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In order to solve problems such as low pollutant concentrations, large treatment volumes and high purification costs in tailwater treatment of recirculating aquaculture systems, a new renewable biomass ash filter material was developed to remove nitrogen and phosphorus from tailwater, which is environment-friendly, economical and highly effective. Properties of biomass ash filter materials produced under different conditions were studied through orthogonal experiments with sintering temperature, keeping time and material trapped time as factors and the main control factors affecting the properties of filter materials were obtained. The pore evolution and forming principle of the filter material during the sintering process can be inferred by characterizing and analyzing the structural characteristics and microscopic morphology of biomass ash filter materials produced at different sintering temperatures. This helps to clarify the performance control mechanism of these filter materials via their different structures. Based on this, the biomass ash filter material that has the best performance could be selected as a test group. And commercial filter materials including biochar, ceramic granules and natural zeolite were used as control groups to conduct phosphate and nitrite adsorption tests to evaluate the adsorption performance of the biomass ash filter material. The results show that sintering temperature is the main control factor affecting the properties of biomass ash filter materials. As the sintering temperature increases, wollastonite, melilite and anorthite phases are generated sequentially in the filter materials, which leads to a series of microstructure transformations, such as crystallization, vitrification and precipitation. This is the reason for the formation of the different pore structures. In this process, water pores in the filter materials are gradually converted into closed pores. This causes positive effects of high sintering temperature on stomatal porosity, total porosity, and compressive strength. It also brings negative effects of high sintering temperature on permeable porosity, water pore rate, water absorption and permeability, pH and EC values. The performance control mechanism of these filter materials exists because of the two contrary effects. Without aging, the biomass ash filter material produced by sintering at 1 170 ℃ for 40 minutes has better performance. This kind of filter material has a high saturation water absorption and average permeability rate, short water holding time, good formability and pore structure with a compressive strength of 0.74 MPa and total porosity of 65.49%. Its pH and EC values meet the demands of water purification. The unit adsorption capacity and removal rate of this filter material on phosphate can reach 0.996 mg/g and 2.767%, respectively. The phosphate adsorption effect is significantly better than that of biochar, ceramic granules and natural zeolite. The unit adsorption capacity and removal rate of this filter material on nitrite are 0.317 mg/g and 0.881%, respectively, which is equivalent to that of ceramic granules, significantly higher than natural zeolite and slightly inferior to biochar. The new renewable biomass ash filter material improves the defects of current mainstream filter materials for water purification. It is expected to meet the demand for nitrogen and phosphorus removal from circulating aquaculture tail water and can be used widely. [ABSTRACT FROM AUTHOR]

The mechanical properties and electrochemical stability of high-entropy alloys are substantially affected by their composition distribution and crystal structure. However, the details concerning the conditions of milling and sintering for sintered alloys have rarely been reported. In this work, a series of CrMnFeCoNi alloys were fabricated by ball milling and spark plasm sintering for different periods. Their crystal structure, density, hardness, and corrosion resistance were investigated. As a result, a partial alloying of Cr, Mn, Fe, Co, and Ni was achieved by ball milling. However, Cr-rich particles, including Mn, were formed in the milled powders. The sintered alloys inherited the Cr-rich particles to form Cr-rich zones. The formation and change of chromium carbide were also confirmed in sintered alloys. Extended milling or sintering to 12 h achieved high hardness and corrosion resistance for the sintered alloys. The Cr-rich zones showed high hardness and Kelvin potential, which affect both the hardness and the corrosion resistance. [ABSTRACT FROM AUTHOR]

Accurate online recognition of raw material particle size is crucial for the green and efficient operation of blast furnaces. In this study, a high-resolution image acquisition system for blast furnace raw materials was established, and multiple batches of samples were collected for sintered ore and coke particle size analysis. To improve the robustness and generalization capability of the model, image enhancement techniques such as translation, scaling, cropping, random rotation, and brightness adjustment were applied to obtain the basic image datasets for sintered ore and coke. Among four mainstream instance segmentation algorithms, YOLACT++ was selected as the base network. To enhance the recognition accuracy of raw material similarities and subtle features, improvements were made to the YOLACT++ backbone network by replacing the original ResNet101 with DetNet59, and a composite loss function was constructed. Based on the enhanced YOLACT++ algorithm, a particle size recognition model was developed, achieving accuracy rates (PA), recall rates (Recall), F1 scores, and mean intersection over union (MIoU) all exceeding 90%. To address issues such as misidentification of sintered ore voids and over-segmentation in the particle size recognition model, an optimized 3D point cloud concavity and convexity segmentation algorithm was employed. By re-inputting the segmented 3D point cloud results into the particle size recognition model, problems such as void misidentification and over-segmentation were effectively resolved, achieving the multimodal fusion of deep learning and 3D point clouds and improving the accuracy and stability of sintered ore particle size recognition. [ABSTRACT FROM AUTHOR]

Among the raw material production industries that use a large amount of limestone, the effectiveness of limestone usage in the steel production industry has been evaluated and the optimization of limestone addition ratio has been investigated. Based on the past research and development results concerning the CaO added basic sinter production technology, the phenomena of permeability deterioration caused by the excessive CaO addition and the actual operation tests, the multi-component calcium ferrites (SFCA) in sinter that have been currently intensively researched and developed have been evaluated. The reducibility of sinter in blast furnace has so far focused on the lumpy zone up to 1000 °C, but in the future research, it will be necessary focused on the reducibility and permeability in the cohesive zone up to 1000~1500 °C. The current chemical compositions of SFCA has the good reducibility and permeability in the cohesive zone, but the research and development are needed to maintain the appropriate range of CaO (CaO/SiO2 = 1.5~2.0) and further to improve the reducibility and permeability. The future progress of the research and development has been presented.

