Beneficiation of Low-Grade Rare Earth Ore from Khalzan Buregtei Deposit (Mongolia) by Magnetic Separation

The global demand for rare earth elements (REEs) is expected to increase significantly because of their importance in renewable energy and clean storage technologies, which are critical for drastic carbon dioxide emission reduction to achieve a carbon-neutral society. REE ore deposits around the world are scarce and those that have been identified but remain unexploited need to be developed to supply future demands. In this study, the Khalzan Buregtei deposit located in western Mongolia was studied with the aim of upgrading low-grade REE ore via magnetic separation techniques. The total REE content in this ore was ~6720 ppm (~3540 ppm light REE (LREE) + ~3180 ppm heavy REE (HREE)) with bastnaesite, pyrochlore, synchysite, and columbite-(Fe) identified as the main REE-bearing minerals. As the particle size fraction decreased from −4.0 + 2.0 mm to −0.5 + 0.1 mm, the recovery by dry high-intensity magnetic separation (DHIMS) increased from 20% to 70% of total rare earth oxide (TREO) while the enrichment ratio reached 2.8 from 1.3. Although effective, gangue minerals such as quartz and aluminosilicates were recovered (~22%) due most likely to insufficient liberation. Meanwhile, the wet high-intensity magnetic separation (WHIMS) could produce a magnetic concentrate with TREO recovery of ~80% and enrichment ratio of 5.5 under the following conditions: particle size fraction, −106 + 75 μm; feed flow rate, 3.2 L/min; magnetic induction, 0.8 T. These results indicate that combining DHIMS and WHIMS to upgrade the low-grade REE ore from the Khalzan Buregtei deposit is an effective approach.

Runoff Characteristics and Soil Loss Mechanism in the Weathered Granite Area under Simulated Rainfall

Soils developed from the parent materials of highly weathered granite are particularly susceptible to soil erosion. Therefore, it is of great significance to conduct in-depth research on runoff characteristics and soil loss mechanisms in weathered granite areas. Using the weathered granite area in the hilly region of southeastern China as the research object, we conducted indoor artificial rainfall simulation experiments involving three slope steepnesses (SSs), 8°, 15°, and 25°, and five rainfall intensities (RIs), 0.5, 1.0, 1.5, 2.0, and 2.5 mm/min. The results showed that sediment load (SL) has positively linear relationships with mean runoff velocity (V), Reynolds number (Re), Froude number (Fr), shear stress (τ), and stream power (w). The eroded sediment was principally composed of silt and clay that accounted for 65.41–73.41% of the total SL. There was a boundary point at 0.02 mm for the particle size distribution (PSD) of the eroded sediment. The enrichment ratio (Er) of sand-grained particles (0.02–2 mm) ranged from approximately 0.45 to 0.65, while the Er of fine-grained particles (<0.02 mm) ranged from approximately 1.37 to 1.80. These results increase our understanding of the relationships among RI, SS, runoff, and soil losses from weathered granite hillslopes, particularly the relationships between different hydraulic parameters and sediment size characteristics.

Structure of a Fe4O6-Heteraadamantane-Type Hexacation Stabilized by Chelating Organophosphine Oxide Ligands

Heteraadamantanes are compounds of interest due to their spectroscopic and magnetic properties, which make them promising materials for non-linear optics and semiconductors. Herein we report the comprehensive structural characterization of a new coordination compound of the formula [(µ-OH′)2(µ-OH″)4(O = P(Ph2)CH2CH2(Ph2)P = O)4{Fe(MeOH)}4](PF6)4(Cl)2 with the chelating ligand Ph2P(O)-CH2CH2-P(O)Ph2. The compound crystallizes as a polynuclear metal complex with the adamantane-like core [Fe4O6] in the space group I-43d of a cubic system. The single-crystal XRD analysis showed that the crystal contains one symmetrically independent octahedrally coordinated Fe atom in the oxidation state +3. The adamantine-like scaffold of the Fe complex is formed by hydroxy bridging oxygen atoms only. Hirshfeld surface analysis of the bridging oxygen atoms revealed two types of µ-OH groups, which differ in the degree of exposure and participation in long-range interactions. Additionally, the Hirshfeld surface analysis supported by the enrichment ratio calculations exhibited the high propensity of the title complex to form C-H…Cl, C-H…F and C-H…O interactions.

