Manganese In Iron Research Articles

Comparative analysis of methods for the determination of chromium, vanadium, copper, nickel, and manganese in steel and cast iron by flame atomic absorption spectrometry

A comparative analysis of the methods used for determination of a number of elements in steels and cast irons by atomic absorption spectroscopy with flame atomization have been carried out (vanadium by COST 12351-2003, GOST 22536.12-88, GOST 2604.7-84; chromium by GOST 12350-78, GOST 22536.7-88, GOST 2604.6-77; copper by GOST 22536.8-87, GOST 12355-78, GOST 2604.9-83, GOST 4943-2010; manganese by GOST 12348-78, GOST 22536.5-87, GOST 2604. 5-84; nickel by GOST 12352 - 81, GOST 22536.9-88, GOST 2604.8-77, GOST 4940-2010; in alloyed and unalloyed steels and alloyed and unalloyed cast irons). Analysis of the data obtained revealed the possibility of combining the considered Russian national standards into universal multi-element methods for the materials under study. The developed methods have been then certified in the analytical laboratory of the testing center of the Institute for certified reference materials (ICRM). The proposed methods provide an extension of the range of determined concentrations under optimal conditions of analysis. Comparison of the developed methods for the determination of vanadium, chromium, copper, manganese, nickel in steels and cast irons with international standards ASTM E350-18, ASTM E351-18, ASTM E352-18 have been carried out.

THERMODYNAMIC MODELING OF PHASE EQUILIBRIA AT STEEL ALLOYED WITH MANGANESE AND CHROME

In order to analyze the phase equilibria that are realized in the Fe–Mn–Cr–C–O system at the liquid metal existence temperatures, an extensive material on the thermodynamics of the interaction reactions of components dissolved in liquid iron has been generalized and systematized, and a database of mutually consistent data has been created. For the first time, the thermodynamic modeling of liquidus line coordinates has been performed and state diagrams for MnO–Cr2O3 and FeO–MnO–Cr2O3 systems have been plotted. The temperature for MnCr2O4 incongruent melting ( = 1812°С) and the enthalpy and entropy for formation of this compound from the components of the oxide melt of the MnO–Cr2O3 system were calculated ( = 190.77 kJ/mol and ( = 75.62 J/(mol•K), respectively). It is shown that for the FeO–MnO–Cr2O3 system phase diagram, there are extensive areas of equilibrium for the oxide melt with solid oxides solutions FeO, MnO and solid solutions of chromites FeCr2O4, MnCr2O4 with variable composition. The energy parameters of the theory of subregular ionic solutions were determined and used for calculation of the activities of oxide melt components (FeO, Cr2O3, MnO). The data obtained made it possible to refine the boundaries of the liquid metal composition in areas, which is in equilibrium with specific oxide phases. It is shown that at steelmaking temperature (1600°C) and contents of manganese and chromium in liquid iron about 1 wt. %, the formation of spinels’ solid solution inclusions is possible. Increasing the temperature to 1800°C (for example, when metal is blown with oxy-gen) can shift the equilibrium towards the formation of liquid oxide inclusions. The obtained results can be used in modeling of steel alloying with manganese and chromium. The effect of carbon on the nature of the phase equilibria that are realized in the system is taken into account. It is shown that already at a carbon content in the liquid metal at the level of 0.1–0.2 wt. %, there is a wide range of metal compositions that are in equilibrium with the gas phase {CO, CO2}. The obtained results can be used in modeling of the processes of steel alloying with manganese and chromium

Support vector machine for EELS oxidation state determination

Electron Energy-Loss Spectroscopy (EELS) is a powerful and versatile spectroscopic technique used to study the composition and local optoelectronic properties of nanometric materials. Currently, this technique is generating large amounts of spectra per experiment, producing a huge quantity of data to analyse. Several strategies can be applied in order to classify these data to map physical properties at the nanoscale. In the present study, the Support Vector Machine (SVM) algorithm is applied to EELS, and its effectiveness identifying EEL spectra is assessed. Our results evidence the capacity of SVM to determine the oxidation state of iron and manganese in iron and manganese oxides, based on the ELNES of the white lines of the transition metal. The SVM algorithm is first trained with given datasets and then the resulting models are tested through noisy test data sets. We demonstrate that SVM exhibits a very good performance classifying these EEL spectra, despite the usual level of noise and instrumental energy shifts.