This is an article in the field of metallurgical engineering. To provide a theoretical basis for FeO composition control and quality optimization of sinter, the metallurgical properties of sinter ore used in 5800 m3 blast furnace of Shagang, such as drum strength, low-temperature reduction pulverization, medium-temperature reducibility were investigated. The effect of FeO content on the performance of sinter and the factors affecting FeO content were explored through statistical data analysis. The results show that based on Shagang's current raw material quality, ore blending structure and process operating conditions，the increase of FeO content can improve the drum index and RDI+3.15 of sinter. When RI is more than 85%, the FeO content becomes the limiting factor of RI, and the appropriate value of FeO content is about 9.5%. The increase of R, SiO2 content, fine powder and fuel ratio will cause the increase of FeO content, MgO content and negative pressure will cause the decrease of FeO content. Data analysis shows if R is 1.9, the contents of SiO2 and MgO are about 5.2% and 1.8%, respectively. The ratio of fine powder is less than 11%, the ratio of fuel is between 4.5 and 5%, and the negative pressure is below 16 KPa, the average FeO content of sinter is about 9.5%, the corresponding drum index is about 80%. The average values of RDI+3.15 and RI are above 75% and 80%, respectively.

The process of blast furnace production relies heavily on the quality and composition of its charge materials, among which iron ore sinter plays a crucial role. The consistency in the fractional composition is intrinsically linked to the method employed for their fragmentation. This fragmentation, or crushing, is influenced by the type of load applied and is inherently dependent on the design and functionality of the crushing machinery utilized. Based on the mechanics of the crushing process, a mathematical model has been developed to describe the interaction between the sprocket teeth and the material being crushed. This model aids in determining the optimal conditions that facilitate the material entry into the active crushing zone of a toothed rotary crusher. Through this analysis, it becomes evident that rotors outfitted with chevron and spiral-configured sprocket teeth significantly outperform those with a linear arrangement. Experimental investigations into the agglomerate crushing process have shed light on the outcomes of different deformation methods. When subjected to compression deformation, it was observed that the resulting material contained 17.2% of fines smaller than 5 mm and a -10 mm fraction amount to 31.1%. Conversely, a more controlled process emerges during stretching in bending, which remarkably reduces the −10 mm fraction to only 1.6%. Building upon these insights, a modernized toothed rotary crusher featuring a nonlinear rotor was developed and implemented in the sintering production of Branch No. 1 AISW of SMMC. The introduction of this advanced crusher led to notable improvements in the screening process of hot sinter. After employing this upgraded machinery, there was a 2–4% increase in the amount of return material alongside a significant 6–7% reduction in screenings during the classification stage on the conveyor path for supplying blast furnace No. 1 with charge materials. Moreover, this optimization ensured the elimination of oversized pieces, specifically those exceeding 80 mm. [ABSTRACT FROM AUTHOR]

Calcium silicate is the undesirable bonding phase in sinter with relatively high melting point and poor reducibility, while the formation mechanism in sinter is ambiguous. Herein, the phase transformation, phase quantification, and morphology evolution of calcium silicate and calcium ferrite in CaO‐SiO2‐Fe2O3‐Al2O3 systems under different n(Fe2O3)/n(CaO) and Al2O3 content are investigated. It is found that with the increase of n(Fe2O3)/n(CaO), the calcium ferrite phases transform from Ca2Fe2O5 (C2F) to complex calcium ferrite, and calcium silicate phases including β‐Ca2SiO4 (β‐C2S) and γ‐Ca2SiO4 (γ‐C2S) are promoted. Moreover, small amount (2%) of Al2O3 can effectively promote the content of silico‐ferrite of calcium and aluminum (SFCA) increasing from 20.95% to 46.69%, whereas inhibiting the β‐C2S from 51.79% to 42.34%. When the content of Al2O3 is over 4%, the Ca2Al(AlSiO7) phase is formed, where both the SFCA and calcium silicate are inhibited. On this base, the competitive mechanism for the formation of calcium silicate and calcium ferrite is revealed, where the Ca2+ and Si4+ are preferred to react with Fe3+ and Al3+ to form liquid phase SFCA, while the amount for β‐C2S or γ‐C2S can be decreased due to the deprivation of Ca2+ and Si4+. [ABSTRACT FROM AUTHOR]

Among the raw material production industries that use a large amount of limestone, the effectiveness of limestone usage in the steel production industry has been evaluated and the optimization of limestone addition ratio has been investigated. Based on the past research and development results concerning the CaO added basic sinter production technology, the phenomena of permeability deterioration caused by the excessive CaO addition and the actual operation tests, the multi-component calcium ferrites (SFCA) in sinter that have been currently intensively researched and developed have been evaluated. The reducibility of sinter in blast furnace has so far focused on the lumpy zone up to 1000 °C, but in the future research, it will be necessary focused on the reducibility and permeability in the cohesive zone up to 1000~1500 °C. The current chemical compositions of SFCA has the good reducibility and permeability in the cohesive zone, but the research and development are needed to maintain the appropriate range of CaO (CaO/SiO2 = 1.5~2.0) and further to improve the reducibility and permeability. The future progress of the research and development has been presented. [ABSTRACT FROM AUTHOR]

Chromium slag is a solid waste of chromium salt production, which contains highly toxic Cr(VI) and significant amounts of valuable metals, such as Fe and Cr. Recycling chromium slag as a raw sintering material in sintering–ironmaking processes can simultaneously reduce toxic Cr(VI) and recover valuable metals. A micro-sintering experiment, compressive strength test, microhardness test, and first-principles calculation are performed to investigate the influence of Cr2O3 on the sintering microstructure and mechanical properties of the silico-ferrite of calcium and aluminum (SFCA) in order to understand the basis of the sintering process with chromium slag addition. The results show that the microstructure of SFCA changes from blocky to interwoven, with further increasing Cr2O3 content from 0 wt% to 3 wt%, and transforms to blocky with Cr2O3 content increasing to 5 wt%. Cr2O3 reacts with Fe2O3 to form (Fe1−xCrx)2O3 (0 ≤ x ≤ 1), which participates in forming SFCA. With the increase in Cr doping concentrations, the hardness of SFCA first decreases and then increases, and the toughness increases. When Cr2O3 content increases from 0 wt% to 3 wt%, the SFCA microhardness decreases and the compressive strength of the sintered sample increases. Further increasing Cr2O3 contents to 5 wt%, the SFCA microhardness increases, and the compressive strength of sintered sample decreases. [ABSTRACT FROM AUTHOR]

