Cobalt Content Research Articles

Preparation and optimization of La0.6Sr0.4Fe1-yCoyO3-δ cathodes for intermediate temperature solid oxide fuel cells

It is shown in this work that a synthetic route based on the auto-combustion of an ethylene glycol-metal nitrate polymerized gel precursor can be efficiently used to easily produce a range of La0.6Sr0.4Fe1-yCoyO3-δ nanopowders at moderate temperatures. We have been able to determine on air-sintered samples the effect of sintering temperature on the microstructure. At sintering temperatures as low as 1100 to1200 °C, grains are well defined with a uniform round spherical morphology and have a homogeneous sub-micrometer size distribution showing a highly densified microstructure. The electronic conductivity and thermal expansion coefficients (TEC) of sintered LSFC samples have been determined according to the variation of Fe/Co composition. Both measures clearly increase with the Co content. These materials also must exhibit chemical stability with electrolytes, most commonly used for intermediate temperature solid oxide fuel cells (IT-SOFCs). In this way, the material as obtained is optimized in terms of chemical homogeneity and good stoichiometric control, microstructural characteristics of sintered samples, and finally the adequate Cobalt content to avoid high TEC mismatch with other components of the SOFC. This is a crucial issue as it causes an important thermo¬mechanical stress; promote extensive microcraking and significant performance degradation. Finally, these cathodes must exhibit acceptable electrochemical parameters for use in IT-SOFC.

Interactive association of metals and Life’s Essential 8 with mortality in U.S. adults: a prospective cohort study from the NHANES dataset

BackgroundLife’s Essential 8 (LE8) is a novel assessment of cardiovascular health (CVH) by evaluating lifestyle, and reports of the associations between LE8 and urinary metals on mortality have been very limited. This study aimed to conduct a prospective cohort study and investigate the combined effects of metals and LE8 on mortality in U.S. adults.MethodsThis study enrolled participants with complete information on urinary metals, LE8, mortality status, and confounders from the National Health and Nutrition Examination Survey (2005–2018). The Cox regression model, adaptive lasso penalized regression, and restricted cubic spline were used to analyze the individual effects of metals and LE8 on all-cause mortality. The additive and multiplicative interaction scales and quantile g-computation were used to evaluate the interaction and combined effects. Stratified analyses were performed to clarify whether metals and LE8 interacted with other variables to influence all-cause mortality.ResultsA total of 8017 participants were included in this study. The concentrations of cadmium, cobalt, lead, antimony, and thorium were greater in the low CVH group than in the high CVH group [median (µg/L): 0.29 vs. 0.19, 0.36 vs. 0.35, 0.48 vs. 0.39, 0.05 vs. 0.04, and 0.07 vs. 0.06]. The interaction between cadmium and LE8 was statistically significant, with a synergy index of 1.169 (95% CI: 1.004, 1.361). The stratified analyses showed that the interaction between age and LE8 had an impact on all-cause mortality (P for interaction = 0.004).ConclusionsIn this representative sample of the U.S. population, we found that the combined effect of cadmium, lead, thallium, and LE8 was positively associated with all-cause mortality. Furthermore, the interaction between cadmium and LE8 influenced all-cause mortality. So people should adopt healthy behaviors and reduce heavy metal exposure to minimize the risk of adverse health outcomes.

The Effect of Cryogenic Treatment on a High Co Bearing DIN 1.2888 Steel Used as Die in Hot Forging Process

