红土镍矿的固相还原动力学

采用非等温热分析法对红土镍矿固相还原动力学进行了研究，由热失重曲线确定了红土镍矿固相还原的反应机理函数f(a)，在此基础上求解出动力学参数，并对建立的动力学模型进行了验证，分析了红土镍矿固相还原机理. 结果表明，红土镍矿失重率与加热温度密切相关，而升温速率对其影响很小；模型计算值与实测值具有良好的相关性；固相还原过程可分为473~773和773~1223 K两个阶段，反应活化能分别为171.91和52.75 kJ/mol，与挥发分的析出和镍、铁氧化物的还原对应；反应属随机成核和随后生长型机理函数，其微分形式为f(a)=1/4(1-a)-ln(1-a)]-3，反应速率主要由碳气化反应控制.

Solid State Deoxidization Kinetics of Nickel Laterite Ore

Solid state deoxidization kinetics of nickel laterite ore was studied using non-isothermal thermal analysis method. The conversion function f(α) and kinetic parameters of solid state deoxidization were determined by the TG curves, kinetics model established verified, and the reduction mechanism of nickel laterite ore analyzed. The results indicate that weight-loss rate can be considered as a function of the temperature, and heating rate has less effect. There was clear relationship between calculated values for mathematical model and measured values. The process of solid state deoxidization can be divided into two stages for 473~773 and 773~1223 K with activation energy 171.91 and 52.75 kJ/mol, which are corresponding to releasing stage of volatiles and reduction of nickel and ferrous oxides. The reaction mechanism belongs to random nucleation and growth, with differential form f(a)= 1/4(1-a)-ln(1-a)]-3.. The solid state deoxidization rate of nickel laterite ore is controlled by Boudouard reaction.