钙镁复合助熔剂对长平煤灰熔融特性影响研究
|
摘要
以高灰熔融温度长平煤为对象,分别向其中添加单助熔剂CaO、MgO和钙镁复合助熔剂,在高温还原性气氛下,分别利用X-射线衍射仪(XRD)、扫描电子显微镜-能谱仪(SEM-EDX)研究钙镁复合助熔剂对煤灰熔渣晶体矿物转化过程、微观形貌和微区化学组成的影响,揭示钙镁复合助熔剂的助熔机理。结果表明:添加6%钙镁复合助熔剂(WCaO/WMgO=1),可将煤灰熔融温度降至1297℃,且助熔效果优于单助熔剂CaO、MgO;煤灰熔融过程中,离子半径较小的Ca~(2+)、Mg~(2+)容易进入空隙中,引起硅酸盐结构重组,分别形成架状硅酸盐钙长石、岛状硅酸盐镁橄榄石、镁堇青石等;钙长石与镁橄榄石等镁质矿物之间低温共熔体的生成,是钙镁复合助熔剂能够显著降低煤灰熔融温度的主要原因。
Changping coal with high fusion temperature was selected,to which add CaO,MgO and compound flux. The mineral composition,surface morphology and micro-chemical composition were investigated under reducing atmosphere at high temperature by X-ray diffraction( XRD),scanning electron microscopy and energy dispersive X-ray spectroscopy( SEM-EDX),respectively. The results indicate that when the percentage of addition dosage of flux is 6% and the mass ratio of CaO to MgO is 1,the flow temperature of Changping coal ash could be reduced to 1297 ℃,and the efftce of improving fusibility is better than that of CaO and MgO supplementation alone respectively. In the coal ash melting process,Ca~(2+) and Mg~(2+) whose ionic radius is smaller could enter into interspace easilier,resulting in the structure of silicate recombining, then framework silicate anorthite and island-like silicate such as magnesium olivine,magnesium cordierite are formed. The formation of low-temperature eutectic between anorthite and magnesium olivine is the primary reason for calcium and magnesium compound flux could reduce coal ash fusion temperature remarkly.
Changping coal with high fusion temperature was selected,to which add CaO,MgO and compound flux. The mineral composition,surface morphology and micro-chemical composition were investigated under reducing atmosphere at high temperature by X-ray diffraction( XRD),scanning electron microscopy and energy dispersive X-ray spectroscopy( SEM-EDX),respectively. The results indicate that when the percentage of addition dosage of flux is 6% and the mass ratio of CaO to MgO is 1,the flow temperature of Changping coal ash could be reduced to 1297 ℃,and the efftce of improving fusibility is better than that of CaO and MgO supplementation alone respectively. In the coal ash melting process,Ca~(2+) and Mg~(2+) whose ionic radius is smaller could enter into interspace easilier,resulting in the structure of silicate recombining, then framework silicate anorthite and island-like silicate such as magnesium olivine,magnesium cordierite are formed. The formation of low-temperature eutectic between anorthite and magnesium olivine is the primary reason for calcium and magnesium compound flux could reduce coal ash fusion temperature remarkly.
引文
[1]于戈文,许志琴,邓蜀平.气化条件下煤灰熔融性研究[J].煤化工,2005,(5):27-31.
[2]张双全,吴国光.煤化学[M].徐州:中国矿业大学出版社,2009.
[3]袁海平,梁钦锋,刘海峰,等.Ca CO3对煤灰熔融特性和粘温特性影响的研究[J].中国电机工程学报,2012,(20):49-55.
[4]Kong L X,Bai J,Bai Z Q,et al.Effects of Ca CO3on slag flow properties at high temperatures[J].Fuel,2013,(109):76-85.
[5]范浩杰,何柯桂,刘俊杰,等.镁基助熔剂对高灰熔点煤灰熔融影响的机理[J].动力工程学报,2015,25(1):19-24.
[6]高峰,马永静.Mg2+和Na+对高熔点煤灰熔融性的影响[J].燃料化学学报,2012,40(10):1161-1166.
[7]陈晓东,孔令学,白进,等.高温气化条件下Na2O对煤灰中矿物质演化行为的影响[J].燃料化学学报,2016,44(3):263-271.
[8]王大川,梁钦锋,龚欣,等.添加助熔剂后朱集西煤灰熔融特性规律研究[J].燃料化学学报,2015,43(2):153-159.
[9]张子利.钙镁协同作用对煤灰熔融特性的影响研究[D].淮南:安徽理工大学,2013.
[10]辛宇.还原性气氛下钙镁对煤灰熔融性耦合作用机理研究[D].淮南:安徽理工大学,2016.
[11]刘象.煤灰成分对钙镁耦合降低煤灰熔融性的影响研究[D].淮南:安徽理工大学,2016.
[12]Eugene P Bertin.X-射线光谱分析导论[M].北京:地质出版社,1984.
[13]贺可音.硅酸盐物理化学[M].武汉:武汉理工大学出版社,2003.
[14]代百乾,乌晓江,陈玉爽,等.煤灰熔融行为及其矿物质作用机制的量化研究[J].动力工程学报,2014,31(4):70-76.
[2]张双全,吴国光.煤化学[M].徐州:中国矿业大学出版社,2009.
[3]袁海平,梁钦锋,刘海峰,等.Ca CO3对煤灰熔融特性和粘温特性影响的研究[J].中国电机工程学报,2012,(20):49-55.
[4]Kong L X,Bai J,Bai Z Q,et al.Effects of Ca CO3on slag flow properties at high temperatures[J].Fuel,2013,(109):76-85.
[5]范浩杰,何柯桂,刘俊杰,等.镁基助熔剂对高灰熔点煤灰熔融影响的机理[J].动力工程学报,2015,25(1):19-24.
[6]高峰,马永静.Mg2+和Na+对高熔点煤灰熔融性的影响[J].燃料化学学报,2012,40(10):1161-1166.
[7]陈晓东,孔令学,白进,等.高温气化条件下Na2O对煤灰中矿物质演化行为的影响[J].燃料化学学报,2016,44(3):263-271.
[8]王大川,梁钦锋,龚欣,等.添加助熔剂后朱集西煤灰熔融特性规律研究[J].燃料化学学报,2015,43(2):153-159.
[9]张子利.钙镁协同作用对煤灰熔融特性的影响研究[D].淮南:安徽理工大学,2013.
[10]辛宇.还原性气氛下钙镁对煤灰熔融性耦合作用机理研究[D].淮南:安徽理工大学,2016.
[11]刘象.煤灰成分对钙镁耦合降低煤灰熔融性的影响研究[D].淮南:安徽理工大学,2016.
[12]Eugene P Bertin.X-射线光谱分析导论[M].北京:地质出版社,1984.
[13]贺可音.硅酸盐物理化学[M].武汉:武汉理工大学出版社,2003.
[14]代百乾,乌晓江,陈玉爽,等.煤灰熔融行为及其矿物质作用机制的量化研究[J].动力工程学报,2014,31(4):70-76.
© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号 地址：北京市海淀区学院路29号 邮编：100083 电话：办公室：(+86 10)66554848；文献借阅、咨询服务、科技查新：66554700 |