Effects of rare earth on inclusions and corrosion resistance of 10PCuRE weathering steel

The types,morphologies and distributions of nonmetallic inclusions in Cu-P weathering steels with and without rare earth were analyzed through a quantitative image analyzer,scanning electron microscopy(SEM)and energy dispersive spectroscopy(EDS)attached to SEM.Solid-soluble content of rare earth in the steels was analyzed by non-aqua electroanalysis and ICP.The results showed that rare earth modified the types and the morphologies of inclusions in the weathering steels.The small spherical rare earth oxysulfides and rare earth sulphides replaced the elongated MnS inclusions in the RE weathering steels.The rare earth inclusions dispersedly distributed and most inclusions were smaller than 2 μm in size.The optimum content of RE was 0.0065%-0.016% for 10PCuRE weathering steels containing about0.002% oxygen and 0.004% sulfur.Solid-soluble content of rare earth in steels was(14-20)x 10-6,which can act as a micro-alloying element.The corrosion resistance of 10PCuRE weathering steels and Q235 were studied by dry-wet cyclic immersion test.Their corrosion rates were obtained respectively.The polarization curves and pitting corrosion behaviors of weathering steels with and without rare earth were measured by electrochemical methods.The corrosion resistance of Cu-P weathering steels was improved by adding an appropriate amount of rare earth.Less and fewer rare earth inclusions largely decreased pitting susceptibility and rate of pit propagation.The pitting potential and the resistance against pitting corrosion of the RE weathering steel were significantly improved due to the modification of rare earth to inclusions.     

Lanthanide NIR luminescence for telecommunications, bioanalyses and solar energy conversion

Present-day advanced technologies heavily rely on the exciting magnetic and spectroscopic properties of lanthanide ions. In particular, their ability to generate well-characterized and intense near-infrared (NIR) luminescence is exploited in any modern fiber-optic telecommunication network. In this feature article, we first summarize the whereabouts underlying the design of highly luminescent NIR molecular edifices and materials. We then focus on describing the main trends in three applications related to this spectral range: telecommunications, biosciences, and solar energy conversion. In telecommunications, efforts concentrate presently on getting easily processable polymer-based waveguide amplifiers. Upconversion nanophosphors emitting in the visible after NIR excitation are now ubiquitous in many bioanalyses while their application to bio-imaging is still in its early stages; however, highly sensitive NIR-NIR systems start to be at hand for both in vitro and in vivo imaging, as well as dual probes combining magnetic resonance and optical imaging. Finally, both silicon-based and dye-sensitized solar cells benefit from the downconversion and upconversion capabilities of lanthanide ions to harvest UV and NIR solar light and to boost the overall quantum efficiency of these next-generation devices.     

Evaluation of D113 cation exchange resin for the removal of Eu(Ⅲ) from aqueous solution

Batch adsorption experiments were conducted for the adsorption of Eu(Ⅲ) ions from aqueous solution by D113 resin. The results indicated that D113 resin could adsorb Eu(Ⅲ) ion effectively from aqueous solution. The adsorption was strongly dependent on pH of the medium with enhanced adsorption as the pH turned from 3.50 to 7.00 and the optimal adsorption condition was in HAc-NaAc medium with pH value of 6.50. The maximum uptake capacity of Eu(Ⅲ) ions was 290.9 mg/g D113 at 298 K, at an initial pH value of 6.50. The overall adsorption process was best described by Lagergren-first-order kinetics. When Freundlich and Langmuir isotherms were tested, the latter had a better fit with the experimental data. The thermodynamic parameters such as free energy (G) which were all negative, indicated that the adsorption of Eu(Ⅲ) ions onto D113 resin was spontaneous and the positive value of enthalpy (H) showed that the adsorption was endothermic in nature. Thomas model was applied to experimental column data to determine the characteristic parameters of column useful for process design. Furthermore, Eu(Ⅲ) could be eluted by using 3.0 mol/L HCl solution and the D113 resin could be regenerated and reused.     

Phase structure and temperature dependent luminescence properties of Sr2LiSiO4F: Eu2+ and Sr2MgSi2O7: Eu2+ phosphors

Green-emitting Sr2LiSiO4F:Eu2+ and blue-emitting Sr2MgSi2O7:Eu2+ phosphors were synthesized by the conventional high temperature solid-state route,respectively.Their structures and photoluminescenee properties were comparatively investigated.It was found that the mixture phases of Sr2MgSi2O7 and SrF2 were obtained when a part of Sr2+ in Sr2LiSiO4F was replaced by some amount of Mg2+ in order to design the possible SrMgLiSiO4F:Eu2+ phosphor.Based on the photoluminescence analysis,Sr2LiSiO4F:Eu2+ phosphor exhibited a green broad emission band of main peak at 513 nm under the excitation of 365 nm,while the Sr2MgSi2O7:Eu2+ and SrMgLiSiO4F:Eu2+ phosphor showed blue emission centered at 467 nm.The temperature dependent photoluminescence properties and room temperature decay time for the three kinds of phosphors were also discussed in this paper.     

