Partial Pressure Range Research Articles

Iron activity measurements and spinel-slag equilibria in alumina-bearing iron silicate slags

Alumina is a common substance deporting in copper smelting slags when various secondary copper fractions, e.g. e-scrap or WEEE, are used as feedstock as such or along with primary sulphide concentrates. Properties of iron-silicate slags at high alumina concentrations, in the iron-alumina spinel saturation, have been studied at 1300 °C by a high temperature equilibration-quenching method combined with EPMA (electron probe microanalysis) phase composition data from the polished sections. The equilibrations were performed in fixed oxygen activity with platinum or palladium powder, which dissolved iron from the slag and generated a heterogeneous equilibrium system, characterised by the general equilibrium criterium in isothermal and isobaric conditions, as.μalloy(Fe) = μslag(Fe) = μspinel(Fe).This criterium was used for measuring experimentally iron activities of molten silicate slags. The locations of the spinel-liquid slag tie-lines were also determined in the oxygen partial pressure range of 10−6–10−10 atm. A comparison with the recent critical thermodynamic assessments of the Fe–O–Al2O3 system indicates that the iron-alumina spinel-corundum phase boundary in silica-containing systems as a function of oxygen partial pressure is too steep and thus the assessed databases do not match with the experimental data of this study. The liquid slag domain from silica to iron oxide saturation is also smaller than expected earlier, as the spinel primary phase boundary locates at higher silica concentrations than e.g. obtained in the assessments of the Mtox database.

Towards a generalized carbonation kinetic model for CaO-based materials using a modified random pore model

Calcium looping is attracting interest for post-combustion CO2 capture, hydrogen production and energy storage applications. Deactivation of the materials during cycling is a major drawback that has pushed towards the synthesis of CaO-based sorbents with high stability. The present work aims at developing a generalized kinetic model for the carbonation reaction of CaO-based materials composed not only of pristine CaO but in mixture with inert compounds as well. For that purpose, four different materials were used, namely a lime, a calcined dolomite and two synthetic materials containing ZrO2 and MgO as inert phases. The carbonation reaction was studied in a fixed-bed reactor apparatus and in a wide range of temperatures and CO2 partial pressures. A simple modification of the random pore model’s parameters was applied to account also for the inert phase contribution to the materials’ properties. The modified model described well the experimental results for the fast regime of carbonation reaction of all tested materials. Carbonation is a first order reaction with respect to CO2 in the gas phase with an activation energy of 22.1 ± 5.9 kJ/mol. The developed kinetic model can be applied to predict the carbonation rate of CaO-based materials regardless the type and percentage of the contained inert phase.

Oxygen adsorption of molten Ag[sbnd]Cu eutectic alloy and its associated surface modification

The surface tension of liquid AgCu eutectic alloy has been measured in a wide range of oxygen partial pressures using two different methods: the constrained drop method and the electromagnetic levitation method. In order to investigate the influence of oxygen potential on the surface tension of the Ag40Cu (at.%) eutectic alloy, the oxygen partial pressure was varied between 8.62 × 10−15 and 2.42 Pa. At low oxygen partial pressure, the surface tension of the AgCu eutectic alloy measured in the temperature range of 1223–1476 K, shows temperature dependence in a good agreement with previously reported results. At higher oxygen partial pressures, the decrease in surface tension is more pronounced and the oxygen adsorption on the surface accordingly increases. Moreover, at high oxygen partial pressure, the oxygen adsorption on the AgCu eutectic alloy was found to be far greater than the expected saturation limit taking into account the theoretically calculated surface concentration of Cu in the AgCu eutectic alloy and the surface excess of oxygen on the molten Cu at saturation. This phenomenon can be explained with a model where the surface of the AgCu eutectic alloy undergoes Cu-substitution at the Ag sites during the oxygen adsorption process.

