The article presents the results of study of magnetic properties of individual magnetic mineral grains and floccules, formed of such grains. It is shown that discrepancy between theoretical models and experimental results is caused by the lack of data on individual properties of separated particles, kinetics and dynamics of interparticle interactions. A brief description of an installation, that permits to carry out comprehensive studies of magnetic characteristics of individual mineral grains, is presented. The obtained measurements of magnetic characteristics of single grains of different size permitted to explain why with sufficient contrast of magnetic characteristics between metallic and non-metallic minerals, tailings and middlings of different stages of magnetic separation contain liberated grains of magnetite, that theoretically should not be there. It is shown, that one of the obvious reasons is considerable dispersion of magnetic characteristics even for a narrow fraction of minerals, by which «theoretically strongly-magnetic» minerals easily get together with intergrowths into tailings and middlings due to specialties of their structure and on account of magnetic characteristics that are comparable with characteristics of low-grade intergrowths. The results of measurements of magnetic characteristics of mineral particles of different size, that permitted to obtain relationships between magnetic characteristics of floccules and particles forming floccules, are presented. The obtained relationships and character of their dependence on size indicate that the two formations (particle and floccule), participating in magnetic separation process, possess their own parametric characteristics, that earlier were not taken into account in model building and development of applicable devices. The results of the studies indicate that in analysis of magnetic separation processes it is necessary to take into account the circumstances under which the objects participating in separation (whether that be particles or floccules), possess a wide range of magnetic characteristics, determining trajectory of their motion, and motion itself is determined by their individual properties. Consequently, in development of new designs of separators and magnetizers, and calculation of their magnetic systems (field intensity and topography), it is logical to proceed not from a certain average characteristic, e.g., magnetic susceptibility of a certain material, but from actually existing dispersion of real magnetic characteristics of separated minerals.

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