Abstract Hot work steels used as dies in metal forming processes must endure harsh conditions, typically achieved through a martensitic structure. However, retained austenite can persist after martensitic transformation, negatively impacting mechanical properties. Cryogenic treatment (CT) refines martensite, reduces retained austenite, and increases fine carbide density, thus enhancing performance. DIN 1.2888, a hot work tool steel with high cobalt content (~10%) and low carbon content (~0.2%), is less studied concerning the effects of CT. The objective of this study was to investigate how cryogenic treatment affects the mechanical and microstructural properties of DIN 1.2888 steel. Samples underwent conventional heat treatment (HT) and CT at -100, -140, and -180°C for 6 hours, followed by double tempering. Various analytical methods, including X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), and Vickers Microhardness tests, were used to examine the samples. Wear mechanisms were evaluated through pin-on-disc tests under different loads, and impact toughness was measured both at room temperature and the working temperature of dies (350°C). Results indicated that lowering the cryogenic treatment temperature resulted in a slight increase in hardness values from 507HV for the heat-treated sample to 529HV for the sample treated at -180°C. Additionally, the impact toughness improved significantly, with values rising from 12.35J for the heat-treated sample to 23.44J at 350°C for the cryogenically treated sample at -180°C. Wear rates also decreased by approximately 50%, particularly at higher cryogenic treatment temperatures. The improvement in wear resistance was attributed to finer carbide precipitation and a more homogeneous distribution of carbides. These findings suggest that deep cryogenic treatment has a positive effect on DIN 1.2888 steel by decreasing retained austenite and increasing fine carbide density, leading to enhanced mechanical properties and extending the lifespan of the steel in die applications.

Effect of Contact Time on the Sorption of Metal Ions Associated with Produced Water on Pulverized Oyster Shell (OS) as Adsorbent

The aim of this research is to investigate Metal ion sorption potentials of pulverized Oyster Shell as adsorbent in produced water from selected flow stations in the Niger Delta region of Nigeria. Produced water samples were collected from six (6) different oil drilling installations (CC7T, CC8T, WELL 2 GSS, WELL 8 TEB, AZUZUAMA ST 1, AZUZUAMA ST 2) around the Niger Delta area of Nigeria. The waste oyster shell was collected in Akpan-Andem Market in Uyo, Akwa-Ibom State and processed using well established protocols. Atomic Absorption Spectrometer (AAS) was used to determine selected metals’ Nickel (Ni), Cobalt (Co), Copper (Cu), Iron (Fe), Lead (Pb), Calcium (Ca) and Potassium (K) concentrations. The obtained values for Nickel ranged from 0.076mg/l at AZUZU-AMA ST1 flow station to 2.882 mg/l at WELL2-GSS flow station with average value of 0.745 mg/l. The obtained value for Cobalt ranged from ˂0.001 mg/l at CC-8T and CC-7T to 0.277 mg/l at AZUZUAMA ST1. Values obtained for Cu, Fe, Pb, Ca, and K ranged between: 0.195 mg/l at WELL2-GSS to 0.449 mg/l at AZUZU-AMA ST1; 2.785 mg/l to 89.279mg/l; ˂0.001 mg/l to 0.483 mg/l; 16.217 mg/l to 92.714 mg/l and 96.386 mg/l to 105.416 mg/l respectively. Generally, the amount of metal ions absorbed/adsorbed onto pulverized Oyster shell (OS) increased swiftly within 2 hours and slowly with further increase of contact time and then tended to be stable. For pulverized Oyster shell adsorbent, the adsorption/absorption capacity decreases with the increasing contact time. The adsorbent (OS) isn’t good material for removal of Calcium and Cobalt in produced water but was very effective adsorbent for Ni, Fe, and Pb removal in produced water and less effective for Cu and K removal from produced water. The study underscores the need to further probe outcome of above research at different pH and other relevant variables as well as compares its efficiency with other detoxification technologies like Detoxification by chemical reaction (DCR) technology.

Effect of chromium doping on the grain boundary character of WC-Co

The life of cutting tool inserts is critically important for efficient machining, reducing manufacturing cost, embedded energy, and enabling more complex parts to be machined. For these applications, cemented carbide (WC-Co) materials are a prime candidate. The performance of these materials can be limited by early fracture, typically via an intergranular fracture path with respect to carbide grains. This motivates further studies to understand the character of the grain boundary network so that grain boundary engineering (GBE) of WC-Co tools can be used to improve tool life and performance. In this work, we have used Rohrer et al.'s five-parameter grain boundary character distribution (GBCD) analysis to examine the grain boundary network of WC-10wt%Co and WC-10wt%Co-1wt%Cr samples (Rohrer et al., 2004a [1]). It was found that the measured area fraction of the Σ2 boundaries was comparable to the values reported in the literature despite the relatively larger grain sizes (~14 μm) and higher cobalt contents. The result suggests that chromium doping increases the area fraction of Σ2 boundaries from 12.8 % to 14.8 %. It is proposed that this is a consequence of altering the Σ2 boundary energy, as associated with adding chromium.