Environmental risks for application of iron and steel slags in soils in China: A review

Iron and steel slags are smelting wastes, mainly including blast furnace slag (BFS) and steel slag (SS) produced in the iron and steel industry. Utilization of iron and steel slags as resources for solving the problem of slag disposals has attracted much attention with increasing iron and steel smelting slags in China. Because the iron and steel slags contain calcium (Ca), magnesium (Mg), phosphorus (P), and silicon (Si), some have tried to use them as Si- and P-fertilizers, for producing Ca-Mg-P fertilizers, or as soil amendments in agriculture. However, in the iron metallurgical process, several pollutants in iron ores can inevitably transfer into iron and steel slags, resulting in the enrichment of pollutants both in BFS (mainly nickel (Ni), copper (Cu), mercury, zinc (Zn), cadmium (Cd), chromium (Cr), arsenic, lead, selenium, fluorine (F), and chlorine (Cl)) and in SS (mainly Ni, Cr, Cd, Zn, Cu, F, and Cl), in which some of pollutants (especially Cr, Ni, F, and Cl) exceed the limits of environmental quality standards for soils and groundwater. The elements of manganese, barium, and vanadium in iron and steel slags are higher than the background values of soil environment. In order to ensure soil health, food safety, and environmental quality, it is suggested that those industrial solid wastes, such as iron and steel slags, without any pretreatment for reducing harmful pollutants and with environmental safety risk, should not be allowed to use for soil remediation or conditioning directly in farmlands by solid waste disposal methods, to prevent pollutants from entering food chain and harming human health.

A comparative study of growth, biological efficiency, antioxidant activity and molecular structure in wild and commercially cultivated Auricularia cornea strains

Abstract Auricularia cornea, jelly mushroom, is a popular ingredient of traditional Chinese cuisine. This study aimed at evaluating the growth, yield, biological efficiency, total phenolic and flavonoid contents, the antioxidant activity, elemental composition, and molecular structure of the wild and domesticated strain Ac24 and the commercially cultivated edible mushroom A. cornea strains Ac1, Ac3 and Ac15. Based on the weight of the fresh fruiting bodies of A. cornea strains, the maximum yield was obtained from commercial strain Ac1 (237.10 g), followed by Ac3 (224.47 g), Ac15 (158 g) and Ac24 (132.37 g), while the biological efficiency range of A. cornea strains was 52.94–94.84%, with significant differences among the A. cornea strains. Our results revealed that Ac24 contained the highest phenolic content (20.10 mg GAE · g−1), while the highest flavonoid content was found in Ac1 (35.13 mg CE · g−1). The maximum mineral contents and the strains were as follows: copper (7.2 mg · kg−1) and zinc (310 mg · kg−1) in Ac1, manganese (788 mg · kg−1) in Ac3 and iron (310 mg · kg−1) in Ac24. DPPH assay found maximum antioxidant activity in Ac24 (IC50 0.233 mg TX · mL−1), FRAP (591 mg TX · g−1) in Ac15, and erythrocyte haemolysis in Ac24. SEM-EDX and FTIR analyses verified the differences among A. cornea strains. The results revealed that wild, domesticated A. cornea strain Ac24 is a promising dietary source of natural antioxidants and is of high nutritional value, compared to commercially cultivated strains.

