隨著高品位鐵礦資源逐漸枯竭，低品位鐵礦石（含高SiO₂）逐漸成為煉鋼原料發展主流。然而，高SiO₂ 成分於燒結過程中易與CaO生成穩定的矽酸鈣類礦物（C₂S、CS），導致作為結合相之SFCA（Silico-Ferrite of Calcium and Aluminum）生成受限，不僅降低燒結礦的強度與還原性，也影響高爐煉鐵效率與碳排放控制。現有文獻對此類高SiO₂ 系統礦相的轉變行為認知有限，特別是在實際燒結製程中升溫、持溫與冷卻各階段的液相生成與轉變機制，缺乏即時、量化之實驗證據。本研究針對上述問題，以「改善高 SiO₂ 含量之燒結礦條件下 SFCA 生成受限」為目標，採用同步輻射臨場高溫X光繞射（in-situ synchrotron HT- X-ray Diffraction）技術，結合Rietveld精修與熱力學相圖計算，系統探討不同SiO₂ 含量與鹼度條件下鐵礦樣品的燒結礦相演化行為，並進一步設計熱處理製程改質策略。研究發現，在高SiO₂ 與鹼度2條件下，SFCA含量僅16.1 wt%，且出現大量未反應的SFCA-I與矽酸鈣類中間相，顯示高SiO₂ 條件易造成反應資源分散與反應不完全。透過延長高溫持溫時間（1250 °C，30分鐘），可顯著促進SFCA-I向SFCA的轉化，使SFCA含量提升至34.2 wt%，為原樣的2倍。本研究以同步輻射技術即時觀測燒結反應歷程，釐清高SiO₂ 條件下礦相轉化受阻的機理，並提出具體可行之製程改質策略。研究結果有助於提升低品位鐵礦石在燒結製程中的利用效率與結合相品質，進一步改善高SiO₂ 鐵礦於工業應用中的強度不足與還原性不穩定等問題。

This study investigates the formation of SFCA (Silico-Ferrite of Calcium and Aluminum) during the sintering of high-silica (high SiO₂) iron ores. Excess SiO₂ reacts with CaO to form stable silicates (C₂S, CS), reducing CaO availability for SFCA formation and thereby weakening the bonding strength and reducibility of the sinter. Using in-situ synchrotron high-temperature X-ray diffraction (HT-X-ray Diffraction), Rietveld refinement, and thermal profile control, the phase evolution—particularly the transformation of SFCA-I to SFCA—was examined in real time. Results showed that under short isothermal holding, SFCA formation was kinetically hindered, with significant retention of intermediate phases. Extending the holding time at 1250 °C to 30 minutes enhanced diffusion and reaction completeness, increasing SFCA content from 16.1 wt.% to 34.2 wt.%. This confirms that thermal profile optimization can effectively overcome kinetic limitations. The study clarifies the reaction bottlenecks in high-SiO₂ systems and proposes a practical thermal adjustment strategy. The findings offer valuable insights for improving sinter quality while supporting the steel industry's efforts toward raw material diversification, low-carbon processing, and sustainability.

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