Abstract: A method is described for mixing a difficult to wet, finely divided powder, e.g. alumina dust, with an aqueous liquid, e.g. Bayer process spent liquor. In the method, the liquor is introduced into a cylindrical mixing zone having a conical bottom zone, the liquor being continuously introduced into the mixing zone as a high velocity stream tangentially immediately above the conical zone to thereby form a rapidly moving vortex within the mixing zone. The dust is caused to fall into the center of the vortex whereby the dust is rapidly engulfed by the liquor with little or no dusting. The thus formed slurry is continuously removed from the bottom of the conical zone and may be processed through a classification circuit, to be separated as fine seed and returned to the precipitation circuit where the fine particles are agglomerated and grown to larger particles of alumina by contact with Bayer process pregnant liquor.