Coal Ore Research Articles

Separation Processes for Self-Sufficient Recovery of Vanadium Resources in Korea

Vanadium (V) is a transition metal with a silver-gray color. It is commonly used in high-strength alloys because of its ability to improve impact and abrasion resistance, even when only a small amount is added. In recent years, there has been active research into vanadium reduction-oxidation flow batteries (VRFB), which are suitable for use in the development of storage devices for renewable energy applications. Separation and recovery of vanadium from low-grade stone coal ore is currently being investigated in China. Various pre-treatment processes have been studied, such as magnetic separation and gravity separation, that can be used to treat large quantities of ore, as well as flotation processing based on the surface characteristics of the minerals. There is an urgent need for the development of separation technologies to facilitate the self-sufficient extraction of vanadium resources present in Korea.

Steel Production from Metal-Bearing Waste

Analysis of two-stage iron and steel production by means of a blast furnace and an oxygen converter reveals its advantages and disadvantages. The main disadvantage is that carburization and decarburization of the metal are opposing processes and generate large quantities of waste with relatively high iron content. The organization of reduction and smelting of such waste—for the example of converter sludge—shows that direct reduction of iron by solid carbon, without carburization, is possible. Ore–coal pellets are produced experimentally. Their subsequent reduction and smelting yields metal ingots with the composition of steel.

Effect of gangue composition on iron nugget production from iron ore–coal composite pellet

The rotary hearth furnace iron nugget process has advantages of short reaction time, high-quality reduced product and wide adaptability of raw materials and meets the trend in ecofriendly development of iron and steel industry. Although the rotary hearth furnace iron nugget process cannot replace blast furnace process, which is affected by production scale, thermal efficiency and technical maturity, it is still a feasible technology for iron production. In order to realize the efficient utilization of high Al2O3 iron ore resources, preparation of iron nuggets with high Al2O3 iron ore was studied. Using iron concentrate as raw material, the effects of slag basicity, Al2O3 and MgO on melting separation of iron ore–coal composite pellets, such as the melting separation temperature, the melting separation time, the morphology of melting separated product, and the recovery rate of iron nugget, were studied. The results showed that relatively low or high liquidus temperature of slag had a negative effect on reduction and melting separation of iron ore–coal composite pellets. The increase in fluidity index of slag resulted in a decline in the melting separation temperature and time of iron ore–coal composite pellets. Optimum basicity to produce iron nuggets using iron ore–coal composite pellets was 0.8–1.0, 0.4 and 0.8 for iron concentrate containing 2, 4 and 6–10 wt.% Al2O3, respectively. Corresponding liquidus temperature and fluidity index of slag were 1300–1475 °C and above 4.5, respectively. Under this condition, the lowest melting separation temperature and the shortest melting separation time of iron ore–coal composite pellets were 1375 °C and 7 min, respectively. The recovery rate of metallic iron in the form of iron nugget could reach about 94%.

Synthesis of multifunctional photocatalyst vanadium oxide/activated carbon via in situ utilization of stone coal ore

In this work, activated carbon (AC), vanadium oxide (V2O5), and V2O5/AC photocatalyst were prepared by in situ utilization of stone coal ore for the first time. The synthesis conditions for activated carbon (AC) and V2O5/AC were thoroughly investigated via orthogonal experiments and single factor experiments, respectively. The obtained optimal parameters could be directly adopted in practical application about utilization of stone coal ore. The optimal deashing experimental parameters for stone coal ore were: HF concentration of 15%, H2SO4 concentration of 15%, acid leaching temperature of 85 °C, and acid leaching time of 2 h. The as-prepared activated carbon from stone coal ore could be applied to the removal of methylene blue. The as-prepared V2O5/AC photocatalyst possessed a highly visible-light-driven photocatalytic activity for the removal of Rhodamine B (RhB) dye. The RhB degradation ratio could reach to 90.0% after only 3 h photocatalytic reaction. This photocatalyst would be possibly applied to treatment other organic dye wastewater. Actually, this work would extend the application field of stone coal ore. Most importantly, we hope the proposed new concept that in situ utilization of ore can be widely spread and applied.

