Ore Ratio Research Articles

Influence of oxygen carrier on NOx and N2O emissions in biomass combustion within fluidized beds

The Oxygen Carrier Aided Combustion (OCAC) technology has the potential to enhance the combustion efficiency and stability of biomass, while simultaneously facilitating the conversion of NO to N2. However, current research lacks sufficient investigation into the impact of oxygen carriers on the conventional fuel nitrogen (fuel-N) conversion pathway, particularly in relation to N2O. This study comprehensively examines the key operating parameters, including ilmenite ore (OC) ratio, O2 concentration, fluidization velocity, and bed temperature, on NO and N2O emissions during the OCAC of rice husk in a bubbling fluidized bed reactor. The findings suggest that when OC is used as bed material, the conversion of fuel-N to NO decreases by 8.84 % under a 3 % O2 concentration at 750 °C, compared to the sand case. This beneficial effect is further enhanced as the temperature increases. Conversely, the conversion of fuel-N to NO increases by 12.15 % and 7.70 % under 6 % and 9 % O2 concentrations, respectively, compared to the sand case. This suggests a distinct influence mechanism between OCAC and traditional combustion conditions, potentially due to the chemical phases of OC during the redox process. The OCAC operations can lead to an increase in the emission of HCN and N2O under all tested conditions. The potential conversion pathway of fuel-N under OCAC conditions is summarized.

Глубинное строение Северо-Востока России, закономерности размещения и прогноз рудного золота

The principal gold-bearing zone of the Kolyma-Chukotka fold belt is controlled by the Yana-Kolyma downfold of the earth's crust identified on the basis of gravity prospection data; it involves thick (25 km) terrigenous formations and their underlying migmatites as well as the lower layers of the earth's crust and asthenosphere. The Yana-Kolyma downfold is formed under the influence of the protogenic asthenospheric ultramafic magma chamber. According to the analysis of the most important ore-controlling factor (the thickness of the erosion cut), the structures of the deep Yano-Kolyma downfold are the least eroded, and, consequently, the rich placers of the principal gold bearing zone might have been formed from very rich gold motherlodes. This conclusion determines inferred resources in the principal zone and conforms with the calculated ratio of motherlode reserves exceeding placer reserves. The gold ore ratio of 2.6 is used for the prognostic evaluation of the ore gold mineragenic potential of the Kolyma-Chukotka fold belt, which makes 6 000 t.

Study of Galena Ore Powder Sintering and Its Microstructure

Galena is a natural mineral enriched with lead sulfide (PbS). It typically forms in hydrothermal veins associated with igneous rocks and can also occur as a gangue mineral in other ore deposits. PbS is of special importance for scientific research applications due to the possibility of tuning its semiconductor energy gap using nanotechnology in conjunction with powder metallurgy as an easy, controllable production route. In this paper, almost pure PbS was successfully produced starting from a high ratio of PbS phase galena ore. As-received galena lumps were roughly pulverized and milled to produce four particle size ranges of 38, 63, 125, and 250 µm prior to compaction and sintering in a vacuum (pre-flushed with argon gas). SEM coupled with the EDAX analysis unit was employed to investigate the microstructure and chemical composition of the as-received galena and the subsequent products after sintering. The chemical analysis confirmed the high ratio of PbS compound in the as-received galena and sintered products with approximately 85% Pb and 13% S mass ratio. The sintering process of the galena powder was carried out at different values of temperature, time, and compaction pressure. Additionally, the effect of length to diameter ratio of compacted and sintered samples was investigated. XRD analysis confirmed the existence of the PbS phase in the as-received and sintered samples at 700 °C with approximately 98 wt.%, as well as a new phase that is formed at 800 °C with a lower percentage. The micro-hardness of the as-received and sintered samples was measured and compared with the as-received galena ore. The results showed a significant reduction in the hardness of sintered galena powder compared with the bulk as-received galena by 52%. Furthermore, a relative sintered density of 99.3% for the as-received galena density signifies a novel result using powder metallurgy techniques.