Aqueous Two-Phase System–Ion Chromatography for Determination of Thiocyanate in Raw Milk

Thiocyanate could effectively inhibit bacteria in milk and extend the shelf life of milk. However, excessive addition will lead to health risks. Therefore, the determination of thiocyanate in raw milk has received a lot of attention, but the determination could be interfered with by other components in raw milk and the pre-treatment of raw milk is complex. In this study, a new pretreatment method combined with ion chromatography (IC) for rapid and sensitive determination of thiocyanate is proposed. An acetonitrile/(NH4)2SO4 aqueous two-phase system (ATPS) was developed for the separation and enrichment of thiocyanate in raw milk. Response surface methodology was performed to optimize the extraction conditions and an efficient pretreatment were obtained using ATPS composed of 42% acetonitrile (w/w) and 16% (NH4)2SO4 (w/w), with the pH 4.7, and the recovery of thiocyanate reached 107.24 ± 0.5%, and the enrichment ratio was 10.74 ± 0.03. IC was used to establish a thiocyanate enrichment method. The linear range was from 0.05 to 15 mg/L and R2 = 0.998, the limit of detection (LOD) was 0.2 μg/L, the limit of quantification (LQD) was 0.6 μg/L. Hence, it is feasible to combine ATPS with IC for the enrichment and determination of thiocyanate in raw milk.

New Copper (II) Isomer Based on 8-aminoquinoline Ligand: Synthesis, Molecular Structure, Hirshfeld Surface Analysis and Computational Study.

Toward the treating of a multifunctional material, new [Cu(H2O)2(C9H8N2)2]Cl2 isomer 1 has been synthesized by solvothermal method. The single-crystal X-ray study, Hirshfeld surface analysis and computational calculation were discussed. Hydrogen bonding network within the complex enable the formation of 3D network supported by aromatic stacking interactions of quinoline rings in face-to-face and edge-to face fashions. The analysis of Hirshfeld surfaces, facilitate a comprehension of intermolecular interactions in the structure. The enrichment ratio (E) was calculated to examine the propensity of intermolecular interactions to form contacts in crystals. It shows that the favorable contacts responsible for the crystal packing are strong hydrogen bonds and stacking interactions. The reactivity descriptors for 1 such as EHOMO and ELUMO energies, ionization potential (IP), Electron affinity (EA), Mulliken electronegativity (χ) and the Absolute hardness (η) was calculated by PBE functional method with DNP basis set. The possible sites for nucleophilic and electrophilic attacks on 1 were analyzed through Fukui functions.

Proximate Composition, Phytochemical, Mineral and Sensory Analyses of Moringa oleifera Enriched Bread

Aim/background: The study investigated the effect of Moringa oleifera powder on enriched bread samples produced at various levels. Wheat flour and moringa powder were formulated at different percent ratio (1%, 2%, 3% and 4%) to determine the best enrichment ratio. Methods: Proximate, phytochemical, mineral content and sensory evaluation of the bread samples were determined using bread made from 100% wheat flour which served as control. Results: Result for proximate composition showed a progressive drop (p<0.05) in the fibre content of the enriched bread samples with decreasing level of enrichment. The energy value of the bread samples ranged from 392.73 to 394.32 Kcal. For crude protein, sample with 4% moringa enrichment recorded the high protein content which recorded a value of 12.89 %, which was significantly different (p<0.05) from other samples. The sample with 4% moringa enrichment recorded the highest ash content value of 2.67 % and was significantly different (p<0.05) from the other samples. Result of sensory evaluation using a nine-point Hedonic scale showed that enriched bread samples recorded 5.10 to 7.65 for appearance, 5.45 to 6.85 (aroma), 5.35 to 7.75 (texture), 5.55 to 7.70 (mouth feel) and 5.55 to 7.60 (general acceptability). Conclusion: The enrichment of bread products could be best achieved at moringa levels of 2 % and 4%.

Beneficiation of Faya Clay for Drilling Mud Production Using Froth Floatation and Jig Gravity Concentration Techniques

The comparative study for upgrading Faya clay, in Faya Town of Plateau State, Nigeria to oil and Gas drilling mud grade was carried out. The clay was sourced from three veins A, B, and C. The samples were homogenized, crushed and ground. 5 kg of the homogenized sample was used for the experiment and laboratory work. Chemical and mineralogical characterization of the clay sample was carried out using; X-ray fluorescence (XRF) and X-ray diffractorneter (XRD). The clay sample was beneficiated using two methods: froth flotation and gravity concentration method (Jigging). The chemical composition of the crude clay revealed that it contains 16.6% Al2O3, 35.6% SiO2, 0.559% K2O, 0.084% CaO, 6.133% Fe2O3, 0.91 % TiO2 and 38.7 % BaO. The result of XRD analysis shows that quartz is predominant in the sample with 61.7% wt quartz (SiO2). Other minerals found in the sample include 28.59% wt of dickite (Al2 Si205 (0H)), 8.89% wt goethite (Fe0 (0H 4) and 0.83% wt muscovite (KO.92 NaO.08) (Al.86 FeO.07 TiO.02) (Si.3 O.3 AlO.97) O10 (OH)2 at 2 . Froth flotation method is more efficient for the beneficiation of Faya clay as it improves the BaO composition of the clay from 38.7% to 52.2%, with a recovery of 97.2%, an enrichment and ratio of concentration of 1.4 compared with the jigging method, which improved BaO composition from 38.7% in the crude clay to 47.5%, with a recovery of 90.96% and an enrichment ratio of 0.7; and ratio of concentration of 0.7. Froth floatation improved the specific gravity of the clay from 3.3 to 4.31; while jigging improved the specific gravity from 3.3 to 4. 05. Therefore, froth flotation method is more appropriate for the concentration of Faya clay ahead of jigging method of processing.Keywords: Upgrading, Characterization, Faya - clay, Drilling, Production

