Ratio Of Iron Oxides Research Articles

Improving Silica Sand Specifications for Making Colorless Glasses by Using Chemical and Physical Methods

This study was carried out to determine the possibility of reducing the iron oxide ratio in silica sand from Ardhumah, an area, (18) km west of Rutba, a city in Al-Anbar Governorate, to obtain sand specifications appropriate for making colorless glasses (not exceeding 0.02 % iron oxide ratio). The reduction process of iron oxide includes three stages; the first stage is magnetic separation to reduce Fe2O3 from 0.092% to 0.040%, the second stage is re-floatation which has reduced Fe2O3 to 0.024%, finally treatment of the sand output from the first and second stage with diluted HCl or H2SO4, this study showed the possibility of obtaining silica sand with a ratio of Fe2O3 up to 0.016%.

Preparation of Monolayer Dispersed Fe/Attapulgite Desulfurizer and Its Desulfurization Performance at Low Temperature

AbstractFe/ATP (attapulgite) desulfurizers with different loads were prepared by precipitation method. XRD profiles revealed that the loading threshold of monolayer dispersion was 28.75 %. The desulfurizers were characterized by UV‐vis, FT‐IR, TPR, BET, and SEM. The performances of desulfurizers with different loads were compared. When the loading reached the threshold, both the sulfur capacity of the desulfurizer and the availability ratio of iron oxides were the highest. Beyond the threshold, the amount of Fe3+ bound to the skeleton of ATP increased to form skeleton iron, and some iron oxides gathered together, causing decreases in the sulfur capacity. The dissolution amount of Fe3+ showed the bonding strength between active components and ATP by acid dissolution experiments, which became stronger with increases of skeleton iron. Processes of deactivation were fitted by the deactivation model, which revealed that the changes in loadings would impact the deactivation of desulfurizers.

Hydration activity and expansibility of different divalent metal oxide solution compositions in steel slag

Steel slag (SS) accounts for 15–20% of steelmaking output; its application in cement concrete has been limited because of poor stability. In this study, the divalent metal oxide solid solution (RO phase) in SS was analogue synthesised to study its hydration activity and expansibility. The results showed that the hydration activity and expansibility of magnesium oxide (MgO) in the analogue-RO phase is affected by the content of ferrous oxide (FeO); with the increase of molar ratio (x) of iron oxide to magnesium oxide in the analogue-RO phase, the autoclave expansion rate and hydration activity of the cement paste decreased. When x ≤ 0.5, the RO phase had high hydration activity and could cause poor soundness of SS. When x = 1, the RO phase had low hydration activity and could cause slight expansion of SS. When x ≥ 2, the RO phase had no hydration activity and could not cause any expansion of SS. The control of different analogue-RO phase compositions induced different hydration and expansibility, which provided a theoretical basis for the influence of the RO phase on the soundness of SS and enabled measures to be proposed to reduce the expansion of SS, thereby promoting high-volume utilisation of SS in cement and concrete.

Weathering under coastal hyperaridity – Late Quaternary development of spectral, textural, and gravelometric alluvial fan surface characteristics

Hyperarid coasts develop under relatively high air humidity and abundant sea salt aerosols, resulting in physical and chemical weathering processes that distinctly differ from those present in inland deserts. However, neither the geomorphic effects of the weathering processes nor the timescales on which they alter depositional surfaces are sufficiently understood. In this study we therefore integrate spectral, textural, and gravelometric analyses based on high to very high resolution satellite and aerial remote sensing to assess the degree of post-depositional alteration of a multi-stage alluvial fan at the coast of the Atacama Desert. To further deduce the present-day as well as past intensities of responsible weathering processes we establish a morphochronology of the fan's evolution using cosmogenic 10Be exposure dating.Spectral, textural, and gravelometric parameters relatively date a succession of fan generations, assuming the weathering of fan surface sediments prior to deposition can be largely excluded. Under coastal hyperaridity, effects on the spectral surface signatures are primarily explained by the development of weathering rinds and related formation of secondary iron oxides. Spectral iron oxide ratios show little to no change during the Holocene but strongly increase during the Late Glacial, while over longer timescales an asymptotic increase is suggested. Clast breakdown can largely be attributed to salt weathering causing sublinear to roughly linear decreases in mean size, coarseness, and size variation of coarse clasts. Governed by clast breakdown as well as lateral remobilization of clasts, nano-scale surface roughness exhibits a non-monotonic, peak-shaped relationship with age, whereas the micro-relief experiences continuous smoothing due to denudation. Findings are summarized in a conceptual model showing that in hyperarid coastal environments fan surface weathering results over timescales of 104 to 105 a in a fully developed desert pavement. Two hypothetical scenarios are introduced which differ based on whether desert pavements remain stable over timescales exceeding the Late Pleistocene or not. Late Quaternary weathering intensity along the coast of the Atacama Desert is found to be related to sea surface temperature variability and sea level jointly driving the oceanic moisture supply.