Alloy Production from High-Silica Manganese Ore and High-Ash Kazakhstan Coal

Engineering principles are outlined for the production of silicon–aluminum–manganese alloy from high-silica manganese ore and high-ash Kazakhstan coal (from the Borly and Saryadyr fields in the Karaganda and Teniz-Korzhunkol coal basins), Tekturmas quartzite, and Shubarkol long-flame coal. By thermodynamic diagram analysis of the four-component Fe–Si–Al–Mn system on the basis of handbook data (and calculated thermodynamic data where no handbook data are available), a mathematical model of the phase structure may be developed. The aluminum–silicon–manganese composition obtained from the Karaganda and Teniz-Korzhunkol coal, in contrast to the aluminum–silicon–manganese alloy from Ekibastuz coal, is shifted on the thermodynamic diagrams toward tetrahedra with relatively large volume. This indicates increased stability and technological predictability. The results of tests in an ore furnace show that aluminum–silicon–manganese alloy of regular composition may be obtained by a continuous slag-free method from high-ash Borly and Saryadyr coal and unconditioned high-silica manganese ore from the Western Kamys field if Shubarkol long-flame coal and Tekturmas quartzite are added to the batch. The alloy composition may be regulated by adding manganese ore to the weighed batch materials. An alloy with the following composition is obtained: 32–53 wt % Si, 15.5–25.0 wt % Al, 12–32 wt % Mn, 8–20 wt % Fe, 0.02–0.05 wt % P, and 0.2–0.5 wt % C. The resulting alloy does not crumble to powder on storage, thanks to the low phosphorus content and high aluminum content (>10%). The phase components of the experimental alloy are determined. The cost of the alloy is low, since it is produced from high-ash tailings coal and unconditioned high-silica manganese ore, with absolutely no coke. The alloy may be used for the reduction and alloying of steel and also as a reducing agent in the production of refined ferromanganese.

МЕТОДИКА ПРОГНОЗИРОВАНИЯ ВРЕМЕНИ ВЫПОЛНЕНИЯ ОПЕРАЦИИ ПО ПЕРЕВАЛКЕ НАВАЛОЧНЫХ ГРУЗОВ

The process of transshipment of bulk cargo within the Eastern cargo terminal of the sea port of Novorossiysk has been considered. A method for calculating the performance of the crane group has been developed, taking into account the interaction of cordon and rear crane subgroups. The method is based on the practical process flow charts of Novorossiysk port for processing coal, cast iron and iron ore. There has been presented the designed method for calculating the coefficient of predicted performance of cargo handling for transshipping the bulk cargoes (e.g., coal, iron ore and cast iron) based on the data on performance of crane equipment, allocated resources (handling equipment and dock machine operator teams). The forecast performance ratio allows to determine whether the operation schedule is ahead or behind the standard of the process flow charts. The method of calculating the forecast time of transshipment of bulk cargoes has been offered, subject to the influence of meteorological factor on productivity of cargo operations. The formulas for calculating the estimated time of the cargo operations at all possible mutual locations on the time axis of the segments of the weather conditions and the time of the operation have been given.

Modelling of trace material flow distribution in a melter gasifier based on thermodynamic multiphase equilibrium calculations

