轉爐石蒸氣養生體積安定化反應機制探討

The Study of BOF Slag Stabilization Mechanism by Steam Aging Treatment

翁丁財(T.T. Weng) ； 曾耀弘(Y.H. Tseng) ； 潘振君(J.J. Pan) ； 蔡俊緯(J.W. Tsai)

《鑛冶：中國鑛冶工程學會會刊》 64卷4期 (2020/12) Pp. 33-42

https://doi.org/10.30069/MM.202012_64(4).03

摘要

為消除轉爐石體積膨脹性，達到安定化效果，中鋼投入轉爐石蒸氣養生安定化技術之建立。本研究使用2種不同粒徑之轉爐石級配料，經7天蒸氣養生安定化試驗，結果發現細粉料增加4-10%。轉爐石體積膨脹率在第5天已由原渣2.72%降至0.46%，第7天更降低至0.39%，達到道路基底層用料（CNS15358）之規範（≦0.50%）之要求。由XRD晶相分析探討不同粒徑轉爐石之反應行為，發現大粒徑（≧10mm）轉爐石經7天蒸氣養生後，轉爐石中f-CaO相仍然存在，且只有形成少量的Ca(OH)_2相；細粉料（＜4.75mm）則在養生第3天即幾乎完成水和反應，且Ca(OH)_2成為主要之結晶相，顯示細粉料的膨脹性較快被消除。利用SEM解析，推測在蒸氣養生過程中溶出的CaO在轉爐石表面與水形成反應，反應層的厚度＜50μm，經XRD晶相分析，證實是Ca(OH)_2相。

關鍵字

轉爐石 ； 蒸氣養生 ； 體積安定化

並列摘要

To remove expansion property of BOF slag, CSC has devoted efforts to establishing steam aging technique for the stabilization of BOF slag. In this study, 2 kinds of BOF slag aggregates with different sizes were used and examined their properties after 7 days of steam aging. The results show that the expansion of BOF slag decreases from 2.72% to 0.46% (5 days of steam ageing) and further decreases to 0.39% after 7 days of steam aging. The expansion value of steam aged BOF slag is less than 0.5%, which meets the requirement of Chinese National Standard (CNS15358) for graded aggregate material used in bases or subbases. Based on XRD analyses, it is found that free CaO still exists in BOF slag with larger aggregates(≧10mm) after 7 days of steam aging, while free CaO in the fine BOF slag particles (＜4.75mm) is hydrated with water completely in 3 days. According to SEM observation, it is proposed that only the CaO surrounding the surface of BOF slag can be hydrated by steam, the hydrated layer is less than 50μm, which is identified as Ca(OH)_2 by XRD analysis.

並列關鍵字

BOF slag ； steam aging ； stabilization