Advanced interpretation of CO2 adsorption thermodynamics onto porous solids by statistical physics formalism

Three different activated carbons, namely Aquacarb 207EA (AQ), Organosorb-10 (OR-10) and Organosorb-10AA (OR10-AA) are investigated for carbon dioxide (CO2) adsorption from simulated flue-gas, which is one of the promising approaches to mitigate global warming. Adsorption isotherms are determined at three temperatures (303 K, 323 K and 353 K) and over a wide CO2 partial pressure range (0.03–0.3 bar), in a dynamic lab-scale experimental apparatus. Experimental results show that CO2 adsorption capacity is affected by micropore volume, while the chemical properties (mainly pHPZC and acid functional groups) seem to play a secondary role. The CO2 adsorption isotherms are interpreted by three advanced models derived from statistical physics. The selected model allows retrieving useful information about the sorption process by determining the number of captured CO2 molecules per site (nms), the density of receptor sites (Dsr), the total number of adsorbed layers (Nc) and the energetic parameters (−ε1) and (−ε2). The modeling analysis suggests that the captured CO2 molecules aggregate upon adsorption and are anchored with a perpendicular position on the adsorbents surface. The total numbers of adsorbed layers range from 3.12 to 5.56 for the three adsorption systems, and the value increases with temperature as if the diminution of active sites available for CO2 capture on adsorbent surface was partially counterbalanced by a multilayer adsorption mechanism. The adsorption energies retrieved from data analysis are in the range from −11.39 to −21.10 kJ/mol, confirming that, for the investigated systems, adsorption is exothermic and based on physisorption. Finally, the site energy distribution is also estimated to corroborate the surface heterogeneity and the physical nature of the adsorbate/adsorbent interactions.

Smart gas dosage by a peristaltic pump for reactive RF sputtering of composition spread combinatorial hafnium-oxy-nitride layers

Thin metal-oxy-nitride layers are widely used for wavelength selective optical coatings. We aimed to prepare composition spread metal-oxy-nitride combinatorial layers by reactive radiofrequency sputtering for a highly efficient characterization of their optical properties in a wide range of O/N ratios. Affinity of metals requires oxygen proportion, in the Ar-O-N plasma, be set orders of magnitude lower compared to nitrogen. The required low partial pressure range of oxygen was covered by a new concept self-regulating gas inlet assembly based on a peristaltic pump delivering gas from a finite volume vial. Accordingly, oxygen partial pressure was gradually decreasing from 8 × 10−5 mbar towards the base pressure of the chamber. It effected a continuous oxygen depletion and a transition of the deposited film from oxide to nitride. The suitability of our combinatorial method was proved by both energy dispersive spectrometry mapping and ellipsometry of the correlated refractive indices along a composition-spread HfON sample.

Ionic conductivity and thermal expansion of anion-deficient Sr11Mo4O23 perovskite

Transport properties of perovskite-type Sr11Mo4O23 and composite Sr11Mo4O23 - 1 wt% Al2O3 were studied at 400–1300 K in the oxygen partial pressure range from 0.21 down to 10−19 atm. The electromotive force and faradaic efficiency measurements, in combination with the energy-dispersive spectroscopy of the fractured electrochemical cells, unambiguously showed prevailing role of the oxygen ionic conductivity under oxidizing conditions. At temperatures above 600 K, protonic and cationic transport can be neglected. The oxygen ion transference numbers vary in the range of 0.95–1.00 at 973–1223 K. At temperatures lower than 550 K, the total conductivity of Sr11Mo4O23 - 1 wt% Al2O3 composite measured by impedance spectroscopy tends to increase in wet atmospheres, thus indicating that hydration and protonic transport become significant. Reducing oxygen partial pressure below 10−10–10−9 atm leads to a significant increase in the n-type electronic conduction. The average thermal expansion coefficients in oxidizing atmospheres are (14.3–15.0) × 10−6 K−1 at 340–740 K and (18.3–19.2) × 10−6 K−1 at 870–1370 K.

Phase equilibria in the Fe‐V‐O system near “FeO”‐V2O3 isopleth

AbstractPhase equilibria in the “FeO”‐V2O3 system from 1273 to 1808 K and in the range of oxygen partial pressure from 10−15 to 10−4 atm are investigated. High‐temperature quenching, XRD, SEM‐EDS, and DSC are used to determine the phase relations. Stable regions of (FeO)s.s., (V2O3)s.s., and spinel phases are considerably effected by the oxygen partial pressure, and structural models are proposed as (Fe2+, Fe3+, V2+)1‐xO, (V2+, V3+, V4+, Fe3+)2O3+x, and (Fe2+, Fe3+, V3+)(Fe2+, Fe3+, V3+, Va)2O4. Continuous solid solution FeV2O4‐Fe3O4 is formed. The nonstoichiometry of FeV2O4 is attributed to the appearance of vanadium vacancies for electroneutrality due to the oxidation of Fe2+. The standard Gibbs energy of formation for FeV2O4 and component activities in FeV2O4‐Fe3O4 solid solution at 1623 and 1773 K are derived based on the equilibrium oxygen partial pressure. The cation distribution in FeV2O4 at different temperatures is obtained according to site preference energy.

