Iron Powder Research Articles

New Die-Compaction Equations for Powders as a Result of Known Equations Correction—Part 3: Modernization of Plasticity Equations for a Porous Body

Equations of plasticity of a porous body proposed by different authors and obtained under the condition that the yield surface of a porous body has the shape of an ellipsoid of revolution are considered in this paper. Such equations have two independent parameters which are the functions of relative density. Various theoretical dependences of these parameters on the relative density and, as a result, various equations for describing the die-compaction of powders are presented. It is shown that the correction of two density-dependent parameters, taking into account the initial density, makes it possible to significantly increase the accuracy of approximation of experimental data on the powder compaction process (PCP) of various powders. Among the considered “continuum” equations of powder die-compaction, the PCP to a density of 0.95 is the most accurately described by the equation in which the corrected Skorokhod’s theoretical density functions are used and which contains one constant as a result. Another equation which contains four constants allows one to accurately (R2 > 0.9990–0.9999) describe the PCP to a density of >0.95. This equation is obtained by replacing one of two independent parameters in the traditional continuum equation with the lateral pressure coefficient followed by substituting, instead of those parameters, their dependencies on the density in the form of power function. The adequacy of the PCP description by this equation was verified by approximating experimental data on the die-compaction of iron powders to a relative density greater than 0.95, as well as highly plastic powders with a final density of ~1.0.

Influence of Polytetrafluoroethylene Content, Compaction Pressure, and Annealing Treatment on the Magnetic Properties of Iron-Based Soft Magnetic Composites.

To improve the magnetic properties of iron-based soft magnetic composites (SMCs), polytetrafluoroethylene (PTFE) with excellent heat resistance, electrical insulation, and extremely high electrical resistivity was chosen as an insulating coating material for the preparation of iron-based SMCs. The effects of PTFE content, compaction pressure, and annealing treatment on the magnetic properties of Fe/PTFE SMCs were investigated in detail. The results demonstrate that the PTFE insulating layer is successfully coated on the surface of iron powders, which effectively reduces the core loss, increases the resistivity, and improves the frequency stability and the quality factor. Under the combined effect of optimal PTFE content, compaction pressure, and annealing treatment, the iron-based SMCs exhibit a high effective permeability of 56, high saturation magnetization of 192.9 emu/g, and low total core losses of 355 mW/cm3 and 1705 mW/cm3 at 50 kHz for Bm = 50 mT and 100 mT. This work provides a novel insulating coating layer that optimizes magnetic properties and is advantageous for the development of iron-based SMCs. In addition, it also provides a comprehensive understanding of the relationship between process parameters and magnetic properties, which is of great guiding significance for scientific research and industrial production.

An Electrolytic Elemental Iron Powder Effectively Regenerates Hemoglobin in Anemic Rats and Is Relatively Well Absorbed When Compared to Ferrous Sulfate Monohydrate.

Elemental iron powders are used as food fortificants to reduce the incidence of iron deficiency anemia. However, many commercially available iron powders are relatively untested in vivo. The purpose of this study was to determine the hemoglobin regeneration efficiency (HRE) and relative iron bioavailability (RBV) of an electrolytic elemental iron powder (EIP), by treating anemic rats with 14 d iron repletion diets fortified with four different concentrations (12, 24, 36, or 48 mg iron/kg diet) of EIP and bakery-grade ferrous sulfate monohydrate (FS; FeSO4•H2O), or no added iron (control); n = 9-12/group. The HRE of FS was significantly higher (p ≤ 0.05) than EIP at each concentration of dietary iron tested. For EIP, the HREs (ratios) of diets containing 12, 24, 36, and 48 mg iron/kg were 0.356, 0.205, 0.197, and 0.163, respectively. For both EIP and FS, HRE was inversely associated with increasing dietary iron. The RBVs (%) of iron from EIP in diets at 12, 24, 36, and 48 mg iron/kg as compared to FS were 64.5, 59.1, 50.6, and 54.3%, respectively. Overall, findings show that at the concentrations of iron tested, EIP has RBVs greater than 50% and is an effective fortification agent to replenish hemoglobin and correct iron deficiency anemia.

