Potassium ferrites of KFeO 2 and K 1+ xFe 11O 17 systems ( x = 0–1): Studies on leaching behavior in fused iron catalysts

• Published in: Journal of solid state chemistry Vol. 87; no. 2; pp. 264 - 273
• Main Authors: Fan, Li, Wen-Xiang, Wang, Qi-Kun, Han, Ling, Wang
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 1990
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/0022-4596(90)90028-V

Two series of potassium ferrites, KFeO 2 and K 1+ x Fe 11O 17 ( x = 0–1), were prepared by several methods and their leaching process was studied. Because of its structural characteristics, KFeO 2 can be easily hydrolyzed and its structure can be completely destroyed during leaching in water, whereas for K 1+ x Fe 11O 17 only a portion of the potassium ions shifts out of the system and its structure still remains after soaking in water. The kinetic parameters for potassium leaching from the K 1+ x Fe 11O 17 system have also been determined. It is suggested that both types of potassium ferrites coexist in fused iron catalysts for ammonia synthesis: KFeO 2 occurs at boundaries, while K 1+ x Fe 11O 17 mainly remains in the crystal grains of the catalyst. The former belongs to the so-called soluble and the latter to the insoluble potash of the catalyst. The catalytic activity largely depends on the latter.