Integrated management of abatement technology investment and resource extraction

As the need for increased renewable energy generation to meet climate goals grows, so does the demand for critical minerals in the industrial sector. This raises concerns about the availability of supply and the reliability of investment in critical minerals. Based on this, the study proposes an analytical framework for the integrated management of mineral extraction and renewable energy investments. Different from the previous strategy of separate management, this study has established an integrated model that utilizes new energy technology as the downstream application of emission reduction technology. It also utilizes copper, zinc, aluminum, rare earth elements, and other materials as the upstream raw material supply. In terms of minimizing costs, the entire supply chain process is optimized to achieve an empirical case. In addition, considering the significant uncertainty in the process of reducing emissions from new energy technologies, this study also incorporated a forward control stochastic programming method to model and solve it. We obtained confidence intervals for optimal technological investment paths and metal mining paths under various scenarios. Our findings indicate that: (1) Biomass, as a renewable energy technology with the lowest resource demand, should be prioritized for development. However, there is significant uncertainty surrounding the installed capacity of photovoltaics. (2) Copper ore reserves have little impact on the development of renewable energy technologies, while zinc ore and aluminum ore have a greater impact on wind energy and photovoltaics, respectively. (3) By optimizing the cut-off ratio of raw ore under a specific amount of ore storage, we can ensure the availability of materials needed for downstream energy technology.

Changes in Microscale Liquid Formation in Lump and Sinter Mixed Burden Softening and Melting Tests with the Addition of Hydrogen

With the movement toward hydrogen-enriched blast furnace operation to lower greenhouse gas emissions, ferrous burden design must be reconsidered to optimize furnace permeability. Increasing the ratio of direct charge lump ore in the ferrous burden also presents an opportunity to lessen the emissions associated with the production of sinter and pellets. Under traditional blast furnace conditions, lump ore usage is improved by mixing it with the sinter in the burden to promote their favorable high-temperature interactions (both chemical and physical). As such, mechanistic changes to the interaction must be understood to optimize burden design, including for future operations with hydrogen addition. In this study, liquid formation in both the metallic and oxide components of ferrous burdens is microscopically investigated. Oxide liquid and solid phase stability at the interfaces of dissimilar burdens are visualized using a novel mapping technique, and metallic iron is etched to reveal microstructures indicative of carbon. Results indicate that the inclusion of hydrogen promotes the gas carburization of metallic iron in sinter, but not lump. It was concluded that mixed burden softening and melting performance with hydrogen addition were improved through the addition of lump in two ways: the highly metallic lump particles provide structural support for the collapsing sinter bed and also suppress the formation of early liquid slag from the sinter.Graphical

The Study on Alkali Fusion-water Leaching of Silicon From Molybdenum Tailings

Taking the molybdenum tailings produced after beneficiation of the Luanchuan molybdenum mine in Henan Province as the research object, the effects of alkali ore ratio, calcination time and calcination temperature on the activation effect of molybdenum tailings, and the effects of leaching time, leaching temperature and leaching liquid-solid ratio on the silicon leaching rate were investigated by using sodium hydroxide alkali melting-water leaching process. The results show that the optimal conditions for activation are as follows: alkali-ore ratio 1.2:1, calcination time 1 h, calcination temperature 700°C. Under these conditions, the concentration of alkali fusion leaching (Si+Al) of molybdenum tailings is 1.396 mg/L. The optimum conditions for leaching are as follows: leaching time 7 h, leaching temperature 45°C, leaching liquid-solid ratio 6: 1. Under these conditions, the leaching rate of silicon can reach 26.88%. During the calcination process, the crystal structure of quartz is destroyed, and sodium hydroxide reacts with quartz at high temperature to form soluble silicate, which improves the activity of molybdenum tailings and increases the dissolution of silicon

Muti-objective optimization on energy consumption, CO2 emission and production cost for iron and steel industry

Due to high material density, high energy consumption density and CO2 emission density, it is not only difficult but significant to clarify the relationship between energy consumption, the CO2 emission and the production cost in different conditions. However, the previous researches rarely refer how to balance the energy consumption, the CO2 emission and the production cost after the fluctuation of material, energy and carbon price as well as what will happen to them if production structure changes. Therefore, based on the conservation law of mass and energy, to study iron and steel manufacturing process (ISMP), this paper, taking carbon price into consideration, establishes a muti-optimization model of energy consumption, CO2 emission and cost. After optimization with different objectives, the production cost per tonne of crude steel is reduced by 192.03 CNY (7.71%), the CO2 emission per tonne of crude steel is reduced by 224.22 kg (13.37%), and the energy consumption per tonne of steel is reduced by 51.20 kgce (9.10%). Moreover, based on the optimization results under different objectives, it is ironmaking process (coal ratio and ore ratio) and steelmaking process (amount of scrap steel) that has more impact on three above as well as ore blending and coal blending have a great influence on production cost but little effect on energy consumption and CO2 emission.