Co-Deposition of Bimetallic Au-Pt with L-Cysteine on Electrodes and Removal of Copper by Iron Powder for Trace Aqueous Arsenic Detection

Much progress has been made in the determination of As (III), while numerous electrochemical sensors based on metal nanomaterials with significant sensitivity and precision have been developed. However, further research is still required to achieve rapid detection and avoid interference from other metal ions (especially copper ions). In this study, bimetallic AuPt nanoparticles are electrochemically modified with screen printing electrodes. What’s more, L-cysteine also self-assembles with AuNPs through Au-S bond to enhance the electrochemical performance. To overcome the interference of Cu (II) in the sensing process, the reduced iron powder was chosen to remove Cu (II) and other oxidizing organics in aqueous solutions. The lowest detectable amount is 0.139 ppb, a linear range of 1~50 ppb with superlative stability by differential pulse anodic stripping voltammetry. Fortunately, the reduced iron powder could eliminate the Cu (II) with no effect on the As (III) signal.

Preparation of a novel MR fluid for squeeze-shear mode by compositing micron-scale and nano-scale particles

The magnetorheological (MR) fluid under the squeeze-shear mode has an enhanced structure by reducing the distance between particles, significantly increasing the yield stress compared to the single shear mode. The existing research on preparing MR fluid is all based on single shear mode. This work mixes micron-scale carbonyl iron powders and micron-scale soft magnetic particles to prepare the specialized MR fluid for the devices working under squeeze-shear mode. Several kinds of micron-scale carbonyl iron powders and micron-scale soft magnetic particles are selected, of which the magnetic properties are tested to obtain the suitable soft magnetic particles for MR fluid. Then, the optimal combination of micron-scale carbonyl iron powders and micron-scale soft magnetic particles is obtained when the orthogonal test is used to compare the yield stress of different combinations. At the same time, the appropriate surfactants and base carrier fluid were selected, according to the previous work. On this basis, the novel MR fluid is prepared by the base fluid displacement method, and its performances are tested. The results show that the sedimentation rate is 0.8 % after standing for 20 days, which can keep the MR device in a stable state. The viscosity of the novel MR fluid is 8.0 Pa·s at room temperature, exhibiting good liquidity, which allows it to be injected into MR devices. The shear yield stress of the novel MR fluid is 60.28 kPa at the squeeze pressure of 600 kPa, which is 1.5 times higher than that under single shear mode, significantly enhancing the mechanical performance of MR fluid. The novel MR fluid with good sedimentation stability, appropriate viscosity, and better mechanical performance can be applied to more MR devices, especially the MR devices under squeeze-shear mode.

Preparation and Magnetic Properties of Low-Loss Soft Magnetic Composites Using MgO-Phenolic Resin Coating.

Optimizing the interface between a magnetic powder matrix and an oxide-insulating layer is an effective method to improve the permeability and lower eddy current loss of iron-based soft magnetic composites. In this study, in order to improve the bonding strength of the substrate and insulation layer, soft magnetic composites were prepared by pressing and heat treating with reduced iron powder as a magnetic matrix, high-temperature MgO nanoparticles as insulating coating, and phenolic resin as an adhesive. The effects of MgO content on the microstructure and magnetic properties of the composites were investigated. The results of a scanning electron microscopy and an energy-dispersive spectrometer analysis corroborate that the results obtained regarding the frequency characteristics and the resistivity of the iron powder agree with the scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) analysis and confirm their improvement by the presence of an insulating layer of MgO. The resistivity of the sample coated with 4 wt.% MgO is nearly 45 times higher than that of the uncoated sample under the same conditions. The MgO-insulating film formed on the surface of iron powder makes the coated sample have low effective grain size, high resistivity, and low magnetic loss at a high frequency. At 1 kHz, the magnetic loss of the 4 wt.% MgO-coated sample is reduced by 77.3%, and the magnetic loss is only 5.8% compared with the uncoated sample at 50 kHz. This magnetic loss separation study shows that the addition of MgO insulation material can effectively reduce the eddy current loss of the magnetic powder core. The 4 wt.% MgO-coated sample has the lowest hysteresis loss factor and relatively low eddy current loss factor, so it can be determined that the addition of 4 wt.% MgO is the optimum content to attain a low magnetic loss.

