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.     

论课堂教学的“格”及其“立”与“破”

课堂教学的"格"是课堂教学能否产生有效教学的研究重点。文章在分析了格和课堂教学的格后,从课堂教学目标等四个层面探讨了课堂教学格的"立"与"破",进而认为,在这种课堂教学中,教师和学生之间从原有的"权威—服从"关系转变成了"价值引导—自主探究和发现"的关系,学生通过这种自主探究和发现知识的过程,获得了一种成功的体验和自我价值感的实现,提升了自己的生命价值和生命意义。     

让“问题”成为课堂教学的主角——有效的课堂教学“问题”与“设疑”探析

本文根据自己教学中时问题的设计的粗浅认识,从实际的案例出发,分析了如何在课堂教学中设疑与提问,并总结了课堂教学中教师设计有效的“问题”该注意的方面。提出“问题”教学是激发学生的求知欲、促进学生的思维、培养学生创新意识、提高有效课堂教学重要手段。     

单片机“一体化”教学模式的优化研究

文章针对高职类院校"教学做一体化"教学模式展开讨论,分析了传统教学模式在本门专业课教学中的不足,并且提出了"一体化"教学模式应用到实际教学中遇到的问题,探索了其中的原因,作者结合自身在《单片机应用技术》课程中的教学实践,提出了改进的基于工作过程的"一体化"教学模式,在实际中取得了良好的效果。     

论声乐教学中“气”的训练

＂气＂是歌唱的动力及源泉,是声乐艺术的主要表现手段之一,它也是歌者进行歌唱训练时首先要攻克的技术难题。没有良好的气,就没有美感的声音。在声乐教学中,＂气＂的训练是歌唱技术训练的核心。结合声乐教学经验.从声乐理论与教学中＂气＂与声音的关系,声乐教学中＂气＂的训练方法两个方面阐述了＂气＂的技巧对声音训练的重要作用,并且探讨了声乐教学中＂气＂训练的具体方法。     

“研究式”教学法在计算方法实验课程教学中的应用

基于"计算方法"实验课程的特点,针对传统教学法存在的不足,结合具体实例,探讨了"研究式"教学法在"计算方法"实验课程教学中的应用。     

“学习型”大学英语素质教育模式

“学习型”大学英语素质教育模式是在大学英语教学改革实践的基础上形成的。其特点是试图把英语教学与素质教育相结合、教学模式与学习方法相统一。该教学模式是一种“学习型”的系统,能因材施教、因事制宜,自我完善。文章从实践到理论,探讨了大学英语教学思想。     

信息技术与《电子技术》整合的教学过程

按照信息技术与《电子技术》双主整合模式,在《电子技术》的课程中进行了教学实践,具体的教学过程是：导入——课堂教学——实训教学——总结反思,将课堂教学、实训教学、信息技术三者有机地整合在一起。     

“词汇网络包”在大学英语课程教学中的应用

"词汇网络包"是指有紧密语义关联的词汇集合。首先讨论了"词汇网络包"的定义,接着介绍了"词汇网络包"的编写理念和原则,然后探讨了"词汇网络包"的编写体例结构,最后分析了将"词汇网络包"运用于大学英语课程教学中需要注意的问题。从而指出,在大学英语课程教学中,利用"词汇网络包"进行词汇教学是一种有效的词汇教学新模式。     

“阳光体育运动”背景下普通高校篮球教学的改革

为了全面推进体育教学改革,更好地贯彻＂健康第一＂的指导思想,我国启动了＂阳光体育运动＂工程.＂阳光体育＂给篮球教学改革提出了新的要求.文章采用文献法,探讨高校篮球教学目标、教学内容、教学方法和考核评价的改革.     

“信息管理学”教学方法探索

讨论了“信息管理学”课程教学的“双主互动”和案例教学法及其操作要求扣基本原则。