Multi-criteria analysis for mapping susceptibility to iron formation caves development in the Gandarela mountain range (MG), southeast Brazil

In tropical regions, abundant in iron-rich geological materials, caves that are genetically and geographically associated with exploitable mineral deposits may develop. These caves have speleological relevance and are environmentally and legally protected in Brazil. Thus, for better planning of exploitation and environmental licensing, it is necessary to study the genesis and development of the iron formation caves seeking to preserve them without impeding the advancement of mining. This subject is complex, rarely studied, and few are the knowledges on alternatives to predict the occurrence of these caves. This gap justifies the development of research and products capable of assisting decision-makers, planners, and competent authorities in supporting the definition of target sites for speleological prospecting in the field. In this study, the prediction of the factors involved in the development of iron formation caves was evaluated producing a map of susceptibility in a GIS environment using fuzzy logic and an analytical hierarchic process (AHP). Therefore, the variables: iron oxide ratio, slope gradient, normalized difference vegetation index (NDVI), plan curvature, profile curvature, lineament intensity, and height above the nearest drainage (HAND) were selected. These variables were obtained by processing of geospatial data from a region of the Gandarela Range (Minas Gerais, Brazil). The fuzzy logic and AHP techniques were applied, and for the validation of the results, a previously surveyed cave inventory was used. The results showed satisfactory performance of the map produced in predicting areas favorable to the occurrence of iron formation caves, presenting an area under the receiver operating characteristic (ROC) curve of approximately 0.85, which indicates a high prediction rate and validates the proposed method. Such results demonstrate that this susceptibility map was reliable and that the set of criteria and weights used were suitable for mapping areas favorable for speleological prospecting.

Ferric-ferrous iron oxide ratios: Effect on crystallization pressure of granites estimated by Qtz-geobarometry

This study uses selected granite samples to evaluate the effect of redox conditions expressed as molar ferric-ferrous iron oxide ratio, Fe3+# [=Fe2O3/(FeO + Fe2O3)], on estimation of crystallization pressure (P) of granites using the Qtz-geobarometer. The results indicate that calculated P decreases significantly with increasing Fe3+# for calc-alkaline, metaluminous and peraluminous granites, but much less so for peralkaline and evolved granites. For a calc-alkaline, metaluminous or peraluminous granite sample of a fixed silica content, the calculated P values are a polynomial function of Fe3+#. The difference in P for Fe3+# between 0.1 (reduced) and 1.0 (oxidized) is as high as 437 MPa (or 4.37 kb), much higher than the uncertainty of the geobarometer. However, peralkaline and evolved granite samples display much less difference in P for Fe3+# between 0.1 and 1.0, essentially within the uncertainty. Therefore, redox conditions need to be considered when using Qtz-geobarometry to estimate P of calc-alkaline, metaluminous and peraluminous granites, particularly those bearing hornblende with relatively low silica contents, but such corrections may not be required for peralkaline and highly evolved granites.A practical procedure is proposed to calculate Fe3+# from whole-rock geochemical data to obtain improved P estimation, and a Microsoft Excel spreadsheet program is provided. In addition to constraining the emplacement depth, the program can also be used to evaluate the redox conditions using ferric-ferrous iron oxide ratios, both of which are important for mineralization associated with granite intrusions.

Micro-structure and optical spectroscopy of PVA/iron oxide polymer nanocomposites

The current research aims to synthesize and investigate the optical spectroscopy of PVA/iron polymer nanocomposites. The polymer films prepared via dissolving powders and characterized by XRD, SEM and optical spectroscopy measurements. The analysis of XRD depicted the cubic crystal structure of γ-Fe2O3 nanoparticles with average crystallite size 42.40nm. SEM monographs provided the complete interaction between γ-Fe2O3 and PVA polymer matrix. Optical absorption measurements of the PVA/iron oxide polymer nanocomposites displayed a red shift of the absorption edge with the iron oxide content. The optical indirect energy gaps estimated from optical absorption data decreased from 5.0 to 2.4eV with the iron oxide content. In addition, the refractive index values enhanced with the concentration of iron oxide. Comparing the energy gap values estimated from Tauc's formula and optical dielectric loss function confirmed the major electronic transitions as direct allowed. The fluorescence spectra of the PVA/iron polymer nanocomposites displayed emission peaks centered at 421, 451 and 469nm and the intensity reduced with the ratio of iron oxide.