Study on strength and reduction characteristics of iron ore powder-green carbon composite briquettes

The metallurgical industry is a key sector for carbon emissions, and in recent years, there has been widespread attention on the use of biomass resources as a green, renewable, and carbon–neutral energy source material for low carbon ironmaking processes. The waste wood after hydrothermal-pyrolysis carbonization has the characteristics of low content of harmful elements and high content of fixed carbon. In this study, the waste wood after hydrothermal-pyrolysis two-step carbonization treatment was used as a reducing agent for the reduction of iron ore to prepare iron ore powder- green carbon composite briquettes (ICCB) with two carbon–oxygen ratios. The study investigated the effects of reduction behavior and reaction temperature on the reduction performance of the ICCB. The results indicate that with the increase in reaction temperature, the volume of the ICCB gradually contracts, leading to a reduction in mass. The shrinkage rate of the ICCB during self-reduction at 1200℃ is significantly higher than during co-reduction, and the shrinkage effect of the C/O 0.5 ICCB is more pronounced than that of the C/O 0.8 ICCB. Due to the excessive carbon content in the C/O 0.8 ICCB, the carbon cannot be fully consumed during the reaction process, resulting in consistently low compressive strength of the ICCB, with a compressive strength of 12 N after reduction at 1200℃. In contrast, the iron phase in the C/O 0.5 ICCB gradually recrystallizes during the reduction process, ultimately yielding plastic iron briquettes with compressive strengths exceeding 3000 N after different reaction behaviors at 1200℃. In summary, reducing the carbon-to-oxygen ratio and increasing the reaction temperature contribute to the volume contraction and enhanced compressive strength of the ICCB during the reduction process.

Anti−Reflection Metamaterials with Phase Gradient Index Generate Surface Waves for Radar Stealth in the Microwave Regime

AbstractAlthough the conversion of propagating waves into surface waves is anticipated to introduce a novel degree of freedom for radar stealth materials, the manipulation of wavelength and traveling direction of surface waves at small phase gradients remains unclear. Here the aforementioned conversion is demonstrated utilizing a metamaterial composed of carbonyl iron powders, where the momentum mismatch is compensated by the material and the phase gradient index of the aligned meta−atoms. Surface waves are generated in the direction of the phase gradient within a phase span of 180°. The metamaterials with 5−level metastructure (5x:1x) generate surface waves with two wavelengths, and get the ξ/k0 value (ratio of the phase gradient index to the wave vectors of propagating wave) of 7.5 and 4.32, respectively. Furthermore, the dual phase gradient metastructure possesses the capability to alter the trajectory of the leaky microwave, converting it into a waveform resembling that of a vortex, while simultaneously preserving the integrity of surface waves. The sample achieves an effective absorption bandwidth of 5.67–7.96 and 20.19–21.10 GHz with an optimal absorption peak of −40.77 dB at 6.87 GHz. Present study develops a novel mechanism to improve the radar stealth properties of microwave absorption materials.

