学术论文

      硝酸钠对改善赤泥陶粒性能的影响

      Effect of sodium nitrate on improvement in the properties of ceramsite using red mud

      摘要:
      通过对赤泥化学组成、矿物组成和热稳定性分析,进行了以赤泥中方解石本身为发泡剂及外加硝酸钠为发泡剂制备陶粒的研究,并利用X射线衍射和扫描电镜对所得陶粒的组成和内部结构进行了分析.结果表明:在赤泥、废玻璃和膨润土质量比74∶15∶11时,利用赤泥中的方解石可制得容重、吸水率和筒压强度分别为1.43 g.cm-3、1.23%和22.14 MPa的陶粒.外加NaNO3发泡剂能明显降低陶粒的容重.在赤泥、废玻璃、膨润土和NaNO3质量比70.0∶14.2∶10.2∶5.6时,可制得容重、吸水率和筒压强度分别为1.28 g.cm-3、1.54%和12.03 MPa的陶粒.陶粒中晶体矿物主要为钙黄长石,而赤泥中主要晶体矿物为方解石.陶粒中气孔以封闭气孔为主,NaNO3为发泡剂时所得陶粒的气孔率较利用赤泥自身方解石为发泡剂时高,气孔均匀性也较好.
      Abstract:
      Based on analyzing the chemical composition,mineral composition and thermal stability of red mud,the preparation of ceramsite was investigated with calcite itself in red mud or added sodium nitrate as a foaming agent.Main components of the obtained ceramsite were analyzed by X-ray diffraction(XRD) and the internal structure was observed by scanning electron microscopy(SEM).The results show that with calcite itself as a foaming agent,the ceramsite with a bulk density of 1.43g·cm-3,a water absorption rate(WAR) of 1.23% and a cylinder compressive strength(CCS) of 22.14 MPa is prepared when the mass ratio of red mud/waste glass/bentonite is 74∶15∶11.However the bulk density is obviously decreased by adding sodium nitrate.The ceramsite with a bulk density of 1.28g·cm-3,a WAR of 1.54% and a CCS of 12.03 MPa is prepared when the mass ratio of red mud/waste glass/bentonite/sodium nitrate is 70.0∶14.2∶10.2∶5.6.Crystalline phases present in the obtained ceramsite are mainly gehlenite,different from calcite in red mud based on XRD data.SEM images indicate that the majority of pores in the obtained ceramsite are sealed,and when sodium nitrate is used as a foaming agent,the porosity is higher in comparison with calcite in red mud,and the internal pore size is more uniform.
      作者单位: 北京科技大学土木与环境工程学院,北京100083/北京科技大学金属矿山高效开采与安全教育部重点实验室,北京100083
      刊 名: 北京科技大学学报 ISTICEIPKU
      年,卷(期): 2011, 33(10)
      分类号: X758 TU523
      机标分类号: TU5 TM6
      在线出版日期: 2012年4月21日