含钛高炉渣浸出液中钛的协同萃取分离工艺及机理研究

Synergistic extraction separation process and mechanism of titanium from leaching solution of titanium-bearing blast furnace slag

钒钛磁铁矿在高炉冶炼过程中产生大量的冶炼渣,该冶炼渣的钛含量达20%~30%,对钒钛磁铁矿或冶炼渣中的钛资源进行资源化利用一直是重要的研究课题。本文借鉴浸出-萃取提钛工艺,针对已有的萃取体系萃取平衡时间长、钛萃取率低、设备易腐蚀、水相和有机相分相困难等问题,先将机械活化后钒钛磁铁矿高炉渣进行盐酸浸出,然后采用磷酸三丁酯(TBP)与二(2-乙基己基)磷酸(P204)组成的协同萃取体系(稀释剂为磺化煤油)对浸出液中的钛进行萃取试验。试验考察了萃取剂总浓度、萃取温度、萃取相比(O/A)、萃取剂TBP和P204的物质的量的比、氯离子浓度等因素对钛萃取率的影响,同时采用斜率法对萃取机理进行了初步的探究,得到如下结论:在萃取剂物质的量比TBP∶P204=1∶4、萃取时间20 min、萃取温度30℃、萃取相比(O/A)1∶1、氯离子浓度8 mol/L等较佳萃取条件下,钛萃取率可达到98%以上;斜率法研究萃取机理表明,萃合物组成可能为(TiOCl_(2))(HA)_(2)(HB)_(2),其萃取化学反应式可以改写为:TiO^(2+)+2HA+2HB+2Cl-→(TiOCl_(2))(HA)_(2)(HB)_(2)。

Vanadium titanium magnetite produces a large amount of smelting slag in the blast furnace smelting process,and the titanium content of the smelting slag reaches 20%~30%.The resource utilization of vanadium titanium magnetite or titanium resources in the smelting slag has always been an important research topic.In the present work,we referred to the titanium leaching-solvent extraction process.In view of the problems of the existing extraction system,such as long extraction equilibrium time,low titanium extraction rate,equipment corrosion,difficulty in separating aqueous phase and organic phase,the mechanically activated vanadium titanium magnetite blast furnace slag is first leached with hydrochloric acid,then,a synergistic extraction system consisting of tributyl phosphate(TBP)and di(2-ethylhexyl)phosphoric acid(P204)was used(with sulfonated kerosene as the diluent)to extract titanium from the leaching solution.The experiment investigated the effects of the total concentration of extractant,extraction temperature,extraction ratio(O/A),the ratio of extractant TBP to P204,and the concentration of chloride ions on the titanium extraction rate.At the same time,the slope method was employed to preliminarily explore the extraction mechanism.The following conclusions were obtained:under optimal extraction conditions such as chloride ion concentration of 8 mol/L,at the ratio of extractants TBP:P204=1:4,extraction time 20 minutes,extraction temperature 30℃,extraction ratio(O/A)1:1,the titanium extraction rate can reach over 98%.The slope method study on the extraction mechanism shows that the composition of the extract may be[TiOCl_(2)][HA]_(2)[H]_(2),and its extraction chemical reaction equation can be rewritten as:TiO^(2+)+2HA+2HB+2Cl-→[TiOCl_(2)][HA]_(2)[H]_(2).