NiMgAl类水滑石制备条件研究

Study on Conditions of Synthesizing NiMgAl Hydrotalcite-like Compounds

采用共沉淀法合成了不同摩尔投料比的 NiMgAl 类水滑石化合物。测定了 Ni、Mg、Al 单盐以及不同摩尔比的混合硝酸盐溶液的滴定曲线,考察了加料方式、晶化温度、晶化时间、原料配比对类水滑石合成的影响。通过XRD、IR 对合成物进行表征,结果表明,在恒定 pH 值为8～9,n(Mg+Ni)/n(Al)=1～3,n(Mg)/n(Ni)=8～16,晶化温度为65℃,晶化时间6h 的条件下即得到晶相单一的 NiMgAl-HTLcs;随 n(Mg+Ni)/n(Al)的增加,类水滑石结构的规整性提高,n(Mg)/n(Ni)比增加,层间距略有减小。

NiMgAI hydrotalcite-like compounds with different Ni/Mg/Al molar ratios were synthesized by coprecipitation. The titration curve of simplex and the mixed solutions with different Ni/Mg/Al molar ratios were determined. The effects of precipitation method, crystallized temperature, crystallized time and Ni/Mg/Al molar ratio on the structure of NiMgAl-HTLcs were investigated. Then the synthesized compounds were characterized by XRD, IR The results showed that the pure NiMgAl-HTLcs phase can be obtained by constant pH method at the pH value ranging from 8 to 9,（Mg＋Ni）/Al molar ratio is 1 to 3, Mg/Ni molar ratio is 8 to 16 and crystallized temperature,and crystallized time is 65℃ and 6h respectively. It is also founded that the synthesized hydrotalcite-like compounds are more integrated with the increasing of （Mg＋Ni）/Al molar ratio and the interlayer-spacing decreased with the increasing of Mg/ Ni molar ratio.