Iron-rich Materials Research Articles

Urban and suburban's airborne magnetic particles accumulated on Tillandsia capillaris

Air particle pollution is a current issue that can cause adverse problems to human health and the urban environment. A fraction of these emitted particles is magnetite and iron-rich materials, which may be accumulated by biological indicators and effectively characterized by environmental magnetism methods. Thus, we studied this emitted particle fraction using the epiphytic species Tillandsia capillaris growing in northwestern Argentina's urban, suburban, and rural areas. The accumulated airborne magnetic particles' properties revealed valuable information regarding potentially toxic elements, magnetic mineralogy, sizes, morphology, and concentration. Magnetite was detected in samples from all studied areas, and its remanent coercivity values (Hcr = 32.1–42.6 mT) in (sub)urban sites are similar to other reported cities in Latin America. The concentration of these airborne magnetic particles AMP varied between urban sites (mean and (s.d.) values of in situ magnetic susceptibility κis = 16.2 (9.4) × 10−6 SI, and specific magnetic susceptibility χ = 61.9 (31.4) × 10−8 m3 kg−1) and suburban sites (κis = 13.9 (9.9) × 10−6 SI, and χ = 43.9 (32.2) × 10−8 m3 kg−1), and it was distinctively higher than in clean sites. The spatial distribution of AMP was analyzed using a geostatistical model for the concentration-dependent magnetic parameter κis, which showed zones with high magnetic particle accumulation associated with vehicular traffic in the city and industrial emission in a suburban site. Among concentration-dependent magnetic parameters, the κis is recommended for magnetic biomonitoring because Tillandsia species' individuals are not processed for laboratory measurements, preserving them and allowing us the possibility of measurements over time.

Machine learning predictions of high-Curie-temperature materials

Technologies that function at room temperature often require magnets with a high Curie temperature, TC, and can be improved with better materials. Discovering magnetic materials with a substantial TC is challenging because of the large number of candidates and the cost of fabricating and testing them. Using the two largest known datasets of experimental Curie temperatures, we develop machine-learning models to make rapid TC predictions solely based on the chemical composition of a material. We train a random-forest model and a k-NN one and predict on an initial dataset of over 2500 materials and then validate the model on a new dataset containing over 3000 entries. The accuracy is compared for multiple compounds' representations (“descriptors”) and regression approaches. A random-forest model provides the most accurate predictions and is not improved by dimensionality reduction or by using more complex descriptors based on atomic properties. A random-forest model trained on a combination of both datasets shows that cobalt-rich and iron-rich materials have the highest Curie temperatures for all binary and ternary compounds. An analysis of the model reveals systematic error that causes the model to over-predict low-TC materials and under-predict high-TC materials. For exhaustive searches to find new high-TC materials, analysis of the learning rate suggests either that much more data is needed or that more efficient descriptors are necessary.

Momentum enhancement from 3-cm-diameter aluminum sphere impacts into iron and rock at 5 km/s

Utilizing a large two-stage light gas gun and a large pendulum assembly, experiments were performed to measure the momentum enhancement (or increase in momentum transfer due to the ejecta) of an ARMCO iron target, two large hematite rock targets, a target of stones held by concrete, and a concrete block target. The choice of iron and iron rich materials was motivated by interest in the asteroid Psyche and the planned upcoming mission. The target comprised of a collection of stones, to mimic a rubble pile asteroid, was to provide insight into the Double Asteroid Redirection Test (DART) impact. The role of impactor size is important, and these tests were performed at a large scale, with 3-cm-diameter aluminum spheres as the impactor. Save for the concrete block, these impacts were in the vicinity of 5 km/s. There is a distinct difference in the amount of momentum enhancement (measured by β) that occurs with ductile metals vs. brittle materials and this fact shows in these impacts. The momentum enhancement with a relatively brittle aluminum falls in between the two extremes of rock and iron. Computations were performed to compare with the ARMCO iron impacts. Data at a large scale is desirable to quantify momentum enhancement in the context of hypervelocity impactors deflecting celestial bodies such as asteroids or comet nuclei.

