Firing Parameters Effect on the Physical and Mechanical Properties of Scheelite Tailings-Containing Ceramic Masses

The firing parameters in ceramic masses incorporated with 0, 5, and 10 wt% of scheelite tailings were investigated. The ceramic masses were characterized by X-ray fluorescence, granulometric, mineralogical analysis, and Atterberg limits determination. The samples were obtained by uniaxial pressing (20 MPa), sintered at different temperatures (800, 900, and 1000 °C), and heating rates (5, 10, 15, and 20 °C∙min−1). Physical and mechanical tests (water absorption, apparent porosity, and flexural strength) and mineralogical tests were accomplished from the sintered samples. Natural aging tests were also carried out to assess carbonation resistance. For this, some samples were kept in an internal environment (inside the laboratory) for 3 months. The results showed a high content of calcium oxide in the scheelite tailings and a reduction in the plasticity index of the ceramic masses with the tailings addition. The best results were observed for the ceramic mass with 5% tailings. The best results were observed regarding the firing parameters for the temperature equal to 1000 °C, increasing the heating rate to 10 °C∙min−1 without compromising the material properties. The samples kept in an internal environment for 3 months showed a loss of physical and mechanical properties. Such behavior probably occurred due to the onset of the carbonation phenomenon.

Mexican agricultural soil dust as a source of ice nucleating particles

Agricultural soil erosion, both mechanical and eolic, may impact cloud processes as some aerosol particles are able to facilitate ice crystals formation. Given the large agricultural sector in Mexico, this study investigates the ice nucleating abilities of agricultural dust collected at different sites and generated in the laboratory. The immersion freezing mechanism of ice nucleation was simulated in the laboratory via the Universidad Nacional Autónoma de México (UNAM)- Micro Orifice Uniform Deposit Impactor (MOUDI)-Droplet freezing technique (DFT) (UNAM-MOUDI-DFT). The results show that agricultural dust from the Mexican territory promote ice formation in a temperature range from −11.8 ºC to −34.5 ºC, with ice nucleating particle (INP) concentrations between 0.11 L−1 and 41.8 L−1. Furthermore, aerosol samples generated in the laboratory are more efficient than those collected in the field, with T50 values (i.e., the temperature at which 50 % of the droplets freeze) higher by more than 2.9 ºC. The mineralogical analysis indicated a high concentration of feldspars i.e., K-feldspar and plagioclase (> 40 %) in most of the aerosol and soil samples, with K-feldspar significantly correlated with the T50 of particles with sizes between 1.8 µm and 3.2 µm. Similarly, the organic carbon (OC) was correlated with the efficiency of aerosol samples from 3.2 µm to 5.6 µm and 1.0 µm to 1.8 µm. Finally, a decrease in the efficiency as INPs, after heating the samples at 300 ºC for 2 h, evidenced that the organic matter from agricultural soils can influence the role of INPs in mixed-phase clouds.

Piast castle on Ostrów Tumski island in Wrocław

The article briefly presents the author’s hypothesis of architectural changes in the ducal castle on Ostrów Tumski in Wrocław, which was developed based on the results of architectural studies of the relics of the castle walls uncovered in excavations in 2011–2012 and 2014, in combination with the results of laboratory tests such as petrographic and mineralogical analysis of mortars, 14C analysis of charcoal contained in mortars and extensive analysis of brick dimensions using statistical methods. As a result, a chronological stratification into eight phases from the 12th to 15th centuries is proposed. Absolute dating was addressed through radiocarbon analyses and historical context.

Recommendation for lateritic Ni-ore processing: garnierite mineralogical and geochemical approach

The objective of this study is to analyze the mineralogy and geochemistry of garnierite and its implication for Ni laterite processing. Mineralogical analysis using optical microscopic and X-ray diffraction (XRD) methods were performed, whereas chemical composition was obtained by X-ray fluorescence (XRF) method. Genetically, Ni in laterite ore is associated with SiO2 and MgO and is not accompanied by the elements of Co, Fe, Cr, Al, Mn, and Ca. In this study, Ni-laterite ore has Ni content of 2.1%, SiO2 25.42%, S/M ratio 3.7, and Fe/Ni ratio 15.5, meaning that it is more suitable to be processed by pyrometallurgical route. However, there are some characters that still have to go through treatment, namely reducing of Fe from 32.63% to 20%, increasing MgO, and reducing SiO2 by blending. Result of mineralogical analysis shows that the dominant mineral is quartz (44.8%) and talc (38.85%) with small amount of lizardite (16.35%). The high content of quartz and talc and the low in lizardite of the Ni-laterite ore in the study area indicated that it is recommended for pyrometallurgical processing which is also in accordance with its geochemical characteristics.

Analysis of granitoid type of Bukit Nunggal Village, Air Mesu, Central Bangka Regency

The research was conducted in Bukit Nunggal Air Mesu Village, Pangkalan Baru District, Central Bangka Regency, an IUP PT Tanjung Bukit Nunggal with a height of ± 210 meters. This study is to find out more details about the type of granitoid rock which is a unitary hill but it is estimated that it is the intrusion body of several types of granitoid rock. The research method includes analysis of mineralization content and geochemical analysis in the form of XRF. The steps to be taken include literature studies, field research, laboratory analysis including mineralogical analysis and microscopic observations as well as geochemical testing of rock samples using XRF. The sampling procedure for analysis is carried out based on the height and changes in rock texture, on the number of rock types / lithologies available to be observed and examined for their mineralization content. Regionally, the study area consists of a hill which is interpreted as a potential rock for construction mining. It is hoped that this research can produce an analysis of the existing granitoid types by studying the lithology / rock, geological structure and mineral textures. There are 2 types of granite found in Nunggal Hill, namely granite and granite alterated (gneiss), with its main minerals are quartz, feldspar, biotit, opaq and sericytic and chlorite minerals.