Er3+-substituted W-type barium ferrite: preparation and electromagnetic properties

Er3+-substituted W-type barium ferrites Ba1-xErx(Zn0.3Co0.7)2Fe16O27(x=0.00,0.05,0.10,0.15,0.20)were synthesized by polymer adsorbent combustion method.Samples were characterized by X-ray diffraction analysis(XRD),X-ray fluorescence(XRF),scanning electron microscopy(SEM)and network analyzer to investigate the relationships among Er3+concentration,crystal structure,surface mcrphology and electromagnetic properties.All the XRD patterns showed pure phase of W-type barium ferrite when x≤0.15,while the impurity phase of ErFeO3 appeared when x=0.20.The pure W-type barium ferrite showed a hexagonal flake shape.In addition,the microwave electromagnetic properties of samples were analyzed in the frequency range of 2-18 GHz.It was indicated that the electromagnetic properties were significantly improved when Er3+doping content was 0.10.The reasons were also discussed using electromagnetic theory.The optimized ferrite exhibited excellent microwave absoption performance.The maximum of reflection loss(RL)reached about-27.4 dB and RL was below-10dB at the frequency range from 8.4 GHz to 18 GHz,when the thickness was 2.6 mm.     

EXAFS investigation and luminescent properties of nanosized Tb: Lu2O3 phosphors

Nanosized terbium doped Lu2O3 phosphors were synthesized via a modified co-precipitation processing.The as-prepared Tb:Lu2O3 phosphors was consisted of well crystallized nanosized sphere particles with a diameter of about 30 nnx Local structure of Tb ions in Lu2O3 lattice was investigated by an analytical approach based on Fourier transformation of the extended X-ray absorption fine structure(EXAFS) data.X-ray near edge structure (XANES) spectra suggested that all Tb ions doped were tervalonce.EXAFS results indicated that Tb ions have entered the Lu2O3 cubic lattice by means of solid solution.The coordination number and first shell Tb-O distance dropped with the increasing of Tb concentration.Emission spectra of the phosphors was shown to be typical for Tb3+ with main components at 542,550 and 490 nm,derived from irradiative relaxation of 5D4 level.The emission intensity decreased severely with the increasing of Tb concentration from 1 mol.% to 15 tool.%,suggesting a significant concentration quenching above 1 mol.% Tb.The reduction of emission intensity was interpreted by higher distortion derived relaxation among the surface state resident Tb3+ ions.     

Multi-Pass Simulation of Heavy Plate Rolling Including Intermediate Forced Cooling

Thermomechanical Controlled Processing (TMCP) including accelerated cooling after the final hot rolling pass is a well-established technology,widely applied in HSLA steel plate production.However,there are still certain limitations,especially for thicker plate.The rolling schedule includes a long holding period (HP) after the roughing stage to allow the temperature to fall sufficiently for optimised TMCP during finishing.Intermediate Forced Cooling (IFC) applied during the HP can increase productivity by decreasing the required hold time,can restrict austenite grain growth,and can also improve the subsequent strain penetration in thick plate with further metallurgical benefits.Multi-pass plane strain compression (PSC) tests have been performed on the thermomechanical compression (TMC) machine at Sheffield University including different severities of IFC.Clearly it is impossible to simulate all aspects of the temperature and strain gradients present in thick plates in laboratory specimens,and most of the tests were conducted at temperatures and strains calculated by Finite Element modelling as relevant to specific positions through the plate thickness.However,some aspects of the gradients were addressed with tests using cold platens.The results have indeed shown that IFC can shorten the HP and reduce austenite grain growth and its variation across thick plate.     

Overview of Particles and Bubbles in Continuously Cast Steel

This paper gives an overview of phenomena associated with particles and bubbles in continuously cast steel. During steel processing from deoxidation to solidification the inclusion population undergoes changes with opportunities of removal. Flotation is an important separation mechanism. Inclusion particles may accumulate in the solidifying strand, thus forming enriched bands, which depend on the type of casting machine. Bubbles are created during inert gas injection. They also change in size, can float out, but also form accumulation bands. The interaction of bubbles and particles is discussed. Internal structure that recently has been observed on the inner surface of bubbles will be reviewed.     

烦恼 快乐 艺术——池莉“人生三部曲”解读

池莉的"人生三部曲"--<烦恼人生>、<不谈爱情>、<太阳出世>诉尽了普普通通的市民烦恼,小说中主人公被柴米油盐、吃喝拉撒、老婆孩子等琐事所烦着,从而构成他们的"烦恼人生".然而池莉通过自己的艺术创作,以积极的人生态度,又让读者体会到生活本身的快乐,"烦恼人生"中包含着"快乐人生".     

属性块在工程图形中的研究与应用

介绍了在工程图形中用属性块标注表面粗糙度的方法.采用属性块不仅能避免大量重复性的工作,还能节省大量的存储空间,具有提高绘图速度、质量,便于修改,资源共享等应用价值.     