Biochar, compost, iron oxide, manure, and inorganic fertilizer affect bioavailability of arsenic and improve soil quality of an abandoned arsenic-contaminated gold mine spoil

Arsenic (As) contaminated mining spoils pose health threats to environmental resources and humans, and thus, mitigating this potential risk is worth investigating. Here, we studied the impacts of biochar, compost, iron oxide, manure, and inorganic fertilizer on the non-specifically (readily bioavailable)- and specifically- sorbed As and soil quality improvement of an abandoned mine spoil highly contaminated with As (total As = 1807 mg/kg). Compost, iron oxide, manure, and biochar were each applied at 0.5%, 2%, and 5% (w/w) to the contaminated soil; and NPK fertilizer at 0.1, 0.2, and 5.0 g/kg. The non-specifically (readily bioavailable)- and specifically- sorbed As were extracted sequentially and available P, total C and N, dissolved organic carbon, soil soluble anions, and exchangeable cations were extracted after 1- and 28-day incubation. Compost, manure, and biochar at 5% improved the total C and N and exchangeable K+, Mg2+ and Na+. However, manure, compost, and iron oxide at 5% reduced available P from 118.5 to 60.3, 12.6, and 7.1 mg/kg, respectively. As compared to the untreated soil, the addition of iron oxide doses reduced the readily bioavailable As by 93%; while compost, manure, inorganic fertilizers, and biochar increased it by 106–332%, 24–315%, 19–398%, and 28–47%, respectively, with a significantly higher impact for the 5% doses. Furthermore, compost reduced specifically-sorbed As content (14–37%), but the other amendments did not significantly affect it. The impacts of the amendments on the readily bioavailable As was stronger than on specifically-sorbed As; but these were not affected by the incubation period. Arsenic bioavailability in our soil increased with increasing the soil pH and the contents of Cl-, DOC, and exchangeable K+ and Na+. We conclude that iron-rich materials can be used to reduce As bioavailability and to mitigate the associated environmental and human health risk in such mining spoils. However, the carbon-, and P-rich and alkaline materials increased the bioavailability of As, which indicates that these amendments may increase the risk of As, but can be used to enhance phytoextraction efficiency of As in the gold mining spoil.

Using Fly Ash Wastes for the Development of New Building Materials with Improved Compressive Strength.

Fly ash wastes (silica, aluminum and iron-rich materials) could be smartly valorized by their incorporation in concrete formulation, partly replacing the cement. The necessary binding properties can be accomplished by a simple procedure: an alkali activation process, involving partial hydrolysis, followed by gel formation and polycondensation. The correlations between the experimental fly ash processing conditions, particle characteristics (size and morphology) and the compressive strength values of the concrete prepared using this material were investigated by performing a parametric optimization study to deduce the optimal processing set of conditions. The alkali activation procedure included the variation of the NaOH solutions concentration (8–12 M), temperature values (25–65 °C) and the liquid/solid ratio (1–3). The activation led to important modifications of the crystallography of the samples (shown by powder XRD analysis), their morphologies (seen by SEM), particle size distribution and Blaine surface values. The values of the compressive strength of concrete prepared using fly ash derivatives were between 16.8–22.6 MPa. Thus, the processed fly ash qualifies as a proper potential building material, solving disposal-associated problems, as well as saving significant amounts of cement consumed in concrete formulation.

A fast, single column extraction chromatography method for the isolation of neodymium from iron-rich materials prior to radiogenic isotope ratio measurements

A novel separation method is described for the separation of Nd from Fe-rich, silicate samples in view of isotopic analyses.

Oral Limonite Supplement Ameliorates Glucose Intolerance in Diabetic and Obese Mice.

IntroductionDiabetes mellitus is a serious threat to public health worldwide. It causes a substantial economic burden, mental and physical disabilities, poor quality of life, and high mortality. Limonite is formed when iron-rich materials from the underground emerge and oxidized on the ground surface. It is currently used to purify contaminated water, absorption of irritant gases, and improve livestock breeding. Limonite can change the composition of environmental microbial communities. In the present study, we evaluated whether limonite can ameliorate glucose metabolism abnormalities by remodeling the gut microbiome.MethodsThe investigation was performed using mouse models of streptozotocin-induced diabetes mellitus and high-calorie diet-induced metabolic syndrome.ResultsOral limonite supplement was associated with significant body weight recovery, reduced glycemia with improved insulin secretion, increased number of regulatory T cells, and abundant beneficial gut microbial populations in mice with diabetes mellitus compared to control. Similarly, mice with obesity fed with limonite supplements had significantly reduced body weight, insulin resistance, steatohepatitis, and systemic inflammatory response with significant gut microbiome remodeling.ConclusionThis study demonstrates that limonite supplement ameliorates abnormal glucose metabolism in diabetes mellitus and obesity. Gut microbiome remodeling, inhibition of inflammatory cytokines, and the host immune response regulation may explain the limonite’s beneficial activity under pathological conditions in vivo.