Copyright of Erzincan University Journal of Science & Technology is the property of Erzincan Binali Yildirim Universitesi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Multipurpose Utilization of Mineral Resources / Kuangchan Zonghe Liyong is the property of Multipurpose Utilization of Mineral Resources Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To further enhance the recovery rate of low temperature waste heat, the low temperature flue gas in the sinter annular cooler is chosen as the heat source of organic Rankine cycle (ORC) system in the current study, and the system thermal-economic performance evaluation are conducted. The thermal-economic performance models of ORC system are established firstly, and the butane and isopentane are selected to constitute the mixed working fluid. Then the changes of system performance with the mass fraction of isopentane (MR601a) and ORC crucial parameters are evaluated comprehensively, and the bi-objective optimization is applied to ascertain the optimal ORC crucial parameters under various MR601a. The results indicate that the MR601a of 0.6 can obtain the maximum glide temperature. The higher the evaporating temperature is, and the lower the condensing temperature is, the larger the exergy efficiency is, while the smaller the levelized energy cost is. There is an optimal superheat degree to make the ORC system achieve the better overall performance under various MR601a. The exergy efficiency of butane is the maximum with a respectable waste heat recovery rate of 64.18 %, while the levelized energy cost of isopentane in the whole conditions is the minimum with the better economic performance.

Vanadium–titanium ore possesses significant mining and utilization value. The basicity of vanadium–titanium sinter has a direct impact on the formation, location, thickness, permeability, and heat exchange of the cohesive zone in the blast furnace. This paper investigated the influence of increasing the basicity of the sinter on the comprehensive burden's cohesive dripping properties in the blast furnace, while keeping the final slag basicity constant. This study was conducted through cohesive dripping property experiments. The findings indicated that as the sinter basicity in the comprehensive burden structure increased and the corresponding increase in the proportion of pellets occurred, the softening performance of the comprehensive burden improved, the cohesive zone became thinner, the lower edge of the cohesive zone shifted upward, and the softening melting properties became better in general. With an increase in the sinter basicity, the dripping difference pressure of the comprehensive burden decreased, and the dripping rate firstly increased and then decreased. An increase in the sinter basicity of the comprehensive burden structure promoted V reduction, and the V element yield and Cr element yield of the sinter were both increased; the optimal sinter basicity was 2.5, and the corresponding pellet proportion was 42%. [ABSTRACT FROM AUTHOR]

The degree of homogeneity of the sintered ore phase structure directly determines its quality index. A sinter ore quality evaluation method based on the quantification of the homogeneity of the mineral phase structure is proposed. First, the magnetite particle size characteristics in the ore phase structures with different degrees of homogeneity were summarized under a polarized light microscope, and a criterion for evaluating the uniformity of the sintered ore phase structure based on the magnetite content of different particle size grades was determined. Second, a multiple regression model was established for the raw material composition ratio of magnetite with varying particle size grades. Finally, the multiple regression model was optimized using the second-generation non-dominated sorting genetic algorithm (NSGA2). The results show that mineral phase structure analysis categorized the magnetite particle sizes into <30 μm, 30~60 μm, and >60 μm. The adjusted R2 of the multiple regression model of the chemical composition of raw materials and the proportion of magnetite of each particle size grade were all greater than 0.95, and the p values were all <0.05, indicating a high degree of model fitting. Using model analysis, the single factor and the interaction between the multiple factors that significantly influence the proportion of magnetite in the three particle size grades were determined. The multivariate regression model was optimized using the NSGA2 algorithm to determine the ratios of Al2O3 mass% = 1.82, MgO mass% = 1.50, and R(CaO mass%/SiO2 mass%) = 1.84 for the highest degree of uniformity of the sintered ores. Under this sintering condition, the micro-mineral phase structure became more homogeneous, confirming the model's reliability. [ABSTRACT FROM AUTHOR]

The effect of MgO content on the viscosity of blast furnace slag bearing high Al2O3 was studied under laboratory conditions. The viscosity of slag was determined by rotation method. The research results indicate that when the Al2O3 content in blast furnace slag is 17 % -18 %, the MgO content in blast furnace slag should be controlled at 10 %. When the Al2O3 content is 19 %, the MgO content should be controlled at 11 %, and the binary basicity of the slag should be controlled at around 1,10. This type of blast furnace slag has a lower melting point and better fluidity. The purpose of reducing the MgO content in the slag can be achieved by reducing the MgO content in sintered ore, that is, the MgO content in sintered ore should be controlled at 2,0 %-2,5 %. [ABSTRACT FROM AUTHOR]

The mechanical properties and electrochemical stability of high-entropy alloys are substantially affected by their composition distribution and crystal structure. However, the details concerning the conditions of milling and sintering for sintered alloys have rarely been reported. In this work, a series of CrMnFeCoNi alloys were fabricated by ball milling and spark plasm sintering for different periods. Their crystal structure, density, hardness, and corrosion resistance were investigated. As a result, a partial alloying of Cr, Mn, Fe, Co, and Ni was achieved by ball milling. However, Cr-rich particles, including Mn, were formed in the milled powders. The sintered alloys inherited the Cr-rich particles to form Cr-rich zones. The formation and change of chromium carbide were also confirmed in sintered alloys. Extended milling or sintering to 12 h achieved high hardness and corrosion resistance for the sintered alloys. The Cr-rich zones showed high hardness and Kelvin potential, which affect both the hardness and the corrosion resistance.