Slope Gradient Controls Soil Thickness and Chemical Weathering in Subtropical Brazil: Understanding Rates and Timescales of Regional Soilscape Evolution Through a Combination of Field Data and Modeling

AbstractSoil thickness and residence time are regulated by a dynamic interplay between soil formation and lateral transport of soil particles and solutes. To unravel this interplay and infer patterns and rates of chemical weathering, soil physical and chemical properties can be used. Here, we present an integrated approach combining numerical modeling with field measurements to assess the impact of slope gradient on soil thickness and chemical weathering at a regional scale. We first perform a number of synthetic model runs simulating soil formation, weathering, erosion, and deposition, which show that soil thickness and weathering degree decline with increasing slope gradient. We then evaluate how those functional relationships compare to soil‐landscape data observed in the field. Soils are sampled at 100 midslope positions under varying slope gradient. The weathering degree is determined using three chemical weathering indices: ratio of iron oxides to total iron (Fed/Fet), chemical index of alteration (CIA), and total reserve in bases (TRB). Finally, we calibrate the Be2D model to our field data to constrain soil residence times and chemical weathering rates. The modeled weathering rates decrease with increasing soil residence time and decreasing slope gradient. The application of the soil‐landscape evolution model in Southern Brazil shows that weathering rates can vary up to 2 orders of magnitude and depend on hillslope gradient. Notwithstanding model limitations and data uncertainties, we demonstrate the potential of an integrated approach, where field data and numerical modeling are integrated to unravel the timescale of soil weathering along transport over hillslopes.

Effect of magnetite transformations on degradation efficiency of cerium dioxide-magnetite composite

Present investigations are focused on synthesis of magnetite/cerium dioxide reactive sorbents in various weight ratios of components and their characterization of chemical and magnetic properties. The morphology and changes in magnetic transformations in dependence on composition are followed by electron microscopy, X-ray diffraction, Mössbauer spectroscopy and magnetic measurements at room and low temperatures. Degradation efficiency is evaluated from a decomposition of the organophosphorus pesticide parathion methyl using prepared reactive sorbents. The experimental results reveal that the degradation efficiency, expressed by rate constant (mol/h) in dependence on amount of cerium dioxide content (vol.%), is independent on kind of iron oxide but increases with cerium dioxide content. On the contrary, saturation and remanent magnetizations are highly sensitive to relative ratio of iron oxides; magnetite, maghemite and hematite, originating from the initial magnetite transformations in dependence on sample composition.

Synthesis and characterization of magnetic sponge nanocomposite for cleaning archeological lime stones

Sponge-like magnetic nanocomposite consisting of magnetic nanoparticles Fe3O4 associated with a polyacrylamide gel matrix has been synthesized and can be used as an active nanomagnetic container for water-based detergent formulations as oil-in-water microemulsions. This prepared system was applied for gentle, controlled and selective cleaning of the archeological lime stone from iron rust and undesired residues. The embedding of magnetic nanoparticles Fe3O4 into the gel matrix was proved by IR spectroscopy and scanning electron microscopy SEM, showing that the magnetic nanoparticles were successfully embedded in the gel structure. The lime stone samples with corrosion stains were cleaned using the prepared magnetic sponge nanocomposite carrying the water based detergent, followed by characterization of the surface of the samples before and after treatment through SEM, X- ray Florescence XRF and colour measurements. SEM images confirmed the full removal of stains. XRF analysis detected decreasing of the iron oxide ratio from 10.62% to 0.26% after cleaning. The colour measurement recorded the colour changes of the samples' surface before applying of the iron rust and after treatment with the prepared cleaning system and it was that the colour changes were with acceptable ratio and cannot be visible by naked eye.