Iron can be microbially extracted from Lunar and Martian regolith simulants and 3D printed into tough structural materials.

In-situ resource utilization (ISRU) is increasingly acknowledged as an essential requirement for the construction of sustainable extra-terrestrial colonies. Even with decreasing launch costs, the ultimate goal of establishing colonies must be the usage of resources found at the destination of interest. Typical approaches towards ISRU are often constrained by the mass and energy requirements of transporting processing machineries, such as rovers and massive reactors, and the vast amount of consumables needed. Application of self-reproducing bacteria for the extraction of resources is a promising approach to reduce these pitfalls. In this work, the bacterium Shewanella oneidensis was used to reduce three different types of Lunar and Martian regolith simulants, allowing for the magnetic extraction of iron-rich materials. The combination of bacterial treatment and magnetic extraction resulted in a 5.8-times higher quantity of iron and 43.6% higher iron concentration compared to solely magnetic extraction. The materials were 3D printed into cylinders and the mechanical properties were tested, resulting in a 400% improvement in compressive strength in the bacterially treated samples. This work demonstrates a proof of concept for the on-demand production of construction and replacement parts in space exploration.

A geological collection and methodology for tracing the provenance of Palaeolithic colouring materials

Although prehistoric sites frequently contain numerous fragments and traces of many different kinds of colouring matter, intensive study of this type of archaeological remains began only recently. Such studies, aimed at determining how raw materials formed and changed over time, and how they were transported by the groups of humans who used them, are extremely valuable as they reveal shared strategies, that is, cultural traditions and the spaces in which they developed. The scope of this paper focusses on the description of the main geological contexts in which ferruginous colouring materials form and are found. In the framework of a collective research program called Pigmentothèque (iron- and manganese-rich rocks and minerals library), geological surveys are conducted taking into consideration the geological settings in which colouring materials are present and using a common record and sampling methodology which is followed by petrophysical, mineralogical and chemical analyses based on a shared procedure and vocabulary. In order to go beyond descriptions based solely on colour and chemical composition, we describe the great variety of iron-rich materials that can be used to obtain colouring matter. This diversity in the formation and evolution of iron-rich materials must be taken into account when trying to understand past humans’ choices of raw materials, their provenance and the anthropogenic and natural modifications they have undergone. We also describe criteria for recognising cohesive remains of colouring matter during archaeological excavations, so these artefacts can take their place alongside other mineral resources in helping improve our understanding of past societies.

Revisiting the iron-rich “ordinary Portland cement” towards valorisation of wastes: study of Fe-to-Al ratio on the clinker production and the hydration reaction

Ordinary Portland cement (OPC) is a strong and durable material with a well-established composition defined by national and regional standards. The required chemistry limits the amount of iron-rich materials that can be used as a feedstock. The work described in this paper investigates how substitution of iron for aluminium affects OPC clinker production. Herein, it was studied how this substitution affected clinker phase assemblage during the firing process, the paste hydration kinetics and products as well as the mechanical properties of the mortars. Results suggested that Fe to Al replacement did not affect substantially the melt formation at usual production temperatures. The formation of alite and ferrite were promoted, diminishing the formation of aluminate and belite. Regarding the hydration process it was obtained portlandite, ettringite, AFm and hydrogarnet as well as amorphous phase. Additionally, the Fe-rich cements presented longer setting times and slightly lower mechanical strength. These results are a first approach in the study of OPC clinkers with Fe-rich content and additional research provided in the future can enable the use of larger amounts of Fe-rich materials and residues in the OPC raw meal.

Acidification Assessment after Peat Bog Drainage in the Catalan Pyrenees (NE Iberia)

The Pyrenean range (NE Iberian Peninsula) has some favourable lithological and climatic conditions (iron-rich parent materials and udic moisture regimes) for the formation of acid sulfate soils (ASS) that have not been reported on from the region until now. The analyses of a drained peat bog near València d’Àneu revealed a pH (1:2.5) of 3.7. We hypothesize that it contained sulfidic materials that were oxidized during drainage, which could have caused its acidification. The main goal of this study is to understand the characteristics and the potential acidity of these organic soils and the consequences that this could generate in the current environment. In order to do so, several profiles were described and sampled in the field for chemical and micromorphological analyses. The results show that the oxidation of the newly formed pyrite in the soil or pyrite contained in the Cambro–Ordovician parent material was responsible for the low pH and high electrical conductivity (EC). The soils still contain sulfidic materials at present, which could be oxidized in the future, with the consequent risk for water quality. The results will be useful to evaluate the risk of other peats in the Pyrenees becoming acid sulfate soils if drained.

