Addition Of Fe Powders Research Articles

Effect of iron powder on hydrogen sulfide reduction and phosphate removal in semi‐continuous anaerobic digestion treating primary sludge

AbstractBACKGROUNDTo our best knowledge, no experimental study has previously investigated the simultaneous effects of adding Fe powder for the decrease of hydrogen sulfide (H2S) in biogas and the removal of phosphate (PO4‐P) in continuous anaerobic digestion (AD). This study investigated the effects of iron (Fe) powder (5 g L−1) in AD to remove H2S and PO4‐P. A comparative experiment was conducted using two semi‐continuous‐flow anaerobic digesters treating primary sludge at decreasing hydraulic retention times (HRTs) of 20 to 10 days.RESULTSThe addition of Fe powder to AD removed > 98% of H2S at all HRTs, and removed 64–72% of PO4‐P, with the highest removal efficiency at HRT = 10 d. The addition of Fe powder to AD had no noticeable effect on biogas production or pH, but it increased the CH4 content (62.7–66.0% in Fe‐treated vs 58.2–60.4% in the Control) partly due to the greater presence of Methanoregulaceae. The relative abundance of the microbial groups was more affected by HRT than by the addition of Fe powder. The presence of Fe powder notably increased the abundance of Spirochaetaceae and Syntrophaceae.CONCLUSIONAs shown, the addition of Fe powder can improve the management of both H2S in the biogas and PO4‐P in the digested sludge in the AD system. © 2024 Society of Chemical Industry (SCI).

Mechanical properties of ultra-high strength cement-based materials (UHSC) incorporating metal powders and steel fibers

In this work, the mechanical properties of ultra-high strength cement-based materials (UHSC) incorporating metal powders and steel fibers under steam curing and autoclave curing were studied, with the special attention devoted to the flexural load-deflection response and compressive stress-strain behavior. Additionally, the hydration degree, pore structure characteristics and micro interface morphology were investigated to provide a thorough insight into the enhancement mechanism of metal powders and steel fibers on UHSC. The results show that the incorporation of Fe and Cu powders could enhance the flexural performance of UHSC, including the increased flexural strength and energy absorption capacity. Under uniaxial compression, improved peak stress, secant modulus, and energy absorption capacity of UHSC could be observed after the addition of Fe powders, but this improvement was negligible after the addition of Cu powders. Moreover, the statistical damage constitutive model based on strain equivalence hypothesis and improved statistical damage theory could reasonably describe the stress-strain behavior of UHSC under uniaxial compression. Furthermore, incorporating Fe and Cu powders could ameliorate the pore structure of UHSC, in which the harmful pores was converted into less harmful pores. Micro-interface morphology demonstrated that metal powders were closely bonded with cement paste, and no cracks or micro pores could be detected around the interface.

Development of Co-Based Amorphous Composite Coatings Synthesized by Laser Cladding for Neutron Shielding.

Advanced amorphous coatings consisting of Co-based metallic glasses with ultrahigh strength (6 GPa) and high microhardness (up to 17 GPa) can significantly improve the surface properties of matrix materials. However, the intrinsic brittleness of Co-based metallic glasses can lead to the initiation of microcracks caused by the inevitable generation of thermal stress during the laser cladding process, which severely limits the potential application. In this paper, the methods of increasing substrate temperature and fabricating composite coatings with the addition of toughened Fe powders were adopted to inhibit the generation of microcracks in the Co55Ta10B35 amorphous coatings. Moreover, neutron shielding performances of the cladding coatings with high B content were investigated with a wide range of neutron energy (wavelength: 0.15–0.85 nm). The results indicate that the fully amorphous coating and composite ones can be fabricated successfully. The increase in the substrate temperature and the addition of Fe powders can effectively inhibit the initiation and propagation of microcracks. The fully Co-based amorphous coating with high B content (35 at.%) can exhibit excellent neutron shielding performance. With the addition of Fe powders, the neutron shielding performance is reduced gradually due to the dilution effect of B in the composite cladding coatings, but the microcrack will be completely restrained.