Theoretically, the vertical sinter sensible heat recovery process can significantly improve the recovery rate of sinter sensible heat. However, the segregated distribution of the sinter and uneven gas–solid flow in vertical cooling furnaces result in insufficient contact and heat exchange between the high-temperature sinter and the cooling gas, thereby limiting the improvement in the sinter sensible heat recovery rate. A Venturi vertical cooling furnace can improve the contact heat transfer between gases and solids and the uniformity of the sinter and the cooling gas temperature. However, this leads to a significant increase in the gas pressure drop and affects the integrity of the downward movement of the sinter. To control the increase in the gas pressure drop while increasing the sensible heat recovery and maintaining the integral flow of the sinter, this study takes a Meishan Steel vertical cooling furnace as the research object and uses the DEM-CFD coupling model to optimize the structural parameters of the Venturi-type vertical cooling furnace. Firstly, a scaling method was designed to reduce the computational cost. Secondly, based on the on-site conditions, the selection range of structural parameters for the Venturi furnace was determined. Finally, an orthogonal experiment was designed. Taking the sensible heat recovery of the sinter and the pressure drop of the cooling gas as the main index, the integrity of the sinter flow was taken as the secondary index to study the Venturi structure parameters suitable for the Meishan Steel vertical cooling furnace, including the width of the vertical part w, the length of the vertical part l, the contraction angle of the contraction part β, and the expansion angle of the expansion part α. The results showed that the order of structural parameters affecting the sensible heat recovery was w, β, α, and l, and the order of parameters affecting the gas pressure drop was w, β, l, and α. The appropriate structural parameters of the Venturi furnace type, obtained by considering the sensible heat recovery and gas pressure drop, were w = 1.1 m, β = 16°, α = 13°, and l = 0.5 m. In addition, in order to improve the integrity of the sinter flow, it was also necessary to increase the wall friction of the particles in the central area of the vertical section by adding steel plates. The results can provide theoretical guidance for improvements to the Meishan Steel vertical cooling furnace. The operation parameters corresponding to the Venturi furnace type can be studied later. [ABSTRACT FROM AUTHOR]

In order to achieve the goal of resource utilization of High-Ti vanadium titanomagnetite (High-Ti VTM), the high-temperature sintering characteristics of High-Ti VTM were investigated by micro-sintering experiments, while the effects of different ordinary iron ore dosage and basicity on the sintering process parameters and sinter quality were investigated by sintering pot experiments. The results showed that the TiO2 and SiO2 contents increased gradually with increasing dosage of High-Ti VTM, and the liquid phase fluidity index and binder phase strength increased gradually, while the assimilation temperature and intergranular consolidation strength showed a decreasing trend. With the increase of the dosage of ordinary iron ore, the vertical sintering speed was reduced, while the sinter yield and tumble index gradually increased. As the basicity of the sinter gradually increased, the sintering time and the pulverization degree of the sinter gradually increased and the sinter yield gradually decreased, while the vertical sintering speed and the tumble index both showed a trend of first increasing and then decreasing. The results of the study provide data to support the preparation of sinter with High-Ti VTM. [ABSTRACT FROM AUTHOR]

Reduction degradation index (RDI) and reducibility index (RI) of sinter are considered as important metallurgical properties for assessing the quality of sintered ore for blast furnace iron-making. For the sake of promoting the permeability of a blast furnace burden and ensuring the smooth smelting process, mathematical models for the prediction of RDI and RI were constructed using machine learning respectively and the effects of factors such as sinter composition on the RDI and RI of sintered ore were analyzed in this article. From simulation results, the precision of the CatBoost model for predicting RDI can reach 98.32%, and the precision of the XGBoost model for predicting RI can reach 93.47%, meaning that the models are effective for the models to forecast the sinter RDI and RI. Moreover, the influence of 16 factors on RDI and RI was analyzed separately based on the SHapley Additive exPlanations (SHAP) method and the accurate predictive models built. [ABSTRACT FROM AUTHOR]

The effect of MgO content on the viscosity of blast furnace slag bearing high Al2O3 was studied under laboratory conditions. The viscosity of slag was determined by rotation method. The research results indicate that when the Al2O3 content in blast furnace slag is 17 % -18 %, the MgO content in blast furnace slag should be controlled at 10 %. When the Al2O3 content is 19 %, the MgO content should be controlled at 11 %, and the binary basicity of the slag should be controlled at around 1,10. This type of blast furnace slag has a lower melting point and better fluidity. The purpose of reducing the MgO content in the slag can be achieved by reducing the MgO content in sintered ore, that is, the MgO content in sintered ore should be controlled at 2,0 %-2,5 %.

Chromium slag is a solid waste of chromium salt production, which contains highly toxic Cr(VI) and significant amounts of valuable metals, such as Fe and Cr. Recycling chromium slag as a raw sintering material in sintering–ironmaking processes can simultaneously reduce toxic Cr(VI) and recover valuable metals. A micro-sintering experiment, compressive strength test, microhardness test, and first-principles calculation are performed to investigate the influence of Cr2O3 on the sintering microstructure and mechanical properties of the silico-ferrite of calcium and aluminum (SFCA) in order to understand the basis of the sintering process with chromium slag addition. The results show that the microstructure of SFCA changes from blocky to interwoven, with further increasing Cr2O3 content from 0 wt% to 3 wt%, and transforms to blocky with Cr2O3 content increasing to 5 wt%. Cr2O3 reacts with Fe2O3 to form (Fe1−xCrx)2O3 (0 ≤ x ≤ 1), which participates in forming SFCA. With the increase in Cr doping concentrations, the hardness of SFCA first decreases and then increases, and the toughness increases. When Cr2O3 content increases from 0 wt% to 3 wt%, the SFCA microhardness decreases and the compressive strength of the sintered sample increases. Further increasing Cr2O3 contents to 5 wt%, the SFCA microhardness increases, and the compressive strength of sintered sample decreases.