The colouring mechanism of the Brown glaze porcelain of the Yaozhou Kiln in the Northern Song Dynasty

the Brown glaze porcelain is one of the main production for the Yaozhou kiln in the Northern Song Dynasty (960–1127 A.D). To clarify the colouring mechanism of the brown glaze is a key to understand the technology development of the Yaozhou kiln in the 11th century. In order to determine the production process and its features, the brown glaze porcelain samples from Yaozhou kiln were analyzed by optical microscope, SEM, Micro-energy disperses X-ray fluorescence, X-ray diffraction and X-ray absorption fine structure. The results show that the brown glaze has two layers with different colours: the surface of the glaze is brown and the bottom is black; regarding the composition, the surface layer of the glaze contains much more iron than the bottom layer, and the amount of Titanium is high in both parts of the glaze. The crystals concentrated on the surface of the glaze, in addition to alpha -Fe2O3 and Fe3O4 crystals, the epsilon -Fe2O3 crystals which are rarely found also formed on the surface glaze. The brown colour of the glaze is mainly contributed by the several kinds of iron oxides crystals. The red ferric oxide crystals mixed with black ferroferric oxide crystals to present brownish effect. The black bottom glaze reinforce the brown colour. The special brown glaze not only needs the iron rich raw materials but also requires a special firing process, particular to slow down the cooling procedure to create appropriate condition for crystallization. The later kilns of 13th −18th centuries used the similar technology to produce the brown or purple gold porcelain. The study revealed that the Yaozhou kiln is one of the origins of the brown glaze for both aesthetics and technology.

Case study of industrial symbiosis for improved residual material utilisation in the steel industry

Steel production is a material and energy intensive industry which, in addition to steel products, generates residual materials such as metallurgical slag, dust and sludge. These residual materials are recycled and used to a great extent as well in-house as for external purposes. Even so, some materials are currently landfilled due to difficulties in finding use or recycling possibilities. This applies, for example, to zinc-containing sludge and dust from ore-based steel production and certain iron-rich, lime and carbon-containing materials from scrap-based steel production. A case study has been performed with the aim to develop a methodology for evaluating industrial symbiosis possibilities in regard to increased material efficiency in steel production systems. The methodology is based on system analysis of steel production routes in combination with economical assessment of hypothetical business concepts by using residual materials from one industry as secondary raw materials in another. The paper presents case study results and indicates how this methodology could be applied to maximise the residual materials utilisation. By the methodology discussed and with a circular-economic perspective, it is shown that high economic potential for one material could be used to increase the utilisation of other materials with lower economic potential.

Factors influencing As(V) stabilization in the mine soils amended with iron-rich materials.

Chemical stability of As(V) in amended mine-impacted soils was assessed according to functions of incubation period (0, 1, 2, 4, and 6months), amendment dose (2.5 and 5%), and application timing (0 and 3rd month). Six soils contaminated with 26-209mgkg-1 of As(V) were collected from two abandoned mine sites and were treated with two alkaline iron-rich materials (mine discharge sludge (MS) and steel-making slag (SS)). Seventeen to 23% of As(V) in soils was labile. After each designated time, As(V) stability was assessed by the labile fractions determined with sequential extraction procedures (F1-F5). Over 6months, a reduction (26.9-70.4%) of the two labile fractions (F1 and F2) and a quantitative increase (7.4-29.9%) of As(V) in F3 were observed (r 2=0.956). Two recalcitrant fractions (F4 and F5) remained unchanged. Temporal change of As(V) stability in a sample was well described by the two-domain model (k fast, k slow, and Ffast). The stabilization (%) correlated well with the fast-stabilizing domain (Ffast), clay content (%), and Fe oxide content (mgkg-1), but correlated poorly with kinetic rate constants (k fast and k slow). Until the 3rd month, the 2.5%-MS amended sample resulted in lower As(V) stabilization (25-40%) compared to the 5% sample (50-60%). However, the second 2.5% MS addition on the 2.5% sample upon the lapse of the 3rd month led to a substantial reduction (up to 38%) of labile As(V) fraction in the following 4th and 6th months. As a result, an additional 15-25% of As(V) stability was obtained when splitting the amendment dose into 3-month intervals. In conclusion, the As(V) stabilization by Fe-rich amendment is time-dependent and its efficacy can be improved by optimizing the amendment dose and its timing.

