| 摘要 |
This invention relates to a method for dry concentration of metal in a metal containing ore, a concentrate separated therefrom or slag, in which method the ore, the ore concentrate or the slag batch is fed to a pressurized feeding device of a counterjet grinder and fluidized by means of a working gas flow, the fluidized gas-solids mixture is accelerated by means of pressure via two mainly oppositely directed acceleration nozzles to a grinding chamber, whereby the fragile mineral or slag material portion of the solids particles colliding with each other decomposes and loosens from poorly grinding metal-containing particles, and the produced pulverized gas-solids material mixture is immediately led by means of an overpressure prevailing in the grinding chamber (12) of the counterjet grinder to a centrifugal classifier (13), in which the metallically poor fine fraction is removed from the classifier via an axial opening (13a) and the metallically rich coarse fraction is returned to the feeding device (3) of the counterjet grinder for recirculation. The invention is characterized in that the recirculation is repeated, until a desired portion of the inital weight of the ore, ore-concentrate or the slag batch has left the centrifugal classifier (13) as fine fractions, whereby the metallically rich coarse fraction left in the equipment is led via a product removal opening (15) to a next refining step. |
