Abstract:With rapid developments of Chinese economy,the need for alumina becomes urgent as well。But barren bauxite resources, especially less high-quality bauxite resources limit the aluminium industry in China greatly。An A/S of 5.8 bauxite sample from Henan Province was chosen as the subject for the test. After systematic study on it, an efficient reagent system was work out, including dispersant BK500, selective depressant BK501, selective collector for alumino-silicate BK421. A qualified concentrate can be obtained of recovery(Al₂O₃) 81.20%,A/S 10.82 after twice desiliming and desilicating by reverse flotation.