Investigation of the properties of polystyrene-based wood plastic composites: effects of the flame retardant loading and magnetic fields

Abstract Polystyrene-based wood plastic composites (WPCs) containing ammonium polyphosphate (APP) and iron (Fe) powder were prepared in this work by solution blending with the aid of an alternating magnetic field. The mechanical, electrical, thermal and fire performances of the WPCs were analyzed through mechanical testing, thermogravimetry and CONE calorimeter. The addition of Fe powder decreased the tensile strength and increased the impact strength. The APP promoted the formation of sufficient char on the material’s surface and enhanced the flame retardant properties. Furthermore, an alternating magnetic field was used to align the Fe powders. After the magnetic treatment, the electrical conductivity and thermal properties were found to increase considerably compared with those without treatment. The Agari model presented the most reasonable prediction of thermal conductivity as a function of Fe content among three classical thermal conduction models. According to the morphological observations, the iron particles in the composites tended to rearrange along the direction of the magnetic field after treatment, resulting in the enhancement of both thermal and electrical conductivities. The prepared WPCs in this study exhibited good flame retardant properties together with the acceptable mechanical properties of the composites.

Use of Iron Powder to Obtain High Yields of Leptothrix Sheaths in Culture

The Leptothrix species, Fe-oxidizing bacteria, produce an extracellular, microtubular sheath with a complicated organic–inorganic hybrid nature. We have discovered diverse industrial functions for this material, e.g., electrode material for Li-ion batteries, catalyst enhancers, pigments, plant growth promoters, and plant protectants. To consistently obtain material with the qualitative and quantitative stability needed for industrial applications, we focused on developing an optimum culture system for sheath synthesis by the Leptothrix sp. strain OUMS1. Although we have used Fe plates as an Fe source in the liquid silicon-glucose-peptone medium (SGP), the plates do not yield a consistent quality or precise mass, and formation of Fe-encrusted sheath is restricted to a surface of the plates, which limits harvest yield. In this study, to obtain a high yield of sheaths, we cultured OUMS1 in SGP supplemented with Fe powders. The addition of Fe powders to the medium (up to 14.0 g/L) did not adversely influence growth of OUMS1. The final yield of sheaths was about 10-fold greater than in the Fe plate culture. The sheaths also maintained a microtubular form and crystalline texture similar to those produced on Fe plates in SGP. The results proved the usefulness of Fe powder for consistently high yields of Fe-encrusted sheaths of stable quality.

침전법을 이용한 Thiourea 용출용액으로부터 Silver 회수

티오요소 용출용액에 Fe 분말을 첨가하여 silver를 침전법으로 회수하고자하였다. Fe 분말 첨가량, 교반속도, 온도 등과 같은 변수들을 조사하였다. Silver 침전율은 Fe 분말 첨가량, 교반속도 그리고 온도가 증가할수록 증가하였다. 가장 많은 silver 침전율이 나타나는 조건은 Fe 분말 첨가량이 10 g일 때, 교반속도가 500 rpm일 때 였다. Silver 침전율은 Arrhenius 공식에 따라 온도가 증가할수록 증가하였으며, 1차-반응식에 준하여 일어났다. 이들 자료로부터 구한 활성 에너지는 13.73 KJ/mol에서 17.02 KJ/mol이였다. 침전물에 대하여 XRD분석을 수행한 결과 침철석이 검출되었다. 이는 <TEX>$Fe^0$</TEX> 분말 첨가로 인하여 티오요소 용액에서 산화-환원반응이 일어났음을 지시해주는 것이다. In order to apply the silver cementation method using Fe powder from pregnant thiourea leaching solution. Parameters such as the amount of Fe powder addition, agitation speed, and temperature were investigated. The silver cementation rate was increased by the increasing of Fe powder addition, agitation speed, and temperature. The highest silver cementation rate was found when the addition of Fe powder was 50 g/L at the agitation speed of 500 rpm. The silver cementation rate increase with increasing temperature according to the Arrhenius equation and obeys <TEX>$1^{st}$</TEX> order kinetics. The activation energy from the kinetics data was found to be between 13.73 KJ/mol and 17.02 KJ/mol. In the XRD analysis, goethite was detected in the precipitate of the thiourea leach solution. This indicates that an oxidation-reduction reaction had occurred in the thiourea solution due to the addition of the Fe powder.

