemed to be also related to the chemically bound water in the reformation of amorphous C-S-H. In fact, for a fixed water/cement ratio, the increase of chemically bound water explained both, the increase of heat released and the compressive strength of the rehydrated cements. This supports our finding that the calcium silicates or quicklime are not the only responsible for the reactivity of this binder.

Since naturally occurring minerals typically have particle sizes from microns to several nanometers, their investigation, from sampling to individual particle analysis, is a challenging task. This work reports the detection of anatase, which occurs mainly in tropical soils and upon weathering in laterite. Little knowledge of this omnipresent accessory nanomineral, showing strong affinity to the soil formation processes and lateritic profiles is presently available. In bauxites the nano-anatase crystal morphology have not been reported yet. The samples were collected in a bauxite mine south of the Amazon (Juruti, Brazil). The chemical enrichment of anatase was carried out with H2TiF6 and the resulting powders could be characterized with SEM, XRPD and EDX. Subsequently, transmission electron microscopy (TEM) was used to analyze the chemical composition of individual anatase particles by EDX and the unique method of automated electron diffraction tomography (ADT), which probes the reciprocal space of individual nanoparticles. Associated with anatase, crandallite mineral group was also detected. Keywords: kaolinite; iron oxyhydroxides; gorceixite; goyazite; Juruti

Abstract The comparison of the evolution of the mechanical properties (elastic modulus and hardness) after step-wise thermal annealing for 1 and 16 h up to 900 K of a radiation-damaged pyrochlore (∼35% amorphous fraction; 1.8 wt% ThO2) provides insights to the time-temperature dependence of the recrystallization behavior. Especially the elastic modulus, directly related to interatomic bonding, enables the correlation with the amount of amorphous fraction. From this a pronounced effect of the annealing time on percolation behavior could be deduced. Evolved gas analysis indicate dehydration in the course of the structural reorganization process.

This study provides an environmental reconstruction of an archaeological site in the northern part of north-eastern Brazil. To understand how the climate, relative sea-level (RSL), and human activities triggered envi-ronmental changes in Maranha similar to o State during the Holocene, a multi-proxy analysis has been done in a 450 cm long sediment core. The core has been radiocarbon dated and analyzed by its content of pollen, spores, micro -morphological and spot chemical analyzes by Scanning Electron Microscope (SEM), multi-element chemical analyzes, X-ray Powder Diffraction (XRD), charcoal, Loss on Ignition (LOI), and sedimentary characteristics. The site was a tidal channel, part of an estuarine system surrounded by mangrove vegetation between 7920 and 7500 cal yr BP. For this period, the mineralogical and chemical composition showed sediments inputs also coming from marine sources, indicating a transgression of the ocean. The combination of marine transgression and dry environmental conditions allowed mangroves to colonize areas further inland. From 7500 to 1800 cal yr BP, the study site turned into the current freshwater tributary river surrounded by lowlands arboreal and herbaceous vegetation while the Amazon biome expanded. The moister conditions and the RSL regression displaced the mangroves to the current coastal bays about 120 km to the north. The sediment run-off was predominantly continental, as showed by mineralogical and chemical analysis. After 1800 cal yr BP, human influence is noted by increased charcoal and fragmented ceramics in the sediment. Archaeological studies at this region showed that Amerindians built stilt-house villages upon the rivers and lakes, which played stronger role in the envi-ronment. These pre-colonial stilt-houses Maranha similar to o lowland are the only ones found South America.

The need to meet the globally increasing demand for construction materials, while reducing the environmental impact of cement and concrete production, poses a technological and societal dilemma. Detailed knowledge concerning the mineralogical, geochemical, and microstructural features of ancient and modern binders is fundamental for novel, sustainable, cement-based materials to be designed, manufactured, and deployed. This introduction provides several basic concepts related to cement and concrete, as well as a general overview of the role played by these construction materials in ancient civilizations and in today’s society, and of how they are expected to evolve to ensure a sustainable, inclusive, and resilient urban future.

The shift towards lower grade ore deposits, sustainable energy, CO2 reduction, volatile market conditions and digitalization has pushed the mining and minerals industry towards predictive, sustainable and agile analytical solutions to improve safety and increase operational efficiency [...]

