Iron Ore Research Articles

High-temperature thermochemical conversion of iron ore tailings into diopside and akermanite-based composite materials

Iron ore tailings (IOTs), the residue materials generated during iron ore processing, pose environmental challenges due to their massive volume and potential impact on ecosystems. This study proposes a sustainable approach to manage and utilize this solid waste by converting it into value-added composite materials through high-temperature thermochemical reactions. Experiments are conducted in a tubular reactor at various reaction temperatures and times, and the resulting product samples are comprehensively characterized to elucidate their chemical compositional, physical, microstructural, thermal, and electrical properties. The results reveal that at optimal reaction temperatures (1230–1260 °C) and reaction times (20–120 min), the synthesized product is predominantly composed of diopside (CaMgSi2O6) and akermanite (Ca2MgSi2O7). Additionally, we demonstrate that the product can be diopside-rich or akermanite-rich when blending silica and MgO powders into the IOTs to control the starting material composition, opening a promising avenue for large-scale sustainable utilization of industrial solid waste.

Unlocking new export opportunities: An open-source framework for assessing green iron and steel supply chains

Globally traded commodities such as iron and steel are coming under international scrutiny owing to their significant embedded greenhouse emissions. Commodity export-oriented nations must explore opportunities for decarbonising these supply chains or risk losing market share as customers seek cleaner alternatives and as initiatives such as carbon border adjustment mechanisms (CBAM) come into effect. Here we present an open-source model developed to assist industry and other stakeholders in assessing the costs of potential CO2 abatement pathways in supplying green iron ore, green iron, or green steel to key global markets. Using a case study, we assess the development of a green steel supply chain from major iron ore producers of Australia, Brazil, and Sweden, to key markets in Europe, China, and India. Projected costs of renewable energy and other key technologies are used to estimate possible future costs of different decarbonisation pathways. Our modelling suggests that by 2050, export costs of green iron ore, iron and steel could range from 48 to 150, 370–600 and 540–810 USD/tonne respectively. Access to low-cost renewable energy is the key driver of cost reductions for value added products such as iron and steel, and given their substantial renewable energy potential, in 2050 Australia and Brazil could outcompete Sweden in providing these products, with both even outcompeting Sweden in exporting to the European market. The release of our model as open source allows any and all stakeholders to explore the implications of key technology and market uncertainties over least cost green iron and steel supply chains.

Simultaneous removal of vanadium and nitrogen in two-stage vertical flow constructed wetlands: Performance and mechanisms

Vanadium (V(V)) and nitrate, as co-concomitant pollutants in water bodies, pose potential threats to the eco-environment and human health. This study was to reveal the feasibility of simultaneous removal of V(V) and nitrate in the series-wound vertical flow constructed wetlands (CWs) with iron ore (B-CWs)/manganese ore (C-CWs)-wood substrates. The results showed that B-CWs could achieve efficient V(V) and NO3−-N removal with the influent of 2 and 10 mg/L (V(V)/NO3−-N = 1:5), respectively. With the increase of V(V)/NO3−-N ratio (V(V)/NO3−-N = 1:1), B/C-CWs exhibited better combined pollution removal. Even when nitrate was removed (V(V)/NO3−-N = 1:0), the systems could maintain a good capacity for V(V) removal. High V(V) (20 mg/L) significantly inhibited V(V) removal, with a slight recovery of the performance as the decrease of V(V) influent. High NO3−-N concentration (10 mg/L) effectively enhanced V(V) removal and restored C-CWs to the better level. V(IV) precipitates/oxides were the main reducing end-products. High abundance of V(V)-reducing bacteria and iron/manganese cycling pumps ensured efficient V(V) removal.

