无取向电工钢RH脱硫渣系的研究

在15 kg真空感应炉上,用CaO-Al2O3-SiO2-MgO渣系进行脱硫试验,探讨了脱硫渣系碱度、MI、Al2O3、CaF2对脱硫效果的影响。研究结果表明,随脱硫渣系碱度、MI、Al2O3和CaF2含量的增加,脱硫率都呈现先增加后减少的趋势。初始硫含量为0.009 33%~0.010 73%,加入脱硫渣系4 min时间内表观脱硫速率为(0.000 96~0.001 49)%/min,平均脱硫率为81.2%,最高达86.8%。当脱硫渣中w(CaO)=58.15%、w(SiO2)=4.85%、w(Al2O3)=25%、w(MgO)=6%、w(CaF2)=6%,脱硫效果最好,此时钢液中硫为0.001 33%。     

LF钢渣返回利用的脱硫研究

结合生产中LF渣的典型成分,对LF渣返回利用时的脱硫性能及其影响因素进行了研究,探讨了炉渣的初始w(S)、w(Al2O3),钢水的初始w(S)变化对脱硫的影响.实验结果表明,钢水w(Als)=0.025 %～0.033 %时,采用模拟的LF返回精炼渣,可以实现对钢水的脱硫.在炉渣初始w(S)＞0.61 %时,随渣中硫含量的增大,脱硫率快速下降,w(Al2O3)＜25 %时对脱硫的影响不大.在实际应用中,采用精炼终渣部分返回的模式,可以保证LF精炼的脱硫要求.     

Q345钢精炼过程夹杂物成分的变化

通过工业试验研究了Q345钢在钢包精炼过程和RH处理过程中夹杂物成分的变化。结果表明:通过与高碱度、低氧化性渣的反应,钢水中的大部分Al2O3夹杂物转变为具有较低熔点的CaO-Al2O3-MgO夹杂物。研究了RH处理后钙的加入量对夹杂物成分的影响。结果表明:当钢包顶渣的成分控制在w(CaO)=50%～55%、w(CaF2)=5%～8%、w(Al2O3)=25%～30%、w(SiO2)=5%～8%、w(MgO)=5%～10%、w(FeO)<1%,经过钢包精炼和RH处理,每吨钢水中加入0.12 kg钙后,钢水中夹杂物的平均成分处于低熔点(≤1 500℃)区。     

精炼渣对SUS444铁素体不锈钢中夹杂物的影响

在1 873K,MgO坩埚内进行了VOD精炼渣与SUS444铁素体不锈钢之间的脱氧平衡试验,考察了精炼渣对不锈钢中T.O含量及夹杂物组成、数量和尺寸分布的影响。结果表明,脱氧终点钢中w(T.O)=0.006 3%~0.007 4%,提高精炼渣碱度,降低渣中Al2O3的活度,有利于降低钢中T.O含量。精炼渣碱度增加,试样中单位面积夹杂物的个数及夹杂物的平均面积分数都减小。降低渣中Al2O3含量,夹杂物平均粒径也降低。加入脱氧合金后,钢中夹杂物主要为Al2O3、MgO·Al2O3及含有少量SiO2、MnO的复合氧化物;钙处理后,钢中夹杂物主要为球形的MgO·Al2O3-CaO。随着精炼渣中a(MgO)/a(Al2O3)的增加,MgO·Al2O3夹杂物中xMgO/xAl2O3随之增加。根据试验,R=3.5、w(Al2O3)=10%、w(MgO)=10%、w(CaF2)=5%的精炼渣具有良好的精炼效果。     

渣中CaF2含量对无取向电工钢深脱硫的影响

利用GXA型高温熔点测试仪研究了CaF2的含量对渣系熔点的影响,并在15kg真空感应炉中进行了深脱硫试验,试验结果表明:渣系碱度为12,w(Al2O3)为25%,w(CaF2)为6%,w(MgO)为6%时的脱硫效果最高,达到86.8%,w(S)降到0.00133%;CaF2能使炉渣熔点直线下降,在渣中加入4%~6%的CaF2时,可以满足熔点低、成渣速度快的要求.     

