烧结铁矿中FeO含量对其在富氢高炉中还原行为的影响

Japan started the national project “COURSE 50” for CO₂ reduction in the 2000s. This project aimed to establish novel technologies to reduce CO₂ emissions with partially utilization of hydrogen in blast furnace-based ironmaking by 30% by around 2030 and use it for practical applications by 2050. The idea is that instead of coke, hydrogen is used as the reducing agent, leading to lower fossil fuel consumption in the process. It has been reported that the reduction behavior of hematite, magnetite, calcium ferrite, and slag in the sinter is different, and it is also considerably influenced by the sinter morphology. This study aimed to investigate the reduction behavior of sinters in hydrogen enriched blast furnace with different mineral morphologies in CO–CO₂–H₂ mixed gas. As an experimental sample, two sinter samples with significantly different hematite and magnetite ratios were prepared to compare their reduction behaviors. The reduction of wustite to iron was carried out at 1000, 900, and 800°C in a CO–CO₂–H₂ atmosphere for the mineral morphology-controlled sinter, and the following findings were obtained. The reduction rate of smaller amount of FeO led to faster increase of the reduction rate curve at the initial stage of reduction. Macro-observations of reduced samples showed that the reaction proceeded from the outer periphery of the sample toward the inside, and a reaction interface was observed where reduced iron and wustite coexisted. Micro-observations revealed three layers, namely, wustite single phase in the center zone of the sample, iron single phase in the outer periphery zone of the sample, and iron oxide-derived wustite FeO and iron, or calcium ferrite-derived wustite 'FeO' and iron in the reaction interface zone. A two-interface unreacted core model was successfully applied for the kinetic analysis of the reduction reaction, and obtained temperature dependent expressions of the chemical reaction coefficients from each mineral phases.     

Mg和La对Ca–Ti 处理钢中夹杂物演变和组织的影响

The evolution of inclusions and the formation of acicular ferrite (AF) in Ca–Ti treated steel was systematically investigated after Mg and La addition. The inclusions in the molten steel were Ca–Al–O, Ca–Al–Mg–O, and La–Mg–Ca–Al–O after Ca, Mg, and La addition, respectively. The type of oxide inclusion in the final quenched samples was the same as that in the molten steel. However, unlike those in molten steel, the inclusions were Ca–Al–Ti–O + MnS, Ca–Mg–Al–Ti–O + MnS, and La–Ca–Mg–Al–Ti–O + MnS in Mg-free, Mg-containing, and La-containing samples, respectively. The inclusions distributed dispersedly in the La-containing sample. In addition, the average size of the inclusions in the La-containing sample was the smallest, while the number density of inclusions was the highest. The size of effective inclusions (nucleus of AF formation) was mainly in the range of 1–3 μm. In addition, the content of ferrite side plates (FSP) decreased, while the percentage of AF increased by 16.2% due to the increase in the number of effective inclusions in the La-containing sample in this study.     

摩擦焊接碳钢（EN24）和镍基高温合金（IN718）的显微组织和力学性能

Continuous-drive rotary friction welding was performed to join cylindrical specimens of carbon steel (EN24) and nickel-based superalloy (IN718), and the microstructures of three distinct weld zones—the weld interface (WI)/thermo-mechanically affected zone (TMAZ), the heat-affected zone (HAZ), and the base metal—were examined. The joint was observed to be free of defects but featured uneven flash formation. Electron backscatter diffraction (EBSD) analysis showed substantial changes in high-angle grain boundaries, low-angle grain boundaries, and twin boundaries in the TMAZ and HAZ. Moreover, significant refinement in grain size (2–5 μm) was observed at the WI/TMAZ with reference to the base metal. The possible causes of these are discussed. The microhardness profile across the welded joint shows variation in hardness. The changes in hardness are ascribed to grain refinement, phase transformation, and the dissolution of strengthening precipitates. The tensile test results reveal that a joint efficiency of 100% can be achieved using this method.     