Processing of ore from the Nud II deposit by the method of low-temperature roasting with ammonium sulfate

The Murmansk region has a significant amount of sulfide copper-nickel raw materials. Deposits of the Nud massif associated with Monchepluton are promising for processing. The Nud II deposit cut-off grade ore with an initial Ni content of 0.45 % and Cu of 0.39 % has been chosen as the research object. During the research, the ore was mixed with ammonium sulfate, grinded, and the mixture was roasted in a muffle furnace with static air atmosphere. The roasted mixture was leached in heated distilled water with constant stirring. The maximum metals recovery was achieved when crushing to a fraction of –40 µm, the ratio of ore : ammonium sulfate is equal to 1 : 7, roasting temperature 400 °C, roasting duration 300 min. In the mixture roasted at these parameters, reflexes of copper and nickel sulfates were recorded by the x-ray phase analysis (XRD) method. At the stage of water leaching, the maximum recovery was: Ni – 79.1 %, Cu – 75.8 %.

Проблемы и перспективы внедрения многостадийной выемки руды при отработке запасов калийных месторождений

Introduction. Most of the potash deposits in the world are mined using room-and-pillar mining method with natural support, which is accompanied by high mineral losses, as well as a high mine accidents due to the destruction of supporting elements, waterproof strata continuity and breakthroughs of oversalt water and brines into the mined-out void. Methods. Generalisation, systematisation and analysis of theoretical and experimental research on increasing the extraction ratio of potash ore to establish the methods degree for increasing extraction of potash reserves, to identify unexplored and problematic issues, to determine directions and approaches. Results. Theoretical justification of the possibility and expediency of several-stage stoping for potash mining implementing the principle of re-extraction of reserves from pillars with the provision of necessary protection measures of aquifer in the form of backfill. Conclusion. The article presents the results of an analysis of the specifics of underground mining of potash deposits. The concept of several-stage stoping for potash mining is formulated. Generalized variants of several-stage stoping are presented. The main problems of several-stage stoping implementation at potash deposits are described: the problem of gap-filling in rooms; prediction of altered physical and mechanical properties of seams and host rocks; the influence of multiple excavation on water-resistant properties of waterproof strata in several-stage stoping; the role of time in geomechanical processes; rational composition and recipe of backfill preparation; organization of stowing and clean-up operations at the site; technical and economic expediency of several-stage stoping. Possible lines of approach are suggested. Resume. The use of several-stage stoping for potash mining will increase the extraction ratio, improve the reliability of the waterproof strata during mining by replacing potash seams with a continuous fill mass, utilize waste from potash ore processing, and extend the service life of potash mines. A competent scientific and methodological foundation on the implementation of such technology at potash deposits needs to be built for a deep evaluation of the mining and geomechanical processes in the operation areas and the technical and economic performance of several-stage stoping. Suggestions for practical applications and future research line. The variants of several-stage stoping presented in the article can be used to develop methods of potash mining considering specific mining and geological conditions. Application of the described and similar variants of several-stage stoping in practice will significantly increase the extraction ratio while maintaining a minimal impact on the seam. Future research line will focus on the underground deposit development plan and the geomechanical justification of the parameters of the several-stage stoping.

A Comparison Study of Nickel Laterite Reduction using Coal and Coconut Shell Charcoal: A FactSage Simulation

Replacing metallurgical coke with greener material is a long-term challenge in pyrometallurgy. With the fact of biomass abundance in Indonesia, the usage of bio-char as a replacement for coke resulted from coal has been an intensive study. This study compared the performance between anthracite coal and coconut shell charcoal for nickel laterite reduction using the Equilibrium module on FactSage software simulation. The simulation was done by inputting a 4:4:1:20 weight ratio of nickel laterite ore, reductant (coal or coconut shell charcoal), lime and air, respectively. The temperature studied was 1300

Influence mechanism of different reactive Iron Carbon Agglomerates on softening–melting–dropping properties of BF mixed burdens