B2O3在CaO-BaO-SiO2-Al2O3-CaF2精炼渣中的作用

选择w（CaO）=46％，w（BaO）=10％，w（SiO2）=11．2％，w（Al2O3）=11．6％的渣作基础渣系，将B2q作助熔剂替代CaF2，发现B2q和CaF2的助熔效果相当，B2q可用作环保型助熔剂。将CaO-SiO2-BaO-Al2O3-CaF2作基础渣系，B2O3作酸性氧化物，在碱度（m（CaO＋BaO）／m（SiO2＋B2O3））为2．5和2．8时，研究B2O3替代SiO2后精炼渣的熔化性能。结果表明，B2O3替代25％的SiO2后就可大幅度降低粘度，并且发现富硼精炼渣的高温熔化性能稳定，粘度值稳定在0．3～0．5Pa·s。在碱度为2．8wt进行脱硫工艺实验，当w（SiO2）=20．6％时渣剂脱硫率为80％，当w（SiO2）=10．3％，w（B2O3）=10．3％时渣剂脱硫率为91．3％，主要原因是熔化性能良好的熔渣有助于提高传质速率。     

铝脱氧曲轴钢中镁含量的计算分析

采用热力学软件FactSage计算分析了精炼渣成分、Als含量、精炼温度对钢水中镁含量的影响,并通过试验对计算结果进行验证。结果表明:在1 600℃,随着精炼渣碱度的升高以及渣中Al2O3、FeO含量的降低,钢水中Mg含量增加;随着渣中MgO含量的升高,钢水中Mg含量先升高后降低,当渣中w(MgO)为8%时,钢水中w(Mg)达到最大值11.9×10-6;而w(Al2O3)为30%,碱度为15时,钢水中w(Mg)达到最大值11.9×10-6。     

CaF2-SiO2-Al2O3-CaO-MgO五元渣系黏度的试验研究

为了研究含氟渣系成分变化对黏度的影响,根据五因素二次正交旋转回归法设计渣系配方,使用RTW-10熔渣物性测定仪,采用旋转柱体法,在1 600～1 300℃降温过程中对CaF2-SiO2-Al2O3-CaO-MgO渣系的黏度进行连续测定;建立了1 600℃下五元含氟渣系黏度的回归模型,研究了各组元对熔渣黏度的影响.结果表明:当CaF2的含量(质量分数,下同)在10％～70％时,随CaF2含量增加,黏度减小,随SiO2、Al2O3和MgO含量增加,黏度增大,CaO易受其他组元的作用而对黏度产生不同影响;在w(SiO2)=10％、w(MgO) =10％和w(CaF2)=50％时,随w(CaO)增加,黏度先增大后减小,w(CaO)=10％时黏度最大.在w(Al2 O3) =20％、w(MgO)=10％和w(CaF2)=50％时,随着w(CaO)增加,当w(SiO2)＜20％时,黏度先增大后减小;当w(SiO2)＞20％时,黏度持续减小.     

酸性精炼渣系SiO_2-Al_2O_3-CaO-MgO-FeO-MnO中Al_2O_3活度计算模型

为了获得帘线钢软吹终点钢水酸溶铝含量与渣中Al2O3之间平衡的热力学数据,本文根据熔渣结构的分子离子共存理论,建立了Si O2-Al2O3-Ca O-Mg O-Fe O-Mn O六元渣系的活度计算模型.计算得到了炼钢温度下酸性精炼渣中Al2O3的活度值,并分析了w(Mg O)和碱度w(Ca O)/w(Si O2)对Al2O3相关组元活度的影响,为帘线钢钢水软吹酸性渣精炼脱铝提供指导.     

低碳冷镦钢LF精炼渣的优化

通过工业试验对低碳冷镦钢的LF精炼渣成分进行了优化。试验结果表明:适合于冶炼低碳冷镦钢的精炼渣成分为w(CaO)=50%～55%、w(Al2O3)=30%～35%、w(CaF2)=5%～10%、w(SiO2)<5%、w(MgO)<5%、w(FeO)<1%;LF精炼过程可将钢水中w(S)从389×10-6降到50×10-6,w(T.O)从54.0×10-6降到21.1×10-6。当钢水中w(S)<50×10-6,钙处理后夹杂物中平均w(S)<1.9%。将优化后的工艺应用于低碳冷镦钢的批量生产后,精炼渣料消耗降低了6.5 kg/t,吨钢成本降低了10元以上。     

CaO—SiO2—Na2O—CaF2—Al2O3—MgO保护渣系的Al2O3吸收速率和粘度

采用CaO-SiO2-Na2O-CaF2-Al2O3-MgO渣系,通过测定熔渣的粘度和Al2O3吸收速率,研究连铸保护渣的Al2O3吸收速率与粘度及化学成分之间的关系。在一定条件下,当CaO/SiO2为1.2左右时,粘度达到最小值,Al2O3吸收速率达到最大值,分别为0.10?Pa*s、8.403×10-4?kg*m-2*s-1。随着渣中Na2CO3含量、CaF2含量和MgO含量的增加,粘度减小,Al2O3吸收速率增大。随着渣中Al2O3含量的增加,粘度增大,Al2O3吸收速率减小。粘度为Al2O3吸收速率的主要控制因素。随着熔渣粘度的增加,连铸保护渣的Al2O3吸收速率逐渐减小。     

