旋流器串联分级在磁铁矿选矿中的应用研究

为了解决细粒级磨矿的分级问题,在磨矿分级回路中,以串联旋流器组作为分级设备,提高了磨矿浓度和效率,达到了磁铁矿磨至-0．043mm的目的,使高质量铁精矿生产获得成功。     

东天山尾亚钒钛磁铁矿矿床角闪石矿物学特征及成因意义

尾亚钒钛磁铁矿矿床是东天山地区典型的层状岩体型钒钛磁铁矿,其矿石主体为浸染状—稠密浸染状矿石,同时含有少量半块状—块状富矿。应用电子探针对浸染状—稠密浸染状矿石和半块状—块状富矿中的角闪石进行成分分析,并探讨其形成的物理化学条件。结果表明,浸染状—稠密浸染状矿石就位深度浅,在10.1~16.9 km之间,其母岩浆形成温度相对较低(950~981℃)。半块状—块状富矿形成于19.2~20.0 km的深部岩浆房,矿浆具有相对高温(978~993℃)的特征。成矿的绝对氧逸度大于-9.6。深部岩浆房的分异演化对尾亚层状岩体型钒钛磁铁矿矿床富矿体的形成具有至关重要的作用。     

气基竖炉直接还原炼铁技术的发展

在分析国内外直接还原铁市场的基础上,探讨了气基竖炉直接还原炼铁技术发展的市场空间。在中国钢铁行业结构调整过程中,气基竖炉技术由于具有节能环保和产品优质的优势,将会成为我国非高炉炼铁发展最重要的方向。从原料、产品、工艺特性、机械设备等方面对MIDREX和Energiron 2种气基竖炉工艺进行了综合比较,探讨了其各自的优缺点。随着技术进步以及全球经济、资源、能源条件的变化,气基竖炉技术正朝着设备大型化、气源多样化、矿源扩大化的方向发展。     

Engineering Iron Oxide Hollow Nanospheres to Enhance Antimicrobial Property: Understanding the Cytotoxic Origin in Organic Rich Environment

Engineered magnetic iron oxide nanoparticles with surprisingly high antimicrobial activity and excellent safety profiles to mammalian cell lines have been developed. Hematite hollow nanospheres (HNSs) are prepared by a facile hard templating method; reduction of hematite HNSs by H₂ leads to magnetite HNSs. The antimicrobial activity of magnetite HNSs towards Gram negative (Escherichia coli) and Gram positive (Staphylococcus epidermidis) bacteria is evaluated against hematite HNSs and conventional magnetite (C‐magnetite; diameter <50 nm). Superior antibacterial performance is observed for magnetite HNSs towards both E. coli and S. epidermidis over hematite HNSs and C‐magnetite. The origin of the antimicrobial activity of magnetite HNSs is the high leaching of iron ions in the presence of microorganisms, which leads to high generation of reactive oxygen species. Magnetite HNSs allow multiple‐fold increase in the generation of soluble iron ions over hematite HNSs and C‐magnetite, showing that control over both the composition and nanostructure is crucial to tune the antimicrobial activity of iron oxides. Based on the current findings, magnetic HNSs show promising potential antimicrobial applications.     

Oxidation and Induration Characteristics of Pellets Made from Western Australian Ultrafine Magnetite Concentrates and Its Utilization Strategy

Western Australian magnetite concentrates normally have ultrafine granularity and much higher specific surface areas than Chinese magnetite concentrates owing to the significant pre-grinding and beneficiation for saleable iron grade.Such characteristics will inevitably affect the subsequent pelletization process.However,very few investigations have been done before.Thus,the oxidation and induration characteristics of pellet made from a Western Australian ultrafine magnetite concentrate were revealed by conducting routine preheating-roasting tests in an electric tube furnace and investigating the microstructure of fired pellets under an optical microscope in comparison with that of pellets made from typical Chinese magnetite concentrate.The liquidus regions of CaO-SiO_2-Fe_2O_3 and CaOSiO_2-Al_2O_3 ternary systems in air at various temperatures were calculated by FactSage software to explain the importance of liquid phase in the consolidation of fired pellets.The results show that pellet made from ultrafine magnetite concentrate possesses better oxidability and preheating performance than that made from Chinese magnetite concentrate.However,it has inferior roasting performance,usually requiring conditions of roasting at 1 280℃ for at least 30 min to acquire sufficiently high compressive strength,which are attributed to higher temperature sensitivity caused by its smaller particle size and less formation of liquid phase because of low impurities like CaO and Al_2O_3 in raw materials.Correspondingly,its roasting performance can be significantly improved by blending with Chinese magnetite concentrates or increasing the pellet basicity(wCaO/wSiO_2).By comprehensive evaluation,blending with Chinese iron ore concentrates is an appropriate way to utilize Western Australia ultrafine magnetite concentrates.     