In combination with a complex global market environment, the iron and steel industry is dealing with increasing demands for reduction of environmental and greenhouse emissions. Alternative iron making technologies such as Corex® and Finex® can offer solutions for these challenges. The melter gasifier is the central unit operation of these well-established alternative iron making processes. Both offer considerable advantages with respect to economic characteristics and environmental emissions. Similar to the conventional iron making process of the blast furnace route, a variety of different input materials is required for these processes including coal, coke, lump or fine ore, iron ore pellets as well as limestone and dolomite. Most of these raw materials also carry minor amounts of unwanted compounds such as alkali or zinc-based species. The presence of these materials inside a melter gasifier can lead to instability, problematic process conditions and refractory damages. A better understanding of the distribution of these problematic species is therefore of great importance to plant manufacturers and operators. A variety of different multiphase reactions are responsible for the distribution of trace materials within the melter gasifier. In order to get a better understanding of the complex nature of these reactions, a thermodynamic investigation was carried out using calculation routines of HSC Chemistry and FactSage. Based on the findings of this investigation, a multi-zone model was developed using the simulation platform of the gPROMS ModelBuilder®. The model is separated into distinct reaction zones across the height of the melter gasifier to depict the main iron ore reduction process as well as the governing reactions of trace material components. Validation of the model was carried out using reference data of existing plants. The model described in this work is used to analyse the behaviour of trace materials within a melter gasifier. Due to the highly integrated material flows of the Corex® and Finex® iron making processes, the impact on their operational characteristics can be investigated as well. Through this it is possible to optimise the raw material input of these processes, potentially leading to reduced fuel demand and environmental emissions.

Research on the Post-reaction Strength of Iron Coke Hot Briquette Under Different Conditions

The utilization of iron coke hot briquette (ICHB) prepared by carbonizing iron ore–coal composite agglomerate made from hot-pressing the mixture of iron ore and blended coal has been considered to be an effective countermeasure to improve blast furnace ironmaking reaction efficiency and to reduce carbon emissions. The strength of ICHB after gasification reaction is overestimated by the Chinese National Standard (GB/T 4000/2008, equivalent to the Nippon Steel Corporation method) and should be evaluated by different methods. In this study, the post-reaction strength of ICHB with the addition of different ratios of iron ore under various conditions was experimentally investigated to illuminate the degradation mechanism of ICHB reacted with CO2. The results showed that, with increasing the iron ore addition ratio from 0% to 20%, the reactivity of ICHB reacted with CO2 at 1100°C for 2 h is remarkably increased, due to the catalytic effect of metallic iron in ICHB, while the post-reaction strength is distinctly decreased. Furthermore, stopping at the weight loss ratio of 20%, the strengths of ICHB after reaction at 1100°C under a CO2 atmosphere and a CO2/CO=1/1 atmosphere are clearly reduced, from 89.74% to 75.93% and from 85.24% to 73.65%, respectively. Meanwhile, the post-reaction strength of ICHB under CO2 is greater than that obtained under CO2/CO=1/1 atmosphere, since there is more time for the reaction gas to diffuse from the exterior to the interior of the ICHB under the latter condition. Additionally, the post-reaction strength of ICHB decreases with increasing weight loss ratio regardless of the reaction gas composition; however, it can be maintained at a high level.

A novel approach for pre-concentrating vanadium from stone coal ore

Stone coal, a kind of important vanadium-bearing resources in China, accounts for about 87% of the domestic reserves of vanadium. But the currently developed techniques to extract vanadium from stone coal are all confronted with environmental problems. For example, large quantities of caustic or greenhouse gases discharged in the oxidizing roast process, enormous consumptions of acid or alkali in the leaching step and massive tailings containing toxic V5+ ions.With a view to solve those problems, an innovative process for pre-concentration of vanadium from stone coal was designed and confirmed on a laboratory scale. The distinct features of this design are as follows. Firstly, the environment-friendly Fe2O3 is selected as a capturer of vanadium. Secondly, the natural reducing property of stone coal is utilized to promote the formation of magnetic V-rich phase, Fe2VO4. Thirdly, a high-grade vanadium concentrate is obtained by magnetic separation method.The practicability of this design was confirmed using industrial stone coal on a laboratory scale. When 10 mass% Fe2O3 relative to stone coal was added and roasted at 1200 °C for 3 h, a high-grade concentrate containing vanadium higher than 14 mass% was obtained, and more than 91% of the total vanadium in stone coal was recovered.

