Electrochemical Deoxidation of Solid Zirconium Dioxide in Molten Calcium Chloride

The reduction of zirconium dioxide pellets by electro-deoxidation in molten calcium chloride-calcium oxide (900 °C) has been studied. In this technique, the solid oxide is cathodically polarized against a graphite counter electrode under a constant applied potential. Unlike other metal oxides that have been reduced by this technique, only a small area around the cathodic current-collector wire was reduced to zirconium metal with zirconia pellets sintered at ~1100 °C; the rest of the sample was largely calcium zirconate. Pellets sintered above 1200 °C showed better reduction near the cathode wire and the reduction extended to the entire surface of the pellet with the passage of time. However, reduction of the inner core was found to be increasingly difficult, because the surface metal layer thickened on continuous electro-deoxidation. An analysis of the experimental results showed that the poor electrical conductivity of the intermediate compound, CaZrO₃ and its blocky morphology inhibited the electro-deoxidation process. The increase in the sintering temperature of the pellet made it better conducting. However, the pores formed in the thick zirconium metal layer in such samples were too small for an ideal contact between the inner core and the molten electrolyte and hence the reduction of the inner core remained incomplete. Within the scope of this study, it is concluded that preforms with good grain growth and porosity are necessary for the electro-deoxidation of solid zirconium oxide.     

Electrochemical Deoxidation of Titanium and Its Alloy Using Molten Magnesium Chloride

Metallurgical and Materials Transactions B - Oxygen was directly removed from pure titanium and a Ti-6Al-4V alloy by electrolysis in molten MgCl2 at 1173 K (900 °C), where the metal...     

熔盐电解中钛离子电化学沉积行为研究

对熔盐电解提钛工艺中钛离子的电化学沉积行为进行研究,首先通过调整TiCl_4和海绵钛的比例在NaClKCl熔盐中反应制备出不同电解质组分,然后在制备的电解质体系中研究钛离子的电化学沉积行为。低价钛电解质组分的XRD分析结果表明,在993 K的NaCl-KCl熔盐中,当TiCl_4与Ti摩尔比为1∶2时,反应产物主要为2价的TiCl_2,电解质形成NaCl-KCl-TiCl_2体系;当摩尔比为2∶1时,反应产物主要为2.57价的TiCl_2和K_3TiCl_6,电解质形成NaCl-KCl-TiCl_2-K_3TiCl_6体系。两种电解质体系的循环伏安研究结果表明,NaCl-KCl-TiCl_2体系中钛离子的还原历程为Ti~(2+)→Ti,主要受扩散影响,扩散系数为2.93×10~(-5)cm~2/s,而NaCl-KCl-TiCl_2-K_2TiCl_6体系中钛离子还原历程为Ti~(3+)→Ti~(2+)和Ti~(2+)→Ti两步。钛离子电化学沉积产物的SEM分析结果表明在NaCl-KCl-TiCl_2体系中,得到的钛粉产物呈现大颗粒的枝晶状,随着电流密度增大和钛离子浓度减小,钛粉产物颗粒逐步变细;而在NaCl-KCl-TiCl_2-K_2TiCl_6体系中获得产物为细颗粒的多孔状钛粉。     

CaCl2-NaCl熔盐中La2O3电脱氧反应的电化学研究

采用熔盐电解法研究了La2O3电脱氧反应过程。由电位阶越实验及取样电流电位分析和对电解产物进行X衍射分析表明La2O3的电脱氧反应是可以进行的，La2O3得电子还原为低价脱氧产物LaO，接着LaO作为中间产物与阳极气体Cl结合生成氯氧镧。     

Upgrading Titanium Ore Through Selective Chlorination Using Calcium Chloride

To develop a simple and effective process for upgrading low-grade titanium ore (ilmenite, mainly FeTiO₃), a new selective chlorination process based on the use of calcium chloride (CaCl₂) as the chlorine source was investigated in this study. Titanium ore and a titanium ore/CaCl₂ mixture were placed in two separate crucibles inside a gas-tight quartz tube that was then positioned in a horizontal furnace. In the experiments, the titanium ore in the two crucibles reacted with either HCl produced from CaCl₂ or CaCl₂ itself at 1100 K (827 °C), leading to the selective removal of the iron present in the titanium ore as iron chlorides [FeCl _x (l,g) (x = 2, 3)]. Various kinds of titanium ores produced in different countries were used as feedstock, and the influence of the particle size and atmosphere on the selective chlorination was investigated. Under certain conditions, titanium dioxide (TiO₂) with purity of about 97 pct was directly obtained in a single step from titanium ore containing 51 pct TiO₂. Thus, selective chlorination is a feasible method for producing high purity titanium dioxide from low-grade titanium ore.     