The pH dependency of the boron isotopic composition of diatom opal (<i>Thalassiosira weissflogii</i>)

Abstract. The high-latitude oceans are key areas of carbon and heat exchange between the atmosphere and the ocean. As such, they are a focus of both modern oceanographic and palaeoclimate research. However, most palaeoclimate proxies that could provide a long-term perspective are based on calcareous organisms, such as foraminifera, that are scarce or entirely absent in deep-sea sediments south of 50∘ S in the Southern Ocean and north of 40∘ N in the North Pacific. As a result, proxies need to be developed for the opal-based organisms (e.g. diatoms) found at these high latitudes, which dominate the biogenic sediments recovered from these regions. Here we present a method for the analysis of the boron (B) content and isotopic composition (δ11B) of diatom opal. We apply it for the first time to evaluate the relationship between seawater pH, δ11B and B concentration ([B]) in the frustules of the diatom Thalassiosira weissflogii, cultured across a range of carbon dioxide partial pressure (pCO2) and pH values. In agreement with existing data, we find that the [B] of the cultured diatom frustules increases with increasing pH (Mejía et al., 2013). δ11B shows a relatively well defined negative trend with increasing pH, completely distinct from any other biomineral previously measured. This relationship not only has implications for the magnitude of the isotopic fractionation that occurs during boron incorporation into opal, but also allows us to explore the potential of the boron-based proxies for palaeo-pH and palaeo-CO2 reconstruction in high-latitude marine sediments that have, up until now, eluded study due to the lack of suitable carbonate material.

Measurements and modeling of vapor liquid equilibrium of CO2 in amine activated imidazolium ionic liquid solvents

The mean surface temperature has increased considerably over the past few decades primarily due to the huge contribution of CO2, a greenhouse gas. Hence, the reduction of CO2 majorly from the point sources of emission has been a thrust domain of research. This work reports the measurements and modeling of CO2 solubility in newly proposed aqueous solvent blends of 1-butyl-3-methyl-imidazolium acetate ([bmim] [Ac]) and amine activators. Various amine activators viz. 1-(2-aminoethyl) piperazine (AEP) and bis (3-aminopropyl) amine (APA) have been employed in aqueous [bmim] [Ac] over the wide operating temperature and CO2 partial pressure range of (303.15˗323.15) K and (1–390) kPa, respectively. Along with this, qualitative 13C NMR and FTIR analysis have been also performed to assess the proposed reaction scheme. The experimental vapor liquid equilibrium data (VLE) were modeled by modified Kent-Eisenberg equilibrium model including the gas phase non-ideality and Feed forward neural network model. The equilibrium constants associated with [bmim] [Ac], AEP and APA deprotonation, and carbamate formation reactions are regressed to fit the experimental CO2 solubility data. Various important thermophysical properties such as surface tension, viscosity, sound velocity, refractive index and density have also been measured and correlated using established as well as newly proposed models.

Hypothesis for How Hyperoxic Therapy May Facilitate Effective Biologic “Correction” of Autism Spectrum Disorders

The existence of morphological and physiological abnormalities in the autism brain was recognized in the 1960s. Today, in view of many such extensive pathological findings, it has been stated and reiterated that autism spectrum disorder (ASD) has a biological rather than a psychological basis. Despite this, other than pharmacologic agents that address limited aspects of symptoms, development of therapies for ASD has been focused primarily on psychosocial measures based on principles of applied behavioral analysis. With this latter approach, however, a generally accepted intervention or group of interventions which consistently and comprehensively address the needs of most individuals with autism in a cost-effective and time-efficient manner has not yet been established. While examining reports of another medical intervention, hyperbaric oxygen therapy with inspired oxygen partial pressures typically ranging from 0.31 to 1.5 atm. for neurological conditions such as autism, we wondered if increased oxygen partial pressure, alone, without the encumbrance, risk, and cost of hyperbaric exposure would produce useful clinical outcomes. In five pilot cases, therefore, a normobaric hyperoxic treatment we have called Microbaric® Oxygen Therapy (MBO2) was administered to preteen and teenage boys with ASD. All results were positive, some remarkably so, and addressed the full scope of the subject’s symptoms. Also, follow-up for over seven years in several cases suggests these outcomes are permanent. To help encourage controlled research on MBO2 for ASD, we have laid out a hypothetical basis for its efficacy using our own pilot study outcomes and observations together with relevant information from the scientific literature, the most important of which we believe relates to regional brain hypoperfusion, neuroinflammation, and angiogenesis. In investigating research on angiogenesis and autism, we found a 2016 publication concerning autism postmortem brains which identified persistent splitting angiogenesis, as opposed to sprouting angiogenesis, in some regions of all donated autism brains and in none of the age-matched control brains. With this finding and the established effects of hyperoxia on angiogenesis and inflammation, we have developed a hypothesis that potentially accounts for regional cerebral hypoperfusion; delayed, progressive onset of ASD over the early years of life; increased perfusion in hypoperfused regions of the brain following hyperoxic therapy; the broad range of oxygen partial pressures that seem to have impact; permanent reduction in the symptoms of autism resulting from MBO2; and perhaps, a time-efficient and cost-effective method of treating autism that will help upgrade the long-term prognosis for affected individuals.

