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用掺杂稀土的方法制成了抗热冲击的氧化铝载体。研究了稀土在氧化铝中掺入深度对阻滞氧化铝相变、延缓烧结和生成低表面积化合物的效应。对十种稀土的效应进行了比较。提出一种分两步掺杂的技术,可获得甚为满意的结果,所制得的含镧氧化铝在1000℃热冲击2小时后仍为γ-相,1200℃热冲击2小时后仍为δ—相,而未掺杂的氧化铝在相应温度下分别为γ+δ-相和α-相。这类含镧氧化铝试样在800,1000,1200℃热冲击2小时后比表面积仍可达230,126,28米~2/克,而相应的未掺杂氧化铝分别为150,77,8米~2/克。对掺杂稀土的氧化铝的孔径分布、表面酸度、表面化学活性等作了综合考察,证明它和纯氧化铝没有明显的差异,故认为这类载体可能在催化剂制造工业中有广泛的适应性。
A rare earth-doped method was used to produce a thermal shock resistant alumina support. The effects of rare earth incorporation depth in alumina on retardation of alumina phase transformation, delayed sintering and formation of low surface area compounds were investigated. The effects of ten rare earths were compared. A two-step doping technique is proposed to obtain very satisfactory results. The obtained lanthanum-containing alumina is still γ-phase after being thermally shocked at 1000 ° C. for 2 hours and remains at δ-phase, whereas undoped alumina is the γ + δ-phase and the α-phase, respectively, at the corresponding temperatures. Specimens of lanthanum-containing alumina at 800,1000,1200 ℃ thermal shock 2 hours after the surface area can still be up to 230,126,28 m ~ 2 / g, while the corresponding undoped alumina were 150,77,8 m ~ 2 / g. The pore size distribution, surface acidity and surface chemical activity of rare earth-doped alumina were comprehensively investigated to prove that it has no obvious difference from pure alumina. Therefore, it is considered that such carriers may have a wide range of adaptability in the catalyst manufacturing industry .