金属镝中的钙与氧

金属镝中的钙与氧郭锋，韩允斌（内蒙古工业大学稀土研究所呼和浩特０１００６２）稀土金属镝是高磁性能ＮｄＦｅＢ永磁合金的重要添加剂，镝中的Ｃａ、Ｏ直接影响到ＮｄＦｅＢ的性能和生产工艺，目前大多采用真空钙热还原法生产金属镝，通常采取真空精炼的方法降低Ｃａ、...     

CaO—SiO2—FeO—Fe2O3—MgO渣系MgO饱和溶解度的研究

根据熔渣结构的共存理论，建立了ＣａＯ－ＳｉＯ２－ＦｅＯ－Ｆｅ２Ｏ３－ＭｇＯ渣系作用浓度计算模型。分析了ＮＣａＯ、ＮＳｉＯ２、ＮＦｅＯ等对ＭｇＯ饱和溶解度的影响。在１５００－１７５０℃温度范围内，ＭｇＯ饱和溶解度的模型计算值与实测值一致。     

工业硅中金属间化合物

工业硅是在工业电炉内由石英和不同的炭质还原剂生产的．含有高达１％金属杂质。这些金属杂质就是聚集在晶粒边界的硅的化合物，在凝固期间在工业硅中形成的沉淀物。用具有波长色散的Ｘ射线分析扫描电子显微镜，我们鉴定了多达十种二元、三元、四元甚至多元化合物。用这种方法研究了富硅区金属间化合物的物理和化学性质。它们是Ｓｉ２Ｃａ、Ｓｉ２Ａｌ２Ｃａ、Ｓｉ８Ａｌ６Ｆｅ４Ｃａ、Ｓｉ２ＦｅＴｉ，Ｓｉ７Ａｌ８Ｆｅ５、Ｓｉ２Ａｌ３Ｆｅ和Ｓｉ２Ｆｅ（Ａｌ）。根据含有杂质的比例，我们确定了工业硅中每种化合物在给定的冷却条件下存在的区域，计算了平衡相图，以了解固化机理。一些实验表明，计算值和实验值吻合良好。为了确定硅的一个较好的生产方法，我们探讨了金属间化合物在氯甲基化反应上的影响。实验数据显示了冷却条件在金属间化合物稳定性方面的响响。例如，硅在９００℃缓冷，按照反应３Ｓｉ２Ａｌ２Ｃａ＋４Ｓｉ２Ｆｅ→４Ｓｉ２Ａｌ６Ｆｅ４Ｃａ＋２Ｓｉ２Ｃａ＋２Ｓｉ则四元金属间化合物Ｓｉ８Ａｌ６Ｆｅ４Ｃａ大量增加，而三元化合物消失。相图和不平衡反应知识加深了对固化机理以及各种组分和冷却条件下硅的行为的了解．硅的结构和控制结构的参数知识使人们了解硅的特点和改变它的     

硅和硅铁的精炼

本文回顾了硅铁和金属硅中杂质的类型和来源，以及液态金属精炼方法的选择。这篇论文仅涉及氧化精炼的化学，中心是液态Ｆｅ－Ｓｉ合金中碳、氧溶解度和钙、铝在金属和ＣａＯ－ＳｉＯ２－Ａｌ２Ｏ３三元渣间的平衡分配。也讨论了金属中的这些元素对溶解氧的影响。以图示出的等浓度线显示１５００℃时ＣａＯ－ＳｉＯ２－Ａｌ２Ｏ３系的液相范围内钙和铝的分布数据。在精炼工艺中反应途径和动力学限制环节，可参考这些图解释。本文还叙述了避免形成氧化物夹杂所采取的措施。     