CuS/Fe: a novel and highly efficient catalyst system for coupling reaction of aryl halides with diaryl diselenides

The CuS catalyzed coupling reactions of aryl halides and diaryl diselenides were accelerated by the addition of Fe powder in only 3–12 h with good to excellent yields. SEM–EDX indicated that the in situ iron oxides as support against catalyst agglomeration accelerated the reaction. This catalyst system was also demonstrated recyclable without significant loss of catalytic activity.

Some Fundamental Aspects of Highly Reactive Iron Coke Production

It is important to develop the production and utilization technology of highly reactive coke in order to improve the efficiency of blast furnace reactions. In this study, some fundamental aspects of highly reactive iron coke produced in a coke oven chamber were investigated. First, the effects of catalytic Fe powder addition to coal before carbonization on coke strength were investigated. The addition of Fe powder decreased the coal caking property and hence the resultant coke drum index (DI15015). On the other hand it increased coke reactivity (JIS coke reactivity index and CRI) to a great extent. This means that the caking property of blended coals needs to be adjusted higher to produce iron coke with proper strength and high reactivity. Secondly, it was shown that the iron ore reacts with silica brick at 1200°C in a condition similar to that in a coke oven chamber. The iron ore and silica reacted to produce fayalite (2FeO·SiO2) and the brick was damaged. On the other hand, it was proven that the iron ore does not react with silica brick at 1100°C in the above condition. Based on this fundamental study, iron coke with proper strength and high reactivity was successfully produced in a coke oven chamber on a commercial scale by adjusting the coal blend composition and the coke oven temperature. Furthermore it was revealed that about 70% of iron in iron ore powder added to coal was reduced to metallic iron during carbonization.

高反応性フェロコークス製造技術の基礎検討

The development of production and utilization technology of highly reactive coke is significant in order to improve blast furnace reaction efficiency. In this report, some fundamental aspects of highly reactive iron coke produced in a coke oven chamber were investigated. First, the effects of catalytic Fe powder addition to coal before carbonization on coke strength were investigated. The addition of Fe powder decreased coal caking property and hence resultant coke drum index (DI15015). On the other hand it increased coke reactivity (JIS coke reactivity index and CRI) to a great extent. This means that caking property of blended coals needs to be adjusted higher to produce the iron coke with properstrength and high reactivity. Secondly, it was shown that the iron ore reacts with silica brick at 1200°C in a condition similar to that in a cokeoven chamber. The iron ore and silica reacted to produce fayalite (2FeO·SiO2) and the brick was damaged. On the other hand, it was proved that the iron ore does not react with silica brick at 1 100°C in the above condition. Based on this fundamental study, the iron coke with proper strength and high reactivity was successfully produced in coke ovens on a commercial scale by adjusting the coal blend composition and the coke oven temperature. Furthermore it was revealed that about 70% of iron in iron ore powder added to coal was reduced to metallic iron during carbonization in coke ovens.

Production of semiconductor grade high-purity iron

Semiconductor grade high-purity Fe will be required in practical use of β-FeSi 2. However, high-purity Fe with more than 99.9999% in purity has not been produced commercially. Then, a process consisting of anion exchange in a HCl solution, hydrogen reduction and plasma arc melting has been developed for the production of high-purity Fe. All metallic impurities can be virtually removed from Fe by the two anion-exchange steps, in which some elements such as Cu and Mo are separated efficiently under reducing conditions by the addition of Fe powder at the 1st step, and the rest of impurities are surely separated under oxidizing conditions at the 2nd step. Non-metallic impurities such as oxygen, carbon and nitrogen also can be eliminated to very low levels by the hydrogen reduction and the hydrogen plasma arc melting steps.

