本研究以鐵粉為添加劑，在氮氣氛下進行稻殼灰分碳熱還原氮化反應，探討鐵粉添加對反應物反應後的型態結構、轉化率及反應速率等的影響，並研究鐵粉添加劑於本反應中所扮演的角色。實驗中利用直立式管狀高溫爐系統，由氮化前後的重量變化求得稻殼灰分的轉化率，並探討各種操作變因對反應的影響。 本研究主要探討的操作變因包括：氣體流率、鐵粉添加量、樣品造粒壓力、樣品載量與反應溫度等。研究中並對反應物及產物做各種物性測試如：感應耦合電漿質譜分析儀(ICP-MS)、元素分析儀（EA）、比表面積測定儀(BET)、X-射線繞射儀(XRD)、掃描式電子顯微鏡(SEM)等來佐證實驗結果。 實驗結果顯示，增大氮氣流率可增加稻殼灰分的轉化率，當流率大於500 ml/min時，對於轉化率影響就較不明顯。添加鐵粉可以增加稻殼灰分的轉化率，添加1wt%以上則轉化率增加幅度較小。樣品造粒壓力越大則轉化率越大，壓力超過9.65x105 kPa以上則對轉化率較沒影響。減小反應物載量也會增加稻殼灰分的轉化率。溫度升高則對提高轉化率影響甚為顯著。整個反應以氣/固反應為主，鐵粉添加後主要產物為鬚晶狀碳化矽，同時推測鐵粉添加形成Fe-Si液態合金為碳化矽晶體成長的重要機制。在化學反應控制區內，添加1wt%鐵粉，反應活化能為566.69 kJ/mol。 The carbothermal reduction and nitridation of rice husk ash with iron powder addition was investigated by weight change measurement. In this study, the operating variables have been discussed include: nitrogen flow rate, amount of iron powder addition in the reactant, pellet-forming pressure, sample weight, and reaction temperature. The analysis of this experiment is conducted by inductively coupled plasma-mass spectrometer (ICP-MS), element analysis (EA), BET surface area, X-ray diffraction (XRD) and scanning electron microscope (SEM). The experimental results indicated that the conversion of rice husk ash is increased with an increasing nitrogen flow rate and the effect is not appreciable when the flow rate exceeds 500ml/min. The conversion of rice husk ash is increased with an increasing amount of iron powder addition in the reactant. Increasing the pellet-forming pressure could increase the conversion, the effect is not appreciable when the pellet-forming pressure is above 9.65x105 kPa. Moreover, the reaction rate and the conversion of the rice husk ash are significantly increased with higher reaction temperature. The reaction product is fibrous shape β- SiC with iron addition. We conjectured that the formation of liquid Fe-Si alloy is an important way for β- SiC growth. In the chemical reaction controlled region, the activation energy of the reaction is 566.69 kJ /mol when iron powder addition is 1wt% .