Multifunctional carbon nanotube arrays on kapok-derived carbon microtube composites for efficient electromagnetic wave absorption and Cu(II) removal

To cope with different environments of application, electromagnetic wave absorption (EWA) materials with multifunctionality have attracted a wide range of interests. And excessive heavy metal ions in aqueous solutions seriously affect people’s health and pose a major challenge to environmental safety. In this study, carbon microtube/carbon nanotube (CMT/CNT) composites were fabricated via carbonization and chemical vapor deposition (CVD) methods. The CNT wrapped with cobalt nanoparticles were grown in situ on the CMT which derived from kapok fiber. By varying the concentration of cobalt precursors, the EWA and Cu(II) adsorption performances of CMT/CNT can be efficiently tuned. Optimizing the cobalt content to 2 wt% resulted in a minimum reflection loss (RL) of −66.14 dB at a matching thickness of 1.91 mm, with an effective absorption bandwidth (EAB) of 5.35 GHz. The adsorption capacity of Cu(II) by the CMT/CNT composite can reach 102.01 mg/g when the initial Cu(II) concentration is 500 mg/L. This research not only shows great promise for applications in the field of EWA materials but also holds significant potential for heavy metal ion removal and as a catalyst carrier, among other areas.

Effect of the cobalt addition on benzene oxidation of supported MnOx nanocluster catalysts

Abstract By varying the precursor ratios, cobalt doped manganese oxides nanocluster catalysts with different cobalt contents were prepared by colloidal method. Catalysts were applied to gas phase benzene oxidation reaction. Among them, the catalyst with a Mn:Co ratio of 90:10 showed the highest conversion. The addition of cobalt changing the valence of manganese was observed by XANES analysis, and that is thought to be the reason for the high activity.

Characterizing groundwater contamination flow-paths and heavy metal mobilization near a waste site in Southwestern Nigeria

This study investigates potential groundwater contamination near a waste disposal site in southwestern Nigeria. The area's complex geological setting, characterized by fractured rock formations, posed significant challenges for traditional monitoring methods. To address these challenges and comprehensively assess groundwater conditions, we employed a combined approach utilizing Electrical Resistivity Tomography (ERT), Ground Penetrating Radar (GPR), and geochemical analysis of heavy metals and water conductivity. This approach enabled the investigation of groundwater levels, identification of potential contamination zones, and delineation of contaminant flow paths. GPR identified a shallow zone, termed the “shadow zone,” with conductive residues indicating contaminants with anomalous conductivity ranging from 1 to 1.5 m. An intermittent reflection zone at a depth of 1.5–3.5 m suggested the potential presence of leachate-impacted groundwater. ERT confirmed a shallow resistive layer at depths of 0–2 m, attributed to compacted waste and topsoil, around the abandoned main dumpsite. Below this layer, a zone of low resistivity, decreasing downward through a porous weathered zone, was observed. This corresponded to high water conductivity in well data, ranging from 21 to 147 mS/m (equivalent to 6.80 to 47.62 Ω-m), indicating a high conductive anomaly suspected to be a leachate plume at depths of 2–10 m in a sandy-gravelly weathered zone. Validation against ground truth data confirmed the correlation between radar signatures, geoelectrical imaging, and subsurface lithology. Analysis of well and soil samples revealed concerningly elevated concentrations of cadmium, mercury, lead, arsenic, and cobalt, ranging from 641 to 1175 ppb, exceeding established safety limits for drinking water. Additionally, soil samples showed elevated levels of nickel and chromium, generally ranging from <0 to <1 ppb. These findings highlight the significant risk of groundwater contamination due to the proximity of the leachate zone to the groundwater table in the weathered basement complex. This study demonstrates the effective integration of geophysical and geochemical methods for comprehensive mapping of contaminated zones and identification of preferential pathways for contaminant migration. The findings underscore the critical need for implementing comprehensive risk assessment methodologies in similar complex geological settings.