Effects of calcium ferrite slag on dephosphorization of hot metal during pretreatment in the BOF converter

A study was carried out to examine effects of calcium ferrite slag on dephosphorization of hot metal in the steelmaking BOF, with aims to pick up the speed of slag-forming, increase the slag dumping rate. Laboratory tests using a resistance furnace were performed to examine melting characteristics of calcium ferrite pellets, designed with the optimum ratio of iron oxides (total Fe 55%) to CaO of 3:1. The pellets were put in crucibles with furnace temperature held in the range of 1250–1350 °C for 10 min. The results showed that the melting of pellets was nearly completed at 1250°C and main mineral phases, detected by XRD, in the melted samples were CaO•Fe2O3 and 2CaO•Fe2O3. Based on results of the laboratory tests, experiments of full scale were performed using a converter of 120t, charging the hot metal with C 3.46–6.81%, Si 0.1–1.16%, Mn 0.12–0.30%, P 0.10–0.18%, S 0.017–0.13% and temperature of 1234–1430 °C. For the 13 test heats with 6 min of oxygen blowing, the rate of dephosphorization and phosphorus distribution ratio reached to 50–60% and 55.9, respectively, when the calcium ferrite pellets were charged. Averaged slag basicity 1.5–2.0, slag melting point 1280–1310℃, slag viscosity 0.5 pa.s were obtained for the BOF heats adding the calcium ferrite pellet, which ensured the slag foaming height controlled at 2.5–3.0 m during the early stages of the blow. Using above smelting process has increased the rate of slag dumping controlled at 50–70% and enhanced the rate of hot metal dephosphorization over 90%.

Physico-mechanical characterization of sintered glass-ceramics fabricated from iron oxide added waste soda lime glasses

This study aims to highlight the sinter-crystallization behavior and mechanical properties of the glass-ceramics prepared from modified soda lime waste glass. To this purpose, different amounts of iron oxide (Fe2O3) (5-15 weight ratio) were added to the soda lime waste glass. The obtained mixtures were then melted and transformed into the glass-ceramics after a one-step sinter/crystallization heat treatment. According to the obtained results, wollastonite (CaO.SiO2) and diopside (CaO.MgO.2SiO2) precipitated in the sintered specimens, simultaneously or separately, depending on the content of iron oxide. On the basis of dilatometry analysis and the Huggins-Sun measurements, addition of iron oxide into the glass composition and its further addition increased the number of non-bridging oxygens and consequently decreased the glass viscosity. The glass-ceramics sintered at 850 °C showed the negligible water absorption and considerable content of the precipitated crystalline phases. Among them, the glass-ceramic Base-10F (containing 10 weight ratio of iron oxide) was considered as the most promising specimen due to its high mechanical strength (96 MPa), Vickers micro-hardness (491 VHN) and near zero water absorption.

Automated Seasonal Separation of Mine and Non Mine Water Bodies From Landsat 8 OLI/TIRS Using Clay Mineral and Iron Oxide Ratio

Opencast mining has huge effects on water pollution for several reasons. Fresh water is heavily used to process ore. Mine effluent and seepage from various mine related areas especially tailing reservoir, increase water pollution immensely. Monitoring and classification of mine water bodies, which have such environmental impacts, have several research challenges. In the past, land cover classification of a mining region detects mine and non mine water bodies simultaneously. Water bodies inside surface mines have different characteristics from other water bodies. In this paper, a novel method has been proposed to differentiate mine and non mine water bodies over the seasons, which does not require to set a threshold value manually. Here, water body regions are detected over the entire scene by any classical water body detection algorithm. Further, each water body is treated independently, and reflectance properties of a bounding box over each water body region are analyzed. In the past, there were efforts to use clay mineral ratio (CLM) to separate mine and non mine water bodies. In this paper, it has been observed that iron oxide ratio (IO) can also separate mine and non mine water bodies. The accuracy is observed to increase, if the difference of CLM and IO is used for segregation. The proposed algorithm separates these regions by taking into account seasonal variations. Means of differences of CLM and IO of each bounding box have been clustered using K -means clustering algorithm. The automation provides precision and recall for mine, and non mine water bodies as $[77.83\%,76.55\%]$ and $[75.18\%,75.84\%]$ , respectively, using ground truths from high-definition Google Earth images.

Synthesis of Fe2O3/biochar nanocomposites by microwave method for magnetic energy-storage concentration cells

Magnetic nanocomposites have attracted increasing attention due to its widely applications in different areas in recent years. The conventional synthesis of magnetic nanocomposites is usually based on high temperature annealing technique from biomass. In this paper, a microwave method has been developed to prepare iron oxide based magnetic nanocomposites using ferric acetylacetonate ((Fe(acac)3), oleylamine (OAm), oleic acid (OA), and commercial biochar. The reaction is completed in several minutes. Composite structure composed of γ-Fe2O3 nanoparticles with the size of 6–17 nm and biochar is confirmed by TEM, SEM EDX element mapping images. The iron oxide size can be controlled by the microwave time and the ligand ratio. Magnetic properties of the magnetic nanocomposites are studied. The application of the prepared magnetic nanocomposites in magnetic concentration cells are tested with different magnetic fields and different biochar to iron oxide ratios. The method developed in this work on magnetic nanocomposite synthesis will not only facilitate the research progress of magnetic nanocomposite synthesis but also provide an alternative technique to be used in magnetic concentration cells.