Separation of iron and copper in skarn deposits from the Yueshan ore field, eastern China: The control of magma physicochemical conditions

Iron and copper mineralization in the Yueshan ore field is intricately linked to the Cretaceous Yueshan diorite intrusions, yet they frequently materialize as distinct deposits. Despite this, the key factors dictating the segregation of these metals remain poorly understood. To gain insights into the role of magma physicochemical conditions in this segregation, we conduct a comparative analysis of the U-Pb dating, whole-rock geochemistry, and mineral chemistry of the newly uncovered Zhuchong skarn iron deposit (Fe:Cu ratio = 197) and the Anqing skarn copper deposit (Fe:Cu ratio = 35), both situated within the Yueshan ore field of the Middle Lower Yangtze River Valley Metallogenic Belt (MLYB) in eastern China. The garnet U-Pb dating of the Zhuchong and Anqing deposits are 138.3 Ma and 137.2 Ma, respectively, which are consistent with the zircon U-Pb dating (138.3 Ma) of diorites from the Zhuchong and Anqing deposit. The emplacement of diorite intrusions and Fe-Cu mineralization occurred at 137 – 139 Ma, consistent with the Cu-polymetallic mineralization epoch (145 – 137 Ma) in the MLYB. The diorite samples from the Yueshan intrusion and the Zhuchong and the Anqing deposits exhibit typical characteristics of adakites, such as high Sr/Y (28 – 174) and (La/Yb)N (26 – 40), along with similar and enriched Sr-Nd (εNd(t) = − 7.95 ∼ − 7.33) and zircon Hf isotope (−14.9 ∼ − 6.4) compositions. This suggests that the magma source regions for the diorites from the three locations were all likely derived from the melting of sediment-rich subducted oceanic crust with the potential of copper mineralization. However, chemical compositions of zircon, apatite, and amphibole from diorites reveal that diorites in the Zhuchong and Anqing deposits were emplaced at different depth levels and physicochemical conditions. Specially, the diorite in the Zhuchong Fe deposit was emplaced at shallower levels (1.9 km), with higher oxygen fugacity (mean = ΔNNO + 1.9) and fluorine concentration (2096 ppm), water deficiency (3.3 ± 0.4 wt%), sulfur-poor conditions (avg = 494 ppm), lower pressure (49.2 MPa), temperature (746 ℃), and chlorine (945 ppm) concentration relative to the Anqing Cu deposit (Emplacement depth: 2.53 km; oxygen fugacity: ΔNNO + 1.5; F: 1720 ppm; H2Omelt: 3.9 ± 0.4 wt%; S: 816 ppm; P: 66.9 MPa; T: 778 ℃; Cl: 945 ppm).It is proposed that a shallower emplacement depth may have promoted extensive exsolution of magmatic fluids, leading to the outward migration of water, S, Cl, and Cu elements, which resulted in the high iron-copper ratio observed at the Zhuchong Fe deposit. This process could have led to the relative Cl-poor nature and smaller Cu size at the Zhuchong Fe deposit, as well as the widespread development of vein-type copper ore bodies in the region.

Investigation of the effect of mineral composition and size on particle separation in Wet low and high intensities magnetic separators: An industrial case

Magnetic separation is used in ore processing to separate the minerals according to their magnetic susceptibility. Particle size also plays a role in the separation although few industrial results are presented in the literature to discuss this matter. Results from sampling industrial Wet Low Intensity Magnetic Separators (WLIMS) and Wet High Intensity Magnetic Separators (WHIMS) for processing an iron ore show that except for the strongly paramagnetic magnetite (Fe3O4), the recovery of minerals decreases with increasing particle size for both WLIMS and WHIMS. The examination of polished sections of the coarse size fractions from the reject streams of the WHIMS does not provide ground to suspect liberation to be responsible for the reduced recovery of coarse particles. Results also show that it is difficult to establish clear relationships between the mineral recoveries and their reported magnetic susceptibilities for WLIMS while for WHIMS a weak trend is observable.

