Operations, permitting to decrease iron losses in magnetic concentration by means of preliminary magnetic treatment of ore and processing products prior to separation, have been considered. The main magnetization curves J = f(H) and residual magnetization field relationship J_r = f(H) were measured on ballistic installation. It is shown that physical basis for superposed magnetization is available. Application of magnetic treatment is expedient with regard to magnetite ores of any material size, and is aimed at coarse particles recovery increase through magnetic susceptibility accommodation, as well as at additional recovery of small-size particles by using self-magnetic field of coarse particles. The apparatuses used for magnetic treatment differ from the previously known machines in magnetic system design and the method of magnetic forces action on treated material.