转炉吹炼中低碳铬铁的热力学分析

利用碳饱和溶解度数据处理的方法,计算了Ｆｅ－Ｃ－Ｃｒ熔体的热力学性质,得到了Ｃｒ对Ｃ的活度相互作用与温度的关系式,并分析了高碳铬铁转炉法吹炼中低碳铬铁时吹氧脱碳的热力学行为。     

锰铁熔体中磷和锰的热力学性质

通过１４００℃下Ｆｅ－Ｍｎ－Ｃ－Ｐ系中碳的溶解平衡实验，测定了该熔体中碳的溶解度，应用热力学理论计算出，，，并提出了适用于锰铁熔体中磷和锰的活度系数计算式     

Fe—C—P,Fe—Mn—P,Fe—Si—P三元金属熔体作用浓度计算模型

根据含化合物的金属熔体结构的共存理论，推导了１６７３Ｋ下Ｆｅ－Ｃ－Ｐ、Ｆｅ－Ｍｎ－Ｐ、Ｆｅ－Ｓｉ－Ｐ三元金属熔体作用浓度计算模型。计算的磷的作用浓度与相应的实测磷活度相符合，从而证明所得模型可以反映Ｆｅ－Ｃ－Ｐ、Ｆｅ－Ｍｎ－Ｐ、Ｆｅ－Ｓｉ－Ｐ三元熔体的结构本质。同时模型揭示了Ｃ、Ｍｎ、Ｓｉ的摩尔分数对磷的转换系数的影响规律。     

在1200℃下,Cu2S—FeS—SnS熔体的活度

在１２００℃下，用露点技术测量Ｃｕ２Ｓ－ＦｅＳ－ＳｎＳ系的液体硫化物上的ＳｎＳ蒸气压力，从测量过的ＳｎＳ的蒸气压力中得出ＳｎＳ活度。在二元和三元熔体中，用Ｇｉｂｂｓ－Ｄｕｈｅｍ计算法从已知的ＳｎＳ活度数据来计算Ｃｕ２Ｓ和ＦｅＳ的活度。Ｃｕ２Ｓ－ＳｎＳ和Ｃｕ２Ｓ－ＦｅＳ系相对于理想状态显示出负偏差，而ＦｅＳ－ＳｎＳ熔体显示出正偏差。     

Mn—C—Si系锰基熔体的活度与自由能计算

实验测定了１６７３Ｋ时Ｍｎ－Ｃ－Ｓｉ系熔体中Ｓｉ对Ｃ的溶解度的影响，计算得到锰基熔体中一阶和二阶活度相互作用系数以及Ｃ在Ｍｎ液中的标准溶解自由能值。     

碳饱和三元金属熔体热力学性质的计算方法

为了简化金属熔体热力学性质的计算过程和获得任意温度下熔体组元的热力学性质，基于一种碳饱和三元金属熔体热力学性质的计算方法，将三元金属熔体中碳的饱和溶解度分解为温度T和第三组元j的影响因子kj(或mj)两项，得到用T和kj(或mj)表示的组元活度相互作用系数的计算公式。用该公式可以计算出M—C-j三元熔体中组元j在任意温度下的活度相互作用系数，并可得到组元j的活度相互作用系数与温度的关系式。将计算的Fe-C—Cr体系和Mn—C—Fe体系的性质应用于热力学分析，获得了与实际生产比较吻合的结果。     

CaO—SiO2—FeO—Fe2O3—MgO渣系MgO饱和溶解度的研究

根据熔渣结构的共存理论，建立了ＣａＯ－ＳｉＯ２－ＦｅＯ－Ｆｅ２Ｏ３－ＭｇＯ渣系作用浓度计算模型。分析了ＮＣａＯ、ＮＳｉＯ２、ＮＦｅＯ等对ＭｇＯ饱和溶解度的影响。在１５００－１７５０℃温度范围内，ＭｇＯ饱和溶解度的模型计算值与实测值一致。     