ABSTRACT The application of iron carbon agglomerates (ICA) in blast furnace (BF) is considered to be an innovative technology of low-carbon ironmaking. In this paper, the influence mechanism of different reactive ICAs on softening-melting-dropping properties of BF mixed burdens was revealed. The results show that mixing ICA in the ferrous burdens can effectively improve softening-melting dropping properties of mixed burdens and the improvement effect is the best when the iron ore ratio of ICA is 20%~30%. The influence mechanism is: (1) ICA has a coupling effect with the reduction of ferrous burdens, which can promote reduction of ferrous burdens and improve softening-melting performance of mixed burdens. (2) ICA can promote the molten iron carbonization and reduce the viscosity of primary slag, which can improve dropping performance of slag-iron. (3) ICA can support the skeleton of burden bed and space the burdens, which can improve gas permeability of burden bed.

Leaching of rubidium from biotite ore by chlorination roasting and ultrasonic enhancement

Aiming at the problems of the low grade of rubidium (Rb) in biotite, and long leaching time and low leaching efficiency of Rb in mica ore, the chlorination roasting-assisted ultrasonic enhanced water leaching method was employed to extract Rb from biotite ore in this study. During the chlorination roasting process, the optimal conditions were obtained, namely roasting temperature 900 °C, roasting time 40 min, and the mass ratio of ore to calcium chloride 1:1, the optimum leaching rate was 96.75 %. Compared with conventional leaching, the ultrasonic field could greatly shorten the leaching time and realize fast and efficient leaching of Rb. The optimal conditions for ultrasonic enhanced leaching were: ultrasonic power 100 W, leaching temperature 60 °C, leaching time 20 min, liquid–solid ratio 4:1, the Rb leaching rate was 98.73 %, which was 40 min shorter than conventional leaching. The particle size and SEM results indicated that the samples by ultrasonic leaching were smaller, no agglomeration phenomenon in a large area, and the surface of the samples was relatively smooth.

Influence of Lump Ore Ratio and Shapes on the Particle Flow Behavior Inside the Direct Reduction Shaft Furnace by Discrete Element Modeling Model

In recent years, with the attention given to hydrogen reduction‐related technologies, the parameter indicators of direct reduction in the shaft furnace have gained importance. Herein, the numerical simulation of the particle flow field in the shaft furnace is investigated with the help of discrete element method (DEM) model. In contrast to the subregional modeling and the single particle shape study of the previous studies, this study innovatively uses the real shape of the particles and the overall structure of the vertical furnace for modeling. The transient characteristics of solid particle flow under ten lump ore ratios and three shapes are considered. The results show that the mass fraction and the shape of lump ore have little effect on the particle falling speed, but have a significant effect on the particle segregation behavior. In addition, the void ratio responds to the permeability condition in the furnace, which is also influenced by the lump ore proportion and shape.

Synergetic conversion laws of biomass and iron ore for syngas and direct reduced iron co-production

This work describes a system for the co-production of syngas and direct reduced iron (DRI) though the synergetic conversion of biomass and iron ore. Iron ore served as the oxygen carrier and catalyst for biomass gasification, while pine sawdust (biomass) served as the reducing agent for iron ore metallization during this reciprocal conversion process. The effects of conversion temperature, biomass to iron ore ratio and calcination time were investigated. A maximum syngas yield of 72.6% (valid gasification ratio for H and C were 68.8% and 72.7%, respectively) was obtained when biomass was gasified with iron ore (mol ratio C/Fe = 0.8) at 1000 °C for 30 min. DRI with a metallization ratio (MR) of 93.8% was produced concomitantly. The lattice oxygen and catalytic properties of iron ore promoted (i) the conversion of tar and char components into syngas and (ii) the cracking of hydrocarbons into CO and H2. Volatiles derived from biomass enhanced iron ore metallization by accelerating the reduction rate, and bio-char ensured a high MR of the final DRI. The conversion pathway for this was also elucidated. Volatiles and ∼35% of the char reacted with iron ore in the first 10 min to produce all of the H2 in the final syngas and some of the CO. The remaining 65% of the char was gasified in the next 20 min to generate the rest of the CO. The lattice oxygen of iron ore played the key role in early gasification, and the fresh metallic iron played a key role in the subsequent catalysis. This co-conversion approach described herein has potential applications in green fuel gasification or DRI processes.

