Production Of Iron Powder Research Articles

Influence of Hydrogen Reduction Stage Conditions on the Microwave Properties of Fine Iron Powders Obtained via a Spray-Pyrolysis Technique

The relationship between the chemical purity of one-size particles and microwave properties in ferromagnetic materials is not clearly studied. Ferromagnetic nanostructured iron powders were synthesized from iron nitrate solution using ultrasonic spray-pyrolysis and then reduced in H2 flow at 350, 400, 450, and 500 °C. A rise in the concentration of solutions of a precursor from 10 to 20 wt. % led to an increase in mean particle size. The interrelationship was studied between chemical composition and the microwave dispersion of the powders obtained. An increase in the temperature of reduction changes the chemical composition and increases the amplitude of complex microwave permeability, which was studied using solid-state physics methods (XRD, STA, SEM, and VNA). It was found that annealing at 400 °C is the optimal treatment that allows the production of iron powders, consisting of about 90% of α-Fe phase, possessing a particle surface with low roughness and porosity, and demonstrating intense microwave absorption. Annealing at a higher temperature (500 °C) causes an even higher increase in permeability but leads to the destruction of nanostructured spheres into smaller particles due to grain growth. This destruction causes an abrupt increase in permittivity and therefore significantly reduces potential applications of the product. The insight into chemical–magnetic relationships of these materials enhances the data for design applications in magnetic field sensing.

Manufacturing and Properties of Spherical Iron Particles from a By-Product of the Steel Industry

In modern cold rolling mills in the steel industry, iron oxide powder is produced as a by-product when used pickling agents are recycled. Further processing of these iron oxide powders could enable the production of iron powder for various applications in powder metallurgy. For this purpose, a new process route with an eco-friendly hydrogen reduction treatment was developed. The process is able to manufacture a variety of iron particles through minor process adaptations. It was possible to manufacture spherical iron particles with high flowability. The flowability was measured by a Revolution Powder Analyzer, and an avalanche angle of 47.7° of the iron particles was determined. In addition, the bulk density measurements of the processed iron particles collective achieved values of 3.58 g/cm3, and a spherical morphology could be observed by SEM analysis. The achieved properties of the iron particles show high potential for applications where high flowability is required, e.g additive manufacturing, thermal spray and hot isostatic pressing. By adjusting the process conditions of the developed process, irregular iron particles could also be manufactured from the same iron oxide powder with a very high specific surface of 1640 cm2/g and a low bulk density of 1.23 g/cm3. Therefore, the property profile is suitable as a friction powder metallurgy material. In summary, the developed process in combination with the iron oxide powder from steel production offers a cost-efficient and sustainable alternative to conventional iron powders for additive manufacturing and friction applications.

Environmental sustainability challenges of China’s steel production: Impact-oriented water, carbon and fossil energy footprints assessment

The Iron and Steel Industry (ISI) is a difficult-to-mitigate sector that has considerable contributions to energy consumption, water pollution, and CO2 emissions. Despite broad interest in energy consumption and CO2 emissions generated by steel production, there are few impact-oriented Water Footprint (WF) assessments of steel production. This study evaluates the water, carbon and fossil energy footprints generated from rolled steel production on the basis of life cycle assessment. Key contributors attributing to those environmental impacts are also identified so as to explore their potential mitigation. Using the Monte Carlo model, an uncertainty analysis is conducted with the aim of providing reliable results for decision-making. Results show that the impact per ton China’s rolled steel production has on global warming, human health, ecosystem quality, and resources is 4.40 × 103 kg CO2 eq (GSD2 = 1.24), 4.15 × 10-3 Disability Adjusted of Life Years (DALY) (GSD2 = 1.31), 7.08 × 10-5 Species·yr (GSD2 = 2.04), and 4.39 × 104 MJ (GSD2 = 1.28), respectively. Global warming and freshwater ecotoxicity is the dominant contributor to the damage impact on human health and ecosystem quality, respectively. Results also show that the transport (freight ship) of raw materials and the production of iron powder are the two main contributors to the overall impact on the environment that rolled steel production has. Several policy recommendations are proposed in this paper, which focus on adjusting the steel industry’s industrial structure, promoting the national-level carbon emissions trading in the ISI, promoting international cooperation, and improving public awareness of green and low-carbon development. Such policy recommendations provide decision-makers with valuable insights, which thus allow them to prepare the appropriate mitigation policies.