Kinetics of reduction of ferric iron in Fe2O3-CaO-SiO2-Al2O3 slags under argon, CO-CO2, or H2-H2O

The rates of reduction of ferric iron in Fe₂O₃-CaO-SiO₂-Al₂O₃ slags containing 3 to 21 wt pct Fe₂O₃ under impinging argon, CO-CO₂, or H₂-H₂O have been studied at 1370 °C under conditions of enhanced mass transfer in the slag using a rotating alumina disc just in contact with the slag surface. For a 6 wt pct Fe slag at a stirring speed of 900 rpm the observed reduction rates by 50 pct H₂-H₂O were a factor of 2 to 3 times higher than those by 50 pct CO-CO₂ and more than one order of magnitude higher than those under pure argon. The observed rates were analyzed to determine the rate-controlling mechanisms for the present conditions. Analysis of the rate data suggests that the rates under 50 pct H₂-H₂O are predominantly controlled by the slag mass transfer. The derived values of the mass-transfer coefficient followed a square-root dependence on the stirring speed for a given slag and, at a given stirring speed, a linear function of the total iron content of the slags. The rates of oxygen evolution during reduction under pure argon were shown to be consistent with a rate-controlling mechanism involving a fast chemical reaction at the interface and relatively slow mass transfer in the gaseous and the slag phases. The rates of reduction by CO-CO₂ (pCO=0.02 to 0.82 atm) were found to be likely of a mixed control by the slag mass transfer and the interfacial reaction. A significant contribution of oxygen evolution to the overall rates was observed for more-oxidized slags and for experiments with relatively low values of pCO. Assuming a parallel reaction mechanism, the estimated net reduction rates due to CO were found to be of the first order in pCO, with the first-order rate constants being approximately a linear function of the ferric concentration. This article is based on a presentation made in the “Geoffrey Belton Memorial Symposium” held in January 2000, in Sydney, Australia, under the joint sponsorship of ISS and TMS. The original symposium appeared in the October 2000 Vol. 31B issue.     

Al2O3La2O3Y2O3/Cu复合材料的电弧侵蚀特性研究

采用喷射沉积和内氧化法制备出Al₂O₃La₂O₃Y₂O₃/Cu复合材料,研究该材料在直流20 V/20 A的工作条件下触点的电弧侵蚀特性,并与Al₂O₃/Cu材料进行了对比分析.利用电子天平、扫描电镜等方法分析电弧侵蚀后触点的质量变化和表面微观结构.结果表明,通过添加Y₂O₃、La₂O₃稀土氧化物颗粒,可有效降低触头材料的材料转移量.Al₂O₃La₂O₃Y₂O₃/Cu材料的抗熔焊性和抗烧损性优于Al₂O₃/Cu材料的性能.在直流阻性负载条件下Al₂O₃La₂O₃Y₂O₃/Cu阳极触头表面形成凹坑,阴极触头表面形成凸起,触点表面显示出浆糊状凝固物和喷发坑等电弧侵蚀形貌特征.      

CaO-La2O3-B2O3-Eu2O3转光玻璃的合成及荧光性质

X射线衍射研究表明CaO-La2O3-B2O3-Eu2O3体系的玻璃化温度在1025℃附近.荧光光谱和ESR谱研究表明,在CaO-La2O3-B2O3-Eu2O3玻璃体系中存在着Eu2+和Eu3+两种价态离子. 316, 360, 379, 394, 413, 462和532nm锐线激发峰和592,616和650红区发射峰分别对应Eu3+的f-f激发跃迁和5D0-7FJ (J=1,2,3)跃迁发射;351nm和427nm宽带激发峰和蓝区发射分别对应Eu2+的5d-4f激发跃迁和发射.     

Effects of La2O3/Li2O/TiO2- Coating on Electrochemical Performance of LiCoO2 Cathode

Conventional cathode material （LiCoO2） was modified by coating with a thin layer of La2O3/Li2O/TiO2 for improving its performance for lithium ion battery. The morphology and structure of the modified cathode material was characterized by SEM, XRD, and Auger electron spectroscopy. The performance of the cells with the modified cathode material was examined, including the cycling stability, the diffusion coefficient under different voltages, and the C-rate discharge. The results showed that the cell composed of the coated cathode material discharged at a large current density, and possesses a stable cycle performance in the range from 3.0 to 4.4 V. It was explained that the rate of Li ion diffusion increased in the cell while using La2O3/Li2O/TiO2-coated LiCoO2 as the cathode and the coating layer may act as a faster ion conductor （La2O3/Li2O/TiO2）.     