Semi-continuous Operation of Chemical Looping Combustion of Coal Using a Low-Cost Composite Oxygen Carrier

To reach the carbon peak by 2030 and achieve carbon neutrality by 2060, the implementation of low-carbon combustion approaches for fossil fuels (especially coal, a high-carbon fuel) is urgent in China. Chemical looping combustion (CLC) has been considered as one of the most promising technologies for low-carbon, efficient, and clean utilization of coal. However, a low-cost and high-performance oxygen carrier (OC) holds the bottleneck that constrains the industrial application of coal-fueled CLC. In this paper, a low-cost composite OC named Cu13.0Red87.0@C (with the mixing mass ratio of copper ore to red mud being 13.0:87.0, except for a 20 wt % cement bonder) was first prepared by the hydroforming method and then systematically evaluated by designing CLC tests in a semi-continuous fluidized bed using lignite as fuel. The results showed that this composite OC exhibited superior combustion performance in comparison to pure red mud. Moreover, it was found that increasing the temperature could significantly improve the average carbon capture efficiency but had a relatively small positive effect on the average CO2 yield. Additionally, with the elevation of the oxygen/fuel ratio, the resulting average carbon capture efficiency and average CO2 yield both tended to increase. Generally, the semi-continuous unit can simulate the continuously operated fuel reactor with an adjustable bed inventory and solid circulation rate, and it is easy to attain smooth operation of ca. 30 min, achieving both carbon capture efficiency and a CO2 yield of ca. 90%.

Study on Influencing Factors of High-Temperature Basic Characteristics of Iron Ore Powder and Optimization of Ore Blending.

In order to explore the reasonable ore blending of low-silicon magnetite in sintering, it I necessary to realize the efficient utilization of low-silicon ore, further reduce cost, and increase yield. In this study, based on the high-temperature basic characteristics of iron ore powder used in the experiment, sinter pot tests were carried out with different low-silicon ore ratios, and the microstructure of the sinter was observed by scanning electron microscopy (SEM) and energy spectrum analysis (EDS) to determine the optimal matching law of low-silicon ore. The result showed that SiO2, Al2O3, and burning loss in iron ore powder composition were positively correlated with its assimilation, whereas MgO and basicity R2 were negatively correlated with the assimilation of iron ore powder. When the ratio of low-silicon ore was not more than 35%, increasing the ratio of hematite improved the liquid production and increased the production of acicular calcium ferrite. Therefore, the optimization of ore blending based on assimilation can improve the quality of sinter and strengthen the sintering process. This study has certain reference significance for the industrial production of low-silica sintering.

Sintering and Smelting Property Investigations of Ludwigite

In this paper, orthogonal experiments are designed to study the sintering and smelting characteristics of the ludwigite ore. The predominant influencing factors of the optimal ratio, basicity and carbon content on different single sintering indexes, including the vertical sintering speed, yield rate, drum strength and low-temperature reduction pulverization index, are firstly explored by the range analysis method, and the main influencing factors on comprehensive indexes are obtained by a weighted scoring method based on different single index investigation. Considering the sintering characteristics, the primary and secondary influencing factors are: ordinary ore ratio, carbon content and basicity, and the optimal ore blending scheme is: basicity 1.7, ordinary ore blending ratio 60% and carbon content 5%. In terms of the smelting characteristics, the research obtains the order of the influencing factors on the softening start temperature, softening end temperature, softening zone, smelting start temperature, dripping temperature, smelting-dripping zone, maximum pressure difference and gas permeability index of the ludwigite sinters by simply considering various single smelting indexes. On this basis, considering the comprehensive softening-melting-dripping characteristics, the primary and secondary influencing factors are: carbon content, ordinary ore ratio and basicity, and the optimal ore blending scheme is: basicity 1.9, ordinary ore blending ratio 60% and a carbon content of 5.5%. Comprehensively, considering the sintering and smelting property of the ludwigite ore, the primary and secondary influencing factors are: carbon content, ordinary ore ratio and basicity, and the optimal ore blending scheme is: basicity 1.9, ordinary ore blending ratio 60% and a carbon content of 5.5%.

