SEMI-SELF-GRINDING OF PRIMARILY FERROMAGNETIC STOCK Russian patent published in 2014 - IPC B02C19/00 B02C13/00 

FIELD: process engineering.

SUBSTANCE: invention relates to grinding of ferromagnetics and can be used in processing of magnetite and sulphide ores containing magnetite, pyrrotine, that is, minerals with high magnetic susceptibility. This method consists in application of at least one electromagnetic system S configured in circuit "electromagnet-diametrically located electromagnet". At use of several electromagnetic systems S (at S>1), these are arranged in helical line with the shift over drum cylindrical surface. Said drum rotates at n=20D^-1/2, where n is mill drum rpm, D is drum diameter, m, drum electromagnets excite magnetic pulses there inside. Note here that at displacement of electromagnets from 0° making the origin of angular coordinates at intersection of horizontal diameter left end with the drum to 30-50° to ensure increase in fall speed of ferromagnetic lumps at acceleration a, to be summed with gravity acceleration g. Magnetic pulses in the drum are eliminated in sector from 30-50° to 70-110° to resume the motion of balls and stock grinding by abrasion and crushing. Magnetic pulses are excited in section from 70-110° to 180° to trap ferromagnetic stock to be lifted to 180°. Magnetic pulses in the drum are eliminated in sector from 180-0° to deliver stock by friction and inertia to coordinate 225-226°. Another portion of stock is accelerated by magnetic pulses in sector of electromagnets of 0° to 30-50°, electromagnets being transferred the mill right to left. Horizontal components h of acceleration make ferromagnetic lumps crush the stock at <90° and move over lining of the pole and stock layer formed earlier.

EFFECT: higher efficiency of grinding.