氨法制铁黄晶种形成过程研究

Study on seed formation process in preparing ferric yellow by ammoniac method

在铁黄生产用氨水作沉淀剂直接回收反应所生成的(NH_4)_2O_4,用作化学肥料或回收氨。研究了用氨水作沉淀剂时铁黄晶种的形成过程、晶种颜色、物相的变化及晶种的形貌和粒度,探讨了亚铁 Fe^(2+)浓度、空气流量、碱比等对晶种形成的影响。Fe^(2+)的转化率随时间几乎呈直线变化,符合零级反应的动力学特征;在室温、空气流量为 0.10m^3/h、碱比为0.25和 Fe^(2+)离子浓度为20%～40%的条件下可得到黄色、粒度细小且分布均匀、形貌类似针形的铁黄晶种。

Using NH_3·H_2O as precipitating agent in producing ferric yellow can direct recycle the by-product(NH_4)_2SO_4 for the chemical fertilizer or recycle ammonia.Formation of α-FeOOH seed,variation of seed color,physical phase,size and morphology of the seed were studied while using NH_3·H_2O as the precipitating agent.The effects of Fe^(2+) concentration,air-flow and alkali ratio on seed formation were investigated.The results show that it is almost linear relation between time and Fe^(2+) con- version accordingly in compliance with the kinetic feature of zero order reaction,and the ferric yellow seed which is yellow,very fine,uniform and needlelike can be gained at ordinary temperature,0.1 m^3/h of air-flow,0.25 of alkali ratio and 20%-40% of Fe^(2+) concentration.