Effect of NH_4F and Nano-SiO_2 on Morphological Control of α-Al_2O_3 Platelets via Solid-state Reaction

Alpha-alumina(α-Al_2O_3) platelets were prepared via solid-state reaction using pseudo-boehmite as the starting material, while NH_4F and nano-SiO_2 were used as additives, and nitric acid was used as the binder. The effect of these additives on properties of the alumina platelets was determined via scanning electron microscopy, X-ray diffraction, and measurements of the surface area and silicon content. A mechanism governing their role in the synthesis process was proposed. The results indicated that NH_4F could promote the formation of highly crystalline platelets. Addition of nano-SiO_2 could lead to increase in the diameter and reduction in the thickness of the platelets, and could also prevent their transformation to α-Al_2O_3. This addition weakened the effect of NH_4F because of the reaction of nano-SiO_2 with F-species and the formation of volatile SiF_4.

催化剂离子交换洗涤和过滤工艺的关联因素探索

研究了催化剂生产过程中过滤洗涤设备更新以及水洗工艺优化情况,并将实施效果与前期产品各项质量数据进行对比。结果表明,设备更新以及优化工艺后,催化剂产品的杂质离子含量、产品活动及稳定性均有不同程度的改善;同时,在洗涤过滤设备更新后,装置生产运行周期大大延长,确保了整个生产过程的稳定性,对催化剂产品的稳定控制具有积极作用。