Geo-spatial Estimation and Forecasting of LULC Vulnerability Assessment of Mining Activity: A Case Study of Jharia Coal Field, India

Coal is natural deposit minerals and vestibules effect in environment due to operation of mine. Preliminary phase is reconnaissance survey for extraction of coal ores and after that, next operation is happen. In addition, Mining has considered as an eco-unfriendly in natural action but in recent scenarios of Indian coal mines production is very hugs rate with undisciplined nature accompanied by large volumes of hazardous solid, liquid and gaseous material during various mining and related activities. Global aided for the eco-system of mining, associated activities in mining complexes, minimization prevention and extenuation of these encroachments. There are applying geospatial approaches for most important classified classes related to mining activity of land use land cover (LULC) estimation from landsat of four-year data. Vulnerability assessment of classified classes and forecasting of spatial data in future likes features agricultural land, forest, vegetation, mine plantation, scrub land, open cast mine, abandoned mine pit, overburden dump, settlement and water body respectively. It has focused on spatial feature change due to mining activities and mainly use to a case study of Jharia coalfield (JCF), Jharkhand.

Reduction Enhancement Mechanisms of a Low-Grade Iron Ore–Coal Composite by NaCl

The reduction behavior of a low iron grade with high SiO2 content ore–coal composite was investigated in the temperature range of 1143 K to 1263 K (870 °C to 990 °C). Sodium chloride was chosen as an additive to promote this reduction process. The effect of the sodium chloride addition and its mechanism was also investigated. Results showed that the added sodium chloride could enhance the reduction of wustite to iron due to the decrease of fayalite, and a higher metallization ratio of reduced sample was obtained. Thermogravimetric–differential scanning calorimeter analysis showed that sodium chloride could greatly facilitate the gasification process of coal and, thus, provide sufficient carbon monoxide to the reduction process of iron oxides. Meanwhile, sodium chloride promoted the reduction process of iron ore pellets directly as the coal gasification effect was excluded. Microstructures of reduced sample revealed that sodium chloride broke the structure of ore and enhanced the growth of newly formed iron particles. As the ore–coal composite with mol (C/Fe = 1.4) and 3 mass pct sodium chloride addition was roasted at 1233 K (960 °C) for 55 minutes, a reduced sample with metallization ration of 74.45 pct could be obtained.

Energy-saving ferroalloy production

In the laboratory, ore–coal blends consisting of small components (ore, coal, and flux) are prepared. If the coal consumption in the reduction of metals is standardized, ferroalloys with moderate iron content may be obtained; the carbon content in the alloys may be adjusted within the range 0.80–1.5%. This fundamentally new technology for the production of ferrochrome and ferromanganese permits the replacement of electric power by fuel. That considerably reduces production costs, while improving alloy quality and reducing the environmental impact of the process.

Kinetic Behavior of Self-Reducing Pellets Containing Coal of Elephant Grass

Aiming to reducing the gas emissions in the steel mill, in the present study the kinetic behavior of self-reducing pellets containing elephant grass coal and iron ore was investigated through kinetic isotherms for different temperatures. The pellets were isothermally treated in different time intervals for X-Ray diffraction and SEM analyzes. The results obtained by XRD showed that the higher mass of iron in the sample was achieved until the first 24 min. The SEM analysis allowed visualizing the presence of a metallic porous structure closer to edge and whiskers in the center of sample.

Effect of CaO on the reduction behaviour of iron ore–coal composite pellets in multi-layer bed rotary hearth furnace

ABSTRACTThe effect of CaO on the reduction behaviour of iron ore–coal composite pellets has been studied in a laboratory scale multi-layer bed rotary hearth furnace at 1250°C for 20 min. Reduced pellets have been characterised through weight loss, porosity measurement, phase analysis by XRD, and morphology study by SEM. The addition of CaO to the composite pellets showed different effects at different carbon levels. For higher carbon-containing pellets (C/Fe2O3 molar ratio at the upper stoichiometric level of 3), the addition of CaO increased the extent of reduction for all three layers significantly up to a certain limit (4 wt-%); and thereafter the degree of reduction is decreased with a further increase in CaO percentage in the pellets. For low carbon-containing pellets (C/Fe2O3 molar ratio of 1.66), the addition of CaO to the pellets did not show any beneficial effect.