Regulating the surface area increase of zero-valent iron (ZVI) during ball milling: A study of the mechanical mechanism and low-carbon milling

This study investigates the effect of milling parameters on the specific surface area (SSA) increase of zero-valent iron (ZVI) powder, which is crucial for its environmental applications. Combining experimental and orthogonal design methodologies, the research explores how the parameters modulate the SSA. The operational factors are analyzed from the perspectives of bead momentum, kinetic energy, and energy efficiency. A regression model is proposed for the precise fabrication of ZVI with predetermined SSA. Furthermore, the study identifies optimized parameters that minimize energy consumption and carbon emissions. The results suggest that the optimal milling time is 10 min, with larger beads (2.0 mm), higher quality beads (0.75 kg), and higher shaft rotational speed (2000 rpm) significantly enhancing SSA. Discrete Element Method (DEM) simulations reveal micro-mechanical interactions, supporting the parameter selection scheme for maximizing SSA. The findings contribute to optimizing the milling process of the ductile ZVI powder for environmental clean-up.

Towards an efficient metal energy carrier for zero–emission heating and power: Iron powder combustion

In this study, the metal cyclonic combustor (MC2) was utilized to investigate the formation of nanoparticles (nPMs) and NOx during the combustion of iron powder under varying input conditions of equivalence ratio and oxygen concentration. Findings unveiled a consistent trend: both nanoparticle and NOx formations exhibit a similar response to changes in input conditions. Specifically, as the input equivalence ratio was increased or the oxygen concentration decreased, a simultaneous reduction in the formation of these pollutants was observed. This suggests a common influence of these factors on both nanoparticle and NOx formation. Additionally, the research highlighted a critical parameter in maintaining a self-sustainable stationary flame: ensuring that the iron particles remained relatively close together, with a maximum particle-to-particle distance of approximately 0.5 mm or a minimum total iron particle surface area of at least 0.02 mm2 per mm3 volume burner for oxidizer oxygen concentrations ranging from 13.5 % to 21 %. These findings provide valuable insights for optimizing the utilization of iron powder as a suitable option for burning in combustion processes and in the iron energy carrier cycle, enabling good energy conversion while minimizing environmental impacts. Novelty and Significance StatementThis study includes the first-ever measurements of nanoparticles and NOx formation during iron powder combustion at different input equivalence ratios and oxygen concentrations using a practical lab-scale burner. The concept can be adapted for commercial and industrial uses in heating and power. Furthermore, the findings of this study can be used to determine the optimum conditions for low emissions with a self-sustainable stationary flame during iron powder combustion, providing valuable insights into the combustion characteristics of iron powder and offering practical guidance for optimizing its combustion processes in the iron energy carrier cycle.

Preparation of Soft Magnetic Composite Using Cold Sintering Technique

Soft magnetic composites are powder metal products under development as an alternative to 2D laminates in electric motor applications. The 3D design of SMCs offers greater energy efficiency but poses a challenge to maintain adequate strength properties required for application. Soft magnetic composites are fabricated through compaction and heat treatment of iron particles coated with insulated coating to form a dense compact. The soft magnetic properties of the compact are affected by the properties of the iron powder, density of compact as well as the efficacy of forming uniform thin insulating coating at the particle boundary. Additionally, the strength of the compact is also affected by the nature of the insulating boundary at the particle interfaces. We report a low temperature process that involves cold sintering phenomenon to densify and strengthen soft magnetic composites. Iron powders have been modified using a co-precipitation method that forms a hydrated copper/iron oxalate coating on individual iron particles. Warm compaction of the modified iron powders at 100°C resulted in a highly dense soft magnetic composite which demonstrated ~ 3x improvement in strength. The compacts can be further heat treated in air at higher temperatures to form high strength oxide coating iron based soft magnetic composites. Results of the AC and DC magnetic measurements of fabricated cold sintered toroid compacts made as a function of heat treatment temperature reveal that DC permeability increased with heat treatment temperature. Analysis of AC core loss data showed that hysteresis power losses dominated the performance at lower heat treatment temperatures (< 300°C) beyond which dynamic core losses significantly increased.