Recovery of Lithium, Cobalt, and Graphite Contents from Black Mass of LCO-Based Discarded Li-Ion Batteries

Recovery of Lithium, Cobalt, and Graphite Contents from Black Mass of LCO-Based Discarded Li-Ion Batteries

Effects of tailings disposal on the environment: A case study of Nampundwe Mine

Globally, the demand for mineral products is ever increasing. Extraction of these mineral resources results in the continuous production of a huge volume of waste material, including tailing dumps. The mass of tailings usually exceeds the actual resource and often contains hazardous contaminants. This study investigated the effects of tailings disposal on soil, water, and air quality in the Nampundwe area. Water, soil, and dust samples were collected from different locations in the surrounding communities. The constituents analysed in the samples included copper, cobalt, iron, sulfate, and silica. According to the results obtained, some seepages occurred from the tailings impoundment to the shallow aquifer in the area. However, the general water quality meets the Zambia Environmental Management Agency (ZEMA) statutory limits. Recorded concentrations of sulfate (1500 mg/l), copper (1.5 mg/l), cobalt (1.0 mg/l), iron (2.0 mg/l), and silica were between 0.003 mg/l and 705 mg/l, which is far below ZEMA's statutory limit. Silica concentration was also evident in the air. The highest concentration recorded was 260 ppcc (particle per cubic centimeter) recorded in July 2019 from the northern direction of the tailings dam. The concentration was below the statutory limit of 350 ppcc. The topsoil from the northern part of the tailings recorded a silica dust concentration of 39.9 ppcc. Iron was evident in the underground soil with a concentration of 8.01 ppcc, cobalt 0.005 ppcc, copper 0.051 ppcc, while sulfate was recorded as 0.41 ppcc.

Bioaccumulation Patterns of Trace Elements in Jellyfish (Crambionella orsini and Cassiopea andromeda) from Northwestern Coastal Waters of the Persian Gulf

Trace element pollution in the Persian Gulf originates from industrial activities, urbanization, shipping, and oil extraction, leading to accumulation in sediments, water, and marine life such as jellyfish. This study investigated trace element bioaccumulation in two jellyfish species, Crambionella orsini and Cassiopea andromeda, across different locations. Jellyfish samples were collected from the Mahshahr and Dilam ports, and their trace element concentrations were analyzed using inductively coupled plasma mass spectrometry (ICP-MS). The study revealed no significant differences in trace element concentrations between C. orsini and C. andromeda. However, levels of copper, iron, manganese, and nickel were significantly higher in specimens from Mahshahr compared to those from Dilam. No significant differences were observed for cadmium, mercury, vanadium, tin, magnesium, and selenium across sites. Lower concentrations of lead, arsenic, zinc, and cobalt were found in C. orsini from Dilam compared to Mahshahr. Additionally, the study found no significant correlation between trace element concentrations in the water and their accumulation in jellyfish bodies. These findings offer valuable insights into the distribution and bioaccumulation of trace elements in jellyfish populations across different marine environments in the Persian Gulf.