采用超声组装与滚压工艺制备铝–碳纳米管复合材料

This study introduced a novel fabrication of aluminum–carbon nanotube (CNT) composites by employing bulk acoustic waves and accumulative roll bonding (ARB). In this method, CNT particles were aligned using ultrasonic standing wave in an aqueous media, and the arrayed particles were precipitated on the aluminum plate substrate. Then, the plates rolled on each other through the ARB process with four passes. Optical and scanning electron micrographs demonstrated the effective aligning of CNTs on the aluminum substrate with a negligible deviation of arrayed CNTs through the ARB process. The X-ray diffraction pattern of the developed composites showed no peaks for carbon and aluminum carbide. In addition, tensile tests showed that the longitudinal strength of the specimens processed with aligned CNTs was significantly greater than that of the specimens with common randomly dispersed particles. The proposed technique is beneficial for the fabrication of Al–CNT composites with directional mechanical strength.     

活化天然矿石选择性还原二氧化碳为无定形碳

Natural magnetite formed by the isomorphism substitutions of transition metals, including Fe, Ti, Co, etc., was activated by mechanical grinding followed by H₂ reduction. The temperature-programmed reduction of hydrogen (H₂-TPR) and temperature-programmed surface reaction of carbon dioxide (CO₂-TPSR) were carried out to investigate the processes of oxygen loss and CO₂ reduction. The samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and energy-dispersive X-ray spectroscopy (EDS). The results showed that the stability of spinel phases and oxygen-deficient degree significantly increased after natural magnetite was mechanically milled and reduced in H₂ atmosphere. Meanwhile, the activity and selectivity of CO₂ reduction into carbon were enhanced. The deposited carbon on the activated natural magnetite was confirmed as amorphous. The amount of carbon after CO₂ reduction at 300°C for 90 min over the activated natural magnetite was 2.87wt% higher than that over the natural magnetite.     

含钛高炉炉渣微波合成碳化钛及其介电性能测定

The preparation of functional material titanium carbide by the carbothermal reduction of Ti-bearing blast furnace slag with microwave heating is an effective method for valuable metals recovery; it can alleviate the environmental pressure caused by slag stocking. The dynamic dielectric parameters of Ti-bearing blast furnace slag/pulverized coal mixture under high-temperature heating are measured by the cylindrical resonant cavity perturbation method. Combining the transient dipole and large π bond delocalization polarization phenomena, the interaction mechanism of the microwave macroscopic non-thermal effect on the titanium carbide synthesis reaction was revealed. The material thickness range during microwave heating was optimized by the joint analysis of penetration depth and reflection loss, which is of great significance to the design of the microwave reactor for the carbothermal reduction of Ti-bearing blast furnace slag.     

汽车暴露面板带有表面条状缺陷的夹杂物分布特征分析:一种定量电解方法

The specific distribution characteristics of inclusions along with the sliver defect were analyzed in detail to explain the formation mechanism of the sliver defect on the automobile exposed panel surface. A quantitative electrolysis method was used to compare and evaluate the three-dimensional morphology, size, composition, quantity, and distribution of inclusions in the defect and non-defect zone of automobile exposed panel. The Al₂O₃ inclusions were observed to be aggregated or chain-like shape along with the sliver defect of about 3–10 μm. The aggregation sections of the Al₂O₃ inclusions are distributed discretely along the rolling direction, with a spacing of 3–7 mm, a length of 6–7 mm, and a width of about 3 mm. The inclusion area part is 0.04%–0.16% with an average value of 0.08%, the inclusion number density is 40 mm?2 and the inclusion average spacing is 25.13 μm. The inclusion spacing is approximately 40–160 μm, with an average value of 68.76 μm in chain-like inclusion parts. The average area fraction and number density of inclusions in the non-defect region were reduced to about 0.002% and 1–2 mm?2, respectively, with the inclusion spacing of 400 μm and the size of Al₂O₃ being 1–3 μm.     

在酸性溶液中加压氧化三价砷离子和二价铁离子

The co-oxidation of As(III) and Fe(II) in acidic solutions by pressured oxygen was studied under an oxygen pressure between 0.5 and 2.0 MPa at a temperature of 150°C. It was confirmed that without Fe(II) ions, As(III) ions in the solutions are virtually non-oxidizable by pressured oxygen even at a temperature as high as 200°C and an oxygen pressure up to 2.0 MPa. Fe(II) ions in the solutions did have a catalysis effect on the oxidation of As(III), possibly attributable to the production of such strong oxidants as hydroxyl free radicals (OH·) and Fe(IV) in the oxidation process of Fe(II). The effects of such factors as the initial molar ratio of Fe(II)/As(III), initial pH value of the solution, oxygen pressure, and the addition of radical scavengers on the oxidation efficiencies of As(III) and Fe(II) were studied. It was found that the oxidation of As(III) was limited in the co-oxidation process due to the accumulation of the As(III) oxidation product, As(V), in the solutions.     

