Thermodynamics of binary phase diagrams with a miscibility gap and a congruently melting compound and binary phase diagrams with two miscibility gaps

The thermodynamics of phase diagrams with a miscibility gap and a congruently melting compound and phase diagrams with two miscibility gaps are treated using the Hoch-Arpshofen solution model and the Schottky- Wagner disorder model. We extended the Schottky-Wagner disorder model to the liquid phase. In phase diagrams with two miscibility gaps, a liquid compound between the two miscibility gaps must be present to obtain consistent thermodynamic data. We treated the Rb-I₂, Au-Se, and Sn-S binary systems.     

Thermodynamics of binary phase diagrams with a miscibility gap and a congruently melting compound and binary phase diagrams with two miscibility gaps

The thermodynamics of phase diagrams with a miscibility gap and a congruently melting compound and phase diagrams with two miscibility gaps are treated using the Hoch-Arpshofen solution model and the Schottky- Wagner disorder model. We extended the Schottky-Wagner disorder model to the liquid phase. In phase diagrams with two miscibility gaps, a liquid compound between the two miscibility gaps must be present to obtain consistent thermodynamic data. We treated the Rb-I₂, Au-Se, and Sn-S binary systems.     

蓄热式铝熔炼炉熔炼过程的数值模拟

为了更好地研究和优化铝熔炼炉的性能,针对现有的蓄热式圆形铝熔炼炉,在建立合理的铝熔炼炉基本模型的基础上,通过耦合用户自定义熔化模型和氧化烧损模型,运用计算流体力学软件FLUENT实现燃烧空间和熔池的耦合物理场的数值模拟。着重研究不同固液区和不同孔隙率对铝及铝合金熔炼过程的影响。结果表明,该模型较好地反映铝熔炼炉的熔炼现象,可运用该模型进行铝熔炼炉熔炼过程工艺参数的优化研究。同时获得了固液区和孔隙率对熔炼参数影响规律:铝液温度在固液区上升缓慢,而离开固液相线时,铝液温度上升速度加快,炉膛温度和氧化层质量随着熔炼时间分别呈周期性增加和呈抛物线增加;随着氧化层厚度的增加,铝液温度随着孔隙率的增加而增加变得缓慢。     

烧嘴对蓄热式铝熔炼炉熔炼过程的影晌

结合蓄热式铝熔炼炉熔炼过程的特点,运用FLUENTUDF和FLUENTScheme混合编程,耦合用户自定义熔化模型和燃烧器换向及燃烧量变化模型,实现了蓄热式铝熔炼炉熔炼过程的数值模拟。依据优化原则,获得了熔炼时间随影响因子的变化规律：熔炼时间随着旋流数、燃烧器倾角、空气预热温度或天然气流量的增加而缩短;熔炼时间随着燃烧器间水平夹角或空燃比的延长,先减小而后增加：熔炼时间随着燃烧器高度的增加而延长。     

Thermodynamics of solar-grade-silicon refining

Solar energy will shortly be in great demand since it is inexhaustible and cleaner than any conventional energy resources. At present, an expensive grade of silicon for semiconductor (SEG-Si) is used for a solar cell to convert solar energy into electricity. However, the amount of supply is limited and we have to develop an innovative process for silicon production with low energy cost in order to spread the solar cell system widely. Using relatively inexpensive metallurgical grade silicon (MG-Si) as a starting material for making solar grade silicon (SOG-Si) is believed to be one of the ways to make solar cells less expensive. Impurities in MG-Si will shorten the lifetime of excited carriers in silicon solar cell and disturb electric generation. Hence, the removal of impurities from silicon is a significant issue in silicon solar cell fabrication. To discuss the possibility and efficiency of the impurity elimination process, evaluation of thermodynamic properties of impurities in molten silicon such as the activity coefficients and the interaction parameters of harmful impurities has been performed.     

Thermodynamics of phase equilibria

Equations have been proposed and derived for calculation of thermodynamic properties of multicomponent alloys from various types of data. Effects of phase boundaries on activity measurements are discussed, and the use of activity data on condensed phase diagram determination is presented. The activity and phase boundary determinations are discussed, and advantages and shortcomings of selected experimental techniques are noted. A brief review of computer calculation of phase diagrams is presented. This research is part of the effort in material properties at the U.S. Bureau of Mines and at the Polish Academy of Sciences.     

Thermodynamics of nanoscale materials

Nanoscale materials have been considered for and been in use in a variety of industrial engineering applications. The surface tension of silver and copper were calculated at various temperatures using non-ideal or real solution characteristics. The surface concentration of individual components was also calculated. The surface concentration of silver in a binary silver copper system is higher in spite of its lower surface tension as a pure component. It is also shown that the melting temperature of individual elements decrease with decrease in particle size. This trend is true for most metallic elements and is pronounced below a particle size of 20 nm.     