THE INFLUENCE OF THE CHEMICAL COMPOSITION OF WEAR-RESISTANT CAST IRON ON THE INTERPHASE DISTRIBUTION OF MN AFTER ANNEALING AT 690°C

Purpose. The article is aimed to obtain the regression dependences of manganese distribution between carbides and the metal base on the content of pig iron C, Cr, Mn and Ni after annealing at 690°C. Methodology. To achieve this purpose cast iron containing 1.09… 3.91% С; 11.43… 25.57% Cr; 0.6… 5.4% Mn; 0.19… 3.01% Ni and 0.8… 1.2% Si have been studied. To obtain reliable results analytical analysis of publications, microstructural and local micro-X-ray spectral methods, mathematical statistics and regression analysis of the obtained dependences were used. Findings. Using the methods of mathematical statistics, regression dependences of the manganese distribution between the phases and the magnitude of its concentration in the metallic basis of high-chromium cast iron on the content of C, Cr, Mn, and Ni after annealing at 690°C were obtained. During annealing, manganese was redistributed by replacing its atoms with chromium atoms in carbides. The effect of chromium and nickel varied significantly according to the content of manganese in cast iron. The minimum values of the manganese distribution coefficient of 0.16 were observed at the minimum carbon and manganese content and the maximum amount of chromium and nickel. The maximum concentration of manganese in the basis of 5.79% was determined with the minimum content of carbon and nickel and the maximum content of chromium and manganese. This made it possible to determine the chemical compositions of cast iron, which provide the required content of manganese in the metal base after annealing at 690°C. Originality. The regression dependences of the manganese content in the base and the coefficient of its interphase distribution on the content in cast iron of C, Cr, Mn and Ni after annealing at 690°C were obtained. Practical value. The obtained dependences of manganese distribution between phases in high-chromium cast iron after annealing at 690°C can be used during the development of the new wear resistant cast irons in the system Fe-C-Cr-Mn-Ni for castings that require heat treatment.

The Many and Various Roles of Manganese in Iron and Steel Production

Manganese oxide and metallic manganese have made a long and varied contribution to the production of iron and steel through the centuries, long before Sir Robert Hadfield’s alloy manganese steel first produced in 1882. Although quite well known empirically, this contribution has sometimes been misunderstood or misrepresented.The success of some of the early so-called ‘natural steels’ was the presence of manganese oxides in the iron ores used.Manganese oxide was already used as a flux from the early days of the production of crucible steel in Asia and it now appears that it was used as a flux from the inception of the otherwise very different later European crucible steel technologies. After the introduction of crucible steel making in Britain in the 18th century, foreign competitors believed that the reason for the success of the processes used at Sheffield was a secret flux and studies on recently discovered 18th century crucibles in Sheffield have shown that process was indeed fluxed with manganese oxide.The function of manganese in the later European crucible steel industry has been rather overshadowed and confused historically by the very different ‘Carburet of manganese’, a strange concoction, patented by Josiah Heath in 1839 added to iron or steel to purify the metal. At the time the chemistry of the process was misunderstood and many acrimonious and inaccurate claims were made, crucially confusing the very different functions of manganese oxide and manganese metal, overshadowing the part already played by manganese oxide for almost a century previously..Finally manganese and its salts played a crucial role in the Bessemer process of steel making.

Photometry Under the Condition of "Precision Rule"

Taking the determination of manganese in iron and steel as an example, it is proved that following the "precision rule", that is, “to maintain infection consistency of each factor for the each sample in the same measurement series”, the "content determination series" of photometry will present its "content absorption law": In the absorbance domain ,the coordinate points of all content and corresponding absorbance must be in the same straight line. Whether it's trace or high content, the connecting line of the coordinate points of the upper and lower limits of the two standard samples can be used as the "measuring line" of the sample content. The "two standard photometry" is established, which changes the traditional concept and presents the simple, high-speed and high efficiency nature of photometry. It is also the embodiment of normal distribution theory in photometry, so the measured values of samples are normal distribution. Systematic error and abnormal error (statistical outlier) are easy to find, which ensures the reliability of the measurement results. The uncertainty evaluation of the measurement results is simplified, the measurement model of the uncertainty is established, which is concise and practical, and realizes the unity with the allowable error; The new understanding also provides new ideas for the development of photometer: The measuring parts of the photometer shall conform to the "precision rule"; The filter beam has higher sensitivity and better reproducibility.