Dephosphorization study on hydrogen reduction-melting separation of high-phosphorus oolitic hematite

In order to clarify the dephosphorization mechanism of DRI (Direct Reduced Iron) derived from hydrogen reduced high-phosphorus iron ore during the electric arc furnace melting process, slag was prepared using reagent-grade powder based on the gangue mineral composition of high-phosphorus oolitic hematite. By incorporating varying amounts of CaO, FeOx, and reduced iron powder, experiments simulating the dephosphorization of melting separation slag from DRI with different basicity and metallization rates were conducted at 1873 K. The results show that phosphorus in the iron primarily exists in the form of Fe-P-O spherical slag inclusions and FexP, while in the slag, phosphorus mainly resides within the silicate phases. As the amount of CaO added increases, there is a significant decrease in the phosphorus content within the slag inclusions, and the P-containing compounds in the iron gradually shift from FexP and Fe3(PO4)2 to FeO. As the dephosphorization capacity of the slag increases, the distribution of phosphorus-rich phases in the rapidly cooled slag becomes more extensive. When the basicity increases to 3, the phosphorus-rich phases in the slag transition to 2CaO·SiO2 and 3CaO·SiO2. When the basicity is fixed at 2.5, regulating the metallization rate can control the FeOx content in the melting slag, thereby enhancing the dephosphorization ability of slag. The results show that under conditions of a DRI basicity of 2.5 and a metallization rate of 85%, slag/metal separation can produce low-phosphorus iron with 0.022 wt% P, achieving a dephosphorization rate exceeding 95%.

Simulating breakage by compression of iron ore pellets using the discrete breakage model

Simulation of breakage embedded in the discrete element method (DEM) has evolved significantly in recent years, taking advantage of both greater computing power and novel approaches that have become available in both commercial and open-source packages. This work analyzes in detail the simulation of breakage using the discrete breakage model (DBM) in the commercial software Ansys Rocky. Breakage of iron ore pellets under slow compression was studied. After the selection of suitable contact parameters for the pellets, described as polyhedral particles, the model is used to describe their breakage considering fully resolved fragments from the beginning of the simulation. The effects of contact model, time step and number of elements on the ability of the model to represent average breakage response of iron ore pellets under compression is analyzed. An approach was then used to account for the variability in the breakage characteristics of the pellets, which provided a valid description when applied to another pellet sample, also showing capability to describe the size-scale effect on the breakage energy of pellets when applied to pellets of different sizes.

Adaptability analysis of H2-rich gas injection and sintered ore performance with different raw material ratios

As a source substitution technology that reduces pollutants emission and optimizes sinter properties, H2-rich gas injection-assisted iron ore sintering holds significant practical value. This study analyzed the adaptability of this technology to different ore blend ratios and basicity levels by comparing sintering indexes, pore structure, mineral phase composition, and metallurgical performance before and after H2-rich gas injection. The carbon emission reduction following H2-rich gas injection was calculated. The results indicate that increasing the proportion of high-silica, low-alumina ore (Ore-A) and basicity, along with H2-rich gas injection, can effectively enhance sinter yield and quality, but shrink the pore structure of sinter. Under H2-rich gas injection conditions, decreasing Ore-A ratios and increasing basicity can augment SFCA phase formation and mineral phase uniformity, thereby improving the anti-pulverization ability and reductivity of the sinter. H2-rich gas injection presents better adaptability to sintered ore with lower Ore-A ratio and basicity, which can achieve greater improvements in the sintering indexes, RDI, and RI. For a 265 m2 sinter plant producing sinter with 18 wt.% Ore-A and 2.0 basicity, annual CO2 emissions can be reduced by approximately 40,000 t.

