Physico-chemical Properties of Mill Scale Iron Powders (original) (raw)
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Iron Powders from Steel Industry by-products
ISIJ International, 2018
Global iron and steel making industries generate immense number of by-products, among which few are already being utilized for the generation of high value products, while few are still struggling to gather a good market space. Waste utilization is the major concern for every industrial maker. In this context, iron powder which holds immense market in applications like powder metallurgy (PM) parts, welding electrodes, advanced oxidative agents for water treatment, food fortifying agents, metal injection moulding, catalysts, fuels etc., can now be a novel outcome from steel industry by-products. Iron powder can be manufactured by various techniques like reduction, atomization, electrolysis, etc., resulting in fine particles of various morphologies ranging from spherical to irregular shapes and low to high purity. The application of these iron powders is depended on the process, quality and purity of the desired product.
Direct Reduction Recycling of Mill Scale Through Iron Powder Synthesis
ISIJ International, 2019
Mill scale, a potential raw material for recycling from hot rolling mill operations is chosen and one step thermo-chemical reduction technique is employed to beneficiate the iron content in the form of powdered iron. Experiments are conducted at various temperature (600-1 300°C) and time (1-4 h) combinations using hydrogen as reducing atmosphere. Physical and chemical properties of mill scale iron powders (MIP) are analysed using particle size analyser, gas pycnometer and wet chemical testing. MIP are also characterized for phase and morphology using X-ray diffractometer and scanning electron microscopy respectively. Effect of parameters like temperature of reduction, time of reduction, particle size of raw material, sintering and grinding on the iron powder synthesis is well studied. Mill scale iron powder with > 99% degree of metallization, 97% Fe (T), > 96% Fe (met) and 2.63 g/cc apparent density is obtained at 1 200°C, 4 h and 1 300°C, 4 h parameters and this material would stand promising for recycling through nutrition supplements, body warmers, water purification, sound insulators, etc applications.
Preparation of iron Powders by Reduction of Rolling Mill Scale
2013
The objective of this work is the recycling of mill scale formed during the steel hot rolling process with a reducing gas (carbon monoxide) in order to produce iron powder having characteristics required by powder metallurgy. The reduction was carried out at various temperatures (7501050°C) during different times ranging between 40 and 180 min in an atmosphere of pure CO. The produced iron powder was characterized by chemical analysis, x-rays diffraction, optical microscopy and scanning electron microscopy. These methods of investigation confirm the presence of iron, graphite and iron carbide (Fe3C) as the products of reactions. The maximum iron content (98.40% Fe) in the iron powder was obtained by reduction of mill scale at 1050°C for 180 min. A reduction annealing under hydrogen makes it possible to decrease carbon and oxygen content of the reduced iron powder up to acceptable values.
New Processing Route for Production of Fine Spherical Iron Powder
2015
Today fine spherical iron powders are produced dominantly by the carbonyl process. It is used for innovative solutions for a wide spectrum of different applications like diamond tools, magnetorheological fluids, materials absorbing microwaves but mostly for metal injection molding (MIM). Herewith the high powder price has a considerable share on the product costs and is therefore a limiting fact. In this paper the powder properties and sintering results of a fine spherical iron powder which is produced by using iron oxide as a by-product of steelmakers and a patented hydrogen reduction processes will be discussed. Further powder processing steps were identified to separate the sinter cake and adjust the powder properties. Milling technologies and parameters were evaluated which support the particle shearing and spheroidization. The characterized sintered parts demonstrate the high potential of the cost-efficient powder with comparable properties to that of the carbonyl iron powder.
MATERIALS TRANSACTIONS, 2014
The present investigation focuses on the improvements in chemical homogeneity and related powder properties of partially alloyed Fe 1.50Cu1.75Ni0.50Mo powder by using a nanopowder process. The nanosized oxide powders of CuONiOMoO 3 were prepared by ballmilling for the alloying elements and blended with iron powders. The powder mixture was annealed in a reducing atmosphere, in order to reduce the oxide powders and thereafter partially alloyed with the iron powder. The produced powder was used to evaluate the microstructure, chemical composition, compressibility, and sinterability. It was found that the powder had a uniform distribution of alloying elements with high compositional homogeneity. The fine alloying elements were mostly located in the grooves of the iron powder surface, yielding morphological change, which effectively improved the flow, packing and compaction properties of the powder. The nanopowder process also promoted a diffusion reaction during sintering at 1200°C for 2 h with a homogeneous microstructure and chemical composition.