Peruvian scallop Argopecten purpuratus: From a key aquaculture species to a promising biondicator species

The present study analyzed the Peruvian scallop Argopecten purpuratus and its food sources for metal and fatty acid concentrations in order to determine spatial and temporal differences. Metals such as copper (Cu), manganese (Mn), and zinc (Zn) in gills and iron (Fe) and Zn in sediments were the most significant explaining factors for spatial differentiations (degree of contamination), while for fatty acids, it was C14:0, C15:0, C16:0 and C18:0 in A. purpuratus' muscle and in its food sources, which explained more temporal differences (El Niño-Southern Oscillation (ENSO) effect). Gills, digestive gland and intestine were the tissues where metal accumulation was the highest in A. purpuratus. Cd in digestive gland was always high, up to ∼250-fold higher than in other tissues, as previously reported in other bioindicator species for metal pollution. Fatty acids were good biomarkers when annual comparisons were performed, while metals when locations were compared. ENSO 2017 played an important role to disentangle A. purpuratus’ biological conditions and food sources. A. purpuratus from Paracas locations mostly showed higher metal concentrations in gills and digestive glands, and lower fatty acid concentrations in muscle than those from Sechura and Illescas Reserved Zone.

Effect of silicon, manganese and nickel present in iron on the intermetallic growth at iron - aluminum alloy interface

Recent interest in joining aluminum to steel necessitates a critical understanding of growth kinetics of various intermetallic phases that form across the mixed material interface. In order to understand the individual effect of ternary alloying elements present on iron side, growth kinetics of intermetallic layers formed at the interface between iron and aluminum alloy 6061 were studied by dipping pure iron and binary Fe-X alloys in the melt of AA6061, where X was Mn, Ni and Si. The immersion experiments were performed at 750 °C for various time durations from 90 s to 2400 s. The intermetallic layers formed at the interface were Fe2Al5 and FeAl3 in all cases. It was found that the presence of all the three ternary alloying elements in iron reduced the growth of intermetallic layer. Silicon was found to be the best for reducing the growth kinetics of the intermetallics followed by Ni and Mn in that order. The growth of Fe2Al5 layer was found to be diffusion controlled. Thickness of FeAl3 layer was found to increase with time at the beginning and to decrease with time at later stages. This behavior of FeAl3 was attributed to the two competitive processes that are simultaneously occurring at the FeAl3/AA6061 interface during liquid-solid diffusion viz. dissolution and formation of the FeAl3. The effect of the alloying elements on the growth kinetics of the intermetallic layer is explained based on velocity of interface in terms of interdiffusion fluxes and concentration gradients across the interface.

Thermodynamic analysis for the oxidation behaviour of manganese in iron-based melts during demanganisation processes

ABSTRACTIn this study, the influences of the solid oxidants and pure oxygen on oxidation behaviour of manganese in hot metal are investigated. The results indicate that the content of manganese in liquid iron decreases faster by using of iron ore fines than that by using of pure oxygen in the first 10 min. Manganese reversion could be happened by using solid oxidant Fe2O3, whereas it did not occurr under condition of oxygen blowing within 40 min. Meanwhile, the thermodynamic behaviour of manganese between CaO–SiO2–MgO–FeO–Fe2O3–MnO–Al2O3–P2O5 slag and molten steel has also been studied by means of IMCT-LMn model based on the ion and molecule coexistence theory (IMCT). With the aid of the current model, the effects of basicity on activity coefficient of MnO are investigated, which demonstrate that shows a negative correlation with mass percent of FetO in the range of 18.06–36.52%, indicating that the slag can hold more manganese oxide.

