《Laboratory Studies on the Preparation Procedures of Alumina Converted from Aluminum Citrate》.pdf

1832 Ind. Eng. Chem. Res. 2010, 49, 1832–1836 Laboratory Studies on the Preparation Procedures of Alumina Converted from Aluminum Citrate Zhanglong Yu,† Yajing Lv,‡ Yongmei Chen,*,† and Pingyu Wan*,† School of Science, Beijing UniVersity of Chemical Technology, Beijing 100029, People’s Republic of China, and School of Physics and Chemistry, Xihua UniVersity, Chengdu 610039, People’s Republic of China It is a promising technology in the alumina industry using citric acid to extract aluminum from clay or kaolin and obtain the solution of aluminum citrate (AlCit). But the prerequisite of the preparation procedure of alumina started from AlCit is that citric acid should be recycled. A process named AlCit-Dawsonite-alumina is proposed in this paper. By using Dawsonite as an intermediate, citrate groups could be separated and reused. The process was verified in laboratory scale: First, Dawsonite was precipitated from AlCit solution with a satisfied purity and conversion rate. Second, Dawsonite was transformed to alumina with low Na content through the two proposed methods. The structure and purity of the intermediate of Dawsonite and products of alumina were characterized by infrared, thermogravimetric-differential thermal analysis, X-ray diffraction, scanning electron microscopy, and inductively coupled plasma. The results show that the synthesized Dawsonite has a great purity and perfect crystallinity; and the Na content of the final alumina product is lower than 0.2%. 1. Introduction instead of Al O ,