The “natural GMS laboratory” (granulometry-morphometry-situmetry) is located within the Variscan Basement in SE Germany (Fichtelgebirge Mts.), which is uplifted relative to its Permo-Mesozoic foreland along a deep-seated lineamentary fault zone. This transitional study area is crossed by straight to low drainage systems in the basement, turning meandering channel systems into high sinuosity when entering the foreland. Due to its good geological coverage, the entire region is subjected to an advanced-level terrain analysis and completed with a sedimentological study focusing on the GMS tool. Unlike many applications in the past, the three components of the GMS tool that are of almost equal value ought to be used in combination and not as stand-alone procedures so as to be integrated into other near-surface geoscientific methods, e.g., sediment petrography. The strong points of granulometry of coarse-grained/gravel-sized sediments are its extension into the smaller sand and clay grain size intervals using the sorting, mean and/or median values for an environmental analysis. Morphometry can be linked to the compositional geosciences, e.g., mineralogy and geochemistry. The grain shape is intimately connected with the lithology, providing options from triaxial measuring of the lithoclast to the digital image analysis. It is a favorable tool to supplement the provenance of lithoclasts. Situmetry is the key element of hydrodynamic research and directly builds upon its sister methods. Its applications and numerical approaches are useful for the identification and quantification of physical land-forming processes. It is the fan sharpness and the orientation of lithoclasts relative to the direction of the talweg and in relation cross-sectional valley features that integrate the GMS tool into geological and geomorphological mapping, both of which result in a digital terrain model. Horizontal rose diagrams are useful for the upper reaches of drainage systems, be they of alluvial or non-alluvial types, and vertical ones for alluvial channels in the distal and proximal foreland where stacked patterns of depositional terraces are of widespread occurrence. In general, the GMS tool can be applied to sedimentological, geomorphological, petrographic and tectonic objects in basements and foreland basins; in applied geosciences, it is suitable for the identification of mineral resources and of areas vulnerable to geohazards, and in genetic geosciences for the discrimination of supergene chemical and physical depositional and land-forming processes.

Sulfobelite (belite-rich calcium sulfoaluminate (BCSA)) cements are promising alternatives to ordinary Portland cement (OPC) due to their lower carbon dioxide generation and lower energy consumption in the clinkering process. Additionally, they are cost effective because of their less-restrictive raw meal composition compared with that of calcium sulfoaluminate (CSA), in which expensive bauxites are used as the alumina source. Diverse mining residues have been proved to be reliable alumina sources for BCSA production, including the clay residues that cover bauxites (Belterra Clay (BTC)) in the Brazilian Amazon region. The clinkering settings of BCSA using a different (less alumina) BTC were examined in this work. The mineralogy of the BCSA clinkers was optimised by a design of experiments and studied using X-ray powder diffraction, scanning electron microscopy and thermal analysis. The raw meal composition, boron doping and firing temperature were investigated to obtain the optimal clinker composition. Hydration of the cement pastes was investigated by calorimetry and the strength development of mortars was tested and compared with that of a commercial OPC. The BCSA mortars produced with gypsum additions developed compressive strength comparable to that that OPC within 28 days. The main hydrated phase was ettringite, with minor amounts of kuzelite, straetlingite and gibbsite.

To set up recommendations on how to define “reasonable minimum composition thresholds” for CO2 streams to access CO2 pipeline networks, we investigated potential impacts of CO2 streams with different and temporally variable compositions and mass flow rates along the CCS chain. All investigations were based on a generic “CCS cluster scenario” in which CO2 streams captured from a spatial cluster of eleven emitters (seven fossil-fired power plants, two cement plants, one refinery and one steel mill) are collected in a regional pipeline network. The resulting CO2 stream (19.78 Mio t impure CO2 per year) is transported in a trunk line (onshore and offshore) and injected into five generic replicate storage structures (Buntsandstein saline aquifers) offshore. Experimental investigations and modeling of selected impacts revealed beneficial as well as adverse impacts of different impurities and their combinations. Overall, no fundamental technical obstacles for transporting, injecting and storing CO2 streams of the considered variable compositions and mass flow rates were observed. We recommend to define minimum composition thresholds for each specific CCS project through limiting i) the overall CO2 content, ii) maximum contents of relevant impurities or elements, iii) acceptable variability of concentrations of critical impurities, and defining impurity combinations to be avoided.