Study of water adsorption on EDTA dealuminated zeolite Y

Abstract Zeolite Y was synthesized and modified with EDTA dealumination procedure. The modified zeolites were analyzed by X-ray diffraction, X-ray absorption spectroscopy, chemical analysis and water adsorption measurements. We demonstrated that dealumination with bulk organic acid such as EDTA is able to reduce the original intense water affinity. Furthermore, it was found that dealumination with EDTA, in contrast with steaming and HCl dealumination, provides fully controllable, predictable and secure process of Al removal from the zeolites’ frameworks. The shift of the adsorption isotherm in the low partial pressure range represents an interesting result for adsorption-based applications.

Analysis of equilibrium CO 2 solubility in aqueous APDA and its potential blends with AMP / MDEA for postcombustion CO 2 capture

The utility of polyamine-based solvent-activators for the possible application in postcombustion CO2 capture technology has drawn considerable attention recently owing to its higher loading capacity as well as superior kinetics. The current work involves a comprehensive experimental cum theoretical investigation on the equilibrium solubility of CO2 pertaining to aqueous N-(3-aminopropyl)-1,3-propanediamine and its blends with N-methyldiethanolamine and 2-amino-2-methyl-1-propanol. The analysis was conducted within the operating temperature and CO2 partial pressure range of 303.2-323.2 K and 2-200 kPa, respectively. Two different mathematical models based on nonrigorous approaches such as equilibrium based modified Kent-Eisenberg (KE) model and a multilayer feedforward neural network model have been developed to correlate the CO2 solubility data over a wide range of experimental conditions. Both the model predictions are well-validated with the experimental results. The reaction scheme as well as the prevalence of important reaction products was further confirmed with qualitative 13C NMR as well as ATR-FTIR analysis. Apart from these some of the important thermally induced transport properties viz, density, viscosity, and surface tension of the aqueous single and blended systems were measured and correlated with various consistent empirical models such as Redlich-Kister and Grunberg-Nissan model while surface tension data are modeled using temperature-based multiple linear regression technique.

Calcium deactivation during the char-CO2 gasification and its influence on determining the apparent reaction order

CO2 gasification reactivity and the apparent reaction order of chars derived from calcium-rich and calcium-poor lignites have been investigated via thermogravimetry analysis (TGA) in the temperature range from 825 to 900 °C and the CO2 partial pressure range from 0.015 to 0.1 MPa. Chemical forms of Ca species in raw and partially-gasified chars are characterized via X-ray diffraction (XRD). Results indicate that CaO carbonation during the char-CO2 gasification is a direct cause of Ca deactivation, which shows temperature and pressure dependence and follows the equilibrium regularity of CO2 over CaCO3 at different temperatures. The Ca in lignite chars plays a catalytic role at the CO2 partial pressures below 0.1 MPa at temperatures of 875 and 900 °C, while Ca deactivation occurred when the CO2 partial pressures are above 0.05 MPa at 825 °C and above 0.075 MPa at 850 °C. On the one hand, this fact suggests that Ca deactivation exhibits temperature and pressure dependence. On the other hand, char gasification may follow different catalytic mechanisms in the CO2 partial pressure range from 0.015 to 0.1 MPa, from which the determination of the apparent reaction order is less reasonable. The coefficient of determination (R2) reflects the goodness of r-PCO2 fitting, which becomes poor with the increase of CO2 partial pressure when CaO carbonation takes place. Choosing an appropriate CO2 pressure range for a given temperature is necessary to eliminate the effects of Ca deactivation on the determination of gasification reactivity and the apparent reaction order. The apparent reaction order of chars determined at conditions without Ca deactivation increases as the gasification temperature decreases.