Sugarcane bagasse and iron ore tailings thermochemical conversion towards sustainable iron recovery with biogenic carbon and hydrogen production

The recovery of valuable chemical elements from industrial waste is essential for production processes' economic and environmental sustainability. The interaction between the iron ore tailings and sugarcane bagasse, both wastes, has the potential to provide a secondary iron source for future iron and steelmaking processes. This study evaluated the use of volatiles from sugarcane bagasse (SCB) and iron ore tailings (IOT) to the synergistic promotion of carbon deposition, H2 production and conversion of weak magnetic iron oxides in strong magnetic iron phases. The experiments were carried out at 400, 600, 800, and 1000 ºC with different SCB/IOT ratios under an N2 atmosphere. In all tests, SCB and IOT were heated simultaneously in separate beds to prevent direct contact between the materials. The combination of 600 ºC and higher SCB/IOT ratio resulted in a product with 96.7% magnetite, 98% magnetic fraction recovery, and 3.5% deposited carbon. The use of lower SCB/IOT ratio provided an increase in H2 production. Regardless of the mass ratio, heating the IOT and SCB simultaneously up to 1000 ºC led to significant mineralogical transformations, reaching reduced phases such as wüstite, fayalite and metallic iron, which impaired magnetic separation efficiency. The results indicate an alternative for recovering iron from IOT using biomass waste as a renewable reducing agent for the steel industry.

Выбор критериев для сокращения неизвестных в методе Ньютона–Рафсона в задаче нахождения равновесного состава железной руды и топлива

Finding the equilibrium composition of a multicomponent system is required in various industries associated with chemical reactions. Reduction of the unknowns in the original nonlinear equation is possible if most of the unknowns receive values equal to zero as a result of the solution. This situation is typical to solve the problem of finding an equilibrium composition of iron ore and fuel, where the unknowns are the number of moles of all possible reaction products from given simple substances. The dependence of algorithmic complexity on the number of unknowns to solve a SLAEs is expressed through the function O(N3). Therefore, reduction of the unknowns will speed up the computational process. Thus, the solution to the problem of selecting criteria to reduce the number of the unknowns at each iteration of the Newton-Raphson method as applied to the problem of finding the equilibrium composition of iron ore and fuel is relevant. The matrix dimensionality reduction has been achieved using four strategies. The first three strategies involve finding a minimum threshold (removing values that most quickly tend to zero), after which the number of unknowns will decrease. The fourth strategy is associated with reducing the dimension of the original matrix. The results of numerical experiments to reduce the unknowns and speed up calculations are presented. Criteria have been found under which the calculation speed increases by 2–4 times and variables whose value is not equal to zero are not reduced. The criteria to reduce the unknowns implemented in the T-Energу software package make it possible to solve the problem of finding the equilibrium composition of iron ore and fuel 2–4,2 times faster. In this case, the obtained solution for the components of the equilibrium composition with the reduction of the unknowns corresponds to the complete solution with an accuracy of 10–3. Due to acceleration at the same time, it is possible to construct equilibrium compositions over a temperature range with a temperature step that is 4 times smaller.

Experimental Simulation Studies on Non-Uniform Fluidization Characteristics of Two-Component Particles in a Bubbling Fluidized Bed

Taking the fluidized pre-reduction process of iron ore powder bubbling fluidized bed as the background, for the problem of non-uniform structure in the bed of gas-solid fluidization process, the non-uniform fluidization characteristics of bicomponent particles are investigated in a cold two-dimensional bubbling fluidized bed by using a combination of physical experiments and mathematical simulations. Fluidization experiments were carried out under typical working conditions by using glass beads to study the effects of apparent gas velocity, mass ratio, and other factors on the non-uniform structure in the bed. Through the experimental observation of the bubble behavior, the effect of the cyclic change in bubble formation, rise and growth to rupture on the bed uniformity were analyzed. The experiments showed that the fluidized bed of two-component particles would be stratified, and the non-uniformity was strong in the upper part and weak in the lower part, and the apparent gas velocity and particle size were the main influencing factors. Based on the Euler-Lagrange reference frame modeling, the fluidization process of the two-dimensional bubble bed was simulated by the CFD-DEM method. The simulations of typical experimental conditions were carried out to further analyze the velocity distribution and the volume ratio of each phase in the bed from the gas-solid interaction level, revealing that the velocity distribution in the upper part of the bed is not uniform, and the gas flow is strongly perturbed, with intense bubble aggregation. The results reveal the reasons for the non-uniform phenomenon of gas-solid fluidization, which can provide a theoretical basis for the regulation of the non-uniform structure of the fluidization process.