Deoxidation Behavior of Alloys Bearing Barium in Molten Steel

Asdeoxidizers ,siliconandmanganesewereusedinearlysteelmaking ,andaluminiumwasalsoadoptedsevendecadesago .Recently ,variouscom plexdeoxidizershavebeendeveloped ,amongwhichthealloysbearingbariumattractmoreattention .In196 9,HiltyDCetal[1] usedalloysbearingbariumtotreatmoltensteelforthefirsttime .Inthe 1970s ,variousalloysbearingbariumwereusedtotreatmorethan 2 0steelgradesinAmerica ,JapanandformerSoviet ,andmeantimealargeamountofpa persandbookswerepublished[2 -6] .InChina ,alloybearingbariumwa…     

SiAlBaCa合金对钢液脱氧的工业试验

在宝钢电炉分厂的150 t LF/VD精炼设备上进行了SiAlBaCa合金脱氧的工业试验.工业试验结果表明,采用SiAlBaCa脱氧时的全氧含量基本上在各个工位均与采用Al和FeSiAl脱氧相当,其脱氧产物上浮速度要快于用Al脱氧,能够较快地使夹杂物数量达到较低的水平,而且试验中夹杂物的球化作用比较明显.     

含钛超纯铁素体不锈钢的铝脱氧及钙处理实验研究

通过500 kg真空感应炉对0.007%～0.015%C-15.96%～16.94%Cr-0.08%～0.36%Ti-0.015%～0.124%Al铁索体不锈钢的铝脱氧和钙处理实验,以及相应的热力学计算,对Al、Ti竞争氧化及夹杂物改性进行了研究.结果表明,当[Ti]/[Al]低于2.50时,氧化物夹杂主要为Al2O3,随[Ti]/[Al]的增加,钢中的主要夹杂由Al2O3向MgO-Al2O3-TiOx及Al2O3-TiOx转变,夹杂物平均尺寸逐步减小;钙处理后随[Ca]/[Al](0.01～0.08)的升高,钢中含钙复合夹杂的数量比例增加;包裹形复合夹杂的中心为氧化物,周边为TiN或Ti(CN).     

Thermodynamic Properties of Inclusions Formed Aluminum-Titanium Deoxidation of Molten Steel

Titanium alloyed steel has been widely used as automobile sheet steels, thick plate steels, and also stainless steels to improve the mechanical and chemical properties of many grade steels. Since Ti has strong affinity with oxygen, Ti is normally alloyed after Al deoxidation to keep the high yield of Ti. Therefore, Al-Ti deoxidation is one of the common and important secondary refining processes. Although the chemical stability diagram for this system has been reported by many researchers, these diagrams are inconsistent significantly each other. In the present study, the stability region of Al2TiO5 oxide was measured by equilibrating Fe-Al-Ti alloy and Al2TiO5 pellet in Al2O3 crucible at 1873 K. However, inclusions in metal after equilibration were Ti-containing Al2O3 or Al-containing TiOx. The precise phase diagrams and related thermodynamic data for the Al2O3-TiOx-FeO system should be determined.     

钡系复合合金对钢液脱氧行为的试验研究

在实验室研究的基础上,在LF／VD精炼设备上进行了钡系合金对钢液的脱氧工业试验。试验发现采用SiAlBaCa脱氧时的全氧含量基本上在各个工位均低于采用Al和FeSiAl脱氧,其脱氧产物上浮速度要快于用Al脱氧,能够较快地使夹杂物数量达到较低的水平,且试验中夹杂物的球化作用比较明显,同时还探讨了钡系合金脱氧和对夹杂物的变质作用机理。     

用含钡合金进行钢水脱氧的工业试验研究

在实验室研究的基础上,用150 t LF/VD精炼设备进行了含钡合金对钢液脱氧的工业试验研究.分别采用SiAlBaCa、FeSiAl、铝合金进行大生产试验和对比试验.结果表明,经含钡合金处理的钢液,夹杂物聚集、长大和上浮的速度快,钢的氧含量低,夹杂物呈球形,且尺寸细小、分布均匀.     

镁合金对钢液脱氧脱硫的作用

用镁合金脱氧剂在MgO质感应炉上对低碳钢进行了脱氧行为的研究.实验主要选取AlMg、SiCaBaMg、SiCaBaAlMg镁系合金与Al进行脱氧对比,考察了脱氧后钢水的T[O]、[S]以及夹杂物的变化情况.与Al相比,SiCaBaAlMg包芯线、AlMg 1#脱氧效果较明显,镁合金在脱氧的同时具有稳定的脱硫能力,并且脱氧后夹杂物的粒径有不同程度减小.     