Facile and greener hydrothermal honey-based synthesis of Fe3 O 4 /Au core/shell nanoparticles for drug delivery applications.

In the present research, we report a greener, faster, and low-cost synthesis of gold-coated iron oxide nanoparticles (Fe3 O4 /Au-NPs) by different ratios (1:1, 2:1, and 3:1 molar ratio) of iron oxide and gold with natural honey (0.5% w/v) under hydrothermal conditions for 20 minutes. Honey was used as the reducing and stabilizing agent, respectively. The nanoparticles were characterized by X-ray diffraction (XRD), UV-visible spectroscopy, field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDXS), transmission electron microscopy (TEM), selected area electron diffraction (SAED), vibrating sample magnetometer (VSM), and fourier transformed infrared spectroscopy (FT-IR). The XRD analysis indicated the presence of Fe3 O4 /Au-NPs, while the TEM images showed the formation of Fe3 O4 /Au-NPs with diameter range between 3.49 nm and 4.11 nm. The VSM study demonstrated that the magnetic properties were decreased in the Fe3 O4 /Au-NPs compared with the Fe3 O4 -NPs. The cytotoxicity threshold of Fe3 O4 /Au-NPs in the WEHI164 cells was determined by using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. It was demonstrated no significant toxicity in higher concentration up to 140.0 ppm which can become the main candidates for biological and biomedical applications, such as drug delivery.

Coexisting arsenate and arsenite adsorption from water using porous pellet adsorbent: Optimization by response surface methodology

Mesoporous pellet adsorbent developed from mixing at an appropriate ratio of natural clay, iron oxide, iron powder, and rice bran was used to investigate the optimization process of batch adsorption parameters for treating aqueous solution coexisting with arsenate and arsenite. Central composite design under response surface methodology was applied for optimizing and observing both individual and interactive effects of four main influential adsorption factors such as contact time (24-72 h), initial solution pH (3-11), adsorbent dosage (0-20 g/L) and initial adsorbate concentration (0.25-4.25 mg/L). Analysis of variance suggested that experimental data were better fitted by the quadratic model with the values of regression coefficient and adjusted regression coefficient higher than 95%. The model accuracy was supported by the correlation plot of actual and predicted adsorption efficiency data and the residual plots. The Pareto analysis suggested that initial solution pH, initial adsorbate concentration, and adsorbent dosage had greater cumulative effects on the removal system by contributing the percentage effect of 47.69%, 37.07% and 14.26%, respectively. The optimum values of contact time, initial solution pH, adsorbent dosage and initial adsorbate concentration were 52 h, 7, 10 g/L and 0.5 mg/L, respectively. The adsorption efficiency of coexisting arsenate and arsenite solution onto the new developed adsorbent was over 99% under the optimized experimental condition.

Multifunctional Composites Based on Graphite Oxide, Doxorubicin, and Magnetic Nanoparticles for Targeted Drug Delivery

This work is dedicated to the synthesis of a GO@Fe3O4@DOX multifunctional nanocomposite composed of graphite oxide, superparamagnetic iron oxide nanoparticles, and the drug doxorubicin. The final product combines double magnetic and molecular targeting to tumor tissues. Superparamagnetic Fe3O4 nanoparticles are first chemically deposited onto a surface of graphite oxide (GO) with the acquisition of a double GO@Fe3O4 composite. The material is then bound with the antitumor drug doxorubicin. The morphology, phase composition, and magnetic and optical properties of synthesized samples are characterized via thermal gravimetry, X-ray diffraction, magnetic susceptibility measurements, transmission electron microscopy, and via UV-visible and Raman spectroscopy. The optimal ratio of graphite oxide, iron oxide, and doxorubicin for the creation of a potential precursor of the new drug is established. The presence of doxorubicin and iron oxide in the composite is confirmed, making it possible to use an external magnetic field for targeted drug delivery towards the affected tissues. It is also shown that the composite retains its stability for a month in solutions with physiological pH values.

