摘要
研究了钒含量为１％～５％时高岭土的相变过程。结果表明，有钒存在时，高岭土在６６０～７００℃就出现钒－莫来石物相，比正常的莫来石石化温度低４００℃以上。钒－莫来石的反应可描述为钒－高岭土低温共熔体迁移过程。另外，低温钒－莫来石的晶胞体积明显大于常规莫来石的晶胞体积，由此推论，钒进入了莫来石的骨架结构之中，并因此被钝化。试验进一步研究了高岭土和改性高岭土（ＰＡＬ）基质与钒的相互作用，发现ＰＡＬ基质与钒作用，形成莫来石的时间早于稀土氢Ｙ沸石与钒作用形成钒酸稀土的时间。因此，可以认为，改性高岭土对沸石组分具有很好的保护作用。
The phase transformation of kaolin in the presence of 1% to 5% vanadium was investigated. The result indicated that vanadium mullite emerged at 650 ℃ to 700 ℃ which was 400 ℃ lower than conventional mullite formation temperature. The reaction kinetics of vanadium mullite could be expressed as low melting vanadium kaolin eutetic transition. In addition, unit cell volume of the vanadium mullite was found to be larger than the conventional mullite, which could be deduced that vanadium incorporated into mullites' framework and was therefore passivated. Furthermore, the modified PAL kaolin reacted more fast with vanadium to form mullite than the reaction of REHY zeolite with vanadium to form rare earth vanadate, and therefore protected zeolite in cracking catalyst against the vanadium poisoning effectively.
出处
《石油炼制与化工》
CAS
CSCD
北大核心
1998年第11期1-5,共5页
Petroleum Processing and Petrochemicals
关键词
高岭土
钒
莫来石
裂化催化剂
原油
kaolin, vanadium, modification, cracking catalyst
