Abstract: Shake flask test and process test were made on desilication by bacteria leaching using five types of silicate bacteria and five ore samples containing different kinds of silicate minerals (including run-of-mine bauxite ore and artificially mixed ore).The shake flask test results indicate that the five types of bacteria can all well leach out the silicon in the samples with JXF-1 bacterium having the best desilication effect; and the bacteria existence environment and the crystal lattice structure can affect the silicon leaching effect.The process test results show that the continuous leaching process has an evidently better silicon leaching efficiency than that of shake flask and semi-continuous process, and can shorten the leaching time by four days.Using JXF-F as leaching bacterium, Ashby medium mineral salt substrate containing 2% sucrose as bacterial medium solution and leaching solution, the continuous leaching process can obtain concentrates with the silica-aluminum ratio being 12.53 and 17.74 respectively from the run-of-mine ore and artificially mixed ore containing chlorite, with the silicon leaching rate being 70.1% and 83.6% respectively.

Key words: Bauxite, Silicate bacteria, Silicate minerals, Bacterial leaching, Shake flash test, Continuous leaching process