Fe—Mn合金脱氧能力的计算

本文在推导Ｆｅ－Ｍｎ合金熔体作用浓度计算模型的基础上，进一步计算了Ｆｅ－Ｍｎ－Ｏ系金属熔体平衡氧浓度，其结果与实验数据完全一致。     

锰在BaO—BaF2—MnO熔剂和锰铁熔体间的平衡

在１５７３－１６７３Ｋ时测定了锰在ＢａＯ－ＢａＦ２和ＭｎＯ渣和Ｍｎ（６２－７３％）－Ｆｅ－Ｃ饱和熔体之间的平衡分配比，研究了渣的成份、氧分压和温度对锰分配比的影响。发现锰的平衡分配比是随着氧分压和渣中ＢａＯ含量的增加而增加，在氧分压较高时，向ＢａＯ－ＭｎＯ渣中附加ＢａＦ２，为减少锰的损失和使锰铁脱磷能够进行提供了有利条件。在氧分压一定时，在渣与碳饱和锰铁平衡时，ＢａＯ与ＭｎＯ的摩尔分数比是随着渣中     

锰在BaO－BaF_2－MnO熔剂和锰铁熔体间的平衡

在１５７３－１６７３Ｋ时测定了锰在ＢａＯ－ＢａＦ_２和Ｍｎｏ渣和Ｍｎ（６２－７３％）－Ｆｅ－Ｃ饱和熔体之间的平衡分配比．研究了渣的成分、氧分压和温度对标分配比的影响，发现锰的平衡分配比是随着氧分压和渣中ＢａＯ含量的增加而增加．在氧分压较高时．向ＢａＯ－ＭｎＯ渣中附加ＢａＦ２，为减少镜的损失和使锰铁脱磷能够进行提供了有利条件．在氧分压一定时，在渣与碳饱和的镜铁平衡时，ＢａＯ与ＭｎＯ的摩尔分数比是随着渣中ＢａＯ的增加而减少的．温度高导致锰的分配比低．对于ＢａＯ（５０％）－ＢａＦ２（４７％）－ＭｎＯ（３％）渣；温度对锰容量的影响可以表示为：Ｎｎ（１）十１／２０２＝（ＭｎＯ）这个反应热，在研究的温度一定时计算为一定时计算为－４１５ｋＪ／ｍＯｌ     

不锈钢母液的凝固点及流动性的实验研究

对不同含铬量的铁水凝固点和流动性进行了实验测定。结果表明，含铬铁水的凝固点和流动性与普通铁水完全不同，含铬铁水碳饱和时，铁水温度及含铬量是影响其凝固和流动性的主要因素，通过热力学分析解释了碳化物析出影响铁水流动性的原因。     

铝熔体与SiO2颗粒反应现象分析

本文分析了向纯铝液中添加ＳｉＯ_２颗粒产生的现象。试验结果表明，铝熔体与ＳｉＯ_２颗粒能发生放热反应，从而制备出Ａｌ／Ａｌ２Ｏ３颗粒原位复合材料。     

Fe—Ga—X—O熔体热力学测定简报

对攀钢铁水中常见元素Ｓｉ，Ｍｎ，Ｖ，Ｔｉ对Ｇａ的活度的影响进行了研究，测定出了它们之间的相互作用系数。通过研究Ｆｅ－Ｇａ－Ｘ－Ｏ平衡计算了ｅ＾ｘＧａ。     

Thermodynamic Properties of Fe-C-N and Fe-C-B-N Melts

The saturated solubility of carbon and nitrogen in Fe-C-N and Fe-C-B-N melts was measured experimentally at 1 485℃ to obtain the activity interaction coefficients between components in these melts. A new method was used to treat experimental results. Using thermodynamic derivation and calculation, some important interac- tion coefficients between components in these melts were obtained.     