TECHNOLOGY IMPROVEMENT OF HIGH-DISPERSIVE METALLIC IRON POWDERS BASED ON SEDIMENTS OF IRON REMOVAL STATION

Sediments from iron removal stations are a source of environmental pollution. It is necessary to find effective and eco-friendly methods of sediment disposal. The paper investigates the properties of iron-containing sediment in order to develop a technology for its further utilization. It is shown that sediments from the iron removal station of Velizhansky water intake have a stable chemical composition with about 70 % Fe2O3, and a stable particle size distribution, i.e. 20 μm for ≈ 87 % of particles. These parameters allow developing a flow chart for iron reduction in heated carbon monoxide. The involvement of sediments from iron removal stations in the high-dispersive metallic iron powder production eliminates the sediment deposit at landfills or storage tanks and creates a new raw material base for additive technologies.

Novel preparation process of iron powders with semisteel by rotary cup atomizer

ABSTRACT Semisteel, the main by-product of titania slag-smelting process of ilmenite with an electric furnace, cannot be widely used in the steel-making process because of its high sulfur and low carbon contents. Hoganas and water atomization processes are currently the major iron powder production techniques in China, but both have obvious drawbacks. A novel and clean iron powder production process is suggested to enhance the added value of semisteel, improve the production efficiency, and reduce the energy and water consumption. A circle of water curtain was set around a rotary cup atomizer. The iron powders and hot vapor produced in this new process can be applied in the reducing and leaching steps of sulfate process, respectively, which is propitious to cut down the manufacturing cost of titanium dioxide and realize optimized resource allocation and highly effective utilization. The effect of rotating speed on the obtained iron granules was investigated. Result shows that the median diameter of the obtained granules decreases with the increase in rotating speed and varies from 0.55 mm to 0.49 mm when the rotating speed is in the range of 600 rpm to 1000 rpm. The atomization mechanism of the molten semisteel was calculated to follow the ligament formation mode under the given experimental conditions. The obtained iron granules were analyzed by X-ray diffraction and scanning electron microscopy. The surfaces of the iron granules are smooth and are covered with a layer of iron oxides, including Fe3O4, FeO, and relatively small amounts of Fe2O3. Reduction experiments in hydrogen atmosphere at 1173 K (900 °C) were conducted to remove the iron oxides on the surfaces of the iron granules. The oxidation degree of iron powders decreases from 14.06% to 4.33% when the particle size varies from 0.3–0.35 mm to 0.6–0.65 mm. After reduction, the iron powders have dramatically rough surfaces and large specific surface areas, which benefit their reaction as reducing agents in the sulfate process.

Physical and chemical bases of vanadium-containing iron powder production and properties of powder materials on its basis

Physical and chemical features of interaction of vanadium containing iron-carbon melt with the energy carrier by the thermodynamic modeling method as well as reduction and decarbonizing of green compacts in the hydrogen atmosphere have been considered. The structure and proper- ties of bars produced from vanadium-containing iron powder are given. The characteristics of the bars manufactured on the basis of carbonaceous semi-product iron powder and pure uncontaminated powder produced by the carbonyl technique are presented for comparison. A conclusion is drawn on the expediency of bar material preparation directly from powder while omitting the compaction and sintering stages.

Production of Iron Powder by Solid-Phase Reduction of Fine Magnetite

It is shown that the effectiveness of fluidized-bed reactors is limited by the low reaction rate at low temperatures rather than by the small size of particles. Low-temperature hydrogen reduction is associated with low gas utilization and high energy consumption of the gas treatment system. Temperature cannot be increased since coalescence of iron particles causes destruction of the fluidized bed, but mechanical activation allows accelerating the reaction without increase in the process temperature. Since sulfur and phosphorus bond with iron in the reduction of iron oxides, iron and magnetite can be separated from iron sulfides and phosphides using difference in the Curie points for different iron compounds and magnetic separation at ~500 °C. The possibility to create high-temperature magnetic separators for fine materials is pointed out.