Geospatial clustering of auto-antibodies against apolipoprotein A-1, heavy metals, cardiovascular and liver diseases in the general population

Abstract Aims Heavy metals (HM) are combustion-related environmental factors predisposing to cardiovascular (CVD), autoimmune and liver diseases, even below regulatory concentrations. Pro-atherogenic and pro-steatotic auto-antibodies against apolipoprotein A1 (AAA1) are prevalent in the general population for unclear reasons. We explored a putative interplay between HM exposure, AAA1, CVD risk factors and a non-alcoholic fatty liver disease (NAFLD) risk score, using a geospatial clustering approach at the general population level. Methods Getis-Ord, Moran I2 clustering and geographically weighted regression (GWR) geosptatial analyses were carried out on 6361 individuals recruited in the CoLaus/PsyCoLaus general population cohort. Geospatial dependences between serum AAA1, urinary HM (cadmium, arsenic, cobalt) concentrations, SCORE2 CVD risk, and fatty liver index (FLI) were assessed. Results Cadmium and cobalt were found to be associated with higher SCORE2 risk (p&amp;lt;0.04). AAA1 were associated with higher cadmium, cobalt, and cigarette consumption, independently of SCORE2 (p&amp;lt;0.04). AAA1 hotspots overlapped significantly with those of cadmium and FLI, independently of SCORE2. According to GWR, correlations between cadmium and AAA1 were the highest in railways proximity regions, increasing up to 10-fold compared to global associations. AAA1 were not associated with other HM. Conclusions These geospatial footprints highlight independent associations between Cadmium, AAA1, and NAFLD risk score in the general population. We hypothesize that environmental cadmium exposure may facilitate the occurrence of AAA1 in humans. Ongoing experimental studies will confirm/refute a possible causal link. Whether AAA1 could represent an early biological signature of cadmium exposure and subsequent health hazards remains to be shown.

Accumulation of heavy metals (Cr, Cu, As, Cd, Pb, Zn, Fe, Ni, Co) in the water, soil, and plants collected from Edayar Region, Ernakulam, Kerala, India

The accumulation of heavy metals in the environment is a significant concern due to their potential toxicity and persistence. This study investigates the levels of heavy metal contamination in the water, soil, and plants of the Edayar region in Ernakulam, Kerala, India. The region has experienced industrialization and urbanization, leading to concerns about heavy metal pollution. The study aims to assess the concentrations of chromium (Cr), copper (Cu), arsenic (As), cadmium (Cd), lead (Pb), zinc (Zn), iron (Fe), nickel (Ni), and cobalt (Co) in water, soil, aquatic and terrestrial plants. Samples were collected from various locations within the Edayar region, and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was conducted to quantify heavy metal concentrations. The findings of this study will contribute to the assessment of heavy metal pollution in the Edayar region. Plants with a high diversity index were taken for analysis from both aquatic and terrestrial habitats. Scoparia dulcis L. seems to specialize in metal accumulation, possibly for protective purposes. Synedrella nodiflora Gaertn demonstrates adaptability to metal-rich environments through robust metal uptake and tolerance mechanisms. Alternanthera philoxeroides (Mart.) Griseb, on the other hand, appears to have developed mechanisms to manage heavy metal exposure. The results indicate significant levels of heavy metal contamination across all samples, with the highest concentrations detected in soil, followed by water and plants. Chromium and lead levels in soil exceeded the permissible limits set by international standards, posing potential risks to human health and the ecosystem. The accumulation patterns in plants varied, with higher bioaccumulation factors observed for zinc and copper, suggesting their preferential uptake. This study highlights the urgent need for remediation strategies and continuous monitoring to mitigate the impact of heavy metal pollution in the Edayar region. The results will help in understanding the environmental impact of human activities.

Construction of Co-Modified MXene/PES Catalytic Membrane for Effective Separation and Degradation of Tetracycline Antibiotics in Aqueous Solutions

The application of antibiotics has advanced modern medicine significantly. However, the abuse and discharge of antibiotics have led to substantial antibiotic residues in water, posing great harm to natural organisms and humans. To address the problem of antibiotic degradation, this study developed a novel catalytic membrane by depositing Co catalysts onto MXene nanosheets and fabricating the polyethersulfone composite (Co@MXene/PES) using vacuum-assisted self-assembly. The dual role of MXene as both a carrier for Co atoms and an enhancer of interlayer spacing led to improved flux and catalytic degradation capabilities of the membrane. Experimental results confirmed that the Co@MXene/PES membrane effectively degraded antibiotics through peroxymonosulfate activation, achieving up to 95.51% degradation at a cobalt concentration of 0.01 mg/mL. The membrane demonstrated excellent antibacterial properties, minimal flux loss after repeated use, and robust anti-fouling performance, making it a promising solution for efficient antibiotic removal and stable water treatment.

