在傳統一貫作業的煉鋼廠中，所需的煉鐵原料主要包括含鐵原料、提供煉鐵熱能和還原氣體的焦炭，以及助熔劑。作為台灣碳排大戶之一的中國鋼鐵公司，為了響應國際淨零排放的趨勢，開始研發低碳鐵礦原料的添加，包含塊礦與球團礦以及具有較高的還原性的熱壓鐵(Hot Briquetted Iron，HBI)。
本研究進行一系列不同高爐含鐵礦料與熱壓鐵之高溫軟熔試驗，為了與中鋼高爐現場製程所使用之原料相符，實驗中所使用之含鐵原料以及作為鐵礦還原劑之小焦均為中鋼公司高爐製程現場所使用之原料。使用CCD對不同爐料在各溫度點下的軟熔現象進行影像錄製，並利用影像軟體(Image J) 分析不同溫度點下的面積變化率，判別單一爐料及堆疊爐料的軟熔特徵溫度，定義出收縮溫度、軟化溫度、熔融溫度的判定指標。根據不同高爐含鐵礦料之試驗結果，觀測軟化溫度與熔融溫度並對照出高爐中軟熔帶的位置分布。
根據不同鹼基度燒結礦軟熔試驗結果，可以發現渣相黏度及熔點隨著鹼基度的上升而提高，使鐵粒熔出的現象受到阻礙；將燒結礦與HBI進行堆疊，受到HBI較高的軟化、熔化溫度影響，使得堆疊後軟熔帶溫度明顯提升。由於塊礦具有針鐵礦FeO(OH)之成分，使其於高溫試驗中會有50%的機率發生爆裂。再將PBL、RHL兩種塊礦與HBI進行堆疊，經由與HBI堆疊後軟熔帶範圍皆往高爐下部移動且厚度受到明顯改善，從而增加高爐的氣流性將有益於高爐操作。
根據球結礦之初始成分 (wt%)，其渣組成化合物以SiO2占多數，於高溫環境下易形成低熔點Fe2SiO4鐵橄欖石相，使得球結礦於較低溫度940℃開始發生收縮現象；探討球結礦與不同高爐含鐵原料(B2=2.1燒結礦、HBI、PBL塊礦)之堆疊試驗結果，可發現受到球結礦軟熔帶較薄之影響(軟熔帶區間為40°C)，使得堆疊後軟熔帶厚度皆受到改善。將小焦與不同含鐵原料堆疊，除了與PBL塊礦堆疊外，皆能發現堆疊後軟化溫度發生下降的現象，以SEM觀察到鐵相中分布著片狀形石墨之顯微結構，說明發生滲炭現象，且於試驗結束後，小焦皆保持立體狀，預期可使爐內佈料受到支撐作用。

In a traditional integrated steel mill, the primary raw materials for ironmaking include iron-containing materials, coke that provides thermal energy and reducing gas for ironmaking, and flux. China Steel Corporation, one of Taiwan's major carbon emitters, is responding to the global trend of net-zero emissions by developing the addition of low-carbon iron ore materials. These materials include lump ore and pellet ore produced without sintering, as well as Hot Briquetted Iron (HBI), which has a higher reducibility. Their low carbon emissions and low cost provide a competitive advantage.
This study conducts a series of high-temperature softening and melting experiments with different blast furnace iron ore materials and HBI. The iron-containing materials and small coke used as iron ore reductants in the experiments are the same as those used in China Steel's blast furnace processes. Using CCD, the softening and melting phenomena of different furnace materials at various temperature points are recorded on video, and image analysis software (Image J) is used to analyze the rate of area change at different temperature points. The softening characteristic temperatures of single and stacked furnace materials are determined, defining indicators for shrinkage temperature, softening temperature, and melting temperature. Based on the experimental results of different blast furnace iron ore materials, the softening and melting temperatures are observed, and the position distribution of the softening and melting zones in the blast furnace is identified.

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