Archaeometric analysis of prehistoric rupestrian paintings from the Toca do Estevo III site, Piauí, Brazil

The “Toca do Estevo III” is an archaeological site located in the rural area of the municipality of João Costa, state of Piauí, Brazil. The sandstone walls of the shelter are decorated with prehistoric rupestrian inscriptions (zoomorphic and anthropomorphic motifs over a background figuring a large white ounce), painted mainly in light and dark red hues, but also in white and in yellow. The chemical-mineralogical analyses of three samples containing pigments of the prehistoric rupestrian paintings, along with the material of a saline efflorescence, were made in the laboratory by (i) energy dispersive X-ray fluorescence (EDXRF); (ii) 57Fe Mössbauer spectroscopy at 298K, 110K and 21K; (iii) Fourier-transform infrared spectroscopy (FTIR); (iv) scanning electron microscopy (SEM); (v) energy dispersive spectroscopy (EDS) and (vi) powder X-ray diffractometry (XRD). Results indicate that the pigments of the reddish paintings were essentially prepared with a clayey material, which was rich in hematite (α-Fe2O3). Goethite (α-FeOOH), but also some hematite, was found in the yellowish-red painting. From the Mössbauer data, part of the very fine particles of these iron-bearing minerals behaves superparamagnetically; the magnetic relaxation appears to be significantly blocked at ~100K. The saline efflorescence was found to consist mainly of a complex mixture of salts: K2SO4·7KHSO4·H2O; 5ZnO·Al2O3·ZnSO4·15H2O; Ca2Al4Si4O15(OH)2·4H2O and Ca2Al4Si8O24·12H2O. The 57Fe Mössbauer spectroscopy is reaffirmed to be a central technique on the chemical and mineralogical analyses of iron-rich materials from the archaeological heritage, as pigments of prehistoric rupestrian paintings.

Spatial patterns in heavy-mineral concentrations along the Curonian Spit coast, southeastern Baltic Sea

The 98-km-long Curonian Spit is fronted by beaches mainly composed of quartz sand with minor high-density fractions. In this study heavy-mineral concentration (HMC) trends and grain-size statistical parameters were used to assess their role as indicators of natural processes, human activities, and patterns of longshore transport. A total of 92 surface sand samples were collected at 1 km intervals from the middle of the beach along the Baltic Sea shoreline of the spit between Klaipėda strait in Lithuania and Zelenogradsk in Russia. HMC contribution was assessed in the laboratory using bulk low-field magnetic susceptibility (MS) as a proxy for ferrimagnetic and paramagnetic mineral content. Quartz-dominated (background) sand is generally characterized by low MS values of κ < 50 μSI, whereas higher values κ > 150 μSI are typical for heavy-mineral-rich sand. The greatest MS values along the middle of the beach occur in the southern part of the spit and are 40 times higher than in the northern sector. This pattern suggests the existence of a longshore particle flux with HMC distribution having the potential as a useful tracer of longshore sediment transport. Local anomalously high MS excursions are associated with contribution of iron-rich materials from adjacent man-made structures. Therefore, temporally constrained HMC distribution along the middle of the beach reflects the cumulative effect of antecedent geologic framework, longshore sediment transfer, erosional and accretionary processes, wave and wind climate, and local coastal protective structures.

Enhanced magnetic domain relaxation frequency and low power losses in Zn2+ substituted manganese ferrites potential for high frequency applications