High-Voltage Phenomena in Molten Aluminum Chloride Electrolytes

The electrical conductivity of molten aluminum chlorides NaAlCl₄ and KAlCl₄ increases with the electric field and reaches the maximum values (Wien effect) exceeding their usual low-voltage conductivity by 200 and 700%, respectively. These results are obtained on the basis of analysis of microsecond high-voltage discharges in the melts. When high-voltage pulse discharges are completed in the melts, their conductivity increases by 50% and their decomposition potential turns out to decrease by more than 20% (memory effect). The relaxation time of a nonequilibrium state reaches 5 min or more.     

大规格纯钛铸锭脱氧现象及对策

利用真空自耗电弧炉进行了大规格纯钛铸锭的工业生产,研究并分析Ф1040 mm大规格高氧含量纯钛铸锭的底部脱氧现象和氧元素均匀性的问题。纯钛铸锭底部脱氧的原因是海绵钛中的Mg与添加剂TiO₂在一次铸锭熔炼时反应引起的。采用真空自耗电弧炉对梯度加氧自耗电极进行两次熔炼,结果表明:通过梯度加氧的方式可以有效解决纯钛铸锭脱氧的问题,并显著改善纯钛铸锭氧元素成分均匀性,使生产出的Ф1040 mm高氧含量纯钛铸锭头部、尾部氧含量的偏差控制在0.011%范围内。     

钢水微气泡精炼脱氢脱氧的研究

采用旋转桨吹氩，将吹入钢水中的氩气泡破碎成微小气泡，并均匀分布在钢水中，使氢、氧随氩气泡浮出，达到脱氢、脱氧的目的。本主要研究各种因素对精炼钢水脱氢率、脱氧率的影响。结果表明：在本实验条件下，精炼２￣３ｍｉｎ，脱氢率为５０．０７％，脱氧率为４８．５０％，脱硫率为４６．２０％；氩气流量和旋转枪转速最佳值分别为０．２５￣０．２８ｍ＾３／ｈ和４２０ｍ＾３／ｈ和４２０ｒ／ｍｉｎ；另外，精炼效果与精炼时间     

Electrochemical Transport in Molten Lead Silicates

Abstract

Ionic transport in the molten system PbO-SiO₂ is discussed based upon available data on lead and silicon tracer diffusivities, inter diffusion coefficients, electrical conductivity and on measured values of lead and silicon transference numbers. The interrelationship of these parameters is illustrated through a theoretical treatment of the phenomenological transport equations. The Onsager transport coefficients for the independent set of equations are calculated for melt compositions between 0.3 < x _SiO2 < 0.6 at 850°C. The coincidence of large changes in the transport parameters between the orthosilicate and metasilicate compositions and the large changes in the silicate structure is discussed.

Résumé

Les phénomènes de transport ionique dans le systeme PbO-SiO₂ à l'état fondu sont analysés et discutés a partir des valeurs déjà publiées concernant la diffusion des isotopes traceurs de Pb et Si, les coefficients d'interdiffusion de PbO et SiO₂, les conductivityés ioniques et les mesures des nombres de transport pour ces éléments. Un traitement théorique des équations phénoménologiques de transport illustre les différentes relations entre ces paramètres. Les coefficients de transport d'Onsager sont calculés, à l'aide d'un système indépendant d'équations, pour les compositions comprises entre 30 et 60 % de SiO₂ en mole, a 850°C. La possibilité de coincidence des fortes variations des propriétés de transport avec les changements de structure ionique des bains silicates est discutée, pour des compositions correspondant à des structures d'ortho- ou de méta-silicates.     

CaO-Al2O3基精炼渣对钢液脱氧的影响

在MoSi2炉上用二次正交回归实验方法进行了CaO-Al2O3基精炼渣对钢液脱氧影响的实验研究，发现精炼渣与钢中溶解氧的平衡时间为20～30min、平衡溶解氧含量为0.008%～0.0012%，并得到了精炼渣在不同成分下的钢液全氧含量，另外，通过二次正交回归处理，得到了钢液全氧含量与精炼渣的光学碱度，渣中Al2O3含量和CaF2含量之间的关系式；并发现如下规律：随着精炼渣光学碱度的提高，钢液全氧含量几乎呈直线减小；在用铝脱氧的条件下，钢液全氧含量基本上随精炼渣中Al2O3含量的增加而增大，随着精炼渣中CaF2含量的增加，钢液全氧含量呈先增大，后减小的趋势。本实验条件下最佳的渣系组成为CaO57.29%，Al2O39%，MgO10%，SiO28.71%，CaF215%。     

氯化物熔盐电解槽结构优化

以电热场为基础进行了氯化物熔盐电解槽结构优化,以热平衡为前提得出的电流强度与阴阳极间距、阴极插入深度、阳极半径、阴极半径、电解质液面高度五个因素之间的关系,利用二次回归正交设计的方法,设计了不同的氯化物熔盐电解槽结构参数组合,得出了电流强度与各结构参数之间的无因次方程,优化设计了电流效率最高、能耗最低的电解槽模型。