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高Fe2O3含量对铁尾矿陶粒物相和 力学性能的影响
作者：秦晋一，李涵，李晓光，方姣，刘云霄
（长安大学 建筑工程学院，陕西 西安 710061）
摘要：通过对陶粒化学组分、性能指标和微观结构的研究表明：铁尾矿中Fe2O3可以降低陶粒烧结温度，促进晶相形成，但当Fe2O3超过一定阙值，Al2O3/SiO2和RO含量决定了陶粒中莫来石和辉石相的形成，对陶粒结构强度有着重要影响。差热分析表明，强度更高的陶粒中，不同晶相的形成发生在1140 ℃，属于放热反应。同时Fe2O3会被C还原产生气体，促进陶粒孔隙的形成，但是1160 ℃会使陶粒内部液相增多，填充在孔隙间成为封闭孔，使得陶粒强度更高、堆积密度更小。以陕南铁尾矿烧结最佳的烧结温度为1160 ℃，原材料配比为：m（铁尾矿）∶m（膨润土）∶m（铝矾土）=70∶20∶10，堆积密度为832 kg/m3，筒压强度为8.04 MPa。符合GB/T 17431.1—2010对900级陶粒的要求。
关键词：铁尾矿陶粒；Fe2O3；Al2O3/SiO2；莫来石相；烧结温度
中图分类号：TU55+1.3 文献标识码：A 文章编号：1001-702X（2019）07-0083-06
Effect of high Fe2O3 content on phase and mechanical properties of iron tailings ceramsite
QIN Jinyi，LI Han，LI Xiaoguang，FANG Jiao，LIU Yunxiao
（School of Civil Engineering，Chang'an University，Xi'an 710061，China）
Abstract：Based on the study of chemical composition，performance and microstructure characteristics of the ceramsite，the obtained conclusion is：Fe2O3 in tailings can reduce the sintering temperature and promote the formation of crystal phase. However，when the content of Fe2O3 is too much，the Al2O3/SiO2 and RO contents determine the formation of the mullite and pyroxene phases，which plays an important role in the ceramsite structure. Differential thermal analysis proves that in the higher strength ceramsite，different crystal phases are produced at 1140 ℃，which is an exothermic reaction. Meanwhile，Fe2O3 will be reduced by C to produce gas，which promotes the formation of ceramsite pores. However，at 1160 ℃，the internal liquid phase of ceramsite will increase，and the pores will become closed pores，resulting in higher ceramsite strength and lower density. The ceramsite sintered with the unique iron tailings in southern Shaanxi meets the requirements of Class 900 ceramsite according to GB/T 17431.1—2010. The sintering temperature is 1160 ℃ and optimal mass ratio is tailings∶bentonite∶bauxite=70∶20∶10，the ceramsite possesses bulk density of 832 kg/m3 and compressive strength of 8.04 MPa.
Key words：iron tailings ceramsite，Fe2O3，Al2O3/SiO2，mullite，sintering temperature