Determination of the Lithium Content of Molten Aluminum Using a Solid Electrolyte

A lithium probe has been used for the determination of the lithium content of molten aluminum alloys. The electrolyte is a two-phase mixture of Li₃PO₄ and Li₄Si0₄ to give an overall composition of Li_3.6Si_0.6P_0.4O₄. This electrolyte was found to be slightly attacked by pure liquid lithium, but no attack was detected in the aluminum-lithium melts. However, exposure to high humidity caused the electrolyte to degrade. A satisfactory reference electrode was found to be decomposed Li₂Ti₃0₇ consisting of Li₄Ti₅O₁₂ and TiO₂. An activityvs composition plot showed that Henry’s law was obeyed, and the activity coefficient was 0.17 at 984 K and 0.26 at 1050 K. P. C. YAO, formerly Research Student in the Department of Metallurgy and Materials Science, University of Cambridge     

A Reaction Method for Estimating Gibbs Energy and Enthalpy of Formation of Complex Minerals

Metallurgical and Materials Transactions B - New and updated thermodynamic data for simple binary compounds are readily available from both experimental measurements and theoretical calculations....     

Thermodynamic Stabilities of Lanthanum Tungstates Using a Calcium Fluoride Solid Electrolyte Galvanic Cell

Abstract

A knowledge of the thermodynamic stabilities of the lanthanum tungstates measured as the Gibbs energies of formation from the free oxides is important as lanthanum is used as a powerful desulphurizing agent and tungsten as a special alloying element in the production of clean steels and special steels. These data will also be useful as the system La₂O₃ WO₃ can be a model since it exhibits many compounds between the end members. Excepting one EMF work, no information is available in the literature on the thermodynamics of this system. This system exhibits the compounds 5 La₂O₃·22 WO₃, La₂ O₃ · 3 WO₃, La₂O · 2 WO₃, 7 La₂O₃ · 8 WO₃,La₂O · WO₃, 3 La₂O₃ · 2 WO₃ and 5 La₂O₃ · 2 WO₃. The compounds were prepared from reagent grade free oxides by solid state sintering at high temperature followed by X-ray diffraction. The standard Gibbs energies of formation of the compounds from the free oxides were determined by operating the following galvanic cells with calcium fluoride as solid electrolyte.

O₂(g), Pt/ La₂O₃ · LaOF// CaF₂/ / 5 La₂O₃ · 22 WO₃, WO₃, LaOF/Pt, O₂(g)

O₂(g), Pt/La₂O₃ · LaOF//CaF₂//5 La₂O₃ · 22 WO₃, La₂O₃ · 3 WO₃, LaOF/Pt, O₂(g)

O₂(g), Pt/La₂O₃ · LaOF//CaF₂// La₂O₃ · 3 WO₃, La₂O₃ · 2 WO₃ LaOF/Pt, O₂(g)

O₂(g), Pt/La₂O₃ · LaOF//CaF₂// La₂O₃ · 2 WO₃, 7 La₂O₃ · 8 WO₃, LaOF/Pt, O₂(g)

O₂(g), Pt/La₂O₃ · LaOF//CaF₂//La₂O₃ · WO₃, 3La₂O₃ · 2 WO₃ LaOF/Pt, O₂(g)

O₂(g), Pt/La₂O₃ · LaOF//CaF₂//3 La₂O₃ · 2 WO₃, 5La₂O₃ · 2 WO₃ LaOF/Pt, O₂(g)

O₂(g), Pt/ La₂O₃ LaOF// CaF₂/ / 3 La₂O₃2 WO₃, La₂O₃, 2 WO₃ LaOF/Pt, O₂(g)

Stable, reproducible EMFs were obtained in the temperature range 1123 to 1273 K. The net cell reactions are respectively as follows:

5 La₂O₃ + 22 WO₃ = 5 La₂O₃ · 22 WO₃

7 La₂O₃ + 3 (5 La₂O₃ · 22 WO₃) = 22 (La₂O₃ · 3 WO₃)

La₂O₃ + 2 (La₂O₃ · 3 WO₃) = 3 (La₂O₃ · 2 WO₃)

3 La₂O₃ + 4 (La₂O₃) = 7 La₂O₃ · 8 WO₃

La₂O₃ + 7 La₂O₃ · 8 WO₃ = 8 (La₂O₃ · WO₃)

La₂O₃ + 2 (La₂O₃ · WO₃) = 3 La₂O₃ · 2 WO₃

2 La₂O₃ + 3 La₂O₃ · 2 WO₃ = 5 La₂O₃ · 2 WO₃

The standard Gibbs energies of formation of the different lanthanum tungstates are then calculated by appropriately combining from the above cell reactions and their Gibbs energy changes obtained from the experimental EMF data. The present data are discussed in the light of EMF data reported in the literature for WO₃-rich compounds in the system.     

