Centrifugal Casting of High Speed Steel/Nodular Cast Iron Compound Roll Collar

The centrifugal casting of compound HSS/nodular cast iron roll collar was studied,and the factors affecting transition zone quality were analyzed.The pouring temperature and interval in pouring are the main factors affecting transition zone quality.By controlling process parameter and flux adding during casting,high quality roll collar was obtained.The cause,why in the casting of HSS part,segregation appears easily,was analyzed and the countermeasure eliminating segregation was put forward,the measure eliminating heat treatment crackling was also put forward.

Effects of iron compounds on pyrolysis behavior of coals and metallurgical properties of resultant cokes

The utilization of highly reactive and high-strength coke can enhance the efficiency of blast furnace by promoting indirect reduction of iron oxides.Iron compounds,as the main constituent in iron-bearing minerals,have aroused wide interest in preparation of highly reactive iron coke.However,the effects of iron compounds on pyrolysis behavior of coal and metallurgical properties of resultant cokes are still unclear.Thus,three iron compounds,i.e.,Fe;O;,Fe;O;and FeC;O;·2H;O,were adopted to investigate their effects on coal pyrolysis behavior and metallurgical properties of the resultant cokes.The results show that iron compounds have slight effects on the thermal behavior of coal blend originated from thermogravimetric and differential thermogravimetric curves.The apparent activation energy varies with different iron compounds ranging from 94.85 to 110.11 kJ/mol in the primary pyrolysis process,while lower apparent activation energy is required for the secondary pyrolysis process.Iron compounds have an adverse influence on the mechanical properties and carbon structure of cokes.Strong correlations exist among coke reactivity,coke strength after reaction,and the content of metallic iron in cokes or the values of crystallite stacking height,which reflect the dependency of thermal property on metallic iron content and carbon structure of cokes.

Distribution and Form of Iron and Calcium Compounds Before and After Residue Hydrogenation Under Different Space Velocities

The distribution and form of iron and calcium compounds were studied using hydrogenation feedstock and hydrogenation products with different space velocities as the research object.The content of metallic elements,such as calcium and iron in hydrogenation feedstock,and extract samples were determined via flame atomic absorption spectrometry.The water-soluble iron and calcium species in oil samples were determined by an IC2010 high-throughput ion chromatograph.Nearly 60%-80%of the iron or calcium compounds were mainly concentrated in resins and asphaltenes.Iron and calcium compounds mainly exist in the form of oil-soluble metal species in hydrogenation feedstock and hydrogenation products.Under certain conditions of reaction temperature,pressure,and volume ratio of hydrogen to oil,when the reaction space velocity was 0.6 h^(−1),about 30%of the iron or calcium compounds were converted from oil-soluble to water-soluble species after hydrogenation.When the reaction space velocity was decreased from 1.70 to 0.60 h^(−1),the proportion of iron compounds converted from oil-soluble to water-soluble increased from 8.4%to 28%.Moreover,the proportion of calcium compounds converted from oil-soluble to water-soluble increased from 10%to 37%.This denotes that with decreasing reaction space velocity,the ratio of oil-soluble to water-soluble species increases.Water-soluble iron and calcium compounds are present in the form of inorganic salts,such as chlorate and sulfate.This study helps in understanding the removal mechanism of iron and calcium compounds and optimizing the operating conditions of residue hydrogenation.

Tailoring the surface structure of iron compounds to optimize the selectivity of 3-nitrostyrene hydrogenation reaction over Pt catalyst

Selective hydrogenation of substituted nitroarenes is an important reaction to obtain amines.Supported metal catalysts are wildly used in this reaction because the surface structure of supports can tune the properties of the supported metal nanoparticles(NPs)and promote the selectivity to amines.Herein,Pt NPs were immobilized on Fe OOH,Fe_(3)O_(4)andα-Fe_2O_(3)nanorods to synthesize a series of iron compounds supported Pt catalysts by liquid phase reduction method.Chemoselective hydrogenation of 3-nitrostyrene to 3-aminostyrene was used as probe reaction to evaluate the performance of the catalysts.The results show that Pt/Fe OOH exhibits the highest selectivity and activity.Fe OOH support with pores and-OH groups can tune the electronic structure of Pt NPs.The positive charge of Pt NPs supported on Fe OOH is key factor for improving the catalytic performance.