Sintering in incompletely sealed containers without gas flows

The paper presents an analytical review of published data and the authors’ data on the use of incompletely sealed steel containers for the sintering of iron-powder products in air. Consideration is given to additional techniques for removing oxidation products during sintering such as introduction of protective gas microgenerators into containers or use of a fill. It is concluded that it is reasonable and possible to sinter small and medium batches of powder products and to remelt powder waste at existing thermal stations.

Study on Deep Reduction and Efficient Separation of Lingyang Iron Ore

The test for deep reduction and efficient separation of Lingyang iron ore from Linjiang that cannot be separated and utilized by any conventional mineral processing technology was conducted in the Laboratory, and the research results showed that iron from Lingyang iron ore was recovered effectively. In this paper, the effect of reduction temperature, time and coal content on reduction was analyzed, and the process of deep reduction and efficient magnetic separation was investigated. Furthermore, on such optimum conditions of deep reduction as reduction temperature 1275°C, time 50min, and coal content 40%, the reduction products were separated in the flowsheets of magnetic separation after fine grinding and the iron powder products with iron grade 79.58% and recovery 62.77% were obtained.

Study on Deep Reduction and Efficient Separation of Lingyang Iron Ore

The test for deep reduction and efficient separation of Lingyang iron ore from Linjiang that cannot be separated and utilized by any conventional mineral processing technology was conducted in the Laboratory, and the research results showed that iron from Lingyang iron ore was recovered effectively. In this paper, the effect of reduction temperature, time and coal content on reduction was analyzed, and the process of deep reduction and efficient magnetic separation was investigated. Furthermore, on such optimum conditions of deep reduction as reduction temperature 1275°C, time 50min, and coal content 40%, the reduction products were separated in the flowsheets of magnetic separation after fine grinding and the iron powder products with iron grade 79.58% and recovery 62.77% were obtained.

Iron-ore concentrates in iron-powder production

Iron powder may be produced from natural iron ore. The production of iron-ore superconcentrates containing less than 0.3% silica for iron-powder manufacture is considered. The adjustment of magnetite concentrates from Olenegorsk and Lebedinsk enrichment plants and the enrichment of magnetite ore from the Kursk Magnetic Anomaly is investigated. The industrial production of superconcentrates from Olenegorsk magnetite quartzites and of ferrite-strontium powder from superconcentrate is investigated.

Reduction experiment of iron scale by adding waste plastics

The special features of waste plastics in China are huge in total amount, various in type and dispersive in deposition. Therefore, it is necessary to try some new ways that are fit to Chinese situation for disposing waste plastics as metallurgical raw materials more effectively and flexibly. Owing to its high ferrous content and less impurity, the iron scale became ideal raw material to produce pure iron powder. One of the methods to produce pure iron powder is Hoganas Method, by which, after one or multistage of reduction steps, the iron scale can be reduced pure iron powder. However, combining utilization of waste plastics and iron powder production, a series of reduction experiments were arranged and investigated, which is hoped to take use of both thermal and chemical energy contained in waste plastics as well as to improve the reducing condition of iron scale, and hence to develop a new metallurgical way of disposing waste plastics. The results show that under these experimental conditions, the thermal-decomposition of water plastics can conduce to an increase of porosity in the reduction systems. Moreover, better thermodynamics and kinetics conditions for the reduction of scale can be reached. As a result, the reduction rate is increased.

Air-atomized iron powders — past, present, future

This article examines the history and future prospects of the production of iron powders by the atomizing high-carbon melts with compressed air. In terms of their properties, the iron powders obtained by this method are intermediate between water-atomized powders and reduced powders. They can be used to make anti-friction products or structural elements having a density within the range 6.3–6.9 g/cm3. The outlook for these powders is promising in Russia because they are needed for machine construction, especially in the auto industry.