Analisis Pengaruh Serbuk Besi Sebagai Substitusi Agregat Halus pada Lataston Lapis Aus (HRS-WC) Terhadap Kinerja Jalan Beraspal

Damage to flexible pavements is still commonly found in Indonesia. As technology develops, there is some research regarding using iron powder as an alternative replacement material for asphalt mixtures. This research used iron powder waste as a substitute for fine aggregate in Hot Rolled Sheet–Wearing Course with levels of 0%,15%,30%, and 45%. The purpose of this research to determine the Optimum Asphalt Content (OAC) and optimum percentage of iron powder waste addition as a substitute for fine aggregate to the indicator of Marshall test based on The General Specification of Bina Marga 2018 (Revision 2). Based on Marshall testing that has been carried out, the OAC values are 7,5% with an average of stability 2040,46 kg, flow 3,40 mm, MQ 600,24 kg/mm, voids in mix 4,69%, voids in mineral aggregate 18,30%, and voids filled with asphalt 74,39%. While the optimum percentage of iron powder value is 13% with an average of stability 2091,90 kg, flow 3,17 mm, MQ 662,79 kg/mm, voids in mix 3,92%, voids in mineral aggregate 17,59%, and voids filled with asphalt 77,72%. The result met the General Specification of Bina Marga 2018 (Revision 2). The addition of iron powder as a substitute for fine aggregate in HRS-WC is can increase stability but reduce air voids in the asphalt mixture. This result makes the asphalt mixture more impermeable and plastic.

Enhancing electromagnetic shielding property and absorption coefficients via constructing electromagnetic rings in janus composites

Polymer based electromagnetic wave (EMW) shielding materials with high conductivity have excellent electromagnetic shielding properties, but also exhibit high reflection of EMWs, resulting in inevitable secondary electromagnetic pollution. EMW shielding materials with low reflection have extensive potential applications in the next generation of anti-EMW equipment. Herein, a production strategy combining three dimensional (3D) printing technology and solution casting method was proposed to prepare polylactic acid (PLA)@multi-walled carbon nanotubes (MWCNT)/polydimethylsiloxane (PDMS)@carbonyl iron powder (CIP) absorptive electromagnetic shielding Janus composites with a ring-shaped electromagnetic synergistic structure (spiral rings or concentric circular rings). By utilizing PLA and MWCNTs as primary components, a 3D integrated framework that combines a highly conductive reflector and a ring inductance structure can achieve significant EMW shielding performance with low reflection. With PDMS as a matrix and magnetic CIP as functional fillers, a strong magnetic permeability network is provided around the ring inductance frame. The magnetic loss resulting from electromagnetic cooperative ring structure further enhances microwave absorption capacity. The composite materials, benefiting from the synergistic interaction between the electromagnetic rings and the reflector, demonstrate excellent impedance matching and efficient EMW shielding capabilities. Specifically, the PLA@MWCNT/PDMS@CIP Janus composites with ring structure exhibit a notable EMW shielding effectiveness (SE) of 31 dB and a reflection coefficient as minimal as 0.3. Therefore, this study presents a powerful approach to the development of low-reflective materials with high EMW SE, promising potential applications in the next-generation intelligent electronic devices.

Synthesis and properties of silicone-modified polyurethane acrylate for magnetically driven blue light photocurable superhydrophobic coatings

A low surface energy silicone-modified polyurethane acrylate (Si-PUA) has been synthesized and employed as the primary constituent for the magnetically driven photocurable coatings. By integrating magnetically driven assembly technology with blue light photocuring technology, a superhydrophobic coating featuring low surface energy and micro/nano rough structures was successfully fabricated. The influences of hydroxy-terminated polydimethylsiloxane (PDMS) content and the R-value (-NCO/-OH) on the performance of PUA and coating systems were investigated using Photo-DSC, TGA, rheology, tensile testing machine, and SEM-EDS. The molecular structure of Si-PUA was characterized using FT-IR and 1HNMR. The result revealed that the composite coating exhibited a minimum surface energy when the PDMS content was 5 wt% and the R-value was 1.6, resulting in a surface free energy of 24 mJ/m2. When the coating formulation consists of a Si-PUA:HEA ratio of 7:3, an initiator dosage of 2% (with CQ/EDB at a 1:1 ratio), and a carbonyl iron powder (CIP) content of 100 wt%, the resulting photocured film exhibits a surface contact angle of 157.6° and a rolling angle of 5°, thereby satisfying the superhydrophobicity standard.