铁水预处理温度下CaO－SiO_2－FeO－P_2O_5－CaF_2渣系中Ca

对１３００℃和１３５０℃的铁水预处理温度下ＣａＯ－ＳｉＯ＿２－ＦｅＯ－Ｐ＿２Ｏ＿５－ＣａＦ＿２渣系中ＣａＯ饱和溶解量进行了测定。实验结果表明，温度升高对提高ＣａＯ饱和溶解量有利；渣中ＣａＦ＿２、ＦｅＯ含量增加，ＣａＯ饱和溶解量减少；当渣组成位于ＣａＯ＋Ｌ和Ｌ交界上时，与其它区域相比，ＣａＯ达到饱和所需溶解时间最短。     

铁水预处理温度下CaO—SiO2—FeO—P2O5—CaF2渣系中CaO饱和溶解量

对１３００℃和１３５０℃的铁水预处理温度下ＣａＯ－ＳｉＯ２－ＦｅＯ－Ｐ２Ｏ５－ＣａＦ２渣系中ＣａＯ饱和溶解量进行了测定。实验结果表明，温度升高对提高ＣａＯ饱和溶解量有利，渣中ＣａＦ２，ＦｅＯ含量增加，ＣａＯ饱和溶解减少，当渣组成们于ＣａＯ＋Ｌ和Ｌ交界上时，与其它区域相比，ＣａＯ达到饱和所需溶解时间最短。     

炼铅渣系Fe3O4含量与组元关系的研究

利用化学平衡法研究了１２５０℃下的ＳｉＯ２－ＣａＯ－ＦｅＯ－Ｆｅ３Ｏ４（Ｆｅ２Ｏ３）－ＺｎＯ渣系Ｆｅ３Ｏ４含量与其它组元的关系。结果表明,在工业炼铅炉渣的成份范围内,ＳｉＯ２的含量升高,Ｆｅ３Ｏ４的含量就下降,ＣａＯ含量升高,Ｆｅ３Ｏ４的含量也升高;ＦｅＯ含量的变化,对Ｆｅ３Ｏ４的含量影响不大。     

CaO-SiO2-Fe2O3-MnO2-MgO-P2O5系熔剂对钢液脱磷、回磷的实验研究

在１８５３Ｋ的温度下,利用ＣａＯ－ＳｉＯ２－ＦｅＯ３－ＭｎＯ２－ＭｇＯ－Ｐ２Ｏ５系熔剂,对钢液进行脱磷、回磷实验,研究熔剂碱度ＣａＯ／ＳｉＯ２和氧化性（Ｆｅ２Ｏ３＋ＭｎＯ２）对钢液脱磷、回磷的影响,研究得出,防止钢液回磷的先决条件是：控制熔剂碱度和氧化性大于其临界值。实验发现,用适量ＢａＯ取代ＣａＯ基熔剂中的ＣａＯ,可有效控制钢液的回磷。     

高碱度控制氧位渣系（BaO—BaCl2—Cr2O3）对含铬铁水选择氧化脱磷影响的研究

在实验室条件下，以小渣量研究了ＢａＯ－ＢａＣｌ２（或ＢａＦ２）－Ｃｒ２Ｏ３系脱磷剂对高铬铁水脱磷时，脱磷剂中溶剂（ＢａＣｌ２和ＢａＦ２），氧化剂（Ｃｒ２Ｏ３和Ｆｅ２Ｏ３），渣量，铁液中原始〔％Ｃ〕和〔％Ｓｉ〕，以及温度对脱磷率的影响。     