Powder metallurgy abroad

Asian companies are actively entering the market of powder metallurgy products. In 2005, the production of iron powder in Asia increased by 14% and of powder parts by more than 7%. The current manufacture of metal powders and their products in Japan, China, India, and South Korea is discussed. Applications of powder products in Asia are considered. Examples of developments that won awards of the Japan Powder Metallurgy Association (JPMA) in 2006 are shown.

A Comparison of Physical Properties, Screening Procedures and a Human Efficacy Trial for Predicting the Bioavailability of Commercial Elemental Iron Powders used for Food Fortification

Elemental iron powders are widely used to fortify staple foods. Experimental evidence indicates that there is considerable variation in the bioavailability of different products. For some powders, it may be too low to permit a significant impact on iron status. This study was designed to evaluate possible approaches to screening commercial iron powders for predicted bioavailability, to identify products that have the potential to improve iron status, and to ascertain whether bioavailability is related to the method of manufacture. Nine commercial iron powders were allocated to one of five types based on the production process; carbonyl, electrolytic, hydrogen-reduced (H-reduced), carbon monoxide-reduced (CO-reduced), and other reduced. Structure by scanning electron microscopy and physical properties (pycnometric and apparent density, particle size distribution, Fisher subsieve size, and surface area) were determined on all samples. Selected samples (one or more of each type depending on the cost of the assay) were then subjected to five screening procedures that have previously been advocated for predicting bioavailability in humans--issolution rate in 0.1 mol/L HCl, dialyzability and Caco-2 cell iron uptake, both after simulated in vitro gastrointestinal digestion, relative bioavailability (RBV) with respect to ferrous sulfate by the AOAC rat hemoglobin repletion method, and plasma iron tolerance tests in human volunteers. The results for particle size distribution, surface area, Fisher subsieve size, dissolution rate in 0.1 mol/L HCl, and RBV in rats were significantly correlated and consistent for powders of the same type. However, values for different powder types were significantly different. There was no correlation between either dialyzability or Caco-2 cell uptake and the predicted bioavailability estimates based on the physical properties, dissolution rates, RBV in rats, or human efficacy data. Although human plasma iron tolerance tests were in general agreement with the other measures of predicted bioavailability, they did not provide information that would have improved the precision of bioavailability estimates based on physical properties, dissolution in HCl and/or RBV in rats. Our observations indicate that the dissolution rate in 0.1 mol/L HCI under standardized conditions is highly predictive of potential bioavailability and that it would be the most practical approach to developing a reliable and sensitive screening procedure for predicting and monitoring the bioavailability of commercial elemental iron powder products. Some, but not all, of the carbonyl and electrolytic iron powders had the highest predicted bioavailability values. The predicted bioavailability for the reduced iron products was lower and variable, with the lowest values being recorded for the carbon monoxide and other reduced iron products. Two powder types were selected for a human efficacy trial, electrolytic (because it is the iron powder type recommended by WHO) and hydrogen-reduced (because of its widespread use). Electrolytic/A131 and H-reduced/AC-325 had relative efficacies compared with ferrous sulfate monohydrate of 77% and 49%, respectively, based on the change in body iron stores in Thai women with low iron stores, who received an additional 12 mg iron per day, six days per week for 35 weeks in wheat-based snacks. We conclude that there is significant variability in the bioavailability of the commercial iron powders that we evaluated (those used for food fortification at the time that our studies were initiated), and that bioavailability is related in part to production method. The bioavailability of some carbonyl and electrolytic iron powders may be adequate for effective food fortification. The reduced iron powders that we tested are unlikely to have an adequate impact on iron nutrition at the fortification levels currently employed, although preliminary analysis of a new H-reduced product indicates that it may be possible to improve the bioavailability of individual powders of this type of product. We did find significant differences among products in both the electrolytic and carbonyl categories. Therefore, all products should be screened rigorously.