Elemental analysis of residual ash generated during plasma incineration of cellulosic, rubber and plastic waste

Management of plastic, rubber and cellulosic waste from various industries is a challenging task. An engineering scale plasma pyrolysis based incinerator has been commissioned for incineration of combustible waste, including plastic, rubber and cellulose. Operational trials of wastes with simulated composition show a weight reduction factor of more than 18 and volume reduction factor of more than 30. The volume reduction factor is tenfold higher than the compaction process currently practised for rubber and plastic wastes. Representative residual ash samples derived from these runs are subjected to their elemental analysis using EDXRF technique and results are comparable with the published literature. Relative variation of individual elements is attributed to the type of waste and feed composition. Analysis is aided with the calculation of index of geoaccumulation, enrichment factor (EF), contamination factor (CF) and pollution load index (PLI). From this study, it is evident that S, Cr, Zn, As, Se, Hg and Pb are of concern for environment in residual ash from plasma incineration of combustible waste. The efficacy of the incineration process is evaluated; C, H and O reduction achieved is more than 98% and overall enrichment ratio (ER) for the inorganic elements is more than 4.5. This study highlights the importance of elemental composition for the performance analysis of the plasma based incineration as well as hazards evaluation of constituents in residual ash for its further management.

Ecological risk and enrichment of potentially toxic elements in the soil and eroded sediment in an organic vineyard (Tokaj Nagy Hill, Hungary)

Potentially toxic elements (PTEs), such as Cu, Zn, Pb, Ni, Cr, and Co, can accumulate in vineyard soils due to repeated uses of inorganic pesticides and chemical or organic fertilizers. In sloping vineyards, PTEs can also be moved by soil erosion resulting in their accumulation in low-energy zones within the landscape, adversely affecting the soil environment. Our study evaluated the ecological risk related to the pseudo-total and bioavailable PTE contents (Zn, Pb, Co, Ni, Cr, and Cu) in the soil and eroded sediment samples from an organic vineyard in Tokaj (NE Hungary). The contamination status and the ecological risk of target PTEs were assessed by calculating the contamination factor, the pollution load index, the ecological risk factor, and the ecological risk index. The median pollution load indices of 1.15, 1.81, and 1.10 for the topsoil, the sediments, and the subsoil, respectively, demonstrate a moderate multi-element contamination case in the organic vineyard. Target PTEs tented to show increased concentrations in eroded sediments with the highest enrichment ratio (3.36) observed for Cu (Cu in the sediment/Cu in the topsoil), revealing a preferential movement of Cu-rich soil particles by overland flow. Moreover, PTEs were present in the sediments in more bioavailable forms (except Ni, Cr), assessed by an extraction procedure with EDTA. The ecological risk index (< 90) based on the studied PTEs showed an overall low ecological risk in the vineyard. Copper was the predominant factor of the ecological risk. Moreover, the highest ecological risk factor (24.6) observed for the bioavailable Cu content in an eroded sediment sample (representing 82% of the total ecological risk) shows that Cu accumulation in sloping vineyards is an ecological risk, particularly in the sedimentation zones. The high proportions of bioavailable Cu in the vineyard’s soil represent an increasing ecological risk over time, related to repeated treatments of vine plants with Cu-based pesticides.

Unique plasma metabolite signature for adolescents with Klinefelter syndrome reveals altered fatty acid metabolism

Conditions related to cardiometabolic disease, including metabolic syndrome and type 2 diabetes, are common among men with Klinefelter syndrome (KS). The molecular mechanisms underlying this aberrant metabolism in KS are largely unknown, although there is an assumption that chronic testosterone deficiency plays a role. This cross-sectional study compared plasma metabolites in 31 pubertal adolescent males with KS to 32 controls of similar age (14 ± 2 yrs), pubertal stage, and body mass index z-score (0.1 ± 1.2), and then between testosterone treated (n=16) and untreated males with KS. The plasma metabolome in males with KS was distinctly different from controls, with 22% of measured metabolites having a differential abundance and seven metabolites nearly completely separating KS from controls (AUC>0.9, p<0.0001). Multiple saturated free fatty acids were higher in KS while mono- and polyunsaturated fatty acids were lower, and the top significantly enriched pathway was mitochondrial β-oxidation of long-chain saturated fatty acids (enrichment ratio 16, p<0.0001). In contrast, there were no observed differences in metabolite concentrations between testosterone-treated and untreated individuals with KS. In conclusion, the plasma metabolome profile in adolescent males with KS is distinctly different from males without KS independent of age, obesity, pubertal development, or testosterone treatment status, and is suggestive of differences in mitochondrial β-oxidation.