Thermodynamic Properties of Dilute Aluminum in Liquid Zinc

Abstract

The thermodynamic properties of the liquid zinc-aluminum system in the range of 0 to 0.36 mole fraction of aluminum and over a temperature range of 430 to 530 °C were investigated by using an electromotive force (EMF) cell of the type

Al(s)|LiCl–KCl–AlCl₃|Zn–Al(l),Mo

The activity of aluminum was found to show a significant positive deviation from Raoultian behaviour. The activity coefficient of aluminum in the dilute solution range (γ°) and the free energy of solution of aluminum based on the one weight percent (1 wt %) standard state were determined as a function of temperature and found to follow the relationships:

logγ°=(1195/T)?0.874

ΔG_s=5457?11.4T (cal/mole)

Over the temperature range investigated, the self-interaction coefficient of aluminum in liquid zinc (e^Al_Al) was found to be approximately constant at ?0.01.

On a étudié les propriétés thermodynamiques du système liquide zinc-aluminium, entre 0 et 0.36 fraction molaire d'aluminium, à des températures de 430 à 530 °C, en utilisant une cellule à force électromotrice (FEM) du type:

Al(s)|LiCl–KCl–AlCl₃|Zn–Al(l),Mo

On a trouve que l'factivite de l'faluminium montrait une deviation positive importante du comportement Raoultien. On a determine le coefficient d'factivite, γ°, de l'faluminium pour une solution diluee ainsi que l'fenergie libre de solution de l'faluminium, base sur l'fetat standard de un pour-cent en poids (1%), en fonction de la temperature. On a trouve que ceux-ci suivaient les relations suivantes:

logγ°=(1195/T)?0.874

ΔG_s=5457?11.4T (cal/mole)

Dans le domaine de température étudié, on a trouvé que le coefficient d'auto-interaction de l'aluminium dans le zinc liquide (e_Al^Al) était approximativement constant à ?0.01.     

Thermodynamic Parameters of Liquid Iron ― Tungsten Alloys

The activity of tungsten in liquid Fe ― W alloys has been examined over the concentration range 0.95 < x _Fe < 1.0 at 1870 K by the electro-motive force (EMF) method in concentration circuits, in which the reference electrode is W ― WO₂. That activity has very large positive deviations from ideal solution behavior, which decrease as the temperature rises. Calorimetry at 1900 K has given the enthalpies of solution and mixing for iron and tungsten for the composition range 0 < x _W ≤ 0.1. A small amount of heat is released when the alloys are formed. These characteristics of Fe ― W liquids agree with the most reliable published data.     

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铸造铁生产时,为降低成本和提高炉况顺行度,常采用炉外增硅的方式达到生产高牌号铸造铁的目的;由生产实践数据得出硅粉的回收率,对影响回收率的因素分析;增硅经济分析。     

高炉冶炼低硅生铁的热力学分析

通过对高炉冶炼过程中硅元素的还原迁移的热力学计算分析,说明了在高炉环境下,炉渣中的SiO2不能被还原,生铁中的硅完全来自于焦炭和煤粉灰分中游离态的SiO2;Si的溶解反应极大地促进了Si的还原反应;温度是影响硅还原的最关键因素。简述了高炉低硅冶炼工艺的控制要点,包括降低高炉的理论燃烧温度,提高CO分压,提高烧结矿的冶金性能,适度强化,增加喷煤比,并指出精细操作是高炉冶炼低硅生铁的关键。     

铁液洁净度对凝固热力学参数的影响

为了给高洁净钢连铸细晶技术提供相关理论依据，在高温钼丝炉中通过对电解纯铁加金属铝和硅脱氧，获得不同铁液洁净度的试样。利用差热分析法测定了试样在相同冷却速度下的过冷度。利用凝固过程热力学理论研究了铁液洁净度与过冷度、凝固热力学驱动力、形核功和临界晶核半径等的关系。结果表明：随着铁液洁净度的提高，铁液凝固时的过冷度增大，形核所需的凝固热力学驱动力变大，非均质形核功和临界晶核半径减小。     

Recovery of Silicon and Iron Oxides from Alumina-Containing Sweepings of Aluminum Production

The method of recovery of contaminating components from sweepings of the aluminum production for their further return into the electrolyzer is proposed. To concentrate the material, the following processing flowsheet is proposed: milling–classification–reverse flotation–thickening. For the most complete removal of silicon and iron oxides during the flotation of sweepings, the Flotigam 7266 flotation reagent produced by Clariant (Germany), which is a mixture of primary fatty alkyl amines, is used. To remove carbon particles, the combination of pine oil in a mixture with kerosene is used. Flotation is performed using a FML 0.3 flotation machine. The initial material, chamber product, and tails are analyzed for the content of carbon and aluminum, iron, and silicon oxides using X-ray spectral (XSA), X-ray phase (XPA), and chemical analyses. It is established that processing the total material mass does not make it possible to acquire a product with an acceptable content of silicon and iron oxides. Based on the XPA of various fractions of the initial material, it is proposed to process the material fractions containing the minimal amount of contaminating substances (carbon and silicon and iron oxides). Two fractions are selected for processing using the flotation method by the XRS results of various material fractions:–0.071 mm and +5.0 mm. When processing the first of them, the chamber product of the acceptable quality is acquired. A product with a high content of alumina and fluorinated components at low carbon and iron oxide concentrations but a considerable amount of silicon oxide is acquired from a coarse electrolyte-containing fraction (+5.0 mm). The further use of this product is possible to fabricate aluminum–silicon alloys.     