Erratum to: Determination of manganese in iron and iron concentrates by parametric methods of neutron activation analysis, using 59Fe as internal monitor

Erratum to: Determination of manganese in iron and iron concentrates by parametric methods of neutron activation analysis, using 59Fe as internal monitor

Determination of manganese in iron and iron concentrates by parametric methods of neutron activation analysis, using 59Fe as internal monitor

A method for manganese determination in iron concentrates by reactor activation analysis has been developed, on the basis of discounting the contribution of the 56Fe(n,p)56Mn to the total 56Mn activity through the 56Mn/54Mn activity ratio, employing the data on the nuclear constants involved. The possibility of using 59Fe as internal monitor, for the calculation of manganese concentration, is evaluated for different values of both the \(\phi_{\text{epi}} /\phi_{\text{th}}\) ratios and the α parameter.

Heavy-Metal Levels in Feathers of Cattle Egret and Their Surrounding Environment: A Case of the Punjab Province, Pakistan

Levels of 10 heavy metals in cattle egret chick feathers, prey, and surrounding soils from three heronries in Punjab Province, Pakistan, were assessed by atomic absorption spectrophotometry. Mean levels of cadmium (Cd), iron (Fe), chromium (Cr), and lithium (Li) in feathers, manganese (Mn), cobalt (Co), and nickel (Ni) in prey, and lead (Pb), iron (Fe), chromium (Cr), zinc (Zn), cobalt (Co), and lithium (Li) in soils were significantly different among Trimun Headworks, Shorkot, and Mailsi heroneries. Mean levels of Pb (43.10μg/g), Cr (35.77μg/g), Co (18.34μg/g), Cu (0.20μg/g), and Ni (0.22μg/g) in feathers were significantly greater at Mailsi, and Mn (3.07μg/g), Zn (18.83μg/g), and Li (1.5μg/g) levels were significantly greater at Shorkot. Multivariate analysis identified that some metals, such as Fe, Zn, and Li, in feathers were either associated with natural sources or with human-related activities, whereas Ni, Cr, Pb, Cd, Cu, Co, and Mn were correlated mainly with anthropogenic processes. Alarming levels were recorded for Cr, Pb, and Cd in feathers that were above threshold levels that may affect cattle egret flighting capacity and reproduction, thus leading to their population decline in Punjab Province. The results of this study provide evidence for the potential of feathers of cattle egret to be used as a biomonitor for the local heavy-metal contamination.

Dietary exposure to essential and toxic trace elements from a Total diet study in an adult Lebanese urban population

This study assesses, by the Total diet study approach, the adequacy of micronutrient intake (Co, Cu, Fe, Mn, Ni, Zn) and the dietary exposure of a Lebanese adult urban population to two toxic elements (Cd, Pb). The foods that made up the average ‘total diet’ were derived from a previous individual consumption survey. A total of 1215 individual foods were collected, prepared and cooked prior to analysis. Analytical quantification was performed using inductively coupled plasma mass spectrometry. Average daily intakes of Co (11.4 μg/day), Cu (1104.19 μg/day), Fe (13.00 mg/day), Mn (2.04 mg/day), Ni (126.27 μg/day) and Zn (10.97 mg/day) were below toxicological reference values and were found to satisfy nutritional recommendations, except for manganese in men and iron in women. Average dietary exposure to Pb and Cd represented 3.2% and 21.7% of the respective provisional tolerable weekly intakes. Estimates of dietary intakes of iron appeared to be inadequate for 63% of adult women. These findings should constitute a current measure of assessing the adequacy and safety of foods consumed in Lebanon and may be a basis for future monitoring studies.