With the deepening of the concept of interactive reaction and the development of several studies, metallurgists are no longer simply concerned with the metallurgical properties of a single charge. Instead, they comprehensively consider the interactive reaction of composite burdens. The interactive reaction is mainly affected by the chemical composition, microstructure, reduction temperature, and other factors of the ferrous burdens. In this study, taking a sinter with different basicities and a mixed ore of sinter and lump as the research object, the effect of sinter basicity on the smelting and dripping paraments of a composite burden and the interactive reaction between different burdens was investigated using melting–dripping equipment. The results show that the dripping temperature of a single sinter increases with sinter basicity. In the integrated burdens protocol, the proportion of lump ore increased, and the interaction between the burdens was enhanced, which is mainly manifested as a reduced softening start temperature and melting start temperature of the composite burden. The air permeability of the mixed charge was improved. A change of burden structure enhances the interaction between minerals with increasing sinter basicity, resulting in a change in the liquid phase composition, which reduces the melting point of the primary slag phase, and when the basicity of the sintered is too high, it will deteriorate the gas permeability of the material column. This result is not conducive to the intensive smelting of blast furnaces. At the same time, the sintered mineral phase changes throughout the reduction process were characterized using SEM-EDS and XRD, and the main phases in the slag phase are wustite and calcium silicate. The interactive reaction between the sinter and lump produces low melting point materials, which is verified by calculating the phase diagram of CaO–SiO2–FeO. With increasing sinter basicity, the content of 2CaO·SiO2 at different breakpoints decreased. This result shows that the high melting point phase formed during the reduction process of the sinter decreases, the liquid phase formation temperature of the composite burden decreases, and the interaction between the burdens increases. Therefore, appropriately increasing the sinter basicity and increasing the lump ore proportion benefits the enhanced smelting of a blast furnace. The theoretical and experimental results obtained in this research are of great importance for improving the production application of the proportion of lump in the furnace and developing efficient and low-carbon ironmaking.

Este artigo relata o processo de construção da identidade internacional da Universidade Federal de Santa Catarina (UFSC), a partir do trabalho de Tradução Institucional realizado pelo Serviço de Tradução da Secretaria de Relações Institucionais (SINTER). Apresentamos as ações realizadas entre 2016 e 2022 que contribuíram para ampliar e uniformizar a comunicação institucional em língua inglesa e dar maior visibilidade à instituição no cenário global. Dentre elas, destacam-se: a tradução de websites institucionais; a disponibilização de um glossário português-inglês, contendo termos relevantes da estrutura acadêmica e administrativa da UFSC; e a elaboração de um guia de redação em língua inglesa. Essas e outras ações complementares buscaram aproximação com a comunidade universitária, unindo-se aos esforços do processo de internacionalização transversal em curso na UFSC.

In order to enhance the sinter waste heat recovery (WHR) rate efficiently, the organic Rankine cycle (ORC) for power production was applied to take the low-grade sinter cooling flue gas (SCFG) expelled from the waste heat boiler as the heat source. The system thermodynamic, thermo-economic and multi-objective optimization models were constructed firstly, and then R245fa was chosen as the ORC working fluid. Furthermore, the variations of system thermodynamic and thermo-economic performances with the ORC thermal parameters under different inlet temperatures of SCFG were analyzed in detail, and the ideal parameter combination was established through the multi-objective optimization approach. The results show that, the optimal inlet temperature of SCFG is determined to be 160 °C, and under the aforementioned condition of inlet temperature of SCFG, the optimal ORC thermal parameters are determined to be 95 °C for the working fluid evaporation temperature, 10 °C for the working fluid superheat degree, 28 °C for the working fluid condensation temperature and 9 °C for the pinch-point temperature difference in evaporator by considering the system thermodynamic and thermo-economic performances comprehensively. Meanwhile, the WHR rate of SCFG under the above ORC parameter combination could reach 64.86 %, showing remarkable energy-saving effect.

In order to recycle the sinter waste heat efficiently, the possibility of taking the low temperature flue gas emitted from sinter waste heat boiler as heat source of organic Rankine cycle for power generation is investigated in the current study. The thermodynamic and thermo-economic models of basic organic Rankine cycle (BORC) and regenerative organic Rankine cycle (RORC) were constructed, and R236ea, R245fa and R601a were selected as the working fluids of BORC and RORC. Subsequently, the parametric effects on the thermodynamic and thermo-economic performances under various working fluids for BORC and RORC were analyzed and compared, and then the suitable thermal parameters of BORC and RORC were established through the multi-objective optimization. The results show that, the thermal efficiency of RORC is apparently greater than that of BORC for the given thermal parameters, while the levelized energy cost of RORC is a little bigger than that of BORC. The net output power of R236ea is the largest in the whole optimal conditions, and the flue gas waste heat recovery rate of R236ea for BORC is also the largest at a respectable 65.07 %, while the levelized energy cost of R601a is the smallest for BORC and RORC, showing better thermo-economic performance.

Technetium-99m(99mTc) is used worldwide in 85% of nuclear medicine diagnostic imaging procedures. We developed porous MoO2 pellets as an alternative to reactor-based targets in an (n,γ) reaction for producing Technetium-99m (99mTc) in nuclear medicine. The pellets, formed through a manufacturing process involving mixing, sintering, eluting, and drying, offer advantages such as selective dissolution and improved yield. This research offers a potential solution for stable 99mTc production, focusing on porous molybdenum dioxide (MoO2) as a target material due to its insolubility in water. Using potassium molybdate (K2MoO4) as a pore former, we developed porous MoO2 pellets that facilitate efficient technetium extraction and target recycling. This approach offers control over pore formation and shows promise in addressing supply challenges and enhancing 99mTc production. [ABSTRACT FROM AUTHOR]

