铬酸钡与硫酸氢钠固液反应制备重铬酸钠的过程强化
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摘要
铬铁矿液相氧化法可以得到铬酸钠和高浓度碱的混合物,前期研究表明,采用氢氧化钡可以较好地实现从高碱介质中分离铬酸根,形成铬酸钡中间体。然而,钡盐在传统的加热搅拌模式下转化制备重铬酸钠,存在反应过程时间长、效率低的问题。在分析铬酸钡固液反应控制步骤的基础上,研究了球磨搅拌反应模式对该固液转化反应过程的强化作用。系统考察了反应温度、时间、液固比(液固体积质量比)、料球比(物料和磨球的质量比)、物料配比(铬酸钡与硫酸氢钠的物质的量比)、固液混合速率对铬酸钡转化率的影响,并得到了较好的工艺参数:反应温度为180℃、反应时间为120 min、液固比为10 m L/g、料球比为2∶1、物料配比为1∶1、固液混合速率为50 r/min,在此条件下得到铬酸钡的转化率为93%。
A mixture of sodium chromate and high concentration alkali can be obtained by liquid phase oxidation of chromite.Previous studies have shown that barium hydroxide can be used to separate chromate from high alkali medium and form barium chromate intermediate.However,the conversion of barium salt to sodium dichromate in the conventional heating and stirring mode has the problem of long reaction time and low efficiency.Based on the analysis of the control process of solid-liquid reaction of barium chromate,the strengthening effect of the milling reaction mode on the solid-liquid conversion reaction was studied.The effects of reaction temperature,time,liquid-solid ratio(volume and mass ratio),material-ball ratio(mass ratio),reactant amount of substance ratio and solid-liquid mixing rate on the conversion of barium chromate was studied,and the better process parameters were obtained:reaction temperature was 180 ℃,reaction time was 120 min,liquid-solid ratio was10 m L/g,material-ball ratio was 2∶1,reactant amount of substance ratio was 1∶1 and solid-liquid mixing rate was 50 r/min.Under the optimal conditions,the conversion of barium chromate was 93%.
A mixture of sodium chromate and high concentration alkali can be obtained by liquid phase oxidation of chromite.Previous studies have shown that barium hydroxide can be used to separate chromate from high alkali medium and form barium chromate intermediate.However,the conversion of barium salt to sodium dichromate in the conventional heating and stirring mode has the problem of long reaction time and low efficiency.Based on the analysis of the control process of solid-liquid reaction of barium chromate,the strengthening effect of the milling reaction mode on the solid-liquid conversion reaction was studied.The effects of reaction temperature,time,liquid-solid ratio(volume and mass ratio),material-ball ratio(mass ratio),reactant amount of substance ratio and solid-liquid mixing rate on the conversion of barium chromate was studied,and the better process parameters were obtained:reaction temperature was 180 ℃,reaction time was 120 min,liquid-solid ratio was10 m L/g,material-ball ratio was 2∶1,reactant amount of substance ratio was 1∶1 and solid-liquid mixing rate was 50 r/min.Under the optimal conditions,the conversion of barium chromate was 93%.
引文
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[3]Zhang Y,Li Z H,Qi T,et al.Green manufacturing process of chromium compounds[J].Environ.Prog.,2005,24(1):44-50.
[4]张翊.亚熔盐法铬盐清洁工艺铬酸钾中间体钠盐转化工艺研究[D].天津:天津大学,2010.
[5]田颖,王学魁,高毅颖,等.响应面法优化钡盐转化法重铬酸钠的制备工艺[J].化工进展,2011,30(11):2388-2392.
[6]赵中伟,赵天从,李洪桂.固体机械力化学[J].湖南有色金属,1995,11(2):44-48.
[7]陈鼎,陈振华.机械力化学[M].北京:化学工业出版社,2008.
[8]Yuan T,Cao Q,Li J.Effects of mechanical activation on physicochemical properties and alkaline leaching of hemimorphite[J].Hydrometallurgy,2010,104(2):136-141.
[9]Kumar S,Kumar R.Mechanical activation of fly ash:Effect on reaction,structure and properties of resulting geopolymer[J].Ceramics International,2011,37(2):533-541.
[10]陈刚,陈鼎,严红革,等.固液反应球磨工艺[J].材料导报,2005,19(s1):222-224.
[11]Xiao T,Chen D,Ye C L.Preparation of Cu O nanopowders by ultrasonic solid-liquid reaction with ball milling[J].Journal of Synthetic Crystals,2010,39(3):633-637.
[12]陈鼎.固液反应球磨工艺及其原理研究[D].湖南:中南大学,2003:71-72.