Effect of gas mixtures on the reduction and carburization behaviors of vanadium titanomagnetite pellets in H 2 -CO-CH 4 -H 2 O-CO 2 -N 2 atmospheres

Isothermal reduction and comparative analysis of reaction kinetics of sponge iron produced from hematite-charcoal reaction using non-contact direct reduction method

Targeted changes in the physical properties of soils, including through afforestation, are an important component of land use practices that are aimed at obtaining sustainable crop yields, which is especially important for potentially highly fertile chernozem soils. The physical properties of ordinary chernozems under steppe vegetation (used as a control) and plantings of Robinia pseudoacacia L. and Quercus robur L., as well as chernozem luvosol under natural forest vegetation, were studied in the field, as well as in laboratory conditions using soil samples taken from 12 areas established within Dnipropetrovsk region (Ukraine). As a result of the study, it was established that the studied ordinary chernozems and luvic chernozems are classified as silty loam according to their granulometric composition. The growth of acacia and oak plantations led to an increase in sand content and a decrease in silt content, and the growth of natural forest vegetation contributed to an increase in sand and silt content and a decrease in clay content in black soils. The influence of forest vegetation on chernozems led in the 0–20 cm layer to an increase in the content of aggregates of fractions > 2 mm and water-resistant aggregates of fractions > 0.5 mm and a decrease in the content of aggregates of fractions < 1 mm and water-resistant aggregates of fractions < 0.5 mm compared to chernozems under steppe vegetation. The growth of forest vegetation caused a decrease in the density and density of the solid phase, and an increase in the total porosity of chernozems in the layers of 0–20 and 20–40 cm. The influence of forest vegetation on ordinary chernozems and luvic chernozems contributed to an increase in the content of available water for plants and an increase in their water permeability compared to ordinary chernozems under steppe vegetation. Ordinary chernozems under acacia and oak plantations are characterized by increased electrical resistivity, and luvic chernozems under natural forest vegetation are characterized by reduced electrical resistivity compared to ordinary chernozems under steppe vegetation. The growth of forest vegetation contributed to a decrease in the dielectric constant of chernozems. The influence of natural forest vegetation leads to more pronounced changes in the physical properties of chernozems compared to the influence of acacia and oak plantings.

Recently a special attention is being paid on the combination of different ironmaking technologies in the integrated steel plant to maximize the efficiency of the overall process. The utilization of coke oven gas for production of direct reduced iron (DRI) in the integrated steelmaking route is still under evaluation and discussion. In this study, iron ore pellets were isothermally reduced with simulated original and reformed coke oven gas (RCOG) at 700–980°C. The results were compared with those obtained by the reduction of pellets with the original and reformed natural gas (RNG). The highest reduction degree was obtained for the pellets reduced with RCOG while the lowest reduction degree was exhibited by original natural gas. On the other hand the rate of reduction with original coke oven gas was sharply increased at temperature of about 900°C to become higher than that of RNG. A slow down phenomenon appeared at the later stage of reduction due to the intensive carbon deposition. The soot formation increased as CH4 content and/or the temperature of reducing gas increased. Reflected light microscope, scanning electron microscope with EDX, and high performance X-ray diffraction analysis were used to estimate the reduction kinetics and mechanism.

A review of publications on the structure, properties, fabrication methods, and application fields of materials based on the Cr2AlC MAX phase is given. It is noted that the most promising method of formation of such materials is self-propagating high-temperature synthesis (SHS), one of the directions of which is SHS metallurgy. A powder mixture of chromium III and chromium VI oxides of the analytical grade, aluminum of ASD-1 grade, and carbon is used as the base charge in investigations. The adiabatic combustion temperature and composition of final products is calculated using the THERMO special program. Experiments were performed in an SHS reactor with volume V = 3 dm3 under the initial pressure of inert gas (Ar) P0 = 5 MPa. The influence of the ratio of initial reagents on SHS parameters (the combustion rate, pressure increment, and yield of the target product), composition, and microstructure of target products is investigated experimentally. A scientific approach of the formation of cast materials in the Cr–Al–C system consisting of the Cr2AlC MAX phase and phases Cr3C2 and Cr5Al8 by the SHS metallurgy method is developed. The structural-phase states of target products are studied. It is established experimentally that, varying the content of initial reagents (aluminum and carbon) in the charge, it is possible to substantially affect the synthesis regularities, composition, and microstructure of final products. An increase in the content of the Cr2AlC MAX phase in the final product and a decrease in the Cr5Al8 content occur with an increase in the carbon content (above stoichiometric) in the initial mixture. An increase in the aluminum content (above stoichiometric) in the initial mixture leads to an increase in the content of the Cr2AlC MAX phase in the final product and a decrease in the content of the Cr3C2 phase.