Aromatic compound degradation by iron reducing bacteria isolated from irrigated tropical paddy soils

Forty-six candidate phenol/benzoate degrading-iron reducing bacteria were isolated from long term irrigated tropical paddy soils by enrichment procedures.Pure cultures and some prepared mixed cultures were examined for ferric oxide reduction and phenol/benzoate degradation.All the isolates were iron reducers,but only 56.5%could couple iron reduction to phenol and/or benzoate degradation,as evidenced by depletion of phenol and benzoate after one week incubation.Analysis of degradative capability using Biolog...

Iron Fertilization with Enhanced Phytoplankton Productivity under Minimal Sulfur Compounds and Grazing Control Analysis in HNLC Region

The present study investigated quantitatively the significance of HNLC (high-nutrient low-chlorophyll) regions and its grazing control with the improved iron fertilization for climate change. The limitation of iron (Fe) for phytoplankton growth in HNLC regions was confirmed by sulfur compounds (S) such as volcanic ash and hydrogen sulfide (H2S) in batch cultures, whose chemical sediment of Fe3S4 showed 4.06 wt%. The technologies developed for iron fertilization since 1993 till now were not practical to provide sufficient amounts of bioavailable iron due to sedimentary iron sulfides induced by undersea volcanic sulfur compounds. The proposed technology for iron fertilization was improved to enhance the bioavailable iron to phytoplankton by keeping minimal sulfur compounds in HNLC regions. The low productivity of phytoplankton by grazing control in HNLC regions was 6% diatoms whose 52% was grazed by copepods and 42% by krill on the basis of data analysis in 2000 EisenEx Experiment at boundary of Antarctic and African tectonic plates. All of the previous iron fertilization experiments were conducted at volcanic sulfur compounds enriched HNLC regions. The present study revealed that the enhanced phytoplankton productivity in batch culture without sedimentary iron sulfides can be possible only if sulfur compounds are minimal, as is in Shag Rocks (53°S, 42°W) of South Georgia in Scotia Sea in the Southern Ocean.

Reduction of Sulphur-containing Aromatic Nitro Compounds with Hydrazine Hydrate over Iron(III) Oxide-MgO Catalyst

Sulphur-containing aromatic amines were prepared efficiently in good to excellent yields by reduction of the corresponding sulphur-containing aromatic nitro compounds with hydrazine hydrate in the presence of iron（Ⅲ） oxide-MgO catalyst. The catalyst exhibited high activity and stability for the reduction of sulphur-containing aromatic nitro compounds. The yields of sulphur-containing aromatic amines were up to 91-99 % at 355 K after reduction for 1-4 h over this catalyst.

基于柿子提取物的自制pH检测剂和酸碱变色科普实验

利用柿子提取物中的表没食子儿茶素没食子酸酯(EGCG)与硫酸亚铁的配位反应,研究配合物溶液对不同pH的响应变化,实现对生活中常见的具有酸碱性物质的便携区分应用。本实验原料简单易得、过程安全、现象明显,能让观众们感受到化学变化之美,激发对化学学科的浓厚兴趣。