Finding of Neoarchean (2.71 Ga) Conglomerates in the Kostomuksha Iron Ore Province: On the Youngest Archean Association of the Karelian Craton

Finding of Neoarchean (2.71 Ga) Conglomerates in the Kostomuksha Iron Ore Province: On the Youngest Archean Association of the Karelian Craton

Biochar Organic Fertilizer Combined with Indigenous Microorganisms Enhances the Growth of Landscape Grass Cultivated in a Substrate Mixed with Iron Tailings and Mining Topsoil.

Iron tailings from the mining process occupy vast land areas and pose a significant ecological risk. In order to reuse iron tailings resources and carry out in situ ecological restoration of a mine, in this study, a medium of mixed iron tailings and mining topsoil (m:m = 3:1) was used to plant landscape grasses, including Lolium perenne L. (L. perenne), Pennisetum alopecuroides (L.) Spreng. (P. alopecuroides), Melilotus officinalis (L.) Lam. (M. officinalis), and Medicago sativa L. (M. sativa). Biochar and chicken manure were used as biochar organic fertilizers and indigenous microorganisms were isolated from the rhizosphere soil of tested grasses. They were applied to enhance landscape grass growth by regulating rhizosphere microbial communities and nutrient conditions. The results showed that the biochar organic fertilizers significantly promoted the growth of the four landscape grasses, notably P. alopecuroides, increasing plant height, root length, root weight, and leaf fresh weight by 169%, 60%, 211%, and 388%, respectively. Additionally, L. perenne exhibited the greatest height increase (10%) following the application of bacterial solutions. Moreover, indigenous bacterial solutions enhanced chlorophyll content and phenylalanine ammonia-lyase (PAL) activity, with P. alopecuroides showing the highest chlorophyll increase of 58% and M. sativa exhibiting a 30.58% rise in PAL activity. The biochar organic fertilizer also significantly elevated soluble protein content in P. alopecuroides and M. sativa by 195% and 152%, respectively. It also effectively enhanced peroxidase (POD) activity in Poaceae grasses by 120% to 160%. After adding indigenous microorganisms, the rhizosphere soil of the landscape grass showed the highest Shannon-Wiener diversity index, reaching 3.561. The rhizosphere soil of M. officinalis had the highest microbial richness, with a value of 39. Additionally, the addition of indigenous microorganisms increased the nitrogen, phosphorus, and potassium content of the four plants by 8-19%, 6-14%, and 8-18%, respectively. This study offers a new approach for managing mining waste and ecological restoration in mining areas.

Determining the impact of different types of biofuels on the quality of iron ore pellets

The object of this study is the process of roasting iron ore pellets. The study solves the task of replacing fossil fuel with plant-based fuel in order to reduce environmental load and ensure the stable quality of pellets, which is necessary for use in blast furnaces. The influence of biofuel content at a given temperature and air speed on the strength of pellets after roasting was studied. As a result of the research, it was established that the fuel content has a decisive effect on the strength of pellets. Among all types of fuel that were investigated, pellets with the addition of sunflower husks and wood had the highest strength that meets the requirements for blast furnace melting of 200 kilograms. The use of wheat straw and charcoal does not make it possible to completely replace solid fuel in the layer of pellets. The results show that the use of up to 0.36 % of sunflower husk makes it possible to increase the strength of burned pellets compared to samples without biofuel content. Adding all other considered types of fuel reduced the strength of the pellets. These results are explained by the different content of lignin, cellulose, and hemicellulose, which determines the characteristics of the biomass. The high content of cellulose and hemicellulose allows for high hydrophilicity due to the high number of OH groups and positively affects the formation of raw pellets. Volatile substances released during the combustion of biofuel contribute to the formation of spherical pores, as well as their uniform distribution, which prevents the propagation of cracks under load. Research results make it possible to establish the optimal roasting mode, decrease harmful emissions, and bring down costs by reducing fossil fuel consumption

