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

摘要

A processing technology was developed for alumina extractionfrom Al dross with the calcining-leaching process. The aluminumdross was mixed with soda and sintered at 1173K to yield solublealuminates. Subsequently the sintered dross was leached withsulfuric acid to produce a solution containing aluminum.Theunwanted metal ions, including Fe~(3+) and Na~(+), were removed byethylene diamine tetraacetic acid (EDTA) and water washing.Then NH_4HCO_3, was added controlling the crystallization ofNH_4AlO(OH)HCO_3, and the drying and calcining process wascarried out, resulting in ultra fine Al_2O_3 powders with high purity.The characteristics of the Al_2O_3 powders were examined bymeans of XRD and SEM. The extraction efficiency of Al2O3 cansurpass 98% by optimization of the calcination and lixiviationprocesses. Well-dispersed fibriform Al2O3 powders were obtainedby calcining at 1000°C and the purity of the ultra fine Al2O3powders was more than 99.36%