The ever-increasing development of applying the iron pieces made by powder metallurgy in car industries and other usages depends on making pieces with high density and consequently acceptable physical and mechanical properties. Regarding the effect of decrease in the powder bits' size on improvement of the mechanical characteristics and on decrease in the temperature of sinter, the experiments on the pure iron powder with the bits' size of 5, 45, 63 micron in which 20% of iron nanopowder was added to the powder with the bits' size of 45 micron, have been studied. Mere iron nanopowder also was applied for experiments. Pieces are compacted under 300-850 MPa and lubricants by0.4 and 0.6 percent of the total weight was mixed with the powders. Various amounts of sintering time and sintering temperature were considered for the sintering of the samples. The survey suggested that applying micro powders resulted in an increase in the linear density and the strength at the relatively high temperatures and high keeping times. Sintering temperature and shrinkage has declined considerably with the decrease in the powder size and as a result the strength increases. High strength for products made by smaller powders under high pressures and low sintering temperatures using lubricated frame wall are obtained. SEM pictures from the fracture junctions of the samples show the decrease in porosity due to the close impact of the smaller powder size.
Effect of Iron Ore Pellet Size on its Properties and Microstructure
The properties of the pellets and their microstructure mainly depend on the raw material mix proportion, raw material chemical composition and the physicochemical conditions like the temperature and oxygen partial pressure within the induration machine. The pelletising plant products are in the size range of 8 to 16 mm. With increasing pellet size, the sintering intensity, thermo-chemical conditions and formation of different phases vary across its cross section. The time required for varies reactions within the pellet is directly proportional to the pellet size. Because of differences in pellet size, the reduction and oxidation process takes place under different conditions resulting in different phases and microstructures. In this work, detailed studies were carried out on pellets of different size (8 to 16 mm) produced from a 4.2 Mtpa pellet plant for their physical, metallurgical and microstructural properties. It was observed that the pellets in the size range of +8 to -12 mm s...
Production of sponge iron powder by reduction of rolling mill scale
Ironmaking & Steelmaking, 2012
Rolling mill scale is a solid by-product of the steelmaking industry that contains metallic iron (Fe) and three types of iron oxides: wustite (FeO), hematite (α-Fe 2 O 3) and magnetite (Fe 3 O 4). It also contains traces of non-ferrous metals, alkaline compounds and oils from the rolling process. A study is made of the reduction of mill scale to sponge iron using coke at different temperatures and times. The reduced samples are studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Oxygen analysis is carried out by combustion in a LECO oven. The reduction of mill scale allows the new use and development of this material to obtain sponge iron that can be re-used to the electric furnace as metallic load in steel manufacturing or as a raw material in the production of iron-base powder metallurgy parts.
Modification of the Surface of the Iron Powder as an Ingredient of the High Calorific Mixture
Textural properties of iron powders obtained by reduction of iron(II) compounds and by electrolysis were determined. Their specific surfaces were 0.38 and 0.43 m 2 g -1 respectively, and the prevailing grain sizes amounted to 10 and 43 µm respectively. Total content of the determined metallic impurities was 0.055 wt.% in the preparation obtained by the electrolysis while in the preparation obtained by reduction it was 0.025 wt.%. It was proved that in initial samples the α-Fe2O3 phase occurred in the outer oxide layer present on the surface of Fe grains, and below this phase a layer of magnetite was found, the thickness of which was considerably greater in iron obtained by electrolysis. Measurements of selected properties showed that modification of the iron powder surface carried out by reduction with dihydrogen led to decreasing the linear rate of burning of the high calorific mixture Fe/KClO 4 but it did not affect its calorific value. Moreover, it was found that modification of ...
Characterization of Iron Production with Millscale by Product Reduction
2021
Millscale is a large by product of metal factory. Many methods to recycled it to many applications. The aim of this research is recycled millscale to produce the iron by reduction method with graphite as reductant agent. The reduction process was deed by milled millscale and graphite powder with 4:1 weight ratio was by used High Energy Milling with 4, 6, 12 hours milling time variations. The powder then was characterized by X-Ray Diffraction (XRD), Vibrating Sample Magnetometer (VSM) and SEM-EDS test. The XRD test result is Fe3C as a main phase then carbon, magnetite, wustite and Iron as a minor phase. The percentage of iron composition is increase during milling times amount to 6; 10.9; 13 %. The remanence for the 4, 6, and 12 hours of milling time variation, is 2.89, 3.39, and 4.98 emu/g, for the coercivity (Hc) is 209.58, 188.47, and 223.65 Oe and the magnetic saturation number is 22.59, 30.7, 39.15 emu/g, from Hc value it is concluded that the powder has superparamagnetic behavi...