A high-temperature system based on the laser flash method to measure the thermal diffusivity of melts

A high-temperature measuring system has been developed to undertake measurements of thennal difusivity and specific heat up to 1900 K. The overall design allows measurements on solids to be undertaken using the accepted standard techniques and analytical procedures. The specific design for molten materials and especially slags is based on the differential threelayer technique utilizing a special cell which can be accomodated in the system. In this method, the liquid specimen is sandwiched between an upper inner platinum crucible and a lower outer platinum crucible, to provide a three-layered sandwich. A laser pulse irradiates the surface of the upper platinum crucible and the temperature response of the surface of the lower platinum crucible is observed. For the purpose of accurate measurement of specimen thickness at the measuring temperature, two runs are performed in which the thicknesses arel andl+°Dl, wherel is unknown butl can be set accurately with a built-in micrometer. The thermal difusivity is obtained through a curve-fitting method by a personal computer using a three-layer analysis with a correction for the radiative component based on the transparent body assumption. Following verification of the basic performance, using solids of known properties and water and ethanol, a continuous casting mixture has been evaluated. The initial results on the fluids are in good agreement with those in the literature.Paper presented at the Twelfth Symposium on Thermophysical Properties, June 19–24, 1994, Boulder, Colorado, U.S.A.     

Thermodynamic Activities of “FeO” in some Binary “FeO”‐Containing Slags

In the present investigation, experimental measurements of the thermodynamic activities of iron oxide in the Al₂O₃‐“FeO”, CaO‐“FeO” and “FeO”‐SiO₂ systems were performed in the temperature range 1823‐1873 K by using gas equilibration technique. The molten slag, kept in a Pt‐crucible was brought to equilibrium with a gas mixture of known oxygen partial pressure. A part of the Fe from the “FeO” was reduced during the equilibration and got dissolved in the Pt phase. The samples were quenched after the required equilibration time and the slag phase as well as the platinum crucible was subjected to chemical analysis. The activities of “FeO” in the slag were calculated from the experimental data using thermodynamic information on the Fe‐Pt binary metallic system generated and assessed earlier. The experimental results are compared with earlier thermodynamic studies of the slag systems. Reassessment with the KTH slag model is performed and the results are compared with other thermodynamic models, viz. F*A*C*T? and Thermo‐Calc? respectively. The experimental activities predicted by the KTH slag model are in good agreement with the experimental data available in the literature. A general agreement between the various models is also observed.     

单纯形优化法在稀土富渣化选除钙中的应用

介绍了一种单纯形试验机优化方法及其在冶金中应用。该方法与一般的正交试验法比较：一是试验次数少；二是可以找出最佳条件的一个稳定区域，为冶金试验提供了一种新的试验方法。     

干法乙炔电石渣中生电石的定量分析

介绍了干法乙炔生产过程产生的电石渣中生电石含量的定量分析方法，指出该方法具有准确度高、简便易行的特点。     

A Review of the Relationship between Viscosity and the Structure of Calcium‐Silicate‐Based Slags in Ironmaking

This review focuses on elucidating the viscosity of ironmaking slags and the effect of various components in the multi‐component calcium‐silicate‐based slag system on the viscosity. Using various widely used spectroscopic techniques including Fourier transform infrared (FTIR), Raman, X‐ray photoelectron spectroscopy (XPS), and nuclear magnetic resonance (NMR), the viscous behavior and the slag structure of this system were correlated. In particular, the review begins with an introduction to the viscous behavior of binary silicate systems and an identification of the intricate details of the slag structure. Using the binary system as a basis, the compounded effect of typical ironmaking slag components such as Al₂O₃, MgO, alkali oxides, and TiO₂ on the viscosity is introduced through expansion to a quinary slag system. Using a combination of the aforementioned spectroscopic methods, the meticulous details of the slag structure were ascertained, and the depolymerization or polymerization mechanisms of the silicate and alumino‐silicate structures were subsequently identified. This review also compares well‐known viscosity prediction models with experimentally measured values and identifies potential fields of research in the ironmaking industry associated with slag viscosities.     

鞍钢超低磷钢生产实践

针对不同的工艺路线开展了超低磷钢生产技术研究,结合各生产线的装备特点,开发出各自的深脱磷方法。实现了双渣法转炉出钢磷含量小于0.006 0%、双联法转炉出钢磷含量在0.003 0%～0.005 0%之间的目标,并在生产超低磷钢试验中磷含量达到了0.001 8%的实绩。     

富锰渣热兑锰除尘灰及粉锰矿余热回收技术研究

研究了用富锰渣显热热兑锰除尘灰及粉锰矿得到富锰渣的液态富锰渣富余热能回收利用技术。实现了提高锰除尘灰、粉锰矿的附加值,调节富锰渣化学特性,节能降耗、改善生产指标的效果。     

利用钢渣、炼铁除尘灰生产氧化锌

文章介绍了以钢铁生产中产生的固废冶金渣及收尘系统产生的尘灰为原料,通过回收其中的有用成份锌,实现了对固体废物的资源化和综合利用的方法和工艺,产生了良好的经济效益,减轻了环境污染。     

The Effect of MgO on the Viscosity of the CaO‐SiO2‐20 wt%Al2O3‐MgO Slag System

The viscosities of CaO‐SiO₂‐20 wt%Al₂O₃‐MgO slags (CaO/SiO₂ = 1.0–1.2, wt%MgO = 5–13) were measured to estimate the effect of MgO on the viscous behaviour at elevated temperatures. The slag viscosity at 1773 K decreased with increasing MgO contents, which was typical of a basic oxide component at relatively low basicity (CaO/SiO₂) of 1.0. The FT‐IR spectroscopic analysis of the slag structure seems to verify this behaviour. However, an unexpected contradiction with the temperature dependence was observed above 10 wt%MgO and above CaO/SiO₂ of 1.2. Although the apparent activation energy was expected to decrease with additions of the basic oxide component MgO, the apparent activation energy increased. This unexpected behaviour seems to be related to the change in the primary phase field correlating to the phase diagram corresponding to the slag composition. Therefore, in order to understand the viscosity at both high Al₂O₃ and MgO, not only should the typical depolymerization of the slag structure with high MgO content be considered but also the primary phases of which the molten slag originates.     

A Study on the Effect of Na2O on the Viscosity for Ironmaking Slags

The viscosities of CaO‐SiO₂‐10wt%MgO‐20wt%Al₂O₃‐Na₂O slags (CaO/SiO₂ = 0.8–1.2, wt%Na₂O = 0–10) were measured to estimate the effect of Na₂O on the viscous behavior at elevated temperatures. The slag viscosity at 1773 K decreased with increasing Na₂O contents, which is observed in a basic oxide component. However, the FT‐IR spectroscopic analysis of the slag structure seemed to verify that [AlO₄]‐tetrahedra depolymerized more readily than [SiO₄]‐tetrahedra due to ionic charge compensation which has a tendency to be more effective on [AlO₄]‐tetrahedra. Hence, for the present slag system, the viscosity decreased with additions of Na₂O by providing network breaking O^2‐ ions, and the charge balance by Na⁺ ions independently contributed to the depolymerization of the network structure of the molten slag. In addition, Na₂O also lowered the critical temperature (T_CR) resulting in a larger temperature difference between the operating temperature (T_OP) and T_CR, which can enhance operational stability.