Ultra-high purification of iron by anion exchange in hydrochloric acid solutions

Promising applications in advanced electronics have created a demand for ultra-high purity iron. Anion exchange in chloride solutions may offer an efficient and practical way of purification. Examination of anion-exchange distribution functions revealed a variety of behavior patterns to be exploited. Elution tests in laboratory-scale columns suggested that virtually all the impurities can be separated from the iron chloride solution by anion exchange. The hydrochloric acid concentration and volume of the rinsing and eluent solutions determine the efficiency of the procedure. Separation of certain elements (e.g. copper and molybdenum) requires strict control of redox conditions. The designed procedure consists of two anion-exchange steps. In the first step and during solution preparation, those impurities are separated which can be precipitated by iron, or sorbed in the resin at low HCl solutions under reducing conditions determined by the addition of Fe powder. The remaining impurities are separated from iron, applying a second ion exchange step under oxidizing conditions. Performance characteristics (yield, purification ratio and volume efficiency) of the separation indicate the optimum parameters of the rinsing and eluent solutions and the suitable way of defining the collected volume fraction of the effluent.

Catalytic Graphitization of Carbon by Iron

It was studied by using Fe powder that the effects of the kind of carbon on the catalytic graphitization.Raw carbon materials used in this experiment were three kinds of carbons with various graphitizability from coal tar pitch and typical non-graphitizable carbon from phenol formaldehyde resin. The raw carbons were heated up to 900°C and then were crushed to under 100 mesh. The additional amounts of Fe powder (under 325 mesh) were 1, 3, and 5 wt% respectively. The mixture of the carbon and Fe powder were heat-treated at the temperature range from 1200°C to 1800°C for 1 hour under N2 gas.Three kinds of effects were caused by the addition of Fe powder, that is, (1) the deposition of the graphitic structure component, (2) the deposition of turbostratic structure component, and (3) the improvement of the crystallinity of residual broad component. Behavior of (3) was observed in all kinds of the carbons and was more remarkable in the graphitizable carbon. In addition, this behavior was enhanced with the increase of HT T. The behavior of (1) was also observed in all carbons, and the depositting amount of this component was increased with the deterioration of the graphitizability of carbon specimens and with the increase of HT T. The turbostratic structure component was depositted only in the non-graphitizable carbons at above 1400°C of HTT.

Zinc-Ferriteに関する研究 (第5報)

In the present experiment, an attempt to promote the acid dissolution of zinc-ferrite was made to obtain a high zinc extraction in the electrolytic zinc process, and the following results were obtained.(1) By an addition of Fe powder in the leaching solution, the dissolution rate of zinc-ferrite increases markedly. The increase in dissolution rate of zinc-ferrite increases markedly. The increase in dissolution rate is, however, not due to the direct contact of Fe powder with zinc-ferrite particles, but due to the action of Fe2+which is produced by the dissolution of Fe powder.(2) The dissolution rate is enhanced by the cathodic polarization, which is achieved by the contact of zinc-ferrite particles with cathodically polarized electrodes.(3) The addition of Fe2+as FeSO4·E7H2O in the leaching solution gives an increase in dissolution rate of zinc-ferrite. The simultaneous addition of Fe3+with Fe2+lowers the dissolution rate considerably.These results suggest that the increase in dissolution rate by the above methods would be caused by the increase in concentration of anion vacancy at the surface of zinc-ferrite. This agrees with the conclusion of the previous papers.From the discussion on the dissolution mechanism of oxides, based on the results of our works and others', it is concluded that the dissolution of the oxides containing Fe3+would be promoted under reducing conditions.