Iron Oxide to Mitigate Hydrogen Sulfide Gas Release from Gypsum-Bedded Dairy Manure Storages

Abstract. To mitigate noxious hydrogen sulfide (H2S) gas release that has been observed from gypsum-laden dairy manure, three additives were studied in sequential investigations. Three trials with specific aims were conducted using experimental vessels containing 15 kg of dairy manure each. Trial 1 investigated two additives: iron oxide (specifically, iron oxide-hydroxide, FeOOH) and a proprietary gypsum-lime based product (DriMatt). Trial 2 investigated effective ratios of gypsum to iron oxide and a modified DriMatt additive, and trial 3 evaluated iron oxide at the most effective ratio. Manure agitation events were monitored in the first two trials, while gas releases were continuously monitored in trial 3 during and between agitations. Hydrogen sulfide concentrations were captured using electrochemical sensors or a Fourier transfer infrared (FTIR) gas analyzer assembly over an incubation period of two months for the first two trials and over 40 days for the third trial. Additionally, nutrient analyses were performed for each trial. Extremely high concentrations of H2S were observed during most manure agitation events (500 to 8000 ppm), while minimum releases (<10 ppm) were found when samples were static. Means of maximum concentrations of H2S were compared among treatments in each trial. Statistical tests showed that adding iron oxide to gypsum-laden manure reduced H2S production by an average of 94% compared to treatments without iron oxide. With a 1:1 molar ratio of iron oxide to gypsum, the level of H2S released was diminished to as low as the control manure (without gypsum). Therefore, iron oxide is a promising additive to mitigate H2S production in gypsum-laden dairy manure during agitation events. Keywords: Additive, Dairy, Gas, Gypsum bedding, Hydrogen sulfide, Iron oxide, Manure, Safety, Storage.

Immobilization of Acidithiobacillus ferrooxidans on cotton gauze for biological oxidation of ferrous ions in a batch bioreactor.

The ability of Acidithiobacillus ferrooxidans to oxidize ferrous iron has been extensively studied in bioleaching to recover metal resources. Although immobilization of A. ferrooxidans is of great importance to achieve high bioleaching performance in practical application, the reported approaches of immobilization of A. ferrooxidans are still limited. This paper is attempting to develop a novel method to immobilize A. ferrooxidans by a less-costly effective carrier from zeolite, activated carbon, and cotton gauze. The results showed that cotton gauze was the most suitable carrier to immobilize A. ferrooxidans cells in comparison with zeolite and activated carbon. Acidithiobacillus ferrooxidans immobilized on the cotton gauze by gravity dehydration could achieve an average ferrous iron oxidation rate of 0.73 g/(L·h). Furthermore, the ferrous iron oxidation ratio attained in the bioreactor under batch operation was maintained above 97.83%. All results indicated that cotton gauze could be an efficient carrier for immobilizing A. ferrooxidans cells for the biooxidation of ferrous ions.

Wüstite-based catalyst for ammonia synthesis: Structure, property and performance

Fused iron catalyst is an active and classical catalyst both for ammonia synthesis and Fischer-Tropsch synthesis which are two typical industrial processes. As it is of significance to catalysis science as well as its importance to industry, fused iron catalyst is an ideal model system for heterogeneous catalysis research. However, the precursors of fused iron catalysts were confined to Fe3O4 in the most studies. The discovery of wüstite (Fe1-xO) based catalyst is a key innovation for fused iron catalyst which necessitates the further research to obtain deeper insight into this novel catalyst.This paper summarized three major scientific issues involved in the development of wüstite based catalyst, namely, the physicochemical properties, characteristics of wüstite, as well as the mechanism leading to the high activity. Based on this novel catalyst, new concepts and opinions were proposed, and the insights and principles obtained are as follow. Hump like activity trend of reduced catalyst was first obtained with varying of Fe2+/Fe3+ in the catalyst precursor. Molecular ratio of iron oxides, single phase theory and structure of active sites were suggested to elucidate the high activity of wüstite based catalyst. In addition, new concepts and opinions such as the disproportionation of metastable wüstite and its inhibition, matching of promoters with the structural characteristics of wüstite, synergy between acidic site and basic site on the surface of catalyst, role of Al2O3 in the re-structuring of catalyst surface, mechanism of competitive reduction, strong H2 adsorption, active sites, micro-structure of α-Fe and the essence of high activity were proposed to bring light to the structure-activity relationship forming the theory system with single phase theory as the kernel of wüstite catalyst. These regularities and the theory system significantly promoted and enriched the scientific knowledge of fused iron catalyst. It is unexpected that a knowledge based improvement of a catalyst would have a strong effect on other fields of catalysis research.