高自然開口率填充砂配方開發技術與燒結特性探討

Fabrication and Sintering Behavior of Filler Sand with High Free Opening Performance

郭家宏(C.H. Kuo) ； 潘建男(C.N. Pan) ； 陳立軒(L.H. Chen) ； 吳志鴻(C.H. Wu) ； 蕭家科(C.K. Hsiao)

《鑛冶：中國鑛冶工程學會會刊》 65卷3期 (2021/09) Pp. 17-29

https://doi.org/10.30069/MM.202109_65(3).02

摘要

盛鋼桶填充砂是用以阻隔鋼液與滑門系統的乾式不定形耐火材料，其燒結特性更是攸關開口率的表現。中鋼煉鋼一廠盛鋼桶精煉製程雖有98%的自然開口率，但是其吹氧開口爐數仍然偏高，不但提高了煉鋼的成本，更增加人員操作的工安風險。因此，本研究因應煉鋼一廠欲再提升開口率的需求，開發高自然開口率的填充砂。經調查後具體解析出煉鋼一廠不自然開口的原因主要為填充砂的燒結層偏厚、且容易被鋼液滲透。而進一步觀察成分調整與粒度分佈對於填充砂燒結行為的影響，可以發現提高Cr_2O_3/SiO_2成分比例、增加燒結助劑用量、或者縮減矽砂粒度皆可降低燒結層形成溫度。而以現用料鉻質填充砂為基礎，將Cr_2O_3/SiO_2比例微幅拉高0.12，並把燒結助劑添加量增加1%，進而開發出新配方填充砂，其具備適當的荷重軟化溫度T_0可與盛鋼桶預熱溫度相匹配，並得到最佳化的燒結層厚度為7～8 mm。新填充砂已完成煉鋼一廠試用，達成實績目標：一共試用499爐，僅5爐吹氧開口，自然開口率達99%。

關鍵字

填充砂 ； 開口率 ； 燒結層

並列摘要

Ladle filler sand is one kind of dry monolithic refractory that can be used to keep the slide gate system apart from the molten steel. The sintering behavior of filler sand can determine the free opening performance. Even though ladle filler sand in CSC No.1 B.O.F (Basic oxygen steelmaking) Plant has a free opening rate of 98%, ratio of oxygen lancing is still high, leading to an increase in steelmaking cost and unsafe operation environment. Therefore, this study aimed to develop the ladle filler sand with high free-opening efficiency. After investigation, causes of non-free opening were mainly concluded that the sintered layer of filler sand was thicker and easily penetrated by the molten steel. Further observing the influence of composition and particle distribution on the sintering behavior of filler sands, it can be found that the higher Cr_2O_3/SiO_2 ratio, the increase in amount of sintering agent, and the decrease in particle size of silica sand can reduce the formation temperature of the sintered layer. Based on the current chromite-based filler sand, the new filler sand were developed with higher Cr_2O_3/SiO_2 ratio and amount of sintering agent increased by 0.12 and 1%, respectively. The superior properties of the new filler sand achieve an appropriate softening temperature T_0 that can fit with the preheating temperature of ladles, and an optimum thickness of the sintered layer, 7~8 mm. Finally, a new record, 99%, of free opening rate was achieved in No.1 Steel Plant after near five hundreds ladle tests.

並列關鍵字

Filler sand ； Free opening rate ； Sintered layer