The present investigation deals with the feasibility study of the process development for production of Directly Reduced Iron (DRI) using waste/low grade iron ore (slime), mill scale and waste/less reactive coal (partly oxidized coal i.e. Jhama coal). In order to get most green and dry strength for safe handling and transportation, the pellets of iron ore slime and the pellets of mill scale were made in disc pelletizer with optimum moisture. Dried iron ore slime pellets reduced the bed of Jhama coal fines at different temperature and sintering time. Detailed investigation for the reduction kinetics of slime pellets with Jhama coal has been carried out to explore the feasibility of slime pellets reduction. Based on reduction kinetics, process criterion for reduction of pellets with Jhama coal is optimized to produce highly metallic DRI. The Reduction of dried pellets was carried out without in duration/firing higher temperature as compared to the conventional DRI process yielding high energy efficient and cost-effective process. An optimized work flow sheet and innovative process has been developed for production of high quality DRI utilizing waste iron ore slime and less reactive coal (Jhama coal). The DRI produced from this process have high metallization (<92%) suitable for blast furnace and electrical for iron and steel making. I. Introduction Mill scale is an iron oxide waste generated during steelmaking process, casting and rolling. The mill scale contains very high percentage of iron which is generated during making of steel towards production of various long and flat products. The major part of mill scale in an integrated steel plant is recycled for in house consumption; but no commercial process for its utilization is so far available for the secondary sector in industries. So it is either dumped or exported at a very low price. It is appeared on the outer surfaces of plates, sheets or profiles when they are being produced by rolling red hot iron or steel billet in rolling mills. It is composed of iron oxides mostly ferric and is bluish black in color. It is regularly less than 0.1 mm (0.0039 in) thick and initially adheres to the steel surface and protects it from atmospheric corrosion contributed no break occurs in this coating. Here some preliminary results of a laboratory scale investigation has been done which involves pelletization of mill scale, using steel plant waste as an additive and following reduction of the air dried pellet by non-cooking coal fines under conditions, simulating a tunnel kiln. The results of this investigation indicate that the green pellets could be successfully handled, without generating much of fines and could be change to highly metalized Directly Reduced Iron (DRI) at a moderate temperature and at a reasonably low heating time.Mill scale, a high iron containing body was thus used as a waste for a long time and was dumped. However, in recent past a convincing part of mill scale is being exported to China at a very low price. Though a small amount of mill scale is utilised in ferroalloys, cement and petrochemicals industry, there is a potential for production of almost 1.0 Mt of steel, alike with the current level of mill scale generation. All the above calls for an initiative to find satisfactory means for effective utilization of mill scale. The generation of steel and corresponding mill scale in India is given in figure 1.

The decline in ascorbic acid content is associated with cadmium toxicity of rice seedlings

Reduction of iron ore fines by coal fines in packed and fluidized beds has been studied. The investigation includes study of the kinetic aspects of reduction, carbon and sulfur content of the direct reduced iron (DRI) produced, and metallography of the products. For both processes, the kinetic data fit the first-order reaction model. Reduction in a fluidized bed is much faster than in a packed bed system. In both cases, DRI contains a substantial amount of free carbon at the initial stages of reduction. At the later stages of reduction, the carbon present in the DRI is mainly in the combined state. For identical temperatures and particle sizes, reaction in fluidized bed is much faster compared to that in a packed bed. At any particular degree of reduction, sulfur content in DRI samples produced by fluidized bed reduction is always more than that of DRI samples produced by packed bed reduction. Scanning electron microscopy (SEM) micrographs reveal that metallic whiskers formed during reduction in packed beds only. These whiskers become more prominent at higher temperatures and longer times.

The purpose of the scientific publication is a comparative analysis of the chemical composition and microstructure of modern samples of typical chernozems (Vermic Haplic Chernozem) and meadow-typical chernozem soils (Gleyic Chernozem) with 130-year-old samples taken by V.I. Vernadsky in the Kremenchuk district of Poltava region. Age-related changes in the content of organic matter and oxides revealed significant differences in the genesis of natural and agrogenic edaphotopes of the southern of Poltava region. In the conditions of natural edaphotopes, an increase in the total humus content by an average of 0.8 % in five cases out of six is recorded. On the other hand, for all soil samples from agrogenic edaphotopes, a decrease in the humus content by an average of 1.1 % is identified. A slight (1.1 times) but more intense increase in the content of silica (SiO2) in agrogenic edaphotopes (almost 10 %), compared with edaphotopes of natural biogeocenoses (by 5.5 %), as well as an increase in the content of alumina (Al2O3) on average in two times (by 3.7 %) are established. A decrease in the content of Phosphorus compounds by an average of 1.4 times (by 0.1%) against the background of an increase in the content of substances containing Potassium by 7.5 times (by 1.4 %) is registered. The homogeneity of the micromorphological organization of organogenic and mineral components of soils of modern samples and samples taken 130 years ago is revealed. Based on the research results, recommendations for the scientific substantiation of a comprehensive project of environmental measures aimed at protection and balanced uses of Poltava soils are formulated.