Thermodynamics of nanostructured materials

Published data on the influence of the effective nanoparticle size and the atomicity of clusters on the physicochemical properties of substances are considered. An interpretation is suggested for the analytical relations of the first and second laws of thermodynamics considered with conversion of the substance and the dependence of the chemical potential of reagents on the effective nanoparticle size taken into account.     

Thermodynamics of particle coarsening

The coarsening of precipitate particles during the heat treatment of alloys depends both on the diffusivity of the surrounding phase and on the concentration differences given by the Gibbs-Thomson equation, both of which depend on the solution thermodynamics of the surrounding phase. However, it is now known that thermodynamic terms cancel in the theory; therefore coarsening is independent of solution behavior. The equations that confirm this prediction for multicomponent systems are derived and discussed. In addition, it is shown for ternary and higher order systems that a generalized form of the Gibbs-Thomson equation gives a vector that is normal to the matrix-precipitate phase diagram boundary.     

非平衡态热力学分析

为了研究非平衡态热力学理论在具体的冶金过程中的应用，本文用该理论模拟计算了转炉的炼钢过程,并建立了该过程的数学模型。得到了转炉冶炼过程的脱碳速度表达式、钢液中硅锰含量变化表达式、氧含量变化表达式以及温度变化表达式。用C语言对整个冶炼过程进行模拟,结果表明非平衡态热力学模型能够描述整个冶炼过程主要元素的成分变化和熔池温度变化,对转炉炼钢生产实际的过程控制提供了新的理论和方法。     

Thermodynamics of Blast Furnace

A detailed analysis in which the blast furnace is considered as a continuous counter-current reactor. The stoichiometric and thermodynamic conditions are applied to individual reactions within the furnace as well as to the overall process.     

Electrode Potential Thermodynamics

A problem of determining the electrode potential by substituting the chemical potentials of electrons in metals of the electrochemical circuit into the expression for the chemical affinity of the reaction taking place in a galvanic cell is solved.     

旋流数对铝熔炼炉熔炼过程的影响

针对现有的圆形铝熔炼炉,结合铝熔炼炉熔炼过程的特点,在铝熔炼炉热平衡测试的基础上,建立了合理的铝熔炼炉数学模型,并运用计算流体力学软件FLUENT实现燃烧空间和熔池的耦合物理场的数值模拟。同时分析了不同旋流数对铝熔炼炉熔炼过程的影响,依据提出的优化准则,确实旋流数大于0.6时能够获得最佳的熔炼性能。     

Thermodynamics of Iron-Fused Sulphate Systems

Abstract

A thermodynamic treatment of the corrosion behaviour of Fe in molten Li²SO⁴?K²SO⁴ eutectic at 600° is carried out by considering the formation of oxides other than FeO.

Stability diagrams in relation to the redox and acid-baee equilibria in the melt are constructed. Possible cathodic reactions are discussed and the formation of Fe sulphides as corrosion producss is taken into account. Regions of corrosion, immunity and thermodynamic passivity are defined on the assumption of both oxide and sulphide formation.     

Thermodynamics of cementite layer formation

The formation of cementite layers upon carburization of iron is described by a thermodynamic approach assuming the establishment of an equilibrium within the carburizing gas atmosphere and between the solid and the gas. Based on that, the suppression of soot formation by adding ammonia to the gas, which has recently been reported in the literature as a kinetically determined surprising phenomenon, can be explained sufficiently well and, hence, proves to be a thermodynamically predictable effect.     

开创铝熔炼技术新时代的等温熔炼炉

铝工业特别是原铝生产上业既是高能耗工业又是温室气体高排放行业,节能减排有着重要意义;铝工业下游产品行业的单位产品平均能耗虽然还不到上游产品的1／18,但由于产量大,总能耗高,也应是节能重点行业之一。美国能源部拨款给阿波格技术公司、爱励铝业公司、德雷克塞尔大学、阿贡国家实验室研发的铝合金等温熔炼炉（ITM）,在铝及铝合金熔炼技术发展史上有着划时代的意义,与当前的常规反射炉相比,可节能70％,减排80％,铝的烧损下降4个百分点,在节源（资源与能源）减排方面意义重大。等温熔炼炉在美国已商业化试生产成功,正在作扩大试生产工作,开发大的商业化生产炉,预计2010年美国可能有20％左右的下游铝产品是用此项技术熔炼的,首先得到应用的是铸造行业与压铸件生产行业。此技术不但适合于铝工业,其他冶金部门也全面适用,还可用于熔化玻璃。