Structural problems of mining region innovative development (Kuzbass, Western Siberia)

At present, the issues of overcoming the negative structural shift in Russian economy, accelerating economic growth, reducing technological and social- and-economic gap between Russia and the developed countries are strategically important. Modern structure of Russian economy which had been developed as a part of market model does not generate the innovative type of development. In this situation, mining regions, the structure of which was formed in the early 20th century and is represented by the extractive industries, are undergoing the greatest problems of innovative development. Therefore, despite high urbanization and industrial development level the economy of Kuzbass (Western Siberia, Russia) is characterized by significant structural problems. They are associated with primary extractive nature of the regional industry, in which coal and iron ore, metallurgical and chemical industries dominate. They highly depend on Russian and global market of raw materials, widely use low-productive technologies, and they are characterized by high level of fixed capital depreciation and insufficient pace of innovative infrastructure development. The solution of the structural problems of economic development of mining region is connected with technological modernization of extractive industries and use of modern materials for the production of high-tech products.

Performance of Alkali-Resistant Glass Fibers Modified with Refused Coal Ore

Performance of Alkali-Resistant Glass Fibers Modified with Refused Coal Ore

Using Mathematical Simulation to Evaluate the Efficiency of Iron Ore–Coal Brexes in Blast-Furnace Smelting

A mathematical model of the blast-furnace process developed by the MISiS is used to analyze the efficiency of a charge containing, in equal portions, coal-containing brexes made of iron-ore concentrate, superfluxed sinter, and non-fluxed oxidized pellets. Mathematical simulation shows that replacing 50% of sinter production by clean brex production will reduce the coke consumption by at least 10% and the dust and gas emissions of sintering plants by 50%.

The Identification of Selected Issues of Port Facilities Wear in Dusty Environments of Bulk Cargoes

The article addresses issues of wear selected port facilities in the conditions of the occurrence of dusty fraction of bulk cargoes on examples of coal and iron ore. Presented in the article results basis on simulation studies on the laboratory stand "pin-on-roll" for the conditions of pollution of lubricants dust loads, taking into account the impact of the simulated marine environment containing corrosive saline mist.

Reduction Behaviour of Iron Ore–Coal Composite Pellets in Rotary Hearth Furnace (RHF): Effect of Pellet Shape, Size, and Bed Packing Material

Reduction of iron ore–coal composite pellets in multi-layers at rotary hearth furnace (RHF) is limited by heat and mass transfer. Effect of various parameters like pellet shape, size, and bed packing material that are supposed to influence the heat and mass transfer in the pellet bed, have been investigated, on the reduction behaviour of iron ore–coal composite pellets at 1250 °C for 20 min in a laboratory scale RHF. Reduced pellets have been characterised through weight loss measurement, estimation of shrinkage, porosity, and qualitative, quantitative phase analysis by XRD. A significant difference in the degree of reduction is observed layer-wise in the pellet bed with the variation in pellet shape and size. Pellet bed without any packing material or packed with coal have demonstrated higher degrees of reduction compared to the pellet bed packed with graphite and sand.

Study of the effect of ultrasonic treatment on mineral materials of different morphologies

Coal, iron and manganese ore samples were exposed to different ultrasonic intensities of 250, 300 and 350 W/L for five minutes and to an ultrosonic intensity of 270 W/L for different time durations of 3, 5 and 7 minutes. The ultrasonically treated samples showed reductions in D80 particle diameters of 6 percent for the coal samples, 5.95 percent for the iron ore samples and 35.63 percent for the manganese ore samples during grinding. The ultrasonic treatment was also observed to assist in reducing ash content in the coal product by 8 percent and to reduce manganese losses in rejects by about 5 percent. Ultrasonic treatment was concluded to be capable of assisting in the comminution of friable ores more prominently than the hard and porous materials.