高校体育教学中开展救护教育的必要性与实施途径研究——基于生命教育的视角

运用文献资料法和逻辑分析法等方法,从生命教育的视角对高校体育课教学中开展救护技能教育的必要性和实施途径进行研究。认为:生命教育是教育的前提,而基本的生命救护知识是生命教育的重要组成部分。体育课堂教学是实施救护教育的最佳途径。可通过加强宣传、救护知识进课程、理论与实践相结合的教学形式、加强教师专业知识培训等途径来实施救护教学,以期为我国高校的救护教育起到推广作用。     

基础教育课程改革对高师教学改革的挑战

在新一轮基础教育课程改革中,教学观念、教师角色、学习方式等的变化对高师教学改革提出了严峻挑战.加强高师教学内容、教学方法、教学手段和教学评价改革,是高师教育自身发展的需要,也是实施素质教育、发展基础教育的重要使命.     

深入研究人文教育的本质与规律,构建全方位高校人文教育体系

人文教育的实质是人性教育,核心是涵养人文精神,特征表现为价值理性。人文教育规律表现为：教学过程的引导性;学习过程的探索性;学习方法的内省性、体验性;实践活动的必要性;教育形式的多样性。要提高人文教育的效果,必须精选教学内容,激发学生的学习兴趣,培育具有人文精神和素质的教师队伍,构建＂一个渠道,两方渗透,三项活动,四种氛围＂的全方位人文教育体系。     

论大众化教育阶段的高校教学管理工作

高等学校的教学管理工作必须适应高等学校发展的要求.我国高等教育在从精英向大众高等教育的转变过程中,教学管理工作必须进行相应的改革.论述了高校教学管理工作的特点,对大众化教育阶段如何做好教学管理工作进行了初步的探讨.     

思想政治教育中信仰教育弱化问题研究

目前高校的信仰教育弱化问题主要表现为：信仰教育的客体对信仰教育的认识模糊、态度淡漠、主流信仰状况不容乐观，信仰教育主体的意识不强，信仰教育的内部机制不协调等；信仰教育弱化问题的成因，主要归结为社会大环境等宏观因素，以往信仰教育的误区以及评价体系等中观因素，大学生群体的身心特点等微观因素；解决信仰教育弱化问题主要从提高对信仰教育的认识，把握信仰教育的特点和规律，创新信仰教育的原则和方法做起。     

论素质教育与高校体育俱乐部制

在高校体育教学中实行体育俱乐部制，使素质教育深入到了体育教育中，是使有共同爱好、兴趣、目标的学生共同完成体育教学任务的一种教学模式。它迎合了素质教育尊重学生人格，承认学生的个性差异，重视学生的个性发展，培养了学生的创造能力，改变了以前的“传习式”教学模式，使得学生能够主动地、生动活泼地进行学习。     

利用现代教育技术促进教学改革

现代教育技术是现代教学的重要组成部分,制约着教学的质量和水平。当前教学改革已成为教育改革的核心要求和必然趋势。本文分析了现代教育技术的优势,阐述了利用现代教育技术促进教学改革的实现途径。     

理科学科德育简论

由教学的教育性原则引出学科德育的概念,由中央与教育部的相关文件得出实施学科德育的必要性,给出了理科学科德育的界定,总结数学学科德育的理论研究与教学实践,指出数学学科德育的实施与若干发达国家的德育做法的相似性,简要探讨了理科学科德育.     

多媒体教学在医学教育桥梁性课程的应用与思考

文章结合西藏高等医学教育的实际情况,指出多媒体教学方法在医学教育桥梁性课程中所起的积极作用,并对教学过程中应注意的问题进行了总结和分析,为提高医学教育桥梁性课程的教学质量提供了理论依据。     

《学记》的教育思想及其现代诠释

《学记》是中国古代一部专门阐释教育、教学问题的论著,它总结了我国先秦时期儒家教育和教学方面的经验和理论,其包含“建国君民”、“化民成俗”的教育理念,“教学相长”、“善教善学”的教育方法,“豫时孙摩”、“长善救失”的教学原则等.这些教育理念、教育方法以及教学原则启发当下教育要坚持以人为本,培育和提升教师及学生的素质;树立现代教育理念,改革课程设置;创新教育方法,改变传统的教育模式.