The beneficiation process of bauxite (Al-ore) generates over 10 mi tons of waste clay disposed of in tailing ponds. The purpose of this work was to test this material to produce CSA–based cements. Raw mixtures with the clay were formulated to maximize ye'elimite contents in the clinkers. A CSA-belite clinker composed of 46% of ye'elimite, 40% of belite, and minor amounts of Fe-perovskite and brownmillerite was produced. Cement pastes using clinker to gypsum ratios of 90:10, 85:15, and 75:25 developed compressive strength higher than a Portland cement. The pastes have major contents of ettringite and kuzelite depending on the sulfate additions, besides straetlingite, aluminium hydroxide and hemicarboaluminate. The waste clay is as a potential raw material for CSA-belite low-CO2 cements.

Provenance analysis and terrain analysis backed by radiometric age dating have been combined for the first time and conducted as a composite in a foreland-basement transition zone with mutual benefits for both disciplines. A meticulous provenance analysis enables a fine-tuning during studies of the landscapes and relief generations, while a detailed terrain analysis is essential for the disentanglement of lithological-geodynamic processes that often are telescoped into each other by sedimentological processes. The basic drivers for the denudation, transport and deposition processes of the various clast communities (gravel, sand, clay) are the climate change from a tropical (Neogene) to a glacial/temperate Earth and the brittle neotectonics along the margin of the study area (Rhine Graben Rift N-S, Eger/Ohře Graben Rift E-W). As a result of this composite approach the landscape formation in the study area is described as follows: (1) (Paleogene)-Neogene peneplanation in the basement, (2) Quaternary straight to low sinuosity drainage in the basement, (3) Late Pleistocene to Holocene high-sinuosity drainage in the proximal foreland and (4) Holocene (to Late Pleistocene) meandering fluvial rivers evolving in the distal foreland. In additions to these geomorphological results progress can be made in the geodynamic evolution of the study/source area. Five Proterozoic to Late Paleozoic lithological units are identified: (1) Para-metamorphic rocks, (2) greenstones, (3) basic volcano-sedimentary rocks, (4) sedimentary units abundant in chert and (5) felsic volcanics. By means of these sedimentological finds a more detailed picture of the Variscan orogeny can be presented.

Um Arka area represents a portion of the Neoproterozoic Pan-African belt in the south Eastern Desert of Egypt. The present paper aims to investigate and evaluate the primary dispersion haloes of Au and associated elements. For this purpose, Au and associated elements have been determined in 105 quartz, dyke and country rock samples using both Inductively Coupled Plasma Optic Emission Spectrometry and Inductively Coupled Plasma Mass Spectrometry. Here, the statistical processing and mapping techniques of the analytical data have been applied. The results revealed that all the analyzed elements have been deviated from the normality, and there is a noticeable lack of correlation of both Au and Ag with As, Ba, Co, Cr, Cu, Fe, Ga, Hf, Hg, Mn, Mo, Nb, Ni, Pb, Rb, Sb, Sc, Sn, Sr, Th, Ti, U, V, Y, Zn, and Zr due to long history of Au mining activities. The primary dispersion patterns of Au, Ag, As, Hg and Sb referred to new sites of Au mineralization represented by the quartz veins, the country rocks, dykes, and tectonic zones. Moreover, Sn mineralization is expected to exist in the granitic rocks and Ni mineralization is expected to be in the metagabbroic rocks. Therefore, the area hosted three mineralized events involved Au-, Ni- and Sn- mineralizations that might be derived from a probable single major episode of mineralization sourced by hydrothermal solutions of Um Arka granitoid pluton. The primary dispersion patterns in the area were controlled by tectonic zones, lithology, and supergene processes. Finally, the Um Arka area is fruitful for Au-, Sn-, Ni- mineralization, and a promising target with success for the exploration project and starting new mining works.