Sinter sensible heat recovery via a vertical cooling furnace is a new type of waste heat recovery process proposed based on coke dry quenching. However, the segregation of the burden in a vertical cooling furnace is serious, resulting in a large amount of cooling gas escaping from the short-circuit channel of the vertical cooling furnace, which seriously affects the uniform gas–solid heat transfer in the furnace. To improve the burden distribution and gas flow in such a furnace, this paper proposes a Venturi-type vertical cooling furnace. Based on the single silo of a vertical cooling furnace in Meishan Steel, a slot model was established, and the improvement effect of the Venturi furnace structure on the burden distribution and gas flow was studied using the DEM–CFD coupling method. The results show that compared with the existing furnace type, the inclined wall of the Venturi furnace changed the direction of the high Dnv (average diameter) channel from vertical to inclined-vertical and reduced the Dnv from >0.033 m to 0.028~0.03 m in the vertical part of the variable-diameter section, thus reducing the influence area of the high Dnv channel. The minimum and average values of the voidage in the contraction part of the variable-diameter section increased from 0.28 and 0.315 to 0.31 and 0.33, respectively, which caused the voidage distribution to change from U-shaped to W-shaped along the longitudinal direction while simultaneously reducing the longitudinal fluctuation range of the voidage from 0.28~0.39 to 0.298~0.37. The gas flow direction changed from vertical-upward to vertical-inclined-upward, which increased the gas–solid contact. The gas velocity increased significantly. In the vertical section, the average gas velocity was 2.34 m/s, which was 30.73% higher than the velocity of 1.79 m/s of the existing furnace type. In the variable-diameter section, the average gas velocity was 3.52 m/s, which was 72.55% higher than the velocity of 2.04 m/s of the existing furnace type. The high-speed gas channel basically only existed in the sidewall area and the center area of the vertical section, and the length was reduced from 3.11 m to 2.52 m, which reduced the influence area. In the variable-diameter section, the high-speed gas channel disappeared, and the uniformity of the gas velocity distribution was greatly improved. The gas pressure drop increased from 4140 Pa to 6410 Pa, with an increase of 54.83%. Therefore, when designing the Venturi furnace type, it was necessary to take into consideration the improvement in the gas velocity distribution and the increase in the pressure drop. The research results of this paper can provide guidance for the structure optimization of the sinter vertical cooling furnace. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Production Engineering / Revista Brasileira de Engenharia de Produção is the property of Brazilian Journal of Production Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Sinters in the rift valleys of southern Tibet, including silica sinter and travertine deposits, are the products of hydrothermal activity under regional tectonic movement. Their formation age is significant for studying hydrothermal activity history in this region. Electron spin resonance (ESR) dating is a practical dating method for determining the age of silica sinter and travertine deposits. However, silica sinter's ESR signals vary due to the complex composition. Meanwhile, these ESR signals are mixed, superimposed, and interfere with each other, affecting the ESR signal's measurement. Furthermore, ESR dating has been applied less in travertine samples in southern Tibet, which is not conducive to a comprehensive understanding of the hydrothermal activity history in southern Tibet. Studying the applicability of ESR dating of southern Tibetan silica sinter and travertine deposits helps obtain accurate ESR ages. It lays the chronologic foundation for researching tectonic activities in these rift valleys. This research applied ESR dating to the silica sinter and travertine deposits collected separately from the Targejia thermal field area and the Xiakangjian hot spring area, located in the Ngri-Xigaze area in southern Tibet. We performed ESR dating tests, including how to choose ESR signals, the effect of additional doses, and the thermal stability of ESR signals in travertine. Based on these tests, relatively accurate, reliable ESR ages of silica sinter and travertine were obtained. The results show that: According to the ESR dating results, the silica sinter samples collected from the fourth and third terrace of the Targejia geothermal field were formed at 177±20 and 81±16 ka, respectively, and the travertine deposits collected from the floodplain and first terrace of the Xiakangjian hot spring were formed at 106±32 ka and 264±26 ka, respectively. In terms of irradiation dose, sinter samples collected from southern Tibet respond well to irradiation dose in the range of 0~7680 Gy; In terms of temperature, silica sinter samples are less affected by closure temperature, and the thermal behavior of the ESR signal at g=2.0034 of travertine in southern Tibet is stable in the range of 20 ℃~250 ℃ that is suitable for ESR dating. Regarding mineral structure, The travertine in southern Tibet has better mineral purity and crystallinity; thus, the ESR age results are relatively accurate.

Vanadium–titanium ore possesses significant mining and utilization value. The basicity of vanadium–titanium sinter has a direct impact on the formation, location, thickness, permeability, and heat exchange of the cohesive zone in the blast furnace. This paper investigated the influence of increasing the basicity of the sinter on the comprehensive burden’s cohesive dripping properties in the blast furnace, while keeping the final slag basicity constant. This study was conducted through cohesive dripping property experiments. The findings indicated that as the sinter basicity in the comprehensive burden structure increased and the corresponding increase in the proportion of pellets occurred, the softening performance of the comprehensive burden improved, the cohesive zone became thinner, the lower edge of the cohesive zone shifted upward, and the softening melting properties became better in general. With an increase in the sinter basicity, the dripping difference pressure of the comprehensive burden decreased, and the dripping rate firstly increased and then decreased. An increase in the sinter basicity of the comprehensive burden structure promoted V reduction, and the V element yield and Cr element yield of the sinter were both increased; the optimal sinter basicity was 2.5, and the corresponding pellet proportion was 42%.

Uniformly dispersed nano‐sized aluminum nitride powders were prepared by the sol–gel foaming method using aluminum nitrate as the aluminum source, sucrose as the carbon source, and ammonium chloride as the foaming agent. The effects of ammonium chloride content on the particle size and the sintering properties of aluminum nitride were investigated. The results showed that when the molar ratio of ammonium chloride to aluminum nitrate was.5, the colloidal foams were uniform, large, and fluffy, and amorphous alumina precursors with uniform particles could be prepared. Aluminum nitride powder with a particle size of 22–27 nm can be obtained by calcining these precursors in nitrogen atmosphere at 1400°C for 2 h. At the same time, aluminum nitride bulk material with a relative density of 95% can be obtained by sintering the compact samples in nitrogen atmosphere at 1700°C for 2 h. [ABSTRACT FROM AUTHOR]