Fe C N金属熔体作用浓度计算模型

 实验在MoSi2电阻炉内用饱和浓度法测试了Fe C N体系氮的浓度和活度,并根据含化合物的金属熔体结构的共存理论模型,推导了Fe C N金属熔体作用浓度计算模型。实验测得1 485 ℃碳饱和的Fe C N熔体中在氮分压01 MPa时氮的溶解度为0006 5%,并且计算的作用浓度与相应的实测活度相符合,从而证明所得模型可以反映Fe C N金属熔体的结构本质,由模型得出金属熔体高碳含量有利于脱氮。     

Relationship between Thermodynamic Parameters for Mn-Fe Melt and Temperature

The carbon solubility in Mn Fe melts were measured at 1 350℃ , 1 375℃, 1 425℃and 1 450℃, and accordingly the calculated equations were obtained. By thermodynamic derivation and calculation, some relationships between thermodynamic parameters for Mn-Fe melt and temperature were obtained.     

Possible failure of emf oxygen sensor in liquid iron containing dissolved calcium or magnesium

The solubility products of CaO and MgO in liquid iron, measured using the emf oxygen sensor, are several orders of magnitude greater than those calculated from the thermochemical data. This would imply that the values of Δ and Δ derived from the solubility products are, by a large amount, less negative than those given in the compiled thermochemical tables. As is shown in this paper, the values of Δ derived indirectly from numerous experimental data on various gas-solid (-liquid) reactions involving pure CaO, are in general accord with the compiled thermochemical data. It is surmised from these observations that the oxygen activities in liquid iron saturated with CaO or MgO, measured by the emf cell, giving high solubility products of CaO and MgO, may be attributed to the failure of the emf oxygen sensor in liquid iron containing dissolved calcium or magnesium. Two reaction mechanisms are discussed in the paper to account for the malfunction of the oxygen sensor under highly reducing conditions, which will prevail in liquid iron containing even a small amount of dissolved calcium or magnesium. These two mechanisms are (i) redox reaction at the (Y₂O₃)ThO₂ electrolyte/melt interface and (ii) oxygen flux through the electrolyte from the reference electrode Cr–Cr₂O₃ to the melt/electrolyte interface. Suggestions are made for some experimental work to confirm or refute the argument presented in this communication.     

THE ROLE OF REACTIONS BETWEEN CRUCIBLE AND MELT DURING REFINING OF PLATINUM BY VACUUM INDUCTION MELTING

Abstract

Secondary platinum and Pt alloys can be purified by the selective evaporation of undesirable elements in a vacuum induction melting process. Investigations were made concerning reactions among four different crucible materials and the melt of pure platinum. Relations between the vacuum evaporation of copper, iron, antimony and aluminum additions in a platinum melt and the used crucible were also studied. Minimum enrichments and reactions between the melt and the crucible material are the aim for industrial purposes. The requirements concerning the iron concentration in the cast and resulting devices are especially high. Experimental results show that there can be a marked reaction between the crucibles and the pure Pt melt depending on time, applied atmosphere and the crucible material used. Refining experiments showed that it is possible to reduce the concentration of some elements clearly below 10 ppm, although the complete removal of iron is almost impossible. The refining behaviour can generally be attributed to the nominal composition of the used crucibles, its reactions with the melt and the applied atmosphere.

On peut purifier le platine secondaire et les alliages au Pt par évaporation sélective des éléments indésirables lors d’une opération de fusion par induction sous vide. On a effectué des recherches concernant les réactions entre quatre matériaux différents de creuset et le bain de platine pur. En outre, on a étudié les relations entre l’évaporation sous vide des additions de cuivre, de fer, d’antimoine et d’aluminium dans un bain de platine et le creuset utilisé. Pour fins industrielles, on vise des enrichissements et réactions minimales entre le bain et le matériau du creuset. En particulier, les exigences concernant la concentration du fer dans la coulée et les objets qui en résultent sont élevées. Les résultats expérimentaux montrent qu’il peut y avoir une réaction notable entre les creusets et le bain de Pt pur, dépendant du temps, de l’atmosphère appliquée et du matériau utilisé pour le creuset. Des expériences d’affinage ont montré qu’il est possible de réduire la concentration de certains éléments nettement au-dessous de 10 ppm, bien que l’enlèvement complet du fer est presque impossible. On peut généralement attribuer le comportement d’affinage à la composition nominale des creusets utilisés, aux réactions avec le bain et à l’atmosphère appliquée.