The flotation of dickite from quartz using sodium oleate as a collector has been investigated. When the mixture of dickite and quartz coarser than 5 mu m is preconditioned in diluted HCl solution, dickite can be selectively floated from quartz at pH about 7. After diluted HCl preconditioning, not only the aluminum displaced from the dickite lattice is released to the solution, but also the active sites are created on the dickite surface, playing an important role in selective activation of dickite. In this case, the concentration of aluminum in the preconditioning solution is so low that quartz is not activated. It is ascertained that chemisorption of oleate increases with diluted HCl preconditioning.