Absence of superconductivity in Nd0.8Sr0.2NiOx thin films without chemical reduction

The recently reported superconductivity 9-15 K in Nd0.8Sr0.2NiO2/SrTiO3 heterostructures that were fabricated by a soft-chemical topotactic reduction approach based on precursor Nd0.8Sr0.2NiO3 thin films deposited on SrTiO3 substrates, has excited an immediate surge of research interest. To explore an alternative physical path instead of chemical reduction for realizing superconductivity in this compound, using pulsed laser deposition, we systematically fabricated 63 Nd0.8Sr0.2NiOx (NSNO) thin films at a wide range of oxygen partial pressures on various different oxide substrates. Transport measurements did not find any signature of superconductivity in all the 63 thin-film samples. With reducing the oxygen content in the NSNO films by lowering the deposition oxygen pressure, the NSNO films are getting more resistive and finally become insulating. Furthermore, we tried to cap a 20-nm-thick amorphous LaAlO3 layer on a Nd0.8Sr0.2NiO3 thin film deposited at a high oxygen pressure of 150 mTorr to create oxygen vacancies on its surface and did not succeed in higher conductivity either. Our experimental results together with the recent report on the absence of superconductivity in synthesized bulk Nd0.8Sr0.2NiO2 crystals suggest that the chemical reduction approach could be unique for yielding superconductivity in NSNO/SrTiO3 heterostructures. However, SrTiO3 substrates could be reduced to generate oxygen vacancies during the chemical reduction process as well, which may thus partially contribute to conductivity.

A UHV standard with option to be used as partial pressure standard

Partial pressure measurement has become indispensable for many applications and contributes to the complete characterization of a vacuum system. In this work, an ultrahigh vacuum (UHV) standard was established for calibrating partial pressure analyzers as a partial pressure standard, and a new method was introduced to generate standard partial pressures, which was named ‘the dynamic expansion method based on static expansion vacuum standard injection mode’. The method can produce standard partial pressures in the range from 10–5 Pa to 10–10 Pa. The relative standard uncertainty budgets of generated partial pressures (k = 1) were in the range from 2.8% up to 5.0% from 10–5 Pa to 10–9 Pa for nitrogen. Employing this method, the sensitivity calibrations of quadrupole mass spectrometry (QMS) were performed in the partial pressure range of 8.62 × 10−5 Pa to 1.51 × 10−10 Pa with single inert He, Ar, and Kr gas in secondary electron multiplier (SEM) mode. Similarly, the calibrations were carried out using active gases (H2, CH4, N2, O2, and CO2) in the range 8.56 × 10−5 Pa to 1.50 × 10−9 Pa. Additionally, the SEM gains were calibrated for these high-purity gases, on the basis of SEM gain coefficients. QMS sensitivities equivalent to Faraday cup mode were attained, and it was found that the results were approximately consistent with those of previous studies. The data were also in agreement with our theoretical calculation values excluding CH4.

The Influence of Temperature on the Gas/Slag/Matte/Spinel Equilibria in the Cu-Fe-O-S-Si System at Fixed P(SO2) = 0.25 atm

Equilibria between gas/slag/matte/spinel phases in the Cu-Fe-O-S-Si system have been experimentally studied at 1523 K (1250 °C), P(SO2) = 0.25 atm, and a range of oxygen partial pressures. The experimental technique involved high temperature equilibration using spinel substrates in controlled gas atmospheres (CO/CO2/SO2/Ar), rapid quenching of the equilibrated phases, and direct measurement of phase compositions using Electron Probe X-ray Microanalysis. The influence of temperature on the gas/slag/matte/spinel equilibria has been analyzed. Comparisons with previous studies on the gas/slag/matte/tridymite equilibria and the most recent thermodynamic database have been provided. This is the first systematic study on the influence of temperature on the gas/slag/matte/spinel equilibria in the Cu-Fe-O-S-Si system at P(SO2) = 0.25 atm.