Single iron particle combustion - A morphology study of partially oxidized iron particles

In recent years, metal fuels were discussed as a contribution to meeting the challenges of the energy transition to a climate-friendly, sustainable energy economy. One material system with high potential to store and release a large amount of energy is iron powder and its reducible solid product iron oxide powder. In this study, the evolution of the particle morphology during single particle combustion in a laminar flow reactor is analyzed. Partially oxidized iron particles are sampled at different heights above the burner and their internal morphological structure is revealed qualitatively and quantitatively by tomography and microscopy methods (μCT, SEM, EDX, EBSD). The findings show that interfacial phenomena might play a major role when describing single particle combustion as the existence of two liquid phases with emulsification phenomena can be detected. Based on the results, a morphological description of the oxidation progress is proposed within the frame of this work.

Leaching of base metals in PCBs and copper cementation by iron powder

When dealing with electronic waste, printed circuit boards (PCBs) are some of the most important materials in terms of recovery possibilities, because of their high content of precious metals and base metals, notably copper (> 20% w/w), in addition to organic resins and ceramic materials. Efficient hydrometallurgical metals recovery from electronic waste is an important on-going research topic, and the present study consisted in the development of a process for the concentration of precious metals by leaching and recovery of major base metals mainly copper.A fraction of crushed PCBs concentrated in metals with more than 50 % copper was used for the leaching tests for two types of components: processor cards and mobile phone cards. For the leaching process, two steps were carried out. A first step consisted in leaching the concentrate three times with sulfuric acid and hydrogen peroxide, a second step consisted in lead removal by nitric acid leaching.The obtained results exhibit that, for processor cards, the first stage of leaching allowed the extraction of about 98 % of copper. Other base metals, zinc (99.8 %) and nickel (96 %) were also significantly leached. Precious metals were less leached except Ag with 88 % of release. The second stage of leaching with nitric acid allowed significant removal of lead (66 %). For mobile phone cards, the first stage of leaching led to an almost complete extraction of Cu (>98 %) and some other base metals (Fe, Ni, Sn, and Zn > 90 %). Al, Co and Mn were also extracted at 76 %, 78 % and 81 % respectively. Precious metals remained in the residue, except Pd which was leached at 16 %. The second stage of leaching with dilute nitric acid solution was not necessary for mobile phone cards, as it was responsible of an important Ag release from residue (80 %).

Exploring higher-order harmonic eddy current in soft magnetic composites

Electric motors, as the key building blocks of electric vehicles require high power density to enable driving over long distances with minimal power loss. In this regard, considerable research efforts have focused on searching for new magnetic materials, with soft magnetic composites (SMCs) considered promising. However, the eddy currents generated in SMCs are the primary contributors to power loss owing to their induced magnetic field reduction, harmonics that can distort the power waveform, and overheating. While eddy currents have been sufficiently investigated at the macroscopic level, information on their microscopic characteristics and contributions, particularly those depending on harmonic orders, has remained elusive. Here, we propose a systematic way to explore in detail the harmonics of eddy currents in two model systems including a power inductor and iron powder disk, using the atomic force microscopy based technique, so called multidimensional magnetic force microscopy (MMFM). Using MMFM, we show key effects of harmonics related to eddy currents by unveiling each contribution toward magnetic signals. In particular, the MMFM images show local variations in the nth harmonic of the eddy current signals within the spatially mapped magnetic features. These results show the proposed approach is effective to explore the harmonics of eddy currents, offering fundamental insight for development of highly efficient electric motors.