Comparative life cycle assessment of natural gas and coal-based directly reduced iron (DRI) production: A case study for India

Direct reduced iron (DRI) shaft furnace flow field has important influence to the DRI production process, and the ventilation is a key factor for the velocity and pressure distribution of the gas flow in the furnace. At present works, the direct reducing gas velocity distribution and pressure distribution of DRI shaft furnace were studied with different ventilation. By the analysis of numerical simulation, the result was found that the direct reducing gas velocity increase with height in the shaft furnace reduction section. The velocity of the direct reducing gas augment with the increase of ventilation. The direct reducing gas pressure add with increasing height in the shaft furnace reduction section. With ventilation increasing, the pressure of the shaft furnace ventral part increase, and the pressure gradient increase in the direction of height in the DRI shaft furnace.

Influence of roasting characteristics on gas-based direct reduction behavior of Hongge vanadium titanomagnetite pellet with simulated shaft furnace gases

With the plants of runner type (Chiba No. 45 and No. 74), various nutrient treatments were held on acid-washed sand of the fruiting zone throughout the experiment. Flactional analyses of calcium and organic acid were carried out in the pods of each treatment, namely the samples were extracted by 66 % alcohol, 2 % acetic acid and 1 N hydrochloric acid in the case of calcium, and by distilled water and 1 N hydrochloric acid in the case of organic acid. And constituent organic acids were determinated by paper chromatographic methods. 1. Production of unfilled fruit remarkably increased in the plants which received distilled water, minus calcium, plus nitrogen, plus phosphorus, plus potassium and p1us magnesium. In both cases of shell and seed, content of 1 N HCl soluble calcium made a sharp distinction between the above treatments and other nutrient treatments such as complete, minus nitrogen, minus phosphorus, minus potassium, minus magnesium and plus calcium during the peanut development. But in young fruit, the content of calcium by fractional analysis was almost equal irrespective of the treatments of complete, distilled water and minus calcium. 2. The content of free acid (H2O soluble acid) lessened considerably during fruit development in all treatments holding calcium element. This decrease in acid content was due chiefly to the decrease in contents of free citric and malonic acid. However, the content of free acid in all treatments with-holding calcium such as plus potassium, remained nearly unchanged in shell, and increased in abnormal seed during the season. This increase in acid content of the seed was mainly caused by the increase in content of malonic acid. The content of combined acid (HCl soluble acid) increassed parallel with the content of HCl soluble calcium in shell. And this increased amount was due chiefly to the increase in the content of oxalic acid, so that, it can be conjectured that calcium absorbed from fruiting zone combines with oxalic acid in shell during the maturity. In fact, there were not observed the existence of oxalic acid and the increasing amount of HCl soluble calcium in any treatment of calcium deficiency. But the similar relation was not clear among seeds in all treatments.