(K0.48Na0.52)NbO3-0.03Bi0.5Na0.5ZrO3 (KNNS-0.03BNZ) ceramics were prepared doped with 3 mol% Bi0.5Na0.5ZrO3 (BNZ), and the effect of sintering temperature on dielectric and piezoelectric properties of KNNS-0.03BNZ was also investigated. KNNS-0.03BNZ ceramics at all sintering temperatures exhibit a single perovskite structure, and the change of sintering temperature has no significant effect on the phase composition of KNNS 0.03BNZ ceramics. The Raman shifts of the ν1 and ν5 vibration modes have irregular changes in all sintering temperature ranges, indicating that there are polycrystalline phases coexisting in this region. With the change of sintering temperature, Tc slightly shifts to the high temperature direction, and TR-T slightly shifts to the high temperature direction, dielectric constant εr continuously increases, while dielectric loss tanδ firstly decreasing and then increasing. Thanks to the presence of a small amount of liquid phase in the ceramics sintered at 1160 °C, piezoelectric coefficient d33 reaches 280 pC/N. [ABSTRACT FROM AUTHOR]

In this study, potassium vapor was prepared by using potassium carbonate (K2CO3) and activated carbon (C) reagents to simulate the actual situation of adsorbing potassium vapor from the sinter in the blast furnace. The potassium-rich sinter was characterized by X-ray diffraction (XRD), flame atomic absorption spectrometry (FAAS), and scanning electron microscopy (SEM-EDS). The effects of potassium vapor content on the enrichment ratio, adsorption rate, and low-temperature reduction degradation index (RDI+3.15mm) of sinter have been studied. The results show that with the increase of potassium vapor content, the enrichment ratio of potassium in the sinter increases, and the adsorption rate of potassium in the sinter increases first and then decreases, which was opposite to the trend of the low-temperature reductive degradation index of the sinter. When the potassium vapor content was increased by 50 times, the enrichment ratio and low-temperature reduction powder of the sinter are the highest, which were 2576% and 85.3%, respectively, and the adsorption rate of the sinter was the lowest, which is 51.5%. Meanwhile, potassium vapor changes from physical adsorption K2CO3 to chemical adsorption KFeO2 as the potassium vapor content increases. In addition, the transformation of the occurrence form of potassium vapor in the sinter during the rising process has also been clarified. [ABSTRACT FROM AUTHOR]

On the aero-engine combustor liner, a phenomenon of overheating resembling a hot spot exists, accompanied by a preferential peeling of the YSZ thermal barrier coating that will negatively affect the service life of the component. The hot spot temperatures will affect the ineffectiveness of YSZ, so in this paper, the morphological and property changes of YSZ sintering is investigated experimentally, and a coupled analysis of the YSZ crack propagation mode under the hot spot is performed using ABAQUS. The results show that the pore fractal size D of YSZ increases by 15%. Inside the hot spot region, the coating has a shear stress of 75 MPa. By inserting cohesive units globally in the FEM to simulate the random crack initiation and propagation, unlike the thinning of YSZ layered peeling caused by uniform superheating, the hot spot will cause the crack initiation at the tip of the pores inside the coating and the oblique propagation, eventually forming an oblique crack connection through the pores. When the temperature gradient reaches 30 K/mm, the crack propagation is 40% greater than in a uniform temperature field; consequently, the YSZ in the hot spot boundary region with a greater temperature gradient results in more severe bulk peeling. [ABSTRACT FROM AUTHOR]

The assessment of selected quality parameters of sinter and the effect of the its quality on the efficiency of blast furnace process is presented. The analysis of chemical composition of sinter was conducted. As a main quality parameter sinter richness (Fe content) was selected. Then influence of sinter richness on two parameters of efficiency was calculated. The study was carried out in cooperation with a Blast-Furnace Department of a Polish steelworks and was based on the results coming from this Department. The analysis covers the period of one calendar year. [ABSTRACT FROM AUTHOR]

We report a systematic evaluation of the magnetic properties of FeAl2O4 focusing on the relationship between the fabrication conditions and its structural characteristics, in order to improve ceramics processing in applications of this material. For this purpose, the most important factor to control is the inversion parameter, expressed as y in the (Fe1−yAly)(Al1−y/2Fey/2)2O4 composition, which is relatively high for the spinel aluminate of a transition metal. The magnetic properties of these samples all show the spin glass phenomenon at low temperatures, and the cusp temperature depends systematically on this y value. This means that the evaluation of these magnetic properties will be an effective way to predict some characteristics of product FeAl2O4. Additionally, this study found an anomaly in the structural and magnetic characteristics of FeAl2O4 fabricated at a low temperature. This is thought to originate in a tiny and a small amount of impurity. It will be key for discussing the quality of chemically synthesized FeAl2O4, which is typically produced at low temperatures. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Geomechanics is the property of Journal of Geomechanics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We report a systematic evaluation of the magnetic properties of FeAl2O4 focusing on the relationship between the fabrication conditions and its structural characteristics, in order to improve ceramics processing in applications of this material. For this purpose, the most important factor to control is the inversion parameter, expressed as y in the (Fe1−yAly)(Al1−y/2Fey/2)2O4 composition, which is relatively high for the spinel aluminate of a transition metal. The magnetic properties of these samples all show the spin glass phenomenon at low temperatures, and the cusp temperature depends systematically on this y value. This means that the evaluation of these magnetic properties will be an effective way to predict some characteristics of product FeAl2O4. Additionally, this study found an anomaly in the structural and magnetic characteristics of FeAl2O4 fabricated at a low temperature. This is thought to originate in a tiny and a small amount of impurity. It will be key for discussing the quality of chemically synthesized FeAl2O4, which is typically produced at low temperatures. [ABSTRACT FROM AUTHOR]

