HIGH PURITY ALUMINA POWDERS EXTRACTED FROM ALUMINUM DROSS BY THE CALCINING LEACHING PROCESS

摘要

A processing technology was developed for alumina extraction from Al dross with the calcining-leaching process. The aluminum dross was mixed with soda and sintered at 1173K to yield soluble aluminates. Subsequently the sintered dross was leached with sulfuric acid to produce a solution containing aluminum The unwanted metal ions, including Fe~(3+) and Na~+, were removed by ethylene diamine tetraacetic acid (EDTA) and water washing. Then NH_4HCO_3, was added controlling the crystallization of NH_4AlO(OH)HCO_3, and the drying and calcining process was carried out, resulting in ultra fine Al_2O_3 powders with high purity. The characteristics of the Al_2O_3 powders were examined by means of XRD and SEM. The extraction efficiency of Al_2O_3 can surpass 98 by optimization of the calcination and lixiviation processes. Well-dispersed fibriform A_l2O_3 powders were obtained by calcining at 1000 and the purity of the ultra fine Al_2O_3 powders was more than 99.36%.