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在常压、温度435℃到530℃的条件下研究了A6型氨合成催化剂的还原。发现温度低于515℃时,A6型催化剂不可能全部还原,而只可能达到一个极限还原度。相应于435℃、490℃和515℃时的极限还原度是22％、82％和100％。 X光结构分析表明,未还原的催化剂是尖晶石结构,还原后是α-Fe。愈难还原的尖晶石部分其晶胞参数愈小。 在300大气压下对不同还原度的样品进行了活性试验,用T方程计算了反应速度常数。发现催化剂愈难还原的部分经还原后其比活性愈高。
The reduction of A6-type ammonia synthesis catalyst was studied at atmospheric pressure, temperature from 435 ℃ to 530 ℃. When the temperature was found to be lower than 515 ° C, it was impossible to reduce the A6 type catalyst completely, but only to reach an ultimate reduction degree. The limiting reductions corresponding to 435 ° C, 490 ° C and 515 ° C are 22%, 82% and 100%. X-ray structural analysis shows that the unreduced catalyst is a spinel structure and is reduced to α-Fe. The more difficult to restore the spinel part of the smaller unit cell parameters. The activity of samples with different reduction degree was tested at 300 atmospheres, and the reaction rate constant was calculated by T-equation. It was found that the harder to reduce the catalyst after reduction by the higher specific activity.