Debonding inspection with an enhanced miniature EMAT based on multiple pulse echoes

The present paper proposes a non-contact ultrasonic testing method for the debonding inspection of metal-based composite structures, utilizing an improved electromagnetic acoustic transducer (EMAT). The enhanced EMAT incorporates a carbonyl iron powder coil backplate and a small butterfly coil to enhance the detecting ability for interfacial bonding. A two-dimensional finite element model is developed to quantify the effectiveness of the carbonyl iron powder coil backplate on increasing the eddy current density and the magnetic flux density in the specimen. An experimental setup was designed using the Ritec SNAP 5000 and the improved EMATs to examine an aluminium-epoxy resin composite structure. Ultrasonic C-scan images of the specimen's bonding interface were obtained from the experiment. Both simulation and experimental results show that carbonyl iron powder coil backplates can increase the efficiency of the EMATs. By investigating the influence of echo number on debonding detection, it was revealed that employing higher-order echoes and utilizing carbonyl iron powder as the coil backplate can enhance the debonding detection capability. The C-scan imaging results indicate that the utilization of high-order echoes enhances imaging quality, and the employment of high-quality miniaturized EMATs enhances the capability for quantitative analysis of debonding defects.

Selection of Various Indications of Tempering Lubricant Concentration Reuse in the Wet Rolling Process

ABSTRACTDiscarded tempering lubricants retained significant reuse potential, making their recycling a vital step in reducing resource wastage and wastewater treatment costs in the strip steel industry. Hence, developing an accurate, rapid evaluation indicator for recycled fluid concentration was essential for facilitating this process. Research showed that among common evaluation indicators for metal fluids, three—electrical conductivity, refractive index and total base number (TBN)—due to their high linear correlation with tempering lubricant concentration (R2 &gt; 0.995), could be utilised to monitor the dynamic changes in the concentration of tempering lubricants. Subsequent experiments on reused tempering lubricants revealed that electrical conductivity, significantly altered by iron powder (7%–24% variance), and refractive index, impacted by hydraulic oil (3% deviation), highlighted contaminant challenges; yet, filtration effectively mitigated iron powder's effect on TBN. Finally, A 17‐day reused tempering lubricants simulation demonstrated consistent effectiveness of the three indicators in monitoring the need to update tempering lubricant concentration. However, in terms of sensitivity, precision, and particularly stability and relative mean deviation, the TBN concentration evaluation indicator outperformed, with TBN (3.38%) &lt; Refractive Index (7.92%) &lt; Electrical Conductivity (11.05%). This indicates the TBN method's superior stability over conductivity and refractive index methods, with its accuracy deviation below 2%, making it a stable, simple and reliable metric worthy of broader adoption.

Hemoglobin Regeneration Efficiency and Relative Iron Bioavailability of Four Elemental Iron Powders in Rats.

Effective food fortification strategies using elemental iron powders (EIPs) are needed to combat iron deficiency anemia. The purpose of this study was to determine hemoglobin regeneration efficiency (HRE) and relative iron bioavailability (RBV) of four food-grade EIPs (El-Lyte (EL), Hi-Sol (HS), H-325 (H3), and A-131 (A1)) by treating anemic rats with 14 d iron repletion diets (uncooked and cooked), fortified with a 12, 24, or 36 mg iron/kg diet of the EIPs, ferrous sulfate monohydrate (FS, FeSO4•H2O), or no added iron (control), n = 9-12/group. The ability of EL and HS to maintain hemoglobin for 6 weeks on the 6 mg iron/kg diet was also studied. The dissolution rate of iron from the EIPs was measured in hydrochloric acid at pH 1.0. Compared to FS, the EL, HS, and A1 EIPs had >50% overall RBV, with the following order: HS > A1 > EL > H3 (p ≤ 0.05); the effect of cooking was not significant (p > 0.05). Dissolution testing revealed that the mean RBV of the EIPs was positively associated with the percentage of iron solubility. In the 6-week maintenance study, EL and HS maintained hemoglobin as well as FS. Overall, the findings show that at the concentrations of iron tested, these EIPs are effective fortification agents to replenish hemoglobin and correct iron deficiency anemia.