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.     

高等学校实验教学质量监控点的研究

实验教学在高等学校人才培养中具有重要地位和作用，实施监控是保证人才质量的有效措施。阐述了实验教学质量监控点的概念和功能，设置了包括实验教学理念、实验教学体系、实验教学方法、实验教学考试、实验教学队伍、实验教学信息平台、实验教学开放、实验教学管理制度、实验教学评估、实验教学投入等10个监控点，研究了实验教学监控点内涵及其实践效果。     

谈体育教学组织、教法的选择与运用

体育教学组织、教法的选择与运用对提高教学质量，增强学生体质起着至关重要的作用。从构成体育教学组织和教法的理论基础，树立科学的教学思想，克服体育教学组织和教法的单一化倾向，提供多种体育教学组织和教法的互相融合以及学生的心理发展规律等方面进行分析，力求为教学研究提供一些理论依据。     

基于研究型教学模式的高等数学教改探析

阐述了研究型教学模式的内涵、理论基础和基本特征。研究型教学模式是一种新的教学模式,它是以创新型人才培养为指导,以提高学生综合素质为目的,以学生积极主动参与为基础的教学模式。因此,基于研究型教学模式的高等数学教学改革,对提高学生学习兴趣、培养开拓型和创新型人才具有十分重要的意义,它弥补了传统教学中忽视的内容。结合多年的教学实践,提出了一系列基于研究型教学模式的高等数学教学改革的方法和对策。它包括确定以学生为主体的研究型教学目标,讲授研究型教学内容,采用研究型教学方法,进行研究型课程考核等。实践证明,上述改革方案对提高教学质量和增强学生综合素质起到了积极的作用。     

论信息技术教育的发展与教学变革

阐明了现代教育技术的发展趋势是教学信息数字化、教学媒体交互化、教学过程智能化、教学操作简便化、教学评估实时化、教学管理自动化,同时指出计算机教育技术的发展对教学活动中的教学观念、组织形式和教学方法产生了巨大影响。     

大学英语教学改革探析

根据大学英语教学现状及其存在的问题,我们从教学观念、教学模式、教学方法、教学手段几方面探讨教学改革的途径,目的在于形成大学英语教学的全新思想,促进大学英语教学的深入改革。     

高职思想政治理论课有效教学的策略研究

在理清高职思想政治理论课有效教学的内涵、特征的基础上,分析影响高职思想政治理论课有效教学的因素,从教学理念、教学目标、教学内容、教学方法、教学过程、教学风格、教学评价和教学反思8个方面提出了增强有效教学的策略。     

增强高校思想政治理论课教学实效性三题——基于加涅相关理论的思考

加涅把有关教学实效性的探讨与教学设计、教学起点和教学结果相结合的思想,对高校思想政治理论课提高教学实效性有重要的启示。“帮助学生”的教学设计及其与教学方法、教学规程的结合,体现了加涅教学设计的基本思想。对教学开端的调查和测量,强化课程的吸引力和感染力,减少确定性告知和重复则让教学的开端及其展开更加有效。把“态度”作为学习高校思想政治理论课的重要收获,并明示态度学习和转变的着力点和基本方法,则让认定和评判高校思想政治理论课教学的实效性有了新的尺度和标准。     

浅谈力学教学中的逻辑思维

培养学生的逻辑思维能力是力学教学中基本的教学方法,本文介绍了在四中教学过程中培养学生的逻辑思维能力,概念教学,基础知识教学,习题教学,复习课教学。     

高职院校非测绘类专业测量学教学改革探索

文章通过分析传统测量学教学中存在的问题,从测量学教学实践出发,对教学内容、教材建设、教学方法、教学手段和考核方式等方面提出了测量学教学改革的几点措施。     

论大学英语教学中的文化教学

文化教学是英语教学不可缺少的组成部分,在大学英语教学中导入文化教学势在必行。本文从四个方面论述文化教学在大学英语教学中的重要作用,并探讨教师在文化教学中的作用。