The quadripartite/ orthogonal and domal Central European Watershed (CEW) at the NW edge of the Bohemian Massif has been studied by a terrain analysis (fluvial, colluvial, cryogenic, aeolian landforms) combined with geochronological dating (hydraulic correlation) of landforms and the resultant hydrographic correlation of relief generations. It resulted in a morphostratigraphic review (subdivided into a protostage- creating the terrestrial platform, prestages - controlling the physical and chemical regime of the landform series, and stages- fine-tuning of the modern landscape) of the Late Cretaceous to Quaternary relief generations that lead to the creation of the "3 + 1" model of the CEW. The term "3 + 1" refers to a triple junction supplemented with a fourth branch. The characteristic land-form type of the CEW is called the "intermediate sediment trap", a wetland caused by structural or impact-related damming processes. The evolution of the CEW is discussed by a set of four different drivers: The endogenous 1st order drivers are activities along lineamentary fault zones which demarcate the watershed systems. The 2nd order endogenous driver is the alkaline volcanic activity from the Late Cretaceous to the Holocene which contributed to dome-and starlike geomorphological expression. The 3rd order impact-related driver of the Ries Meteorite impact provoked a deflection and damming of channels thereby leading to one of the intermediate sediment traps. The 4th exogenous driver is the climate change. It is accountable for the transition from fluvial incision during the Late Cretaceous and Paleogene (humid-tropical climate zone) to a planation during the Neogene (tropical wet and dry paleoclimate zone). The Quaternary humid mid-latitude, dry continental, and (peri)glacial climate zones put the final touch on the CEW's geomorphological outward appearance. The influence of mining, metallurgy, and mineral processing on the landscape debated in the final stage 8 heralds the onset of the Anthropocene in the CEW. This review of the evolution of the CEW also lends support to the idea that an advanced terrain analysis can be an efficient tool for mineral exploration.

Among the strategies for CO2 reduction in the field of sustainable low-CO2 cementitious materials, some new cement types, instead of ordinary Portland cements (OPC), are discussed. Calcium-sulphoaluminate (CSA) or ye’elimite dominating cement types, like Belite-Calcium-Sulphoaluminate (BCSA), Belite-Calcium-Sulphoaluminateferrite (BCSAF or BYF), Belite-Ternesite-Calcium-Sulphoaluminate (BTCSA or BTY), have comparable properties to OPC, but with the advantages of much less CO2 emission during their production and 15% enlowered clinkering temperature. Nevertheless, CSA large-scale production is limited due to the expensiveness of bauxite and its need as a raw material for the aluminum industry. Therefore, the promising new CSA cement types need alternative Al-rich raw materials. Belterra Clay (BTC), an alumina-rich clay overburden on the bauxites of Brazilian Amazon, can be considered as an important raw material for the production of CSA eco-cement types. The wide distribution of BTC in the Amazon region, its high alumina contents, simple mineralogy and wide distribution direct on the surface makes it an easy-to-exploit and encouraging raw material to produce CSA cement types. Preliminary results, using Belterra Clay from Rondon do Pará in Eastern Amazon/Brazil, show the formation of different CSA clinkers with approximately 35% of ye’elimite at 1250°C. Belite, ternesite, ferrite, Fe-perovskite and other minor phases can also be present in variable contents. The clinkers show fast hydration when mixed to gypsum. The produced CSA binders save about 30% of CO2 emissions in comparison to OPC production due to mineral formation. Less energy consumption is expected due to 200°C lower clinkering temperatures and easier clinker grindability. The use of Belterra Clay, a mining overburden, to produce CSA cement types is highlighted.

The onshore Cretaceous Zululand Basin of South Africa was investigated for CO2 storage potential using NZA, ZA, ZB, and ZC boreholes drilled by Petroleum Oil and Gas Corporation of South Africa in the 1960s for hydrocarbon exploration. Basin fill comprises clastic sedimentary rocks, pyroclastic deposits and carbonates of the Makatini, Mzinene and St. Lucia formations. Digital image analyses showed 20% average porosity and ca. 1.0 mD permeability for Aptian and Cenomanian sandstones, identified for CO2 storage. Siltstones overlying the sandstones were identified as caprocks. XRD analysis shows that the average composition of the sandstones is 34.45 wt% quartz, 29.53 wt% feldspars, 2.40 wt% micas, 32.91 wt% clays, 3.10 wt% Fe-oxides, 4.44 wt% carbonates and 2.00 wt% organic materials, with sulphides and sulphates traces, which is supported by petrography and SEM. XRF results for sandstone geochemistry range from 29.72 - 62.51 wt% SiO2, 6.95 - 13.44 wt% Al2O3, 3.06 - 48.81 wt% CaO, 1.90 - 4.51 wt% MgO, 1.04 - 2.19 wt% K2O, 1.00 - 3.67 wt% Na2O, and low TiO2, Cr2O3, P2O5 contents. Siltstones show similar mineral composition and geochemistry to sandstones, but are fine-grained, impermeable with porosity below 5%, and have a high clay content. CO2-H2O-rock interaction experiments were performed under 100 degrees C and 100 bars using autoclaves and showed reaction of sandstones and siltstones with scCO(2). These rocks are geomechanically soft and recorded a maximum of 15 MPa using Enerpac P141 apparatus. Further geochemical and geomechanical modelling is necessary to fully understand the in-situ behaviour of these rocks.