水基凝胶注YSZ固体电解质薄膜干燥过程研究

用水基凝胶注法制备出YSZ固体电解质薄膜，研究了温度、湿度和坯体厚度对干燥过程的影响规律。结果表明温度和湿度对干燥失重速率的影响比坯体厚度的影响大，温度越高，湿度越小，坯体厚度越小，YSZ薄膜失重速率越大。同时利用物理机制对干燥过程进行了解释，验证了YSZ薄膜的干燥过程分为明显的三个阶段，而且第一阶段干燥速率明显高于第二、第三阶段的干燥速率，第三阶段干燥速率受外界条件影响相对较小。对于厚度为O．1mm的YSZ薄膜，选择40℃和RH=60％的干燥工艺，效果最佳。     

用固体氧化物电解质装置对金属溶液进行电解脱氧

用自组装的氧化物ＺｒＯ２（ＭｇＯ）固体电解质电解脱氧装置,研究了１４２３－１８７３Ｋ范围内铜液和钢液的脱氧反应,并对其脱氧反应机制进行了讨论了。结果表明：氧含量为０．４５％的铜液,经本装置脱氧７０ｍｉｎ后,氧含量可降到０．０３％,脱氧率达９０％;氧含量为０．００１８％的钢液,经本装置脱氧２０ｍｉｎ后,氧含量可降到０．０００２％,脱氧率大于９０％,这充分证明了该固体氧化物电解质电解脱氧装置的可用性。     

电导电极法测定铝电解质的分子比

在电解生产中电解质需要保持适当的分子比以维持正常生产。本文就电导电极法对电解质的分子比的分析进行了探讨。     

流体能源计量监控系统的建设

详细论述了天铁集团流体监控系统总体设计方案及组态王软件的功能。该系统的建设提高了流体计量数据的真实、可靠性,为能源计量、成本核算、生产指挥、领导决策提供了第一手的数据资料。     

使用Gibbs最小能法分析三氯氢硅的还原过程

基于目前西门子法多晶硅生产过程中三氯氢硅的还原过程的研究,介绍了Gibbs最小能法的模型方程的建立和求解过程;并通过模拟计算结果与生产统计数据的对比,证明了所建模型的正确性.同时,利用Gibbs最小能法分析了原料中四氯化硅、三氯氢硅、二氯二氢硅、氯化氢的含量以及反应温度对还原产物中各种物质含量的影响,为相关的工程技术人...     

熔盐电解法制备Al-Sr合金中反电动势和电流效率的研究

研究了在SrCl2-SrF2-BaF2的电解质体系中熔盐电解法制备高浓度Al-Sr合金,采用连续脉冲-计算机法测定电解过程的反电动势并且对反电动势和电流效率的影响因素进行了详细的研究。结果发现：增加阴极电流密度,反电动势随之增加;升高极距,反电动势亦有所增加。延长电解时间,反电动势逐渐升高而电流效率达到73.2%后逐渐下降。加大电流强度,延长电解时间,减少铝基母合金质量,可制得高浓度的Al-Sr合金,合金中锶的质量分数最高可达34.8%。实验表明,只要控制好各项工艺参数,可以生产锶的质量分数在20%以内的任意浓度Al-Sr合金。     

甲醛法测定锌电解液中铵根含量

对甲醛法测定铵根含量的方法进行了研究,建立以EDTA-Ca为掩蔽剂,消除重金属离子的干扰,采用酸碱滴定的甲醛法测定有大量重金属离子存在的锌电解液中的铵根含量的方法,为监测具体生产情况提供可靠保证。     

