(1. 重慶大學 材料科學與工程學院，重慶 400044；
2. 昆明理工大學 省部共建復雜有色金屬資源清潔利用國家重點實驗室，昆明 650093)
摘 要: 采用熱分析動力學方法，研究了Na2CO3作用下硅鎂質型紅土鎳礦非等溫碳熱還原的動力學規(guī)律，確定了主要的動力學參數，查明了還原過程的物相變化。結果表明：添加Na2CO3可降低碳熱還原開始溫度約250 ℃，并加速碳的氣化反應；碳熱還原過程可分為三個階段，即初始階段(α=0~0.15)、中期階段(α=0.15~0.60)和衰變階段(α=0.60~1.0)。初始階段的活化能隨著還原反應的進行由223 kJ/mol快速下降到76 kJ/mol，受二維擴散控制；中期階段活化能先增加后降低，該階段受化學反應控制；衰變階段主要發(fā)生FeO及Fe2SiO4的還原反應，活化能由184 kJ/mol緩慢減小到132 kJ/mol，隨后又增加到173 kJ/mol，該階段受化學反應控制。與無添加劑相比，添加Na2CO3后極大地促進了紅土鎳礦的碳熱還原，降低了整個過程的活化能。
關鍵字: 紅土鎳礦；動力學；非等溫；碳熱還原；碳酸鈉
（1. College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China;
2. State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming 650093, China）
Abstract:Kinetics study of non-isothermal carbothermic reduction of nickel laterite ore was carried out in the presence of Na2CO3. Based on the thermogravimetry and kinetic analysis methods, relevant kinetic parameters were determined and the phase transformation during reduction was revealed. The results indicate that the starting temperature of carbothermic reduction is reduced and the gasification of carbon is intensified after adding Na2CO3. The reduction process can be divided into three stages: the initial stage (α=0-0.15), the middle stage (α=0.15-0.60) and the decaying stage (α=0.60-1.0). The activation energy of initial stage decreases from 223 kJ/mol to 76 kJ/mol in which the two-dimensional diffusion is identified as the mechanism function. For the middle stage, the activation energy firstly increases and then decreases. The chemical reaction mechanism is found to be the best fit. The decaying stage also belongs to chemical reaction mechanism, while the activation energy of this stage decreases from 184 kJ/mol to 132 kJ/mol and then increases to 173 kJ/mol. The reductions of Fe and Fe2SiO4 are the main reactions in this stage. Compared to the reduction in the absence additive, the reduction process is enhanced and the corresponding activation energy can be reduced after adding Na2CO3.
Key words: nickel laterite ore; kinetics; non-isothermal; carbothermic reduction; Na2CO3
