沉淀-煅烧法制备锡酸镧

以La（NO）3·6H2O和Na2SnO3·3H2O为原料，分别采用直接沉淀法和氨水沉淀法在室温下制备锡酸镧 （La2Sn2O7）的前驱体产物。对直接沉淀法所得前驱体产物进行热重分析，并对该前驱体不同温度下的煅烧产物进行X射线衍射（XRD）分析，确定最佳煅烧温度为850 ℃，再在此温度下煅烧前驱体制得La2Sn2O7。XRD和扫描电子显微镜（SEM）结果表明，直接沉淀-煅烧法和氨水沉淀-煅烧法制备的La2Sn2O7均为立方晶体结构；采用氨水沉淀-煅烧法，当pH=12时和直接沉淀-煅烧法所得前驱体煅烧产物均为直径约50 nm的类球状颗粒，且颗粒之间基本无团聚。

Preparation of lanthanum stannate by precipitation-calcination method

Precursor of lanthanum stannate（La2Sn2O7） was prepared by direct-precipitation method and ammonia sedimenta- tion method respectively，with La（NO）3·6H2O and Na2SnO3·3H2O as main raw materials.The precursor obtained by direct- precipitation method was tested by thermo-gravimetry analysis and was calcinated at different temperatures，then the corre- sponding calcinates were tested by X-ray diffraction（XRD） and the optimum calcination temperature（850 ℃） was confirmed. La2Sn2O7 was obtained by calcinating the precusor at 850 ℃.XRD and scanning electron microscope（SEM） results showed that all target products obtained by the above two methods were cubic crystal structure La2Sn2O7.When the pH=12，the target products obtained by ammonia sedimentation-calcination method and the products prepared by direct-precipitation-calcination method were spherical particles with diameters of about 50 nm，moreover，there were no obvious agglomeration between the particles.