A radioisotope method for testing the content of pearlite in wear-resistant cast iron

A radioisotope X-ray fluorescence method for determining the content of manganese in wear-resistant cast iron and subsequent determination of the content of pearlite using a correlation equation is presented. Its physical concept is based on the use of an experimental sensor with a movable selective chrome filter, which enables the characteristic X-ray K-radiation of cast iron to be recorded as the internal standard. Owing to the use of this method in industry, the amount of substandard products may be reduced.

Determination of Trace Amount of Manganese in High-purity Iron

Determination of Trace Amount of Manganese in High-purity Iron

Energy of mixing and magnetic state of components of Fe-Mn alloys: A first-principles calculation for the ground state

Methods of first-principles computer simulation have been used to calculate the magnetic moments at the component atoms and the energies of mixing in substitutional fcc and bcc solid solutions of manganese in iron. It has been established that the energies of mixing in α and γ solid solutions have not only different magnitudes but even different signs. It is shown that in α solid solutions there is a thermodynamic anomaly at a manganese concentration of approximately 1.5 at. %, namely, a change in the concentration dependence of the energy of mixing caused by a reorientation of magnetic moments at manganese atoms. With increasing Mn content in dilute solutions, there occurs a continuous variation of the orientation of magnetic moments of manganese atoms from strictly antiparallel with respect to the ferromagnetic iron matrix to predominantly parallel one.

Investigation of manganese-doped iron ammonia synthesis catalysts

The iron catalysts for ammonia synthesis doped with manganese in amounts up to 3 wt.% has been investigated. The addition of manganese oxide did not influence the distribution of other promoters in the catalyst precursors, manganese oxide itself was entirely incorporated into phases of iron oxides, its concentration in the wustite phase was about twice that in the magnetite phase. At concentrations of manganese below 0.4 wt.% the activity of manganese-doped catalyst was about 10% higher than that of standard industrial catalyst in the temperatures 500 and 450 °C after reduction, and in 400 °C after overheating. At higher concentrations the manganese acted as a catalyst’s poison. The cause for the higher activity of catalysts of low manganese content is surface area development, poisoning effect is due to occupation of active sites by manganese atoms at manganese content exceeding 0.4 wt.%. The corresponding surface coverage calculated according to Langmuir–Maclean’s model of segregation amounted to θ=0.25. The estimated value of free energy of segregation of manganese in iron in the overheated catalysts amounted to approximately −15 kJ/mol. Before overheating no segregation process was observed. The surface coverage exceeding θ≈0.3 caused formation of a new phase of manganese oxide on the surface of catalyst. Little effect of manganese addition on specific surface area and mean iron crystallite size is observed after reduction. After overheating manganese caused the rise of specific surface area due to higher energy of manganeseoxygen bond than that of ironoxygen bond. Together with increasing surface area the mean diameter of iron crystallites also increased.

Excess chromium alters uptake and translocation of certain nutrients in citrullus

Citrullus plants were grown in refined sand with varying levels of chromium to determine their tolerance limit to excess chromium. The plants were maintained in control nutrient solution for 24 days and on the 25th day chromium as dichromate was added at 0.05, 0.1, 0.2, 0.3 and 0.4 mM. A control set of plants was grown in the same nutrient solution without chromium. At chromium levels >0.2 mM plants showed growth depression, with chlorosis and loss of turgor of middle leaves. Affected leaves had narrow lamina; tendrils were thin, short and did not have coiling property. Later chlorosis became severe and changed to necrosis in patches. Petiole along with lamina became wilted, rugged and hung down due to complete loss of water. At lower chromium concentration, (0.05, 0.1 and 0.2 mM) only depression in growth was observed. With increase in chromium concentration of nutrient solution accumulation of chromium in different parts of Citrullus was increased. Increase in concentrations of phosphorus, manganese and decrease in iron, copper, zinc and sulphur were observed in leaves. Toxicity of chromium was greater at 0.2–0.4 mM, compared to lower concentrations. Threshold of toxicity and toxicity of Cr in old leaves were, respectively, 0.9 and 3.9 μg g −1 dry matter of citrullus.