Viscosity and structure relationship with equimolar substitution of CaO with MgO in the CaO–MgO–Al_(2)O_(3)–SiO_(2)slag melts  

作　　者：Yong Hou Shuo Zhang Jie Dang Jia Guo Hanghang Zhou Xuewei Lü 

机构地区：[1]College of Materials Science and Engineering,Chongqing University,Chongqing 400044,China [2]Chongqing Key Laboratory of Vanadium-Titanium Metallurgy and New Materials,Chongqing University,Chongqing 400044,China

出　　处：《International Journal of Minerals,Metallurgy and Materials》2025年第1期70-79,共10页矿物冶金与材料学报（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(Nos.52425408 and 52304345);the Fundamental Research Funds for the Central Universities,China(No.2023CDJXY-016);the Postdoctoral Science Foundation of Chongqing(No.CSTB2023NSCQ-BHX0174)。

摘　　要：Currently,the Al_(2)O_(3)content in the high-alumina slag systems within blast furnaces is generally limited to 16wt%–18.5wt%,making it challenging to overcome this limitation.Unlike most studies that concentrated on managing the MgO/Al_(2)O_(3)ratio or basicity,this paper explored the effect of equimolar substitution of MgO for CaO on the viscosity and structure of a high-alumina CaO-MgO-Al_(2)O_(3)-SiO_(2)slag system,providing theoretical guidance and data to facilitate the application of high-alumina ores.The results revealed that the viscosity first decreased and then increased with higher MgO substitution,reaching a minimum at 15mol%MgO concentration.Fourier transform infrared spectroscopy(FTIR)results found that the depths of the troughs representing[SiO_(4)]tetrahedra,[AlO_(4)]tetrahedra,and Si-O-Al bending became progressively deeper with increased MgO substitution.Deconvolution of the Raman spectra showed that the average number of bridging oxygens per Si atom and the X_(Q^(3))/X_(Q^(2))(X_(Q^(i))is the molar fraction of Q^(i) unit,and i is the number of bridging oxygens in a[SiO_(4)]tetrahedral unit)ratio increased from 2.30 and 1.02 to 2.52 and 2.14,respectively,indicating a progressive polymerization of the silicate structure.X-ray photoelectron spectroscopy(XPS)results highlighted that non-bridging oxygen content decreased from 77.97mol% to 63.41mol% with increasing MgO concentration,whereas bridging oxygen and free oxygen contents increased.Structural analysis demonstrated a gradual increase in the polymerization degree of the tetrahedral structure with the increase in MgO substitution.However,bond strength is another important factor affecting the slag viscosity.The occurrence of a viscosity minimum can be attributed to the complex evolution of bond strengths of non-bridging oxygens generated during depolymerization of the[SiO_(4)]and[AlO_(4)]tetrahedral structures by CaO and MgO.

关 键 词：ALUMINOSILICATE VISCOSITY STRUCTURE spectroscopy 

分 类 号：TF534[冶金工程—钢铁冶金]