氧化锰在锰铁渣中的热力学活度及金属与渣相间锰的分布

研究了埋弧炉锰铁生产中由ＭｎＯ－ＣａＯ－ＭｇＯ－ＳｉＯ２－Ａｌ２Ｏ３组成的标准炉渣。渣中Ａｌ２Ｏ３含量固定在５％。本研究目标集中在１５００℃时锰铁渣中ＭｎＯ的热力学活度上。为了达到校准的目的，在１３００、１４００和１５００℃时重新测定了Ｍｎ在Ｐｔ－Ｍｎ合金中的热力学活度。在１５００℃ＣＯ气氛下研究了碳饱和的Ｍｎ－Ｓｉ－Ｆｅ－Ｃ合金与ＭｎＯ－ＣａＯ－ＭｇＯ－ＳｉＯ２－Ａｌ２Ｏ３渣之间的平衡。在试验中发现，ａＭｎＯ值随着ＭｎＯ的增加而增大，趋向于随ＣａＯ／ＭｇＯ比的增大而增大。ａＭｎＯ值也随着碱度的增大而增大。在渣－金属平衡试验中，金属相中碳和硅的含量为反比关系。当硅含量一定时，由于Ｍｎ／Ｆｅ比增加，碳在金相中的溶解度增加。金属中含硅量随着渣中ＳｉＯ２含量的增加而增加．以及当ＭｇＯ代替渣中的ＣａＯ时，金属中含硅量增加。增大渣碱度使金属相含硅量降低。     

碱度对镁质熔剂性球团矿强度的影响机理

为探索碱度对镁质熔剂性球团矿强度的影响机理,以唐山某钢厂原料为基础,通过造球和焙烧试验,采用XRD、偏光显微镜、场发射扫描电镜分析和Matlab软件计算分析,分别从球团矿矿物组成、液相生成和微观结构、微观形貌和元素分布等方面深入分析了碱度对球团矿抗压强度的影响机理.研究表明,随着碱度升高,球团矿抗压强度呈升高趋势.球团...     

利用转炉渣制备微晶玻璃

以转炉渣为原料,采用熔融法制备转炉渣微晶玻璃。利用XRD、SEM和EDX等方法研究了不同热处理时间对转炉渣微晶玻璃析晶行为的影响。随热处理时间的延长,晶体中铁的原子分数逐渐增加而镁逐渐减少,晶体析出量也逐渐增加,晶相为Ca(Fe,Mg)Si2O6和Ca1.018(Mg0.733Fe0.293)((Si1.67Fe0.304)O6);热处理时间75 min时体积密度达到最大值,为3.912 g/cm3,而微晶玻璃的显微硬度变化不大     

Thermodynamic modeling of the interaction of high-level element and oxygen in iron-based melt

The main reactions of calcium, cerium, lanthanum, silicon, and complex alloys with the active additive Ca–Si, Ca–Al, Ce–Si, La–Si, Ce–La, or Ce–Ca–Al are subjected to thermal analysis. On the basis of binary and ternary fusibility diagrams, the thermodynamic data are refined for the main reactions between complex alloys with rare-earth elements and the oxygen present in the liquid metal. Solubility surfaces are plotted for components of the Fe–Si–Ce–O, Fe–Si–La–O, Fe–Ce–La–O, and Fe–Ca–Al–Ce–O systems. From those diagrams, optimal compositions of complex alloys with rare-earth elements in terms of nonmetallic-inclusion formation are established by plotting the consumption of the active components. For each group of steels, the quantitative elementary composition of the active components used for reduction and modification of the nonmetallic inclusions must be calculated. The chemical and phase composition of the nonmetallic inclusions may be very complex even in the final stages of the reduction of oxides. A method is developed for taking account of the polyvalency of cerium in reduction processes. The thermodynamic data and diagrams obtained help provide a better understanding of the complex heterogeneous processes within multicomponent systems that contain liquid metals. In combination with experimental data for the solubility surfaces of the components and the consumption diagrams, it is possible to track the transitions from the nonequilibrium state of the metallurgical system to the equilibrium state. In other words, the degree of refining of the metal and the equilibrium composition of the nonmetallic inclusions may be determined.     