Nowadays electronic industries prerequisites magnetic materials, i.e., iron rich materials and their magnetic alloys. However, with the advent of high frequency applications, the standard techniques of reducing eddy current losses, using iron cores, were no longer efficient or cost effective. Current market trends of the switched mode power supplies industries required even low energy losses in power conversion with maintenance of adequate initial permeability. From the above point of view, in the present study we aimed at the production of Manganese–Zinc ferrites prepared via solution combustion method using mixture of fuels and achieved low loss, high saturation magnetization, high permeability, and high magnetic domain relaxation frequency. The as-synthesized Zn2+ substituted MnFe2O4 were characterized by X-ray diffractometer (XRD) and transmission electron microscopy (TEM). The fractions of Mn2+, Zn2+ and Fe2+ cations occupying tetrahedral sites along with Fe occupying octahedral sites within the unit cell of all ferrite samples were estimated by Raman scattering spectroscopy. The magnetic domain relaxation was investigated by inductance spectroscopy (IS) and the observed magnetic domain relaxation frequency (fr) was increased with the increase in grain size. The real and imaginary part of permeability (μ′ and μ″) increased with frequency and showed a maximum above 100MHz. This can be explained on the basis of spin rotation and domain wall motion. The saturation magnetization (Ms), remnant magnetization (Mr) and magneton number (µB) decreased gradually with increasing Zn2+ concentration. The decrease in the saturation magnetization was discussed with Yafet–Kittel (Y–K) model. The Zn2+ concentration increases the relative number of ferric ions on the A sites, reduces the A–B interactions. The frequency dependent total power losses decreased as the zinc concentration increased. At 1MHz, the total power loss (Pt) changed from 358mW/cm3 for x=0–165mW/cm3 for x=0.9. Pt for all the Zn doped samples exhibited the temperature stability up to 100°C.

Iron stocks of buried Podzols: Endogenic iron deficits and potential exogenic enrichment in the Maashorst region, SE Netherlands

Podzolation is the dominant soil forming process in chemical poor sandy soils. It is well studied how iron concentrations of podzols are effected by translocation of active iron from eluvial to illuvial horizons and leaching to the aquifer. Iron stocks of Podzols, in contrasts, have not been widely studied for comparison purposes of individual soil horizons or between soils. In this study we provide an analysis of the iron stocks for two buried Podzols developed in Late-Glacial aeolian coversands. Chemical analyses of the active and immobile iron fractions in each of the horizons in both profiles show that more iron has been involved in the podzolation process, than the amount which can be derived by chemical weathering of minerals in the overlying soil horizons. This deficit in endogenic iron therefore requires exogenic enrichment to explain the observed iron concentrations during podzolation. The contribution of exogenic iron was studied using micrometeorites as a proxy for atmospheric deposition. These particles of cosmic origins are part of a continuous flux of iron-rich materials into the Earth's atmosphere and they are deposited over time on every square meter of land surface. Their extraction from ectorganic F horizon of initial Podzols helped illustrate that atmospheric deposition in the form of aerosol and aeolian (e.g. Sahara) dust, micrometeorites and other hydrolysable particles are a relevant iron contribution in soil development. The requisite active iron for podzolation can therefore be derived from chemical weathering of atmospheric iron sources in the acidic soil environment.

Immobilization of iron rich steel industry waste and products characterization

The steel industry produces large amount of wastes, some of which are today used in other industrial sectors; iron oxide rich wastes are difficult to recycle and vitrification is one of the most efficient techniques to stabilize them and produce materials suitable for new applications. The waste considered in this study comes from the purification of fumes captured by hoods during agglomeration process in the sinter plant. These dusts have been vitrified on a laboratory scale by the addition of glass cullet coming from diversified harvest of municipal waste, varying the glass/dust ratio from 80:20 to 50:50. The as produced materials have been characterized by means of XRD analysis and SEM images, and leaching tests have been carried out to evaluate their chemical stability. The electrical and magnetic properties of these iron rich materials have been evaluated too. The resistivity of the samples produced with 45% and 50% of waste are 20 and 1.5×103Ωm respectively, considerably lower than the common soda-lime glass resistivity value (1012Ωm). Moreover the materials show a ferromagnetic behaviour; the Curie Temperature of the materials lies in the range from T=395°C to T=533°C, confirming the presence of magnetite/maghemite phases.

RETRACTED ARTICLE: Elemental content variations in crushed mortar specimens measured by Instrumental Neutron Activation Analysis (INAA)

Previous investigations concerning neutron emission measurements highlighted piezonuclear fission reactions during mechanical tests on iron-rich materials. Based on our experimental evidences, iron can be considered one of the most convenient elements as regards fission into aluminium or into magnesium and silicon. In the present investigation, we apply the Instrumental Neutron Activation Analysis (INAA) in order to provide experimental evidence of elemental content variations in mortar specimens subjected to compression tests up to crushing failure. To emphasize such a phenomenon, the specimens were highly enriched with iron oxides. Twenty-four chemical elements, including iron, aluminum, magnesium, and silicon, were quantified before and after the mechanical tests by means of chemical and INAA analyses. Our intention was mainly that of confirming low energy nuclear reactions involving fission of iron into aluminum. To this purpose, the concentrations of aluminum before and after the compression tests of the mortar specimens are presented and discussed.