Rectorite is a kind of rare clay mineral. In this work, the sorption of Cu(II) on Ca-rectorite and the effects of static magnetic fields on the sorption have been studied. The results from this study indicated that (1) apparent equilibrium for the sorption of copper onto Ca-rectorite is attained within the first hour; (2) magnetic treatment enhances the potential of Ca-rectorite suspensions in the absence of Cu and reduces that of the suspension in the presence of Cu; (3) magnetic treatment promotes the sorption of Cu onto Ca-rectorite, especially at low Cu concentrations; (4) the effects of static magnetic fields decrease the pH of Ca-rectorite suspensions whether they contain copper or not. The effect mechanisms of static magnetic field on the sorption of Cu onto Ca-rectorite were discussed. (C) 2004 Elsevier Inc. All rights reserved.