CaO含量对CaF2-Al2O3-CaO-Ce2O3渣系中Ce2O3行为的影响

在Fe-Cr-Al合金中添加微量的稀土元素可显著改善合金的使用性能, 文中以电渣重熔生产Fe-Cr-Al合金所用稀土渣为研究对象, 根据离子-分子共存理论(IMCT)建立了1 823 K时CaF₂-Al₂O₃-CaO-Ce₂O₃四元渣系热力学质量作用浓度模型.结果表明:当渣系中CaO和Al₂O₃的质量百分数之比维持在1:1, 即w_CaO /w_Al2O3=1时, 随着Ce₂O₃含量增加, 渣中铈铝酸盐Ce₂O₃·Al₂O₃质量作用浓度(活度)显著增加, 但炉渣物相种类没有变化.渣系中Ce₂O₃含量分别在10 %, 20 %, 30 %, 40 %时, w_CaO /w_Al2O3值对组元活度的影响各不相同但有共同特征, 表现在处于约1.0~1.8时, CaO活度增加最迅速, Ce₂O₃活度增加, Ce₂O₃·Al₂O₃活度下降, 说明渣中CaO含量增加促进了Ce₂O₃·Al₂O₃分解而导致Ce₂O₃活度增加, 选取渣系进行熔融和X射线衍射实验, 用jade 5.0软件分析物相, 实验结果与计算一致.      

Synthesis of ZrO2-HfO2-Y2O3-Sc2O3 Nano-Particles by Sol-Gel Technique in Aqueous Solution of Alcohol

Zirconium dioxide is a significant material withgood physicochemical characteristics . It is used inmanyfields such as energysources ,material and envi-ronment . Cubic phase zirconium dioxide doped withyttria (YSZ) is alreadyin wide use in solid oxygenfu-…     

Water and solute activities of the solution systems of H2So4-Cuso4-H2O and Hci-Cuci2-H2O

The activities of water, α(H₂O), in the solution system of H₂SO₄-CuSO₄-H₂O were determined by an isopiestic method and those in the solution system of HCl-CuCl₂-H₂O by a transpiration method, both at 298 K. The activities of H₂SO₄ and H⁺ in the solution system of H₂SO₄-CuSO₄-H₂O were also determined at 298 K by the emf method. The water activities in both systems obeyed the Zdanovskii rule relatively well. The α(H₂O) experimentally determined in the sulfate system showed a satisfactory agreement with those calculated from the Robinson-Bower equation, assuming the complete dissociations of H₂SO₄ and CuSO₄, whereas a good agreement between the calculated and experimentally determined α(H₂O) for the chloride system was obtained when the formation of Cu(II) chloro-complexes was taken into consideration. The mean activity coefficients, γ_±, of solutes, including H₂SO₄, HC1, and CuCl₂ in these solution systems, were calculated at 298 K by the McKay-Perring method using the activity data. The γ_±(H₂SO₄) values in the solution system of H₂SO₄-CuSO₄-H₂O were in good agreement with those determined by the emf method. On the other hand, the γ_±(CuSO₄) were calculated at the same temperature based upon the Gibbs-Duhem equation using both measured α(H₂O) and calculated γ_±(H₂SO₄) values, because of solubility limitations.     

SnCl2－HgCl2－K2Cr2O7容量法测定的矿石中TFe时HgCl2用量的选择

为了保持应用已久的有汞测铁经典方法中的许多优点而减轻HgCl2对环境的污染的缺点,对方法中HgCl2的用量由5m^[1]减少为2ml进行理论上的探讨,并以试验结果加以论证。     

CaO--TiO2--Fe2O3三元系中Ca3TiFe2O8的生成机理

钒钛磁铁矿是烧结矿重要的原料之一,Ca₃TiFe₂O₈作为钒钛烧结矿中矿物被发现之后,其生成机理尚不明确.本文采用X射线衍射分析、元素能谱分析和TG-DSC分析相结合的方法,研究了Ca₃TiFe₂O₈的生成机理以及不同温度、CaO与TiO₂含量下Ca₃TiFe₂O₈的生成规律.实验结果表明,Ca₃TiFe₂O₈由Ca₂ Fe₂O₅和CaTiO₃反应生成,即CaO和Fe₂O₃反应生成Ca₂ Fe₂O₅;其后,与CaTiO₃反应生成Ca₃TiFe₂O₈.反应时间越长,Ca₃TiFe₂O₈的生成量越大,但反应温度对Ca₃TiFe₂O₈生成的影响并不明显.另外,还发现CaO含量越高,Ca₃TiFe₂O₈越易于生成,而且等摩尔Fe₂O₃和CaO下只要存在TiO₂,就会有Ca₃TiFe₂O₈生成.