攀西某钒钛磁铁矿的物质组成与结构特征研究

利用化学分析、光谱分析、X射线衍射物相定性分析、矿相显微镜、扫描电镜、MLA工艺矿物参数自动定量分析等手段对攀西某钒钛磁铁矿的化学组成、矿物组成、结构构造特征进行系统研究。研究结果表明,矿石的化学组成主要为铁、钛、钒,其中TFe含量为31%左右,TiO_2含量约为11%,V2O5含量约为0.5%,均达到了工业利用的标准,是矿石选矿回收利用的主要组分;其次为铬、锰、钴、镍、铜,是矿石中的有益伴生元素。矿石的金属矿物主要为钛磁铁矿(约43.09%~45.09%)和钛铁矿(11.67%~13.17%),可供工业上选别铁精矿和钛精矿;其次为黄铁矿、方铅矿、闪锌矿、黄铜矿等硫化物矿物,可经选矿得到硫钴精矿。矿石主要呈浸染状构造,矿物颗粒主要呈半自形-他形结构、包含结构、海绵陨铁结构、交代残余结构和固溶体分离结构。研究结果明确了该矿区矿石综合利用的物质基础,查明了矿石的结构构造特征,为矿石选矿工艺的制定提供了重要的基础资料。     

利用铁盐去除钒铬溶液中杂质砷

针对攀枝花红格南矿区钒钛磁铁矿冶炼的钒渣焙烧后浸出液中含砷较高,传统工艺处理时得到的钒产品中砷含量高于国家标准的情况,采用铁盐法除砷,制备高纯的V_2O_5产品。考察了初始p H、温度、反应时间、w_(Fe)/w_(As)、静置沉淀p H等因素对除砷率和钒损的影响。试验结果表明,最佳工艺条件为:初始p H=3,温度40℃,w_(Fe)/w_(As)=4~5,反应时间40~50 min,然后加入Na OH调节p H至6,保温10 min,静置12 h。在此条件下,得到As的去除率大于85%,V的损失率小于5%。溶液中的As含量小于0.08 g/L,得到的V_2O_5(纯度98%)产品中As含量小于0.01%,符合行业标准YB/T 5304-2011。     

怀集县铁山冢铁矿地质特征及成因浅析

怀集县铁山冢铁矿位于广东肇庆,属矽卡岩型铁矿床。矿体主要呈透镜体状或囊状分布于黑云母花岗岩与砂岩的接触带中,围岩为矽卡岩体,受构造及接触带共同控制。矿脉与围岩界线清楚,矿体厚度变化较大。矿石有用组分主要为磁铁矿。     

Atomic force microscopy imaging of fragments from the Martian meteorite ALH84001

A combination of scanning electron microscopy (SEM) and environmental scanning electron microscopy (ESEM) techniques, as well as atomic force microscopy (AFM) methods has been used to study fragments of the Martian meteorite ALH84001. Images of the same areas on the meteorite were obtained prior to and following gold/palladium coating by mapping the surface of the fragment using ESEM coupled with energy-dispersive X-ray analysis. Viewing of the fragments demonstrated the presence of structures, previously described as nanofossils by McKay et al . (Search for past life on Mars — possible relic biogenic activity in martian meteorite ALH84001. Science , 1996, pp. 924–930) of NASA who used SEM imaging of gold-coated meteorite samples. Careful imaging of the fragments revealed that the observed structures were not an artefact introduced by the coating procedure.     

攀钢炼铁精料技术进步及冶炼实践

攀钢钒太磁铁精矿采用一段磨矿工艺,其粒度粗,制粒性能差,同时因精矿ＴＦｅ、ＳｉＯ２低,ＴｉＯ２、Ａｌ２Ｏ３高,造成烧结性能差,影响烧结矿强度、成品率及产率,不能满足高炉精料的要求。近年来,攀钢采用一系列先进的精料技术与强化措施,使烧结矿产质量,特别是强度与冶金性能有了很大的改善,高炉冶炼钒钛磁铁矿取得新进展。