The major findings of an extensive laboratory investigation on the removal and use of hydrolyzable metals in foam separations are described in terms of the aqueous chemistry of the metals examined. These metals included iron(III), zinc(II), copper(II) and lead(II) and the surfactant collectors were lauric acid, sodium lauryl sulfate, stearylamine, and hexadecyltrimethyl ammonium bromide (CTAB). Aluminum sulfate was used as the coagulant for the sol studies with B. cereus, illite, and titanium dioxide. Solution and operating variables that were studied. Solution pH was found to be the single most important variable affecting the process. As compared to ion removal by foam fractionation or the colloid flotation of discrete particles, the precipitate flotation of condensed metal hydroxide or the microflotation of coagulated particles was found to be more efficient and much less dependent on most of the variables examined.