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.     

基于Gini修正G1组合赋权的低碳经济评价模型与实证

主要目的是通过构建低碳经济评价模型实现对低碳经济发展水平的评价,并找出低碳经济发展的影响因素,低碳经济评价结果可以对低碳经济发展的政策制定提供理论依据和参考.首先,根据低碳经济的涵义构建低碳经济评价指标体系;然后,利用G1赋权法和Gini赋权法构造了基于客观修正主观的组合赋权方法,确定评价指标的组合权重;最后,对秦皇岛市2005~2015年的低碳经济发展水平进行了实证研究,判断秦皇岛市的低碳经济发展水平,找出影响秦皇岛市低碳经济发展的因素,为秦皇岛市低碳经济发展政策制定提供理论依据和参考.     

农村发展主体的低碳经济意识教育研究

就农村经济发展而言,农民是根本主体。发挥农民发展低碳经济的主体力量,必须提升其低碳经济意识。低碳经济教育是提升农民低碳经济意识的基本方式。对农民进行低碳经济教育的内容多样,核心是对农民进行生态道德教育;由于乡村精英是低碳经济教育的重点,要增强其发展低碳经济的使命感,使其真正成为发展低碳经济的领头羊;妇女的性别特征使其能在农村低碳经济发展中发挥特殊的作用,同时也意味对其低碳经济教育应因＂性＂而别;应该将幼儿、中小学学生培育为农村低碳经济发展的后备军,农村幼儿低碳经济教育应坚持生本教育理念,农村中小学的低碳经济教育应以课堂教育为主展开。     

民族地区低碳金融支持低碳经济发展措施分析

在世界经济向低碳经济转型以及后危机背景下,提出民族地区发展低碳经济产业的理论依据,论证了民族地区低碳金融支持低碳经济发展的必要性,及民族地区低碳金融支持低碳经济发展的主要内容。通过分析民族地区金融机构支持低碳经济发展的主要措施,引导理论界和实务部门重视民族地区低碳金融对低碳经济产业的转型支持,并提出金融机构在民族地区发展低碳金融业务的对策建议。     

基于DEA法的内蒙古发展低碳经济的效率评价

低碳经济被认为是有效减少二氧化碳排放的可行的经济运行模式,但是由于区域的差异,低碳经济的发展程度不同,因此对于低碳经济的有效评价成为必须。目前我国对于区域低碳经济的评价研究较少,对中国内蒙古地区近10年数据的利用数据包络法(DEA法),根据投入及产出的结果分析内蒙古发展低碳经济的效率,并以此为依据提出内蒙古低碳经济的发展对策。     

低碳经济下的工程经济风险与防范管理研究

在世界进入新的世纪之后,人们普遍对低碳经济转型的过程开始关注起来,而在这个重要的时期,我国以低碳、环保、节能为主题在各个领域开展了低碳型经济的发展。在国内,项目的多种类的特性让低碳转型期内的经济风险加大,并且在考虑风险的范围内存在一定的差异。由于低碳经济的存在,本文研究了在低碳型经济下工程经济的风险及防范措施,研究低碳时代的发展和变革,给未来的发展奠定良好的基础。     

国外发展低碳经济的启示

阐述了低碳经济的发展历程,通过美国、欧洲联盟等国应对气候变化、发展低碳经济的案例,介绍了国外低碳经济的发展手段,提出了我国发展低碳经济的建议。     

基于三螺旋理论的我国低碳经济发展构想

介绍了三螺旋理论,应用三螺旋理论对中国低碳经济的发展进行了战略性的分析,从充分发挥政府在低碳经济中的主导作用、强化企业社会责任、发挥大学在低碳经济中的作用等方面提出了我国低碳经济的发展构想。     

发挥低碳金融作用促进广西低碳经济发展

诠释了如何发挥金融市场的导向和调节作用支持广西低碳经济产业发展;如何培育和完善碳金融交易体系,加快开发碳金融衍生工具,促进广西低碳经济发展.广西的金融业应树立低碳金融理念,将金融服务拓展到低碳经济各个层面,让金融业成为低碳理念推广的"践行者",最终推动广西经济发展方式的转型和产业结构的调整和优化,促进广西经济又好又快发...     

东莞发展低碳经济的现状、挑战与路径选择——从发达国家的低碳路径探索看

世界经济历经工业化、信息化之后,正在走向低碳化,低碳经济时代已经来临,这种大背景,对有“世界工厂”之称的东莞,既是挑战,也是机遇。通过对西方发达国家走过的低碳经济发展路径的简要综述,分析了东莞传统经济的高碳特性,东莞发展低碳经济的现状及问题与挑战,并针对东莞未来推动低碳经济发展的进程提出了相关建议。     

“节能减排”背景下中小型城市低碳经济发展模式调查研究——以山东德州为例

为了解德州市低碳经济发展现状,分析其成功经验,探究我国中小型城市低碳经济发展的普适模式,从德州市城乡居民的低碳意识、低碳科技推广应用和新能源工程、宏观政策等方面对德州低碳经济成功范例展开调查分析.在此基础上建立了德州市发展低碳经济的"四驱循环动力模型",最后对德州模式进行了总结说明,并对中小型城市如何实现低碳发展提出了针对性建议.