Effects of Additives on Sulfur Transformation,Crystallite Structure and Properties of Coke during Coking of High-sulfur Coal

High-sulfur coal,as an alternative coal source,has a relatively high proportion in coal reserves.However,the feature of high sulfur content,which can cause environmental pollution and poor quality of molten iron,restrains its utilization in coking industry.Coking experiments of high-sulfur coal with Fe2O3,La2O3 and Ca O as additives were carried out in order to fix the sulfur in coke.The effects of additives on sulfur distribution,crystallite structure,surface morphology and properties of coke were investigated.The results indicate that Ca O can be used as sulfur-fixing agent in coking process,and Ca S is the main mineralogical phase of the sulfur-contained mineral constituents in coke.Fe2O3 and La2O3 facilitate the conversion of Ca O to Ca S.The additives mainly influence the crystallite height and the average interlayer spacing d002 of coke.The addition of La2O3 increases the value of the crystallite height while the addition of Ca O and Fe2O3 decreases it.Ca O leads the pores of coke to increase with its physical action and agglomerating characteristic.Fe2O3 and C can form(Fe,C),resulting in the pulverization and erosion of the pore wall.La2O3 makes the coke surface become more compact and thinner.The reactivity of coke increases with the decrease of crystallite height and crystallite layer number.     

Effects of Temperature and Atmosphere on Sintering Process of Iron Ores

 The relationship of time to minerals composition in sinters is investigated by mineragraphy are claritied observation and component analysis, and the effects of temperature and atmosphere on mineralization process. Results are obtained as follows. The initial melt forms below the eutectic temperature of CaO·Fe2O3 and CaO·2Fe2O3, which is complex substance containing Ca, Fe, Si and Al, rather than the binary calcium ferrite melt. Minerals composition of binding phase is related to local content of silica in melt, which is influenced by temperature. Appearance of the melt promotes the transition from hematite to magnetite, which then alters the mechanism of calcium ferrite formation. Before the formation of magnetite, the contents of Fe and Ca within the multiple calcium ferrite decrease with temperature, but in the case of magnetite presence, the content of Fe increases solely with increase of temperature and decrease of oxygen potential. Temperature and atmosphere determine minerals composition together, and bring influence on sintering process in different ways. It can be deduced that temperature affects kinetics of the mineralization process, but atmosphere just plays a role in thermodynamics.     

球团矿抗压强度对其冶金性能的影响

对一种细粒度磁铁精矿粉制备的生球团,通过调整其预热及焙烧工艺参数,生产出不同抗压强度的球团矿,并对其孔隙率以及还原度和还原膨胀率进行了测定。试验结果表明,随着球团矿抗压强度的提高,其孔隙率呈下降趋势,其900℃还原度也呈下降趋势,而还原膨胀率变化不大。对不同抗压强度球团矿的矿相进行了测定,结果表明,预热时间的延长,使球团初期的预热氧化过程更加完全,Fe2O3微晶键更好地发育和长大,而焙烧温度的升高,则可以促进后期Fe2O3的再结晶和长大,提高晶键互连程度,晶粒紧密连接成片,孔隙率下降,使焙烧球团具有较高的抗压强度,但结构致密,变得难以还原。     

微量杂质在工业纯钛中的存在形式及其对力学性能的影响

采用差示扫描量热法(DSC)、X射线衍射(XRD)、扫描电镜及其附带的能谱仪(SEM+EDS)、电子探针(EPMA)等分析方法和力学性能测试,研究常温下铁、硅、氯、氮、氧、碳(Fe,Si,Cl,M,O,C)等杂质在工业纯钛中的存在形式、分布状况及其对力学性能的影响。结果表明:在工业纯钛中,铁、硅、氯杂质元素的微区元素浓度较低,只有极少区域存在偏聚;碳元素分布不均匀,微区偏聚现象明显;氧元素在工业纯钛中含量较少且分布均匀;随铁、氮、氧、碳、氯等杂质含量增加,工业纯钛的强度和硬度大幅提高,塑韧性显著降低,最大硬度HB增幅为24,屈服强度和抗拉强度的最大增加幅度分别为144 MPa和122 MPa,伸长率的减幅最大为19.8%。     