The synergistic sintering of ultra-lightweight ceramsite from molybdenum ore tailings, iron ore tailings and waste glass powders: Properties and formation mechanism

Molybdenum ore tailings, iron ore tailings and waste glass powders are important industrial solid wastes, mainly composed of silicate minerals and quartz, which are expected to become alternative resources for inorganic non-metal industrial materials. In this paper, the ultra-lightweight ceramsite was prepared by the synergistic sintering of molybdenum ore tailings, iron ore tailings and waste glass powders according to their characteristics of silicate minerals. The physical and mechanical properties were investigated when the sintering temperature was between 1100 and 1140 °C. The evolution of mineral phases and formation mechanism of pore structure during sintering were studied by XRD, FT-IR, SEM, TG-DSC and HSM. The results showed that in the sintering process, the waste glass powders and the pargasite in iron ore tailings first melted to produce the initial liquid phases. Then the anorthoclase and the quartz in molybdenum ore tailings melted to produce a large amount of liquid phases. These liquid phases covered the gas generated by the oxidation of SiC, thus forming a rich pore structure. At the same time, the [Si2O64−] and Ca2+, Mg2+ in the liquid phases derived from quartz and pargasite melting recrystallized to form diopside, which was conducive to the improvement of mechanical properties of ceramsite. When the raw material ratio of molybdenum ore tailings, iron ore tailings and waste glass powders was 6:2:2 and the sintering temperature was 1120 °C, the pore structure of the ceramsite as prepared was uniform and rich and mostly closed. The density was low and the mechanical propertities were excellent. It has a good application prospect in the field of building thermal insulation and sound insulation.

Hydrogen affection on softening and melting behaviours of high alumina sinter in gas-injection blast furnace

As the Al2O3 content increasing in iron ore, some problems presented in blast furnace (BF) processing, such as worsened burden permeability and slag viscosity. Injection of H2 may improve the permeability and reduce the CO2 emission of BF, because of its less density and higher reduction potential when temperature is higher than 820 °C. Therefore, the influence of H2 concentration on the softening and melting behaviour of high alumina sinter is a worth investigate topic. In this article, the high alumina sintering samples with Al2O3 content of 2.11 wt% are investigated in a specially designed experimental apparatus capable of continuously changing pressure on the burden. The results show that the softening temperature range of the samples is expanded and their melting temperature range is reduced with the increasing of H2 concentration from 0 vol% to 20 vol% in reduction gas. But the overall change on softening-melting temperature range is just from 280 °C to 310 °C, which is relatively small comparing with other references reported results. The addition of H2 promotes the reduction of FeO and is conducive to separate between the iron phase and slag phase before the charge droplet formation, which facilitates the aggregation and precipitation of metallic iron in soften state. Simultaneously, higher H2 concentration leads to more pronounced improvements in the permeability of the high alumina burden.

Valorization of carbonaceous co-product obtained from iron ore-catalyzed methane cracking as support for Pd catalysts in toluene hydrogenation reaction

Iron ore has been proven as an abundant and sustainable catalyst in the production of hydrogen by catalytic cracking of methane. One of the main challenges is the identification of suitable market niches for the utilization of the resulting iron-carbon hybrid in order to make this process economically viable. This study examines the feasibility of using the iron-carbon hybrid obtained from methane cracking as support of Pd catalysts for the hydrogenation of toluene (350 ºC, 35 bar of H2 at room temperature and 90 min). Before supporting Pd, Fe-C hybrid was subjected to different acid functionalization treatments (nitric and/or phosphoric acids). The results indicate that sequential oxidation with nitric acid, followed by phosphoric acid, is the most effective strategy for achieving the highest catalytic activity (1294 mmolToluene gPd⁻¹) and conversion (27 %). Toluene conversion was 1.8 and 14.2 times higher than with the catalysts treated with nitric and phosphoric acid separately. Therefore, this work proves the possibility of employing carbon/Fe hybrid materials obtained in iron ore catalyzed methane cracking as catalytic supports in industrial relevant reactions.