艾萨铜熔炼水淬渣磨浮贫化回收率的分析

铜熔炼电炉渣在使用磨浮贫化回收铜的工艺中,由于熔炼方式、原料结构、工艺操作控制及电炉渣冷却方式不同等原因,导致铜的浮选回收率差异较大,因此需要针对实际情况进行研究。以艾萨铜熔炼急冷水淬电炉渣的磨浮贫化工艺为研究对象,通过分析研究工艺流程中原矿和尾矿的主要成分结构、矿物物相、粒度形态等,并结合生产实践,探明此类电炉渣在磨浮贫化实际工艺生产中因自身属性对铜回收率造成的客观直接影响,从而科学直观地指导生产操作,减少工艺误区。     

艾萨铜熔炼水淬渣磨浮贫化回收率的分析

铜熔炼电炉渣在使用磨浮贫化回收铜的工艺中,由于熔炼方式、原料结构、工艺操作控制及电炉渣冷却方式不同等原因,导致铜的浮选回收率差异较大,因此需要针对实际情况进行研究。以艾萨铜熔炼急冷水淬电炉渣的磨浮贫化工艺为研究对象,通过分析研究工艺流程中原矿和尾矿的主要成分结构、矿物物相、粒度形态等,并结合生产实践,探明此类电炉渣在磨浮贫化实际工艺生产中因自身属性对铜回收率造成的客观直接影响,从而科学直观地指导生产操作,减少工艺误区。     

铜熔炼渣缓冷工艺管理及改进

铜冶炼厂广泛采用渣缓冷工艺回收炉渣中的铜,该工艺可以提高铜的回收率,增加企业的经济效益.文章介绍了铜熔炼渣的缓冷工艺和主要设施,讨论了渣缓冷工艺存在的主要问题并提出了解决措施,为铜熔炼渣缓冷工艺的生产管理提供参考.     

缓冷制度对铜渣结晶性能的影响

研究了高温铜渣缓冷制度对渣中铜相分子结晶及铜渣浮选性能的影响。结果表明,炉渣冷却速度越慢,渣中铜相分子粒度越大,越有利于铜的选别分离。随着铜渣冷却速度变慢,铜渣中矿物晶型由细小分散变得完整连续,且易浮选回收的铜相分子聚集体亦逐渐增多变大,揭示了冷却速度变慢铜浮选回收率增高的主要机理。     

铜熔炼渣和吹炼渣混合浮选的生产实践

东营方圆有色金属有限公司采用浮选工艺对铜熔炼渣和吹炼渣进行混合选矿,以回收炉渣中的铜等有价金属。实际生产中采用三段破碎+两段球磨的浮选工艺,通过合理控制破碎粒度、磨矿粒度以及加药量等工艺参数,有效地提高了铜等金属的回收率。     

转炉渣含铜矿物晶相优化工艺研究

研究了某转炉渣的化学组成与铜和铁的物相组成,查明了含铜矿物的赋存形式和嵌部特征。结果表明,炉渣冷却过程中其黏度会影响铜结晶的大小,氧化钙作为添加剂可以降低炉渣黏度,促进微细铜颗粒更好的结晶长大,实现晶相优化。     

澳斯麦特熔炼渣回收铜实验研究

针对澳炉缓冷渣的性质特点,从炉渣冷却制度、磨矿细度、浮选药剂等方面考查了对选铜指标的影响,提出了最佳选铜技术条件。闭路试验表明,采用阶段磨矿阶段选别工艺,可获得铜精矿铜品位16.11%,回收率69.90%比较理想的技术指标。实现了澳炉炉渣的综合再利用,这对经济、社会和环境效益都具有十分重要的现实意义。     

铜冶炼炉渣缓冷技术研究与生产实践

国内铜冶炼厂广泛采用缓冷工艺回收炉渣中铜,该工艺可以提高冶炼厂铜回收率和冶炼炉对原料的适应性。缓冷炉渣经过选矿后,铜精矿返回冶炼系统,尾矿作为生产水泥的原料。介绍了铜冶炼炉渣缓冷工艺及生产实践中存在的主要问题,进行了原因分析并提出了解决措施。     

铜冶炼炉渣综合利用技术的研究与探讨

铜冶炼渣具有硬度大、密度大、夹杂冰铜块的特点,综合回收难度大,生产成本高。为回收炉渣中铜、铁资源,主流选矿工艺为半自磨+球磨+浮选+磁选,可获得合格的铜精矿和多种用途的铁精矿产品。其指标的高低与炉渣冷却方式、碎磨方式、选矿工艺等密切相关,我国尾渣品位已经降至0.35%以下,比国外尾渣品位降低0.05个百分点以上。     

铜冶炼炉渣回收选铁创效生产实践

金通公司采用炉渣缓冷、浮选回收铜,再磁选回收选铁工艺。经过生产组织及关键工艺控制指标优化,并加以技术攻关,在保障炉渣有效回收选铜各项指标后,产出了 50% 以上的铁精矿,熔炼渣与吹炼渣混合磁选铁精矿较原矿产率达到 35%,大幅度实现了尾矿减量化,更为公司增创了大额效益。