基于Unet网络的烧结混合料粒度检测模型

目前烧结生产中混合料粒度主要通过人工检测方式获取,该操作方式不连续,且准确度有待提高,难以确定粒度分布与烧结生产参数之间的定量关系。因此,本文提出一种烧结混合料粒度检测模型,该模型采用CCD工业相机和工业光源作为混合料图像的主要采集设备;在图像预处理过程中,使用加权平均法用于图像的灰度化处理;在粒度检测模型构建中,应用Unet网络对烧结混合料图像进行分割处理。结果表明:工业光源的使用提高了采集时的亮度,也能在最大程度上降低外界光线的影响,确保烧结混合料图像的稳定性;图像预处理有助于分辨烧结混合料的颗粒特征,在此基础上,使用中值滤波和直方图均衡化更适合表征图像中混合料颗粒的边缘,并将颗粒内部特征模糊化,对噪声及其他不利因素有很好的去除效果;训练好的Unet网络分割模型对烧结混合料的分割准确率达到91%以上,分割精度误差低于9%,对混合料图像的分割效果较好。该模型的应用可为烧结生产提供及时、准确的粒度分布数据,有助于提高烧结混合料粒度检测效率,帮助企业提升经济效益和社会效益。

铁基改性樟树叶复合材料的制备及吸波性能

生物炭材料因高的电导率而具有吸收电磁波的潜在优异性能,但其吸收性能的提高受阻抗失配制约.为了解决此问题,通常在生物炭材料中加入磁性材料,以提高吸波性能.通过简单的浸渍和烧结,制备铁基生物炭(樟树叶)复合材料.研究结果表明:相对于其他6种铁基生物炭复合材料,该文制备的铁基生物炭复合材料具有较强的综合吸波性能.

基于UbD理论的化学逆向教学设计--以“铁及其化合物”单元教学为例

以铁及其化合物为例,基于UbD理论进行了单元教学设计。以元素观为大概念,明确学习优先次序,增设表现性任务,融合WHERETO要素,构建分类观-转化观-元素观的元素化合物分析模型,得到元素化合物的单元教学启示:聚焦核心大概念,建立认知模型;注重理解多维度,培育高阶思维;评价融入教与学,落实“教、学、评”一体化。

单味中药及中药复方对铁死亡作用的研究进展

铁死亡作为一种新型的细胞死亡形式,近年来备受关注,中药对其作用的研究也逐渐增多。本文着眼于单味中药和中药复方的相关研究,对青蒿素、青黛、麦冬、丹参、天麻、黄芩、番泻叶、虎杖、姜黄等中药提取物或衍生物,以及益肾健脑方、天麻钩藤饮、脑泰方、活血解毒方、安脑平冲方、益气解毒化瘀方、黄芩汤、加味二至丸、化脂复肝颗粒、化瘀祛痰方、心阳片、减味寿胎丸、益气解毒方等多首中药复方对铁死亡作用的研究进行综述,旨在为中医药在铁死亡中的应用和深入研究提供参考。

锂离子电池铁基负极材料研究进展

铁基负极材料具有理论比容量高、反应电位低、环境友好等优势,成为锂离子电池领域的研究热点。然而,铁基负极材料在电池循环中存在体积膨胀大、离子/电子输运能力差等问题,较大地影响了铁基负极材料的广泛应用。基于这些问题,从纳米化构筑、碳材料复合和晶体结构调控等方面,综述了铁基负极材料的相关研究进展,以期为高性能铁基锂离子电池负极材料的研究和发展提供有效建议。

异种材料不锈钢和铝合金焊接技术研究及应用

应急放试验工装采用异种材料304不锈钢和6061铝合金焊接而成。在采用熔钎焊工艺焊接时,由于这两种材料的化学成分不同以及熔点的差异,在焊缝中形成多种Fe-Al脆性金属间化合物以及共晶体混合组织,导致出现严重的裂纹和气孔缺陷。本文进行了304不锈钢/6061铝合金对接和T形结构的焊接工艺研究。首先在304不锈钢侧采用铝铁青铜材料焊接制作中间过渡层,然后采用ER5356焊丝对6061铝合金和过渡层进行焊接,从而使钢和铝之间相互熔合。采用交流方波TIG焊和合适的焊接参数,控制钢和铝异种材料焊接过程中脆性金属间化合物及共晶体混合组织的形成,解决了不锈钢和铝合金异种材料无法熔融焊接的问题。所得到的焊缝力学性能优良,该工艺已成功用于应急放试验工装的焊接加工制造中。