Nonlinearity association of blood cobalt with the risk of anemia among middle-aged and older adults: National Health and Nutrition Examination Survey

ABSTRACT Objective The use of cobalt alloys in medical implants poses a high risk of cobalt exposure, yet there is a lack of evidence regarding the association between blood cobalt levels and anemia. This study aimed to explore the link between blood cobalt levels and the onset of anemia and to identify potential threshold levels of blood cobalt that could affect anemia. Methods The US National Health and Nutrition Examination Survey data from 2017 to 2020 were analyzed for this cross-sectional study. This study primarily employed multivariate logistic regression, stratified interaction analysis, restricted cubic splines (RCS), and threshold effect analysis to explore the relationship between blood cobalt concentration and anemia. Results The study included 5510 participants and among them 12.2% were diagnosed with anemia. Logistic regression model indicates a positive correlation between blood cobalt levels and the risk of anemia. RCS shows that the relationship between ln cobalt concentration and anemia was non-linear (J-shaped). The ln cobalt inflection point was approximately 0.81. The odds ratio of anemia with ln cobalt ≥ 0.81 was 4.00 (95% CI: 2.95–5.43, p < 0.001), the odds ratio of anemia with ln cobalt < 0.81 was 0.73 (95% CI: 0.45–1.18, p = 0.201). Conclusions The analysis unveiled a non-linear relationship, indicating that elevated blood cobalt levels were linked to a heightened likelihood of developing anemia in middle-aged and older adults; the cut-off value of ln cobalt was approximately 0.81. The findings of this study warrant further investigation.

The effect of cobalt content and mechanical activation on combustion in the Ni + Al + Co system

The effect of mechanical activation (MA) and cobalt content on the combustion velocity and maximum combustion temperature, elongation of samples during synthesis, the size of composite particles of the mixture after MA, phase composition and morphology of combustion products in the Ni + Al + Co system is investigated in this work. Activation of the Ni + Al + xCo mixture allowed the samples to burn at room temperature, with a cobalt content of up to 50 wt. %. An increase in the cobalt content in Ni + Al + xCo mixtures led to a decrease in the size of composite particles after MA, elongation of product samples and the maximum synthesis temperature. After MA, the elongation of the product samples and combustion velocity increased many times, the maximum synthesis temperature increased. With an increase in the cobalt content in the Ni + Al + Co mixture, combustion velocity first increases (at 10% Co), then decreases. Solid solutions based on NiAl and Ni3Al intermetallides were synthesized by the SHS method.

Efficiency of Penicillium sp. and Aspergillus sp. for bioleaching lithium cobalt oxide from battery wastes in potato dextrose broth and sucrose medium

Lithium-ion batteries, a primary power source, generate electronic hazardous waste at the end of their lifespan, which is a richer source of highly concentrated metals such as cobalt and lithium than those in natural resources. The waste is a potential renewable resource for the extraction of metals. Bioleaching, a process utilizing microbial activity, was used in this study to investigate the cobalt and lithium leaching efficiency from battery wastes. Two fungal strains, Aspergillus sp. strain JMET 15 and Penicillium sp. strain JMET 24 were used with different organic carbon sources (sucrose medium and potato dextrose broth) at 1 % pulp density. The sucrose medium derived a higher acid quantity and leached higher concentration of cobalt and lithium than in potato dextrose broth. Leaching efficiency by JMET 24 was higher than JMET 15. Cobalt (32.57 % and 27.19 %) and lithium (65.07 % and 40.58 %) were bioleached by JMET 24 and JMET 15, respectively, after 30 d cultivation in the sucrose medium. Lower pulp density was conducted to achieved higher leaching efficiency by JMET24, cobalt (77.87 % and 74.5 %) and lithium (99.88 % and 78.4 %) were bioleached at 0.1 % and 0.5 % pulp density, respectively. Cobalt oxide (Co3O4) was the product of the one-step recovery (leaching and precipitation) process. Cobalt was transformed from lithium cobalt oxide to cobalt phosphate-oxalate by JMET 24 in the sucrose medium. Thus, the potential of bioleaching as an effective method for recovering valuable metals from lithium-ion battery waste is demonstrated, presenting a promising approach for both waste management and resource recovery.

