氧化镧对γ-Al_2O_3高温比表面积的影响

Influence of Lanthana on Specific Surface Area of γ-Al_2O_3 at High Temperature

为解决γ-Al2O3在高温条件下的热稳定性问题,在实验室模拟工业条件,主要从La2O3,γ-Al2O3的制备方法对γ-Al2O3的热稳定性影响进行研究.研究发现以[La(EDTA)]-为浸渍液时,[La(EDTA)]-组分的适量添加可抑制高温下γ-Al2O3比表面积的下降和向α相的转变,从而提高活性氧化铝的热稳定性,使氧化铝在高温下保持较大的比表面积.添加1%[La(EDTA)]-的样品在1 200℃焙烧10 h其比表面积达61.34 m2/g.此外,还研究了以La2O3为添加剂对γ-Al2O3样品热稳定性的影响,发现La2O3的添加未能提高样品的热稳定性.

The thermal stability of γ-Al2O3 at high temperature was studied and simulated industrially in lab, focusing mainly on the influence of the preparation of La2O3 and γ-Al2O3 on the thermal stability of γ-Al2O3. It was found that when using [La（EDTA）]^- as liquid impregnant, keeping properly its concentration can suppress both the reducing specific surface area of γ-Al2O3 and its transform trend towards α-Al2O3 at high temperature, thus improving the thermal stability of γ-Al2O3 to keep its specific surface area bigger. For instance, specific surface area of the samples in which with 1% [La（EDTA）]^- roasted at 1 200 ℃ for 10 h is up to 61.34 m^2/g. Furthermore, the influence of La2O3 as an additive on the thermal stability was studied and the result showed that such an additive fails to improve the thermal stability of γ-Al2O3.