Slag structure information derived from sulphide capacities
Slags are silicate melts that have been extensively used in the extraction and refining of metals. Structure and properties of slags have received a great deal of attention in the past decades. Thermophysical and thermochemical properties of slags depend directly on the structure of slags. For example, viscosity, one of the most important thermophysical properties of steelmaking slags, decreases with an increase in basic oxide content and with elevating temperature. This phenomenon corresponds to a breakdown of the silica network structure. It is found that sulfide capacity measurements also present an interesting path towards an understanding of the structure of slags in view of the relationship between temperature and sulfide capacity in logarithm. The reaction between sulphur in the gas and the basic oxide in the slag, especially at silica contents higher than the orthosilicate compositions involves the polymerization of silicates in order to supply the oxygen ions necessary for reactions with sulphur. The molar sulphide capacities CS = (mol％S)(PO2/PS2)1/2 on four binary systems, MgO-SiO2, CaO-SiO2, MnO-SiO2 and FeO-SiO2 are elucidated so as to compare the magnitudes of the basicities of four metallic oxides and to estimate the temperature dependencies of the basicities of metallic oxides. The enthalpy changes of the reaction 2O- = O + O2- , viz. the silicate polymerization reaction (denoted as △Ho(8)) have been calculated from the slopes of the log CS versus 1/T curves for four binary silicates. The △Ho(8) value is considered in the present work to be an index of the basicity of silicate melts. The basicities obtained on the basis of the △Ho(8) values are in the order MgO < CaO < MnO < FeO, which are determined by two effects: (i) ionicity of chemical bonds between metallic and oxygen ions and (ii) clustering of metallic oxides in silicates. It is also found that the basicity of the FeO-SiO2 system is larger at higher temperatures.
Sulphide capacity structure basicity iconicity of chemical bonds clustering
Lijun Wang Miyuki Hayashi Kuo-chih Chou Seshadri Seetharaman
School of Metallurgical and Ecological Engineering, University of Science & Technology, Beijing 1000 Dept. of Metallurgy and Ceramics Science, Tokyo institute of Technology, Tokyo 152-8552, Japan Dept. of Material Science and Engineering, Royal Institute of Technology, Stockholm SE-10044, Sweden
国际会议
Ninth International Conference on Molten Slags,Fluxes and Salts(第九届国际熔渣、溶剂与熔盐学术会议 MOLTEN12)
北京
英文
1-9
2012-05-27（万方平台首次上网日期，不代表论文的发表时间）