Evaluation of Solid Waste Management System Using Fuzzy Composition

Evaluating the best alternative for a solid waste management system often requires decision makers to consider conflicting, vague, and uncertain information. Fuzzy set theory offers a possible means of managing these kinds of data or information. In this study, we propose a systematic approach to evaluating a solid waste management system in a fuzzy environment. The approach employs three main concepts: linguistic variables, fuzzy numbers, and an analytic hierarchy process. The linguistic variables are used to represent the degree of appropriateness of decision criteria, which are vague or uncertain. These linguistic variables are then translated into fuzzy numbers to reflect their uncertainties and aggregated into the final fuzzy decision value using a hierarchical structure. Through a case study, the approach is applied to the evaluation of a solid waste management system consisting of four different treatment alternatives. The results demonstrate that the developed approach can be a useful tool for evaluating a solid waste management system, where criteria are vague or imprecise.     

示波极谱法直接测定Zn电解液中微量Ge

应用了Ge(Ⅳ)在没食子酸-V(Ⅳ)-EDTA体系中的极谱波。其峰电位为-0.60V,线性范围为5×10-8～2×10-6g/L,检测限为4×10-9g/L。方法无需预处理直接用于Zn电解中微量Ge的测定,结果满意。     

ABB MRF轧制力测量系统故障分析及处理

介绍了马钢2130酸洗连轧线中使用的ABBMRF轧制力测量系统在生产中遇到的故障典型和处理措施。     

Determination of the Cryolite Ratio of KF-NaF-AlF3 Electrolyte by Conductivity Method

Metallurgical and Materials Transactions B - The cryolite ratio (CR) is an important parameter for the electrolyte in aluminum reduction cells. The measurement method for the CR of the KF-NaF-AlF3...     

Measurement of Solid-Liquid Interfacial Energy for Solid Zn in Equilibrium with the ZnMg Eutectic Liquid

The equilibrated grain boundary groove shapes for solid Zn in equilibrium with the ZnMg eutectic liquid were observed on rapidly quenched samples. The Gibbs–Thomson coefficient for the solid Zn has been determined to be (10.64± 0.43) × 10⁻⁸ K m from the observed grain boundary groove shapes with the present numerical model, and the solid-liquid interfacial energy for the solid Zn in equilibrium with the ZnMg eutectic liquid has been obtained to be (89.16 ± 8.02) × 10⁻³Jm⁻² from the Gibbs–Thomson equation. The grain boundary energy for the solid Zn has also been calculated to be (172.97 ± 20.76) × 10⁻³J m⁻² from the observed grain boundary groove shapes. This article is based on a presentation made in the symposium entitled ”Solidification Modeling and Microstructure Formation: In Honor of Professor John Hunt” which occurred March 13-15, 2006, during the TMS Spring Meeting in San Antonio, Texas, under the auspices of the TMS Materials Processing and Manufacturing Division, Solidification Committee.     

火焰原子吸收光谱法测定铜箔电解液中的钙

铜箔的生箔电解液中杂质金属离子钙的含量控制非常重要,但电解液中大量存在的铜离子和硫酸根离子对火焰原子吸收法测定钙含量存在一定的干扰。实验了此两种因素的干扰程度并对消除干扰的方法进行了选择,确立了准确测定铜箔电解液中钙的方法。     

Formation of an Face-Centered Cubic Ta-Rich Solid Solution by Ion Beam Mixing in the Immiscible Ag-Ta System

Ta-rich and a Ag-rich solid solutions, both of face-centered cubic (fcc) structures, are observed in the Ag₁₄Ta₈₆ multilayered films on 200-keV xenon ion beam mixing, and the formation of two co-existing solid solutions is the result of a process of spinodal decomposition. The abnormal fcc Ta-rich solid solution has a Ta concentration larger than 86 at. pct and a lattice constant determined to be around 4.28 Å. Besides, first-principles calculations were employed to understand the possibility of a structural phase transition from body-centered cubic to fcc in Ta. Comparing the heat of formation (ΔH _f ) differences between fcc and bcc structures, Ta has the smallest ΔH _f difference among the four refractory metals (Ta, Mo, Nb, and W). It is concluded that the interfacial and irradiation energies play important roles in overcoming the energy barrier for the structural phase transition to take place.     

Gibbs Energy Modeling of the Cu-S Liquid Phase: Completion of the Thermodynamic Calculation of the Cu-S System

Metallurgical and Materials Transactions B - A thorough review and critical evaluation of all experimental sulfur potential and phase diagram data available from the literature has been made for...