“…Since ferroimpurities in the main mass have ferromagnetic properties, method of their magnetic control, assuming separation of ferro impurities from a sample of the analyzed medium and possible subsequent analysis, for example, microscopy (in ferrography [3][4][5][6]), is preferable. At the same time, to carry out objective monitoring, in particular, determining the content of ferroimpurities (as a rule, highly dispersed), a necessary condition for such monitoring is to conduct multiple extraction operations [1,7] (unlike ferrography, where it is assumed a single pass of the sample through the magnetophoresis zone). The question of the recommended (for the achievement of the necessary accuracy of control) multiplicity of magnetic control operations, or rather, validity of the very statement of this question and search for acceptable solutions was specifically discussed in [7].…”