(1. 北京科技大學(xué)鋼鐵冶金新技術(shù)國(guó)家重點(diǎn)實(shí)驗(yàn)室，北京 100083；
2. 首鋼總公司首鋼技術(shù)研究院，北京 100043)
摘 要: 研究焙燒溫度對(duì)MgO含量分別為1.5%和3.0%(質(zhì)量分?jǐn)?shù))的低硅含鎂球團(tuán)的抗壓強(qiáng)度、礦相和還原膨脹率的影響，并基于Arrhenius方程和還原度測(cè)定計(jì)算低硅含鎂球團(tuán)還原反應(yīng)的表觀活化能，分析還原反應(yīng)的速率限制性環(huán)節(jié)。結(jié)果表明：當(dāng)焙燒溫度較低時(shí)，低硅含鎂球團(tuán)內(nèi)形成的鐵酸鎂數(shù)量較少，存在未反應(yīng)的MgO顆粒，其還原過(guò)程主要受氣體擴(kuò)散和界面化學(xué)反應(yīng)混合控制，還原膨脹率高，還原后強(qiáng)度低。1280℃高溫下，焙燒的低硅含鎂球團(tuán)形成的鐵酸鎂數(shù)量多、強(qiáng)度高，還原過(guò)程后期主要受固相擴(kuò)散即鐵離子擴(kuò)散控制，尤其是低硅高鎂球團(tuán)受固相擴(kuò)散控制更明顯，還原過(guò)程中未出現(xiàn)針狀鐵晶粒，還原膨脹率低。
關(guān)鍵字: 低硅含鎂球團(tuán)礦；焙燒溫度；還原膨脹率；表觀活化能
（1. State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China;
2. Shougang Research Institute of Technology, Shougang Group, Beijing 100043, China）
Abstract:The compressive strength, microstructure and reduction swelling rate of low silica magnesium pellets with 1.5% MgO and 3.0% MgO (mass fraction) calcinated at different temperatures were studied. Apparent activation energy of low silica magnesium pellets calcinated at different temperatures was also obtained by Arrhenius formula and reduction test. The rate controlling mechanism of reduction reaction was determined from apparent activation energy together. The results show that, when thecalcination temperature is low, few magnesium ferrites form in low silica magnesium pellets and unreacted MgOexists, and the reduction process is controlled mainly by gas diffusion and interfacial chemical reaction, which results in highreduction swelling rate and deteriorates the strength. While calcination temperature increases to 1280℃, there forms large amount of magnesium ferrites in pellets and the compressive strength of pellets increase significantly. Later stage of reduction reaction of low silica magnesium pellets (specially the pellets with 3.0%MgO)calcinated at high temperature is mainly controlled by solid diffusion, that is ferric ion solid diffusion, so almost no iron whiskers form, which decreases the pellet swelling rate.
Key words: low silica magnesium pellet; calcination temperature; reduction swelling rate; apparent activation energy
