Fluidity and structure of aluminate slags for smelting high-alumina iron ores: Effect of CaO/SiO2 mass ratio

IF 3.2 3区材料科学 Q1 MATERIALS SCIENCE, CERAMICS

Journal of Non-crystalline Solids Pub Date : 2024-10-16 DOI:10.1016/j.jnoncrysol.2024.123264

Shuo Zhang , Xiaohua Liu , Yong Hou , Jia Guo , Hanghang Zhou , Xuewei Lv

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Abstract

Slag regulation is crucial for achieving smelting of high-alumina iron ore in blast furnaces. This study investigated the fluidity and structure of CaO-SiO₂–10 wt.%MgO-30 wt.%Al₂O₃ slag by varying the CaO/SiO₂ ratio (1.0–2.0). The results revealed that viscosity decreased with increasing CaO/SiO₂ ratio, while the free running temperature, defined as the temperature at which the slag can flow freely, initially increased and then decreased, peaking at the range of 1.2–1.6. Interestingly, the free running temperature of slag at basicity 2.0 (1392 °C) was lower than that at basicity 1.0 (1398 °C). Spectroscopic analysis demonstrated that increasing basicity facilitated greater charge compensation of Al³⁺ ions, resulting in an increased amount of [AlO₄] tetrahedra. Moreover, increasing free oxygen promoted the depolymerization of [SiO₄] and [AlO₄] tetrahedra, reducing bridging oxygen and increasing non-bridging oxygen. Consequently, the slag's overall polymerization degree decreased. Furthermore, MD simulations identified two distinct fracture mechanisms of bridging oxygen within the Si-O-Si structure.

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冶炼高铝铁矿石的铝酸盐炉渣的流动性和结构：氧化钙/二氧化硅质量比的影响

炉渣调节对于实现高炉冶炼高铝铁矿石至关重要。本研究通过改变 CaO/SiO2 的比例（1.0-2.0），研究了 CaO-SiO2-10 wt.%MgO-30 wt.%Al2O3 熔渣的流动性和结构。结果表明，粘度随 CaO/SiO2 比率的增加而降低，而自由流动温度（定义为炉渣可自由流动的温度）则先升高后降低，在 1.2-1.6 范围内达到峰值。有趣的是，碱度为 2.0 时炉渣的自由流动温度（1392 °C）低于碱度为 1.0 时的自由流动温度（1398 °C）。光谱分析表明，碱度的增加有利于加大 Al3+ 离子的电荷补偿，从而增加 [AlO4] 四面体的数量。此外，游离氧的增加促进了[SiO4]和[AlO4]四面体的解聚，减少了桥接氧，增加了非桥接氧。因此，炉渣的整体聚合度降低。此外，MD 模拟确定了 Si-O-Si 结构中桥接氧的两种不同断裂机制。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Non-crystalline Solids 工程技术-材料科学：硅酸盐

CiteScore

6.50

自引率

11.40%

发文量

576

审稿时长

35 days

期刊介绍： The Journal of Non-Crystalline Solids publishes review articles, research papers, and Letters to the Editor on amorphous and glassy materials, including inorganic, organic, polymeric, hybrid and metallic systems. Papers on partially glassy materials, such as glass-ceramics and glass-matrix composites, and papers involving the liquid state are also included in so far as the properties of the liquid are relevant for the formation of the solid. In all cases the papers must demonstrate both novelty and importance to the field, by way of significant advances in understanding or application of non-crystalline solids; in the case of Letters, a compelling case must also be made for expedited handling.