Investigation into Biomass Tar-Based Carbon Deposits as Reduction Agents on Iron Ore Using the Tar Impregnation Method

Increasing carbon deposits in iron ore to upgrade the reduction rate can be performed by impregnating iron ore in tar. Carbon containing iron ore was prepared from low-grade iron ore and biomass tar, which was generated from palm kernel shell (PKS) pyrolysis using the impregnation method. The optimum condition of the method was investigated by varying the tar-iron ore ratio (1 and 1.5) and impregnation time (0 and 24 h). After the carbonization of the tar–iron ore mixture in a flow-type quartz tubular fixed-bed reactor at 500 °C for an hour, the carbon deposits adhered well to surfaces of all iron ore samples. The carbon deposits increased when the ratio of tar-iron ore was enhanced. The effect of impregnation time on the formed carbon deposit only applied to the tar-iron ore ratio of 1, but it had a weak effect on the ratio of 1.5. The highest carbon content was obtained from the impregnation of a biomass tar–iron ore mixture with the ratio of 1.5 which was directly carbonized. In addition, the high water content of biomass tar affected the reformation of FeOOH at the impregnation within 24 h. Furthermore, the reduction reactivity of the obtained carbonized ore, which was observed using thermogravimetric analysis, was perceptible. The carbon deposits on iron ore were able to demote total weight loss up to 23%, compared to 8% of the dehydrated ore, during the heating process to 950 °C. The carbon content obtained from iron ore impregnation with biomass tar can act as reduction agents, thereby enhancing the reduction reactivity.

Effect of Carbon Addition on Direct Reduction Behavior of Low Quality Magnetite Ore by Reducing Gas Atmosphere

Recently, direct reduced iron (DRI) has been highlighted as a promising iron source for electric arc furnace (EAF)-based steelmaking. The two typical production methods for DRI are gas-based reduction and reduction using carbon composite pellets. While the gas-based reduction is strongly dependent on the reliable supply of hydrocarbon fuel, reduction using ore-coal composite pellets has relatively low productivity due to solid–solid reactions. To overcome the limitations of the above two processes, and to achieve a more efficient direct reduction process of iron ore, the possibility of combining these two methods was investigated. The experiments focused on performing an initial direct reduction using ore-coal composite pellets followed by a second stage gas reduction. It was assumed that the initial reduction of the carbon composite pellets would enhance the efficiency of the subsequent reduction by gas and the total reduction efficiency. The porosity, as well as the carbon efficiency for direct reduction, were measured to determine the optimal conditions for the initial reduction, such as the size ratio of ore and coal particles. Thereafter, further reduction by the reducing gas was carried out to verify the effect of the preliminary reduction. The reduction kinetics of the reducing gas was also discussed.

Effects of High Proportion Unground Sea Sand Ore on the Preparation Process and Reduction Performance of Oxidized Pellets

The New Zealand sea sand ore is a kind of vanadia–titania magnetite formed by erosion in the coastal zone. Because of its coarse particle size, smooth spherical particles, complex chemical composition, it has been added to sinter as an auxiliary material. Based on the principle of optimizing ore blending to strengthen advantages and weaken disadvantages, this paper used New Zealand sea sand raw ore that has not undergone any pretreatment as the main material and prepared it into oxidized pellets using a disc pelletizer and explored the influence of high-proportion unground sea sand ore on the preparation process and reduction performance of oxidized pellets. The influence of unground sea sand ore on the falling strength, compressive strength, reduction swelling index, and reduction degree of pellets was analyzed by the ICPAES, XRF, XRD, SEM-EDS, and other detection methods, and the change laws and influencing factors of oxidized pellets were analyzed. With the increase of the amount of unground sea sand ore used, the falling strength and compressive strength of the green pellets first decreased and then gradually increased, while the compressive strength of the oxidized pellets first increased and then decreased. At the same time, as the amount of sea sand ore used increased, the reduction process of pellets was restricted. The reduction swelling index and the reduction degree index generally show a downward trend. However, the compressive strength of the pellets gradually increased after reduction. Through the research on the pellet-forming performance and reduction properties of unground sea sand ore, it is shown that when the amount of unground sea sand ore used was 40%, it can still be used as raw material for blast furnace ironmaking. Thus, this research provided specific data support for iron and steel enterprises to improve the ratio of unground sea sand ore and reduce production cost.