Production of iron powder from iron oxide by combined reduction with carbon and methane

Production of iron powder from iron oxide by combined reduction with carbon and methane

Electrodeposition of iron fragile layer on nickel substrate with emphasis on iron powder production

Abstract The study of galvanostatic iron electrodeposition on nickel substrate was carried out in order to establish the most suitable experimental conditions to obtain pure iron fragile layers to be removed and transformed into powder. Under current density of 40 mA cm −2 the deposits obtained were satisfactory to be transformed into a powder. In the light of the cathodic polarization phenomena and Scanning Electron Microscopy (SEM) graphs an explanation has been offered for the various trends observed during the investigation. The optimum storage conditions for the iron powder was found to be in vacuum using the Schlenk technique. The results led to conclude that the use of stainless steel as anode must be avoided since the presence of Mn is not beneficial for the performance of iron electrodes in charge/discharge reactions in Ni/Fe batteries.

Challenges for the iron powder industry in the next millenium : J.Tengzelius. (Höganäs AB, Höganäs, Sweden.)

Semisteel, the main by-product of titania slag-smelting process of ilmenite with an electric furnace, cannot be widely used in the steel-making process because of its high sulfur and low carbon contents. Hoganas and water atomization processes are currently the major iron powder production techniques in China, but both have obvious drawbacks. A novel and clean iron powder production process is suggested to enhance the added value of semisteel, improve the production efficiency, and reduce the energy and water consumption. A circle of water curtain was set around a rotary cup atomizer. The iron powders and hot vapor produced in this new process can be applied in the reducing and leaching steps of sulfate process, respectively, which is propitious to cut down the manufacturing cost of titanium dioxide and realize optimized resource allocation and highly effective utilization. The effect of rotating speed on the obtained iron granules was investigated. Result shows that the median diameter of the obtained granules decreases with the increase in rotating speed and varies from 0.55 mm to 0.49 mm when the rotating speed is in the range of 600 rpm to 1000 rpm. The atomization mechanism of the molten semisteel was calculated to follow the ligament formation mode under the given experimental conditions. The obtained iron granules were analyzed by X-ray diffraction and scanning electron microscopy. The surfaces of the iron granules are smooth and are covered with a layer of iron oxides, including Fe3O4, FeO, and relatively small amounts of Fe2O3. Reduction experiments in hydrogen atmosphere at 1173 K (900 °C) were conducted to remove the iron oxides on the surfaces of the iron granules. The oxidation degree of iron powders decreases from 14.06% to 4.33% when the particle size varies from 0.3–0.35 mm to 0.6–0.65 mm. After reduction, the iron powders have dramatically rough surfaces and large specific surface areas, which benefit their reaction as reducing agents in the sulfate process.

Production of iron powder from iron sulfoheptahydrate

Production of iron powder from iron sulfoheptahydrate

Sintering of Fine Iron Powders Produced from Ferrous Oxalate Dihydrate

The oxalate rather than the nitrate was chosen because of the difficulties in heating the latter and removing the large amounts of nitrogen oxides that would be formed. Many industrial processes, such as the Hogana.s process (magnetite and carbon) and the Pyron process (millscale and hydrogen), involve the decomposition of oxides to produce iron powders. Other techniques involve the chloride, as in the Peace River process,! to produce iron. The ammonium sulphates have been used to produce nickel powders as in the Sherrit-Gordon process.2 The last two processes involve heating the compound in a stream of hydrogen. The Sol-Gel process3 makes use of the hydroxide gels which are reduced in hydrogen; this method is able to produce submicrometre sized powders. More elaborate reduction processes are used by the Domsa process for making iron powders by the reduction of millscale (Fe304) in methane. Other methods using hydrides as reducing agents4 have been used to produce vanadium and chromium powders. Arias5 describes a method used to produce chromium and nickel from their oxides by reduction with magnesium, sodium, or lithium vapour. It is possible to use the carbony16 to produce nickel powders by heating alone, as in the Mond process, and in theory this process could be used to produce iron powders. In many of the processes mentioned it is sometimes difficult to control the final particle size of the powder and, in some iron powder production processes, a crushing/grinding/milling stage has to be introduced. The oxalate has not been used in an industrial metal powder production process so far; however, the present work was part of a larger research programme 7 investigating the kinetics of reduction processes involving metallic salts. The results on the fine iron powders produced from that research by this route are presented here because of