Little is known about the history of the coastal environment in the northern part of northeastern Brazil and the role of sea level and climate change, as well as the human impact during the past. In order to shed more light on coastal ecosystem dynamics and its influencing factors, a 300 cm long sediment core has been taken from Lago Formoso (LF), located around 150 km distance from the present-day coast in Maranhao State. The core has been radiocarbon dated and analyzed by pollen, spores, charcoal, X-Ray Fluorescence (XRF), X-ray Powder Diffraction (XRPD), LOI, and sedimentary characteristics. During the period from 7520 to 6230 cal yr BP occurred a dominance of mangrove vegetation, and a high relative sea level (RSL), indicating that the coast of the Atlantic Ocean was very close to the study area. The following period is characterized by an increased input of marine sediment into LF and vegetational succession, indicating a highstand of RSL between 5500 and 5020 cal yr BP. From 5020 to 2580 cal yr BP, dominant sandy sediments show chemical and mineralogical characteristic typical of continental sources. The study area was represented mainly by herbaceous and arboreal vegetation, while mangroves were absent, indicating an RSL decrease. The period between 2580 and 1350 cal yr BP is marked by the lower water table and the stronger presence of rainforest vegetation, and an increasing presence of palm trees, indicating the beginning of the human settlement. The last period, after 1350 cal yr BP, is marked by an even stronger anthropogenic influence in the study area, as the records of the stilt-house settlements also evidence it. These records together with others from the same region are the only evidence of stilts-houses from the pre-colonial period in South America. (C) 2021 Elsevier Ltd. All rights reserved.

The new mineral species freitalite, C14H10, corresponding to the aromatic hydrocarbon anthracene, has been discovered on the mine dump of the Königin Carola shaft (also named Paul Berndt Mine), Freital, near Dresden, Saxony, Germany. The mineral forms thin blades or flakes of irregular shape up to a few millimetres in size and shows an intense violet or whitish-violet to white colour. Freitalite is a product of pyrolysis of coal at low oxygen fugacity and was formed by sublimation from a gas phase. The mineral is associated with sulfur and hoelite. Elemental analysis gave (in wt. %, average of three analyses) C 94.07, H 5.571 and total 99.641. The empirical formula is C14.00H9.88 (calculated for C = 14). The identity with anthracene was confirmed by infrared and Raman spectroscopy, high-performance liquid chromatography, gas chromatography with mass spectrometry, 1H and 13C NMR spectrometry, and X-ray powder diffraction. Freitalite is monoclinic, P21∕a, with lattice parameters a=8.5572(9), b=6.0220(5), c=11.173(1) Å, β=124.174(1)∘ and V=476.34(3) Å3 refined from powder data. The calculated density of 1.242 g cm−3 (for Z=2) is very close to the measured density of 1.240 g cm−3. Freitalite was accepted as a new mineral by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (IMA 2019-116).

Mineralogical appraisal is an important tool for both mining and industrial processes. X-ray powder diffraction analysis (XRPD) can deliver fast and reliable mineralogical quantification results to aid industrial processes and improve ore recoveries. Furthermore, X-ray fluorescence (XRF) chemical data, thermal analysis (TA), and Fourier-transformed infrared spectroscopy (FTIR) can be used to validate and refine XRPD results. Mineralogical assessment of non-traditional ores, such as mining wastes, is also an important step to consider them for near-future industries. In the Brazilian Amazon, alumina-rich clays cover the largest and most important bauxitic deposits of the region and have been considered as a possible raw material for the local cement and ceramic industry. In this work, a mineralogical evaluation of these clays (Belterra Clays) is performed using XRPD, XRF, TA, and FTIR. XRPD-Rietveld quantification confirmed that kaolinite is the main phase of the clay overburden, followed by variable contents of gibbsite and goethite and minor quantities of hematite, anatase, and quartz. The chemistry derived from Rietveld, based on stoichiometric phase compositions, presents a good correlation with the XRF data and is also supported by the TA and FTIR data. The initially assumed homogeneous composition of Belterra Clay is revealed to be variable by the present mineralogical study.