赤泥硫酸铵焙烧浸出液水解制备偏钛酸的研究

Study on preparation of metatitanic acid by hydrolysis of leaching solution of roasted mixture of red mud and ammonium sulfate

采用选择性水解的方法利用赤泥硫酸铵焙烧熟料浸出液制备偏钛酸以回收钛。首先添加还原铁粉作为还原剂,将浸出液中的三价铁离子还原为二价铁离子,然后控制水解条件,将浸出液中的四价钛离子通过水解反应合成偏钛酸并对其进行分离回收。研究结果表明,浸出液中钛水解的最佳工艺条件:还原铁粉加入量为三价铁离子完全还原为二价铁离子所需铁粉的理论量、水解温度为140℃、水解时间为4 h、终点pH=2.0、添加晶种的含钛量占浸出液总钛含量的9%。在优化的工艺条件下,浸出液中钛的水解率达到95%;偏钛酸产物具有锐钛矿晶型且结晶度较低;产物形貌为不规则的圆形球体颗粒及块状聚集体,具有一定程度的团聚现象;偏钛酸颗粒吸附有一定量的硫酸盐,经计算水解产物组成为TiO_(2)·0.7H_(2)O·0.08SO_(3)。

Metatitanic acid was prepared by controlled hydrolysis of the titanium component in the leaching solution of the roasted mixture of red mud and ammonium sulfate to recover titanium.Firstly,reduced iron powder was added as reducing agent to reduce Fe3+into Fe2+in the leaching solution.Then,the hydrolysis conditions were controlled,and the Ti4+in the leaching solution was hydrolyzed to synthesize metatitanic acid and was separated and recovered.The research results showed that the optimal hydrolysis conditions for the titanium component in the leaching solution were determined as follows:theoretical amount of the added reduced iron powder required for complete reduction of Fe3+into Fe2+,hydrolysis temperature of 140℃,hydrolysis time period of 4 h,hydrolysis ending pH of 2.0,and added titanium amount in the metatitanic acid seed of 9%of the total titanium content in the leaching solution.Under the above optimal process conditions,the hydrolysis efficiency of titanium in the leaching solution was reached as high as 95%.The metatitanic acid product had anatase crystal form and low crystallinity.The morphology of the product was irregular circular spheres with massive agglomeration to a certain extent.Since the metatitanic acid particle adsorbed a certain amount of sulfate,the calculated product composition was determined as TiO_(2)·0.7H_(2)O·0.08SO_(3).