The constraints of sedimentary environment on the evolution of bauxite reservoir characteristics within the benxi formation in the Linxing area, Ordos Basin, China

AbstractThe breakthrough of bauxite natural gas in the Taiyuan Formation in the Longdong area of the Ordos Basin makes bauxite natural gas gradually become a new exploration direction. However, the complex sedimentary conditions and diverse developmental strata of the Linxing region present difficulties for the exploration of bauxite gas. In this research, samples of bauxite cores from significant drilling sections in the Linxing area were obtained for comprehensive geochemical, mineralogical, and pore structure analysis. This study investigates the impact of sedimentary environments on the physical properties of bauxite reservoirs within the Benxi Formation, focusing on lithofacies categorization, mineral composition, and pore structure. This study established a lithofacies categorization system that iron minerals, aluminum minerals + titanium minerals, clay minerals as three end‐member components. The study identified four lithofacies types: pure bauxite, clayey bauxite, mixed bauxite, and bauxite mudstone. According to geochemical analysis, the bauxite rock in the study area is deposited in a semi‐enclosed bay with terrestrial freshwater input. The physical properties of bauxite reservoir in the study area are relatively poor, among which the physical properties of bauxite reservoir are the best. Authigenic minerals like pyrite are often filled in dissolution pores. The constraint of sedimentary environment on bauxite reservoir is mainly manifested as the influence on the formation of diaspore mineral framework, and its acidity and alkalinity are very important for the formation of diaspore. Hence, diaspore commonly forms in the shallow lake environments characterized by pure bauxite rock, exhibiting favorable reservoir conditions. This research examines the impact of mineral composition on bauxite reservoirs through the lens of lithofacies and sedimentary environments. The variations in bauxite rock reservoirs across distinct sedimentary environments have been elucidated. It provides a new guidance for the exploration of natural gas in Benxi Formation bauxite in Ordos Basin.

Phase transformation assisted reduction roasting of low-grade iron ore via industrial biomass as a reductant

Phase transformation assisted reduction roasting of low-grade iron ore via industrial biomass as a reductant

Study on heat storage characteristics and carbon optimisation in the sintering process

In response to the phenomenon of automatic heat storage during the sintering process of iron ore, heat balance analysis concerning the main chemical reactions and physical heat carried by gas and solid materials was conducted. A unit heat storage model for the sintering process was established. Further, a mathematical model to solve the heat transfer characteristics between different sintering layer units was proposed and established based on temperature–time curves of the gas and solid phases. Using these models, the heat storage of each layer unit was calculated under the condition of uniform carbon allocation. Subsequently, the optimisation of carbon allocation at each layer unit for maximising the utilisation of heat storage was investigated. The heat required for sintering by the layer unit was taken as the constraint, and the maximum utilisation of heat stored in each layer unit was taken as the goal to optimise the carbon allocation in the height direction. The calculation results show that as the unit thickness is 100 mm and the total thickness of the layer is 600 mm, the heat transfer ratio of the upper unit to the lower unit is 34.22%, 30.29%, 14.74%, 9.49%, and 1.17%, respectively. The heat storage and available heat storage rate increase with the increase of layer height, with heat storage ranging from 0.69 × 104 to 5.14 × 104 KJ/t and heat storage rate ranging from 11.63% to 49.37%. After optimising carbon allocation, the unit achieved a maximum carbon reduction of 60.04%, resulting in an overall reduction in carbon allocation of 46.20%. This adjustment aligns more closely with the industrial processes.