(1. 中南大學(xué) 資源加工與生物工程學(xué)院，長沙 410083；
2. 華菱集團(tuán) 漣源鋼鐵公司，婁底 417009)
摘 要: 采用光學(xué)顯微鏡、萊卡圖像分析軟件對低品位赤鐵礦煤基直接還原產(chǎn)品中金屬鐵晶粒尺寸進(jìn)行檢測。利用Hillert晶粒長大動力學(xué)模型對低品位赤鐵礦煤基直接還原過程中鐵晶粒的長大行為進(jìn)行研究。結(jié)果表明：在還原溫度為1 200 ℃、還原時間為5~120 min時，金屬鐵晶粒的生長速率常數(shù)k為1.155 μm2/min；在1 200 ℃時，球團(tuán)還原過程中，金屬鐵晶粒的平均尺寸D(μm)與還原時間t(min)的關(guān)系式為D=exp(0.565ln T+0.072)。在還原時間為120 min時，還原球團(tuán)金屬鐵晶粒的平均尺寸D(μm)與還原溫度T(K)的關(guān)系式為D=exp(-8 995 845ln T+ 8.899)。在還原溫度1 000~1 200 ℃范圍內(nèi)，還原球團(tuán)的金屬鐵晶粒生長表觀活化能為132.53 kJ/mol。
關(guān)鍵字: 低品位赤鐵礦；直接還原；鐵晶粒；晶粒尺寸
（1. School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China;
2. Lianyuan Iron and Steel Company, Valin Group, Loudi 417009, China）
Abstract:The size of metal iron grain of low grade hematite during coal based direct reduction was tested using optical microscope and Leica image analysis software. The growth behavior of metal iron grain was investigated using Hillert grain growth dynamic model. The results show that the growth rate constant of metal iron grain is 1.155 μm2/min when reduced at 1 200 ℃ for 5-120 min. The relationship between the average size of metal iron grain D(μm) and reduction time t(min) is D=exp(0.565ln T+0.072) at reduction temperature of 1 200 ℃. The relationship between the average size of metal iron grain D(μm) and reduction temperature T(K) is D=exp(-8 995 845ln T+8.899) when reduced for 120 min. The apparent activation energy of metal ferrous grain growth is 132.53 kJ/mol in a reduction temperature range from 1 000 ℃ to 1 200 ℃.
Key words: low grade hematite; direct reduction; iron grain; grain size
