Centrifugation of solutions of yttrium in trace concentrations

The behaviour of trace quantities of yttrium (approximately 10-11 to 10-12 M) in aqueous solutions was investigated using centrifugation techniques at the radial acceleration 3500 g. The dependence of the fraction of separated 91Y on pH of the solution shows a pronounced maximum at pH 3.5 to 4.6, where the formation of largest pseudocolloidal particles occurs. At higher pH values the formation of smaller pseudocolloidal particles as well as the formation of the particles of the true colloid - the hydroxide 91Y(OH)3 may be assum ed while at pH<3.5 non-colloidal forms of 91Y may be expected. The paper is a continuation of previous communications on the study of trace quantities of 91Y in aqueous solutions. (author)