It is known that flurenizide is a newly synthesized drug with pronounced antimicrobial, immunomodulatory functions. However, its effect on the functional properties of cells, in particular germ cells, is unknown. The aim of this study was to determine the presence of sialic acids as the final components of glycoconjugates, the main macroergic compound - ATP, to evaluate the generation of O2¯ in embryos of lobster (Misgurnus fossilis L.) under the influence of the antibiotic flurenizide. Studies have been performed on embryos of Misgurnus fossilis L. After fertilization, the zygotes were placed in Petri dishes with solutions of flurenizide in concentrations of 0.01; 0.05; 0.15; 1.0; 5.0; 15.0 mM, where allowed to develop. At the development stages, 2 blastomeres, 16 blastomeres, 64 blastomeres, VIII (256 blastomeres) and X divisions (1024 blastomeres) were sampled. In parallel, control studies were performed, where flureniside was not added to the samples. The content of sialic acids, ATP, superoxide anion radical was determined in the selected samples. We found that flureniside at the lowest concentration of 0.01 mM does not cause changes in the content of superoxide anion radical during early embryogenesis. The antibiotic in the maximum concentration causes changes in the content of free radical from the stage of development of 16 blastomeres to 1024 blastomeres, and from the stage of 64 blastomeres there is an increase in its number. Probably flurenizide at a concentration of 15.0 mM is the most reactive. It is known that flurenizide has antioxidant properties, but in its structure there are groups that have a toxic effect, which is most pronounced when exposed to high concentrations. In general, at the stage of development of 16 blastomeres there is a decrease in the amount of О2¯ under the influence of the studied antibiotic. At this time, the content of this free radical in the control increases, compared with other stages of development. Flureniside leads to an increase in the content of superoxide anion radical at development stage 2, 64 blastomeres and is particularly pronounced at concentrations from 0.05 to 15.0 mM at development stages 256 and 1024 blastomeres. 1024 blastomeres are the 10th stage of separation, where desynchronization occurs and the mitotic index decreases. Probably, the changes that take place at this stage of development are related to this. The antibiotic causes an increase in the content of sialic acids in the first stage of crushing (2 blastomeres). In step 16 of the blastomere, flureniside in low concentrations leads to a decrease in the content of sialic acids. However, already at the stage of separation of 64 and 256 blastomeres, the test substance in all concentrations causes a predominant decrease in the amount of sialic acids. At the last stage of synchronous crushing (1024 blastomeres) flurenizide in the maximum investigated concentration (15.0 mM) causes a significant accumulation of sialic acid content. Flureniside at concentrations of 0.15, 5.0 and 15.0 mМ causes a decrease in ATP content in loach embryos at the stage of development of 256 blastomeres by 28, 67 and 38 %, respectively. An increase in ATP content by 33 % occurs under the influence of flurenizide at a concentration of 1.0 mM. The ATP content also increases at the stage of development of embryos of 1024 blastomeres under the influence of flurenizide of all studied concentrations. Analysis of variance has shown that a significant contribution to the growth of ATP, sialic acid and superoxide anion radical, during the early embryogenesis of lobster embryos, is made by the factor of embryo development, while the factor of flureniside has a smaller contribution. Therefore, studies have shown that flurenizide causes increased generation of superoxide anion radical, decreased sialic acid content, as well as changes in ATP content in embryonic cells during early embryogenesis.

Hydrogen metallurgy is a technology that applies hydrogen instead of carbon as a reduction agent to reduce CO2 emission, and the use of hydrogen is beneficial to promoting the sustainable development of the steel industry. Hydrogen metallurgy has numerous applications, such as H2 reduction ironmaking in Japan, ULCORED and hydrogen-based steelmaking in Europe; hydrogen flash ironmaking technology in the US; HYBRIT in the Nordics; Midrex H2™ by Midrex Technologies, Inc. (United States); H2FUTURE by Voestalpine (Austria); and SAL-COS by Salzgitter AG (Germany). Hydrogen-rich blast furnaces (BFs) with COG injection are common in China. Running BFs have been industrially tested by AnSteel, XuSteel, and BenSteel. In a currently under construction pilot plant of a coal gasification-gas-based shaft furnace with an annual output of 10000 t direct reduction iron (DRI), a reducing gas composed of 57vol% H2 and 38vol% CO is prepared via the Ende method. The life cycle of the coal gasification—gas-based shaft furnace—electric furnace short process (30wt% DRI + 70wt% scrap) is assessed with 1 t of molten steel as a functional unit. This plant has a total energy consumption per ton of steel of 263.67 kg standard coal and a CO2 emission per ton of steel of 829.89 kg, which are superior to those of a traditional BF converter process. Considering domestic materials and fuels, hydrogen production and storage, and hydrogen reduction characteristics, we believe that a hydrogen-rich shaft furnace will be suitable in China. Hydrogen production and storage with an economic and large-scale industrialization will promote the further development of a full hydrogen shaft furnace.

Reduction of Fe-bearing FINEX process waste and carbon composite pellets from 1373 K to 1573 K to produce DRI (direct reduced iron) for use in the blast furnace was investigated using a modified thermo-gravimetric analyzer. Reduction from the initial Fe2O3 was not uniform throughout the composite pellet. Oxygen removal from the Fe2O3 rich composite pellets over 84% was only observed at 1573 K. Lower temperatures resulted in significantly un-reduced FeOt due to the premature consumption of the carbon. A peripheral boundary of FeOt·Al2O3 and 2FeO·SiO2 phases surrounding the reducible FeOt was observed in some of the partially reduced cross-sectional SEM (scanning electron microscope) images that could hinder reduction. From the apparent activation energy, interfacial reaction seems to affect the kinetics of the Fe-bearing process waste composite pellets. Bursting of pre-dried composite pellets containing less than 2 mass% moisture was simulated in a RHF hearth simulator. From direct observation of pellets charged between 1173 K to 1573 K, medium-sized pellets between 9.4 to 12.4 mm diameter showed less bursting of the pellet, when charged below 1273 K. In addition, modification of the physical strength of the hard bedrock formed from pellet bursting could be softened with additions of SiO2.