石钢高炉铁水含硅神经网络预报模型

按照现代控制理论,把高炉视为多输入单输出系统,利用人工神经网络方法,结合高炉生产实际,建立了石钢高炉铁液中硅神经网络模型;通过引入动态步长和“惯性项系数”提高了网络收敛速;并不断更新学习样本集,提高了铁液中硅预报的命中率。结果表明,在允许误差为0.1%时,命中率达到86.67%,可为高炉操作提供指导。     

硅锰铝铁合金中Si、P、Al、Mn的联合快速分析

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铁水预处理时氧化脱磷和预脱硅间的热力学分析

从热力学角度分析了铁水预处理时预脱硅和脱磷之间的关系,经理论推导后得到了终点[P]含量和[Si]含量之间关系计算公式。计算发现,一定温度下氧化法脱磷时,终点硅含量越低,其终点磷含量也越低,并提出了铁水预处理脱磷的措施：首先脱硅要脱到较低含量;渣要有较高CaO含量来固定脱磷产物P2O5;脱磷结束后,要尽量扒除冶炼渣,防止温度升高时回磷。     

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用密闭容器蒸汽法测定了1600℃下,纯铁液中镁硫平衡时的镁硫溶度积为K'_MgS=2.36×10^-4,求得平衡常数K_MgS=2.10×10^-4。     

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Ｂｙａｄｄｉｎｇｔｒａｃｅａｍｏｕｎｔｏｆｌａｎｔｈａｎｕｍ(0 0 2 4% ) ,ｔｈｅｍｉｃｒｏｓｔｒｕｃｔｕｒｅｏｆｔｒａｄｉｔｉｏｎａｌＳｎ6 0 Ｐｂ40ｓｏｌｄｅｒａｌｌｏｙｉｓｈｏｍｏｇｅｎｉｚｅｄ ,ｔｈａｔｉｓ ,ｔｈｅｃｏａｒｓｅＳｎ ｒｉｃｈｈａｌｏｗｈｉｃｈｓｕｒｒｏｕｎｄｓｔｈｅｐｒｉｍａｒｙＰｂ ｒｉｃｈｐｈａｓｅｉｓｄｅｐｒｅｓｓｅｄｏｂｖｉｏｕｓｌｙ .Ａｓａｒｅｓｕｌｔ,ｔｈｅｈｉｇｈ ｔｅｍｐｅｒａｔｕｒｅｔｅｎｓｉｌｅｓｔｒｅｎｇｔｈｏｆＳｎ6 0 Ｐｂ40ｓｏｌｄｅｒａｌｌｏｙｉｎｃｒ…     

Silicon Production via Reaction of Silicon Tetrachloride and Aluminum Subchloride

Metallurgical and Materials Transactions B - Silicon tetrachloride reduction by aluminum subchloride was studied experimentally. Aluminum subchloride was synthesized in a reaction of metallic...     

Study on the Kinetics of Aluminum Removal from Liquid Silicon to Slag with Mechanical Stirring

Metallurgical and Materials Transactions B - The kinetics of aluminum removal from silicon melt to CaO-SiO2-Al2O3 slag was studied. A recently designed experimental setup using mechanical stirring...     

生铁中硅的快速分析

对生铁中硅的测定方法进行改进，选用稀H2SO4－HNO3混合酸溶样，采用硅钼光度法，在保持测定方法具有良好的灵敏度、结果具有良好的准确度和稳定性的基础上，提高了分析速度，实现了低硅和高硅试样采用同一种方法进行测定的目标。     

二次加热控制高硅铝合金中初生硅形态的研究

用光学显微镜(OM)及Image Pro Plus金相分析软件对半固态二次加热处理后的过共晶铝硅合金的初生硅组织特征进行分析。结果表明,在过共晶铝硅合金中,通过磷盐变质处理可以让初生硅相细化,平均直径由117μm降至31μm,并通过半固态二次加热使初生硅的形态得到显著的改善,其形状因子为0.67。     

铁水定硅探头的开发研制

利用塞贝克温差热电势原理研究了生铁中Ｓｉ含量与试样冷端温度，温差和温差电动势三者之间的关系，并以此为基础研制成功了具有实用意义的铁水定Ｓｉ探头及相应二次测量仪表，精度为标准偏差０．０１９７％Ｓｉ，测成率为８６．１０％，平均测量时间７３秒。     

Thermodynamic Characteristics of Iron Subgroup Borides

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