红土镍矿还原焙烧的机理研究

利用XRD和TG/DTA技术分别分析了红土镍矿结构和特性,SEM和岩矿相观察分析了800℃、900℃、1 000℃和1100℃还原后的矿样结构和镍、铁还原率和金属化率,并在此基础上探讨了红土镍矿还原焙烧的反应机理。在不同温度条件下,研究了动态CO气氛中红土镍矿的还原焙烧反应动力学。结果表明:还原后的红土镍矿中镍、铁晶粒很细、很分散,选矿难度大。还原焙烧时间不宜过长,40～60 min为佳。还原焙烧温度不应太高,900℃为宜,此温度下,红土镍矿还原3h后,镍的还原率为79.47%、铁还原率和金属化率分别为73.51%和60.27%。红土镍矿还原焙烧过程中镍、铁的表观活化能、反应频率因子和反应级数依次为E_Ni=196.86kJ·mol^-1、E_Fe=116.29 kJ·mol^-1、In(A_Ni/min^-1)=16.76、In(A_Fe/min^-1)=10.29、n_Ni=1.2595和n_Fe=3.2349,确定了还原过程中镍和铁的反应动力学方程。

Stduying on reductive roasting mechanism about nickel laterite

The ore structure and characteristics of nickel laterite were studied by XRD and TG/DTA,and ore structure and the nickel,iron reduction rate and the metallization after the reduction of 800℃,900℃,1000℃and1100℃were analyzed by SEM and Mineral phase.Based on these,the reaction mechanism of reductive roasting about nickel laterite was discussed.At different temperatures,the kinetics of reduction roasting about nickel laterite was researched in dynamic CO atmosphere.The results showed that the iron grained is very small and very scattered after reduction of nickel laterite,so dressing is very difficult.Reduction roasting time for 40⁶minutes is better,not too long.Reduction roasting temperature for 900℃is better,not too high,and at this temperature, the reduction rate of nickel is 79.47%,the reduction rate and the metallization of iron is 73.51%and 60.27%respectirely after 3 hours nickel laterite reduced.The apparent activation energy,the reaction frequency factors,the reaction orders of the nickel and iron reduction were obtained by calculation as follows: E_Ni=196.86kJ ? mol^-1,E_F（?）=116.29 kJ?mol^-1,In(A_Ni/min^-1) =16.76,In(A_Fe/min^-1) =10.29,n_Ni=1.2595 and n_Fe=3.2349, and then the kinetic equations was also determined.