盐酸法钛白粉新工艺副产氯化亚铁制备四氧化三铁

Preparation of Fe3O4 from FeCl2 by-product of new process of titanium dioxide by hydrochloric acid

探索了一种以盐酸法钛白粉新工艺副产氯化亚铁为原料制备四氧化三铁磁粉的放大试验工艺,把副产危废氯化亚铁制备成用途广泛的四氧化三铁磁粉,实现资源的综合利用。研究结果表明:选用氧化钙为沉淀剂与氯化亚铁反应得到氢氧化亚铁,在分散剂辅助作用下通入空气使氢氧化亚铁被氧化成三价氢氧化铁,控制氧化钙及分散剂加料时间间隔为1.5 h、氧化温度为80℃、氧化时间为8.5 h,将氢氧化铁与氢氧化亚铁以物质的量比为2∶1均匀混合,通过正压分离得到固体,控制分离前pH为6.5,最后通过烘干、研磨等后处理得到四氧化三铁磁粉。进行50 kg级别放大试验得到四氧化三铁产品,收率达到97%。该工艺将副产危废转化为有一定经济效益的产品,进一步完善了盐酸法钛白粉新工艺。

An enlarged process for preparing ferrous tetroxide magnetic powder from the by-product ferrous chloride of the new process of titanium dioxide by hydrochloric acid method was explored.The by-product hazardous waste ferrous chloride was prepared into widely used ferrous tetroxide magnetic powder to realize comprehensive utilization of resources.The research results showed that calcium oxide was used as precipitant to react with ferrous chloride to obtain ferrous hydroxide,Ferrous hydroxide was oxidized to trivalent ferric hydroxide by passing air under the aid of dispersant.The calcium oxide and dispersant feeding time interval was 1.5 h,the oxidation temperature was 80℃,and the oxidation time was 8.5 h.The ferric hydroxide and ferrous hydroxide were uniformly mixed with molar ratio of 2∶1.The solid was obtained by positive pressure separation,and the pH before separation was controlled to be 6.5.The ferrite tetroxide magnetic powder was obtained by post-processing of drying and grinding.The process was scaled up to 50 kg to obtain ferric oxide products,and the yield reached 97%.This process converted by-product hazardous waste into products with certain economic benefits,and further improved the new process of titanium dioxide by hydrochloric acid method.