“人工+智能”复合回归管理方法在高炉生产的应用

通过归纳一线人工经验,确定关键参数和权重系数,形成“人工+智能”复合最佳回归公式;通过电脑编辑智能程序,实时采集各关键参数,精准预测绩效指标,进而指导实际生产管理。模型铁水硅成分预测准确度90%以上,改进后铁水平均硅降低约0.04%,实现了高炉生产高效运行,经济效益显著。

我国铁尾矿综合利用途径的研究进展

为了推动我国铁尾矿综合利用工作、有效缓解因尾矿堆存而引发的系列问题,从我国铁尾矿特性、大宗利用技术途径和高值化利用技术途径三个方面详细阐述了目前我国铁尾矿常见的综合利用途径。综合分析发现,有价元素和矿物回收存在低品位、难选别的铁尾矿回收效率有待提高的问题。水泥基材料和充填材料制备技术缺乏相应的产品标准和法律法规。高值化利用技术还需进一步的理论研究和试验验证以便早日实现工业化生产。进一步探讨了铁尾矿利用未来发展展望并提出鼓励加强技术创新与研究、完善法规政策及标准体系、探索多元化利用新途径、加大研发和推广资金支持力度等建议。

Effect of inoculating addition on machinability of gray cast iron

Gray cast irons were inoculated with FeSi75＋RE and FeSi75＋Sr inoculants. The changes of apex angle of the drills before and after being used were used to evaluate machinability of gray cast irons. Effect of FeSi75＋RE and FeSi75＋Sr inoculants on mechanical properties, machinability and sensibility of gray cast iron used in cylinder block were investigated. Experimental results showed that gray cast iron treated with 60%FeSi75＋40% RE inoculants exhibited tensile strength consistently at about 295 MPa along with good hardness and improved metallurgical quality. While gray cast iron inoculated with 20%FeSi75＋80% Sr inoculants exhibited the best machinability, the lowest cross-section sensibility and the least microhardness difference. The tool flank wear of the drill increased correspondingly with the increase of the microhardness difference of the matrix, indicating the great effect of homogeneity of the matrix on the machinability of gray cast iron.

不同钝化材料对降低农田镉砷污染效果及安全性评估的研究

为探讨镉与砷复合污染农田适用的钝化材料,采用盆栽试验,比较研究了赤泥、赤泥+铁粉、玄武岩红泥+石灰石粉、石灰石粉+铁粉和石灰石粉+生物质炭+硫酸亚铁等5种钝化材料对降低水稻籽粒中镉和砷的效果。试验结果揭示了所有测试的钝化材料均能显著改变土壤中镉和砷的化学形态,并降低它们的生物有效性,从而有效减少了水稻籽粒中的镉和砷含量。特别是,以赤泥+铁粉、石灰石粉+铁粉和石灰石粉+生物质炭+硫酸亚铁等3种复合钝化材料的效果最为明显,能够使籽粒中的镉和砷分别降低58%~63%和56%~67%。在试验条件下,5种钝化材料均不会导致土壤质量的明显下降,施用含石灰石粉和生物质炭的钝化材料还有利于降低土壤酸度、增加土壤有机质和阳离子交换量。综合效果,研究表明赤泥+铁粉是一种治理镉砷复合污染农田土壤较为理想的钝化材料。

Application of complex inoculants in improving the processability of grey cast iron for cylinder blocks

Effect of several complex inoculants on mechanical properties, process-ability and sensibility of grey cast iron used in cylinder block were investigated. The experimental results showed that the grey cast iron treated with 60%FeSi75+40%RE complex inoculants has tensile strength consistently at about 295 MPa along with good hardness and improved metallurgy quality. While the grey cast iron inoculated with 20%FeSi75+80%Sr compound inoculants has the best process-ability, the lowest cross-section sensibility and the least microhardness difference. The wear amount of the drill increases correspondingly with the increase of the microhardness difference of matrix structure, indicating the great effect of homogeneousness of matrix structure in the grey cast iron on the machinability of the grey cast iron.