摘要
对用Na_2CO_3作沉淀剂,在FeSO_4水溶液中形成的Fe(OH)_2和FeCO_3的悬浮液中鼓入空气,制备均匀纺锤形α-FeO(OH)微晶的动力学过程进行了研究。证明α-FeO(OH)微晶形成经过了晶核的形成过程和晶核的长大过程。考察了原料起始浓度、反应温度、空气流量对微晶形成过程的影响,文中首次提出利用α-FeO(OH)相形成过成的Avrami数n值来控制α-FeO(OH)微晶轴比大小的方祛,并使用似稳定浓度法确定了晶核长大过程氧化反应的速率方程。
Kinetics of homogeneous spindle-type α-FeO(OH) crystallite formation inFe(OH)_2 and FeCO_3 suspensions system was studied. It was found that the curve ofoxidation reaction reveals a 'S' shape, the dissolution-oxidation equilibrum exists inboth the seed formation of the α-FeO(OH) and seed growth stage. The surface oxidation ofgas, solid. liquid is the rate-determining step for heterogeneous reaction. The activationenergies of seed formation and growth are 70 kJ/ mol·L^(-1) and 55kJ/ mol·L^(-1) respectively. The oxidation rate equation was determined by the quasisteady concen-tration method.