Mineral Composition, Phenolic Content, and In Vitro Antidiabetic and Antioxidant Properties of Aqueous and Organic Extracts of Haloxylon scoparium Aerial Parts

Haloxylon scoparium is a plant widely used in traditional medicine for the treatment of diabetes. Hence, this study focuses on the mineralogical and chemical composition and evaluation of the antidiabetic and antioxidant activities of the aerial part of this species. The mineralogical analysis was done by inductively coupled plasma atomic emission spectrometry (ICP-AES). The phytochemical study consisted in the preparation of different extracts from the aerial part by aqueous and organic extraction using Soxhlet and cold maceration. Then, phytochemical screening was performed on the plant powder and on the extracts, which is completed by spectrophotometric quantification of total polyphenols, flavonoids, and catechic tannins. The evaluation of antidiabetic activity was done by three enzymes: a-amylase, a-glucosidase, and ß-galactosidase, and that of antioxidant activity was done by five methods: H2O2, DPPH, ABTS, FRAP, and reducing power (RP). Mineralogical analysis revealed the presence of iron, potassium, magnesium, phosphorus, sodium, copper, calcium, strontium, selenium, and zinc. The studied part is rich in alkaloids, flavonoids, catechic tannins, and saponins. The methanolic extract is rich in total polyphenols (161.65 ± 1.52 Ug EAG/mg E), and the ethyl acetate extract has high levels of catechic tannins (23.69 ± 0.6 Ug EC/mg E). In addition, the decoctate expresses a high flavonoid content of 306.59 ± 4.35 Ug EQ/mg E. The in vitro evaluation of the antidiabetic activity showed that the decoctate has a higher inhibitory capacity on a-glucosidase (IC50 = 181.7 ± 21.15 ug/mL) than acarbose (IC50 = 195 ± 6.12 ug/mL). The results of the antioxidant activity showed that the methanolic extract and the decoctate present a percentage of hydrogen peroxide (H2O2) scavenging (20.91 ± 0.27 and 16.21 ± 0.39%) higher than that of ascorbic acid (14.35 ± 0.002%). Positive correlations obtained between the total polyphenol content and the antioxidant activity of the extracts were studied. A positive correlation of a-amylase inhibitory activity was also recorded with the antioxidant activity tests.

Mounted Single Particle Characterization for 3D Mineralogical Analysis—MSPaCMAn

This paper demonstrates a new method to classify mineral phases in 3D images of particulate materials obtained by X-ray computed micro-tomography (CT), here named mounted single particle characterization for 3D mineralogical analysis (MSPaCMAn). The method allows minimizing the impact of imaging artefacts that make the classification of voxels inaccurate and thus hinder the use of CT to characterize natural particulate materials. MSPaCMAn consists of (1) sample preparation as particle dispersions; (2) image processing optimized towards the labelling of individual particles in the sample; (3) phase identification performed at the particle level using an interpretation of the grey-values of all voxels in a particle rather than of all voxels in the sample. Additionally, the particle’s geometry and microstructure can be used as classification criteria besides the grey-values. The result is an improved accuracy of phase classification, a higher number of detected phases, a smaller grain size that can be detected, and individual particle statistics can be measured instead of just bulk statistics. Consequently, the method broadens the applicability of 3D imaging techniques for particle analysis at low particle size to voxel size ratio, which is typically limited due to unreliable phase classification and quantification. MSPaCMAn could be the foundation of 3D semi-automated mineralogy similar to the commonly used 2D image-based semi-automated mineralogy methods.

Comparison between Siliceous Concretions from the Ionian Basin and the Apulian Platform Margins (Pre-Apulian Zone), Western Greece: Implication of Differential Diagenesis on Nodules Evolution

Siliceous concretions (nodules), from two different geological settings—the Apulian platform margins in Kefalonia island, and the Ionian Basin in Ithaca, Atokos, and Kastos islands—have been studied both in the field and in the laboratory. Nodule cuttings are mainly characterized by the development of a core, around which a ring (rim) has been formed. Mineralogical study, using X-ray powder diffraction (XRPD) analysis, showed that the rim is usually richer in moganite than the core. Homogeneous concretions, without discernible inner core and outer ring, were observed generally in both settings. Mineralogical analysis of the selected siliceous concretions from Kefalonia island showed the presence mostly of quartz and moganite, while calcite either was absent or participated in a few samples in minor/trace abundances. Moganite was generally abundant in all the samples from Kefalonia island. Concretions from the Ionian Basin showed a variation in the quartz, moganite, and calcite contents. Mineralogical differences were recognized both between the different studied geodynamic settings and internally in the same setting, but with different stages of development. The above-mentioned differential diagenesis on nodules evolution could be related to the presence and/or abundance of stylolites, later fluid flows, restrictions from one area to another due to synchronous fault activity, and the composition of substances dissolved in fluids. Moreover, the development of concretions produced secondary fractures in the surrounding area of the nodule-bearing rocks.