Distribution and enrichment processes of cobalt in the Longqiao iron skarn deposit in Eastern China

Longqiao is a cobalt-rich skarn iron deposit in Eastern China. As a typical representative of its type, it provides an opportunity to study the occurrence, distribution, and factors controlling cobalt in these deposits. Cobalt-bearing ores in Longqiao deposit can be classified into two types: cobalt-bearing diopside-magnetite ore (Co-Di-Mag) and cobalt-bearing phlogopite-magnetite ore (Co-Phl-Mag). Systematic whole-rock geochemical analysis, automated mineral analysis (TESCAN Integrated Mineral Analyzer, TIMA), and LA-ICP-MS trace element analysis were conducted on the two ore types. Three independent cobalt minerals（cobaltite, glaucodot, and carrollite）were found in Co-Di-Mag; no independent cobalt minerals were found in Co-Phl-Mag. TIMA and LA-ICP-MS analyses showed that cobalt in Co-Phl-Mag is mainly hosted in pyrite, so the pyrite content has a decisive role in the overall cobalt content. Cobalt in Co-Di-Mag is controlled by the content of magnetite, pyrite, and cobalt minerals.In both the diopside-magnetite stage (Stage I) and phlogopite-magnetite stage (Stage II), the cobalt mainly occurs in magnetite, and its content gradually decreases from 80 to 30 ppm as the system evolved. During the sulfide stage, minor pyrite deposited near the intrusion, and cobalt occurs in the pyrite lattice and also forms numerous independent cobalt minerals. Pyrite is abundant in the distal part of the ore-body, where all cobalt occurs in pyrite, and independent cobalt minerals are absent.Cobalt mainly occurs in pyrite in Longqiao deposit, which is favorable for beneficiation and recovery. Similar skarn iron deposits are widespread in eastern China, and the cobalt in these deposits has potential for recovery.

A fitting method of unlabeled interference for spectra based on multi-stage cross optimization

When constructing a spectral detection model for a substance, it will be very difficult to ensure the accuracy of the model if there is an unlabeled interference in the spectrum. To overcome the issue, we used a mathematical model to describe the impact mode of single interference on spectra, and pointed out the difficulties of spectral analysis in the case of unknown interference label. Then, a fitting method based on multi-stage cross optimization was proposed, which can fit the impact of single interference on spectra without interference label. Finally, we applied the proposed method on cobalt ion spectral detection with temperature interference. The application results indicate that although the influence modes of temperature interference and cobalt ion concentration on spectra are similar, this method can still accurately fit their influence modes, and the effectiveness of the fitting model was verified through spectral detection for blank sample.

Magnetization Processes of Exchange Coupled Nd2(Fe,Co)14B Alloys in Various Demagnetized States

Processes of magnetization in exchange-coupled rapidly quenched nanocrystalline alloys Nd2(Fe1-xCox)14B, where x = 0, 0.07, 0.2, 0.5, have been studied. Initial magnetization curves and interaction plots δM(H) for various demagnetized states were obtained. Based on comparison of measurement results, influence of the pinning type mechanism on magnetization process in the Nd2(Fe1-xCox)14B melt-spun ribbons is shown. Using δM(H) plots, change in intergrain exchange interaction depending on cobalt concentration in rapidly quenched Nd2(Fe1-xCox)14B nanocrystalline alloys was investigated.