| To obtain a better understanding of quartz and orthoclase activation, zeta potentials of the minerals were studied in the presence of metallic ions such as Mg^(++), Cu^(++), Zn^(++) and Al^(+++). A microelectrophoresis technique has been used to measure the zeta potential, and the results have been correlated with the hydrolysis of the metallic ions in the solution. The experimental results have led to the following conclusions. 1. Zeta potentials of orthoclase in the presence of the metallic ions show a similar behavior to those of quartz. 2. Adsorption of the metallic ions renders the zeta potential of quartz and orthoclase positive. The pH range of positive zeta potential varies with the kind of cation. 3. Zero point of charge(ZPC) of the mineral surface in the presence of metallic ions appears at two different pH of solution. One of two pH of ZPC is consistent with the pH at which M^(II)(OH)^+ and M^(III)(OH)^+_2 or M^(III)(OH)^(++) species are predominant. 4. Comparison of the zeta potential data with the hydrolysis for Mg(II), Cu(II), Zn(II) and Al(III) species suggests that Mg^(++), Cu^(++), Zn^(++) and Al^(+++) are only weakly adsorbed at the mineral surface and that M^(II)(OH)^+ and M^(III)(OH)^+_2 or M^(III)(OH)^(++) are the main metallic ionic species adsorbed. |
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