固态下SiO2对二元铁酸钙形成过程的影响

 铁酸钙作为高碱度烧结矿黏结相的主要组成,其形成受SiO2的影响,但到目前为止,其影响机理尚不是十分明确。通过XRD和矿相显微镜观察,并结合Rietveld法定量分析,研究了SiO2对二元铁酸钙形成过程的影响。结果表明：Fe2O3与CaO反应,700 ℃时形成Ca2Fe2O5,在800 ℃时出现CaFe2O4,随着温度升高,Ca2Fe2O5逐渐向CaFe2O4转变。SiO2存在时,在铁酸钙形成过程中有Ca2SiO4生成,温度低于900 ℃时,受动力学条件的影响,反应速率较低,Ca2SiO4的量相对较少,另外,SiO2的阻碍作用随其质量分数的增加而增强,进而导致已形成的Ca2Fe2O5与Fe2O3未能继续反应形成CaFe2O4而使其质量分数逐渐增多;高于900 ℃时,随着温度的升高,动力学条件改善,离子扩散能力增强,其中,Fe3+通过CaFe2O4层比Ca2+通过Ca2Fe2O5层更容易,进而促进了CaFe2O4形成反应的进行,Ca2Fe2O5向CaFe2O4转变,但随着SiO2质量分数增加,Ca2SiO4的生成量增多,CaO与Fe2O3的接触面积减小,抑制了CaFe2O4的生成。     

Effects of Eu3+ and Dy3+ doping or co-doping on optical and structural properties of BaB2Si2O8 phosphor for white LED applications

A series of Eu3+ and Dy3+ doped/co-doped as well as un-doped BaB2Si2O8 phosphors were synthesized via solid state reaction method. The PL result showed typical blue and green emission from Dy3+ and red emission from Eu3+. The f-f transitions involving the lanthanide ions along with dopant site occupancy were discussed thoroughly. Phonon assisted energy transfer process was observed from Eu3+ to Dy3+, which enhanced the emissions of Dy3+. Combinations of the emissions from Eu3+ and Dy3+ showed a possible white to red tuneable emission on the CIE diagram. The white warmth emissions of the phosphor were revealed to be adjustable through designing the dopant concentration and excitation wavelengths. An unusual energy transfer that originated from Eu3+ to Dy3+ was also discovered and the energy transfer mechanism was discussed. Proposed energy transfer mechanism was investigated using luminescence decay lifetime. All the phosphor exhibited efficient excitation in the UV range which matched well with the emissions from Ga N-based LED chips. This presented the Ba B2Si2O8 phosphor as a promising candidate for white LED applications. The effects of doping on the structural properties and the optical band gap of Ba B2Si2O8 phosphor were also discussed in this study.     

Synthesis of Long Afterglow Phosphors MAl2O4:Eu2+, Dy3+(M=Ca, Sr, Ba) by Microemulsion Method and Their Luminescent Properties

Long afterglow phosphors MAl2O4:Eu2 , Dy3 (M=Ca, Sr, Ba) were synthesized by microemulsion method, and their crystal structure and luminescent properties were compared and investigated. XRD patterns of samples indicate that phosphors CaAl2O4:Eu2 , Dy3 and SrAl2O4:Eu2 , Dy3 are with monoclinic crystal structure and phosphor BaAl2O4:Eu2 , Dy3 is with hexagonal crystal structure. The wide range of excitation spectrum of phosphors MAl2O4:Eu2 , Dy3 (M=Ca,Sr,Ba) indicates that the luminescent materials can be excited by light from ultraviolet ray to visible light and the maximum emission wavelength of phosphors MAl2O4:Eu2 , Dy3 (M=Ca, Sr, Ba) is found mainly at λem of 440 nm (M=Ca), 520 nm (M=Sr) and 496 nm (M=Ba) respectively, the corresponding colors of emission light are blue, green and cyna-green respectively. The afterglow decay tendency of phosphors can be summarized as three processes: initial rapid decay, intermediate transitional decay and very long slow decay. Afterglow decay curves coincide with formula I=At-n, and the sequence of afterglow intensity and time is Sr＞Ca＞Ba.