Behavior of Battery Metals Lithium, Cobalt, Manganese and Lanthanum in Black Copper Smelting

Recycling of metals from different waste streams must be increased in the near future for securing the availability of metals that are critical for high-tech applications, such as batteries for e-mobility. Black copper smelting is a flexible recycling route for many different types of scrap, including Waste Electrical and Electronic Equipment (WEEE) and some end-of-life energy storage materials. Fundamental thermodynamic data about the behavior of battery metals and the effect of slag additives is required for providing data necessary for process development, control, and optimization. The goal of our study is to investigate the suitability of black copper smelting process for recycling of battery metals lithium, cobalt, manganese, and lanthanum. The experiments were performed alumina crucibles at 1300 °C, in oxygen partial pressure range of 10−11–10−8 atm. The slags studied contained 0 to 6 wt% of MgO. Electron probe microanalysis (EPMA) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) techniques were utilized for phase composition quantifications. The results reveal that most cobalt can be recovered into the copper alloy in extremely reducing process conditions, whereas lithium, manganese, and lanthanum deport predominantly in the slag at all investigated oxygen partial pressures.

Coupled Experimental Study and Thermodynamic Modeling of the MgO-MnO-Mn2O3-Ti2O3-TiO2 System

A coupled phase diagram experiment and thermodynamic modeling of the MgO-MnO-Mn2O3-Ti2O3-TiO2 system at 1 bar total pressure is presented. High temperature equilibration and quenching experiments followed by the phase analysis using electron probe microanalysis and X-ray diffraction were performed to obtain complex phase equilibria between solid solutions and liquid phase in air. Low temperature phases during quenching was inevitable in some samples which lead to inaccuracy in the experimental data. The molten oxide phase was described by using the Modified Quasichemical Model, which considers short-range ordering in liquid state, and the Gibbs energies of the extensive solid solutions (pseudobrookite, ilmenite and spinel) were described using the Compound Energy Formalism based on their crystal structures. A set of optimized model parameters of all phases was obtained, which reproduces all the reliable experimental data within experimental error limits from 25 °C to above the liquidus temperatures over the entire range of composition at air atmosphere. The model can also predict the phase equilibria in the range of oxygen partial pressures from metallic saturation to air. The complex phase relationships in the system have been elucidated for the first time and the database of the model parameters can be used with FactSage software to calculate any phase diagrams and thermodynamic properties of the MgO-MnO-Mn2O3-Ti2O3-TiO2 system.

Effect of nitrogen concentrations on optical, structural and mechanical properties of self organized a-C:N films

Low friction and surface hardness has become an important aspect to study and understand surface engineering of diamond like coating. Investigation of structural and mechanical properties of nitrogenated amorphous Diamond Like Carbon coating has been done. The cross-sectional microstructures, elemental compositions and various phase constituent of the coated layers under different processing conditions have been characterized. Films are deposited in presence of 5%–20% with the increasing rate of 5% and 40% of N2 partial pressure along with Ar gas. 20% N2 pressure shows a critical behavior in Raman spectroscopy and XPS. In this condition the film shows more uniform coating with vertical growth structures as well as brittle behavior. The micro-structural changes on the surface due to migration of N2 and its related surface properties have been examined. AFM studies clearly show that the percentage change in average roughness decreases to 17% as the film thickness increases at 20% N2 incorporation. The positive changes in its mechanical properties have been observed by Nano-indentation techniques. Significance of DLC coating in this condition is clearly seen with the increasing sp3compositions by XPS analysis. All results have been correlated and hence critical range of nitrogen partial pressure has been observed between 20%-23% to give similar sp3 fraction and hence properties that of pure DLC films.

Experimental Study on Phosphorus Partitions Between Liquid Iron and Liquid Slags Based on DRI

Phosphorus partition between liquid iron and CaO-SiO2-MgO-FeOx slags have been investigated experimentally. Fe doped with Fe3P was equilibrated, at 1873 K, in a closed system, with a fully liquid, MgO saturated slag in a dense-sintered MgO crucible. Synthetic slags with low CaO/SiO2 ratio (1 to 1.32) and varying FeOx concentrations (10 to 30 wt pct) constituted the slag phase. P2O5 concentrations in the slag varied between 0.3 and 1.5 wt pct for added phosphorus concentrations of 0.06 to 0.316 wt pct. Phosphorus partition has been found to increase with increasing CaO/SiO2 ratios. Phosphorus partition increased with increasing oxygen potential over the investigated oxygen partial pressure range, $$ {\text{p}}_{{{\text{O}}_{ 2} }} = 1.4 \times 10^{ - 5} \;{\text{to}}\;4.8 \times 10^{ - 5} ({\text{Pa}}) $$. The present experimental result has been compared with literature data. The effect of slag basicity on the dephosphorization power of slags has been discussed based on this comparison. The minimum amount of slag to achieve sufficient dephosphorization using DRI has also been calculated and discussed.