Siliceous spicules are micro‐laminated geyserite deposits, or micro‐stromatolites, found around high temperature hot‐springs and geysers, associated with intermittent splashes of water. Understanding conditions of formation of these structures will give insights of critical parameters involved in prebiotic environments and early life. We provide a new data set around two geysers from the El Tatio hydrothermal field, Atacama Desert, Chile, a modern analogue for habitable environments on early Earth and Mars. Small spicules (<5 mm diameter) dominate in the near vent areas, whereas larger spicules (>5 mm diameter) form complex columnar structures in the distal vent (>0.3 m distance from the vent). Hydrodynamics, eruption periodicity, and environmental conditions modulate the temperature and cooling patterns around vents. During geyser eruptions, the temperature of water reaching the ground decreases with the distance from the vent. Cooling is stronger during the evenings, due to strong winds and cold air temperature. Rapid water cooling drives supersaturation of amorphous silica, and therefore precipitation rates increase significantly with distance from the vent. Cooling also controls changes in the bacterial communities, from thin filaments <1 μm diameter predominating closer to the vent, to 1–2 μm diameter filaments in the distal vent. Changes in the silica precipitation rate and biota may control the growth of spicules and the transition to columns. Estimated precipitation rates of silica provide a first approximation of the longevity of these structures and the timing for the formation of internal laminations. Microlamination will form in year time‐scales closer to the vent, and weeks farther from the vent. Key Points: Precipitation rates of silica around the geyser increase with the distance from the ventStrong daily changes in air temperature and wind speed modulate the precipitation rates of silica at El TatioSpicule size and internal lamination increase farther away from the vent due to change in cooling and precipitation rates [ABSTRACT FROM AUTHOR]

The adjustment of sintering raw materials has a decisive influence on the composition of blast furnace slag and the properties of sinter. In order to smelt high-quality molten iron in the blast furnace, the composition of the sinter must be properly adjusted so that the composition of the blast furnace slag and the metallurgical properties of the sinter are optimal for the quality of the iron and are conducive to the smooth operation of the blast furnace. In view of the huge difference in the quality and price of sintering raw materials, this paper proposes an automatic sintering ore blending model to quickly configure sintering raw materials according to the requirements of the production line. This method is based on the calculation process of blast furnace charge, combined with the constraints of process composition and cost performance, to establish a multi-decision sintering ore blending model based on the OLS(Ordinary least squares) algorithm to automatically screen from available raw materials and give the sinter that meets the requirements of the furnace. The plan finally makes TFe, CaO, MgO, SiO2, TiO2, Al2O3, P, Mn, Na2O, K2O, Zn, and other components meet the requirements of the production line, and meet the cost performance requirements of the enterprise for sinter. The model can complete the screening and proportioning of 43 kinds of raw materials within 10 s, and its performance can meet the requirements of the production of variable materials. Combined with an example, a comparative analysis experiment is carried out on the accuracy and practicability of the designed sintering and ore blending model. The experimental results show that the accuracy and efficiency of the method proposed in this paper are higher than those of the current ore blending scheme designed by enterprise engineers. This method can provide an effective reference for the stable operation of the sintering production line. [ABSTRACT FROM AUTHOR]

The metallurgical property of sinter is an important factor affecting the smooth operation of blast furnaces (BF), because it has a great impact on the permeability of BF and solid fuel rate. In order to promote the combustion of solid fuel and the mineralization of flux in sintering process, and eventually improve the strength of sintered ore, a series of investigation on segregation granulation by fuel and flux in coating were carried out, including the sinter pot experiments, the morphology analysis, and the discussion combine with phase diagram. The experimental results show that, (1) as the CaO increased from 0% to 40% and coke breeze increased from 0% to 100%, the sintering indices were improved, the tumble strength of sinter increased from 65.8% to 68.4%, the rate of qualified products increased from 77.4% to 81.0%, and the micro-strength of sinter increased from 68.7% to 75.9%. (2) There are three reasons for the high strength of sinter by segregation granulation of fuel and flux in coating, (a) the complete combustion of solid fuel and release the heat, (b) the effective absorb heat and mineralization of flux, and (c) the improvement of fluidity of bonding phase. The outcomes of the present work may provide a new method to improve the strength of sintered ore and give some reference for better understanding segregation granulation process and using it in actual operation. [ABSTRACT FROM AUTHOR]

In this study, SAA@CS-CB(aluminum-ash carbide slag carbon black doped composite) was prepared by sintering method and modified by impregnation with oxalic acid to obtain SAA@CS-CBoa. Fluoride adsorption experiments were carried out using this composite as adsorbent. With increasing pH values, the adsorption amount of fluoride decreases in the range of 2–11. The pseudo second order equation and Langmuir model were fit to the experimental data, and the adsorption of fluoride by SAA@CS-CBoa exhibited spontaneous and endothermic characteristics. When PO43-, CO32–, SO42-, Cl-, NO3–, Br- and HCO3– anions were individually or combined in solution, the adsorbents exhibited higher fluoride selectivity and sensitivity, while PO43-and CO32– weakened the adsorption of fluoride in solution in the same way regardless of the presence of the other 5 anions. The results of SEM, EDS, XRD and FTIR characterizations showed that the mechanism of fluoride adsorption and removal by SAA@CS-CBoa included the combined effects of electrostatic attraction, surface coordination precipitation and ion exchange. SAA@CS-CBoa is an effective composite material for water adsorption of fluoride, and still has an excellent performance of cyclic regeneration after 10 times adsorption desorption. This study provides a new approach for the utilization of fluoride removal resources for industrial solid waste resource recycling.

The degree of homogeneity of the sintered ore phase structure directly determines its quality index. A sinter ore quality evaluation method based on the quantification of the homogeneity of the mineral phase structure is proposed. First, the magnetite particle size characteristics in the ore phase structures with different degrees of homogeneity were summarized under a polarized light microscope, and a criterion for evaluating the uniformity of the sintered ore phase structure based on the magnetite content of different particle size grades was determined. Second, a multiple regression model was established for the raw material composition ratio of magnetite with varying particle size grades. Finally, the multiple regression model was optimized using the second-generation non-dominated sorting genetic algorithm (NSGA2). The results show that mineral phase structure analysis categorized the magnetite particle sizes into 60 μm. The adjusted R2 of the multiple regression model of the chemical composition of raw materials and the proportion of magnetite of each particle size grade were all greater than 0.95, and the p values were all 2O3 mass% = 1.82, MgO mass% = 1.50, and R(CaO mass%/SiO2 mass%) = 1.84 for the highest degree of uniformity of the sintered ores. Under this sintering condition, the micro-mineral phase structure became more homogeneous, confirming the model’s reliability.