METHOD OF DRY ENRICHMENT OF METAL AND NON-METAL MINERALS AND COUNTERFLOW JET MILL (VERSIONS) Russian patent published in 2010 - IPC B07B9/00 B02C19/06 B02C23/12 

FIELD: process engineering.

SUBSTANCE: set of invention relates to grinding and enrichment of metal and non-metal minerals and can be used in non-ferrous metallurgy and other industries where enrichment if required. Enriched materials consist usually of difficult- and easy-to-grind components. Proposed method comprises feeding gas, a power carrier, and initial stock into counterflow jet mill, selective grinding and enrichment of material in the mill chamber with unloading hard-to-grind lumps from the chamber via unloader, pneumatic grading in mill separator with return of coarse fractions into mill grinding chamber and with removing the mix of gas and finely-ground particles into settling device along with further cleaning of waste power carrier in dust separator. Said mix of gas and finely-ground particles is subjected to secondary grading before settling. In mill operation, feed of initial material is terminated, finely-ground material is subjected to re-grinding, and cleaned flow of difficult-to-grind particles is removed via coarse fraction chute. Then grinding and ejector chambers are cleaned of difficult-to-grind fractions. Proposed counterflow mill comprises loader, initial material feed and coarse fraction return chutes, ejector chambers with accelerating tubes, grinding chamber with unloader, riser pipe, separator, settler and dust separator. Mill comprises additional separator arranged ahead of settler, coarse fraction collector-divider with separation rib, coarse fraction collection hopper with chute and coarse fraction flow switch. In compliance with one version, coarse fraction collector-divider represents a rectangular section with vertical walls; coarse fraction unloading hatch is arranged above separating rib on front wall bottom part. In compliance with another version, coarse fraction divider represents extensible closed-space design with vertical walls. Rear wall of the latter receives the edge of common coarse fraction removal branch pipe and coarse fraction removal hatch is made on the divider front wall bottom part. In compliance with one version, coarse fraction switch is made up of two rectangular opposed plates arranged in inclined plane of collector-divider on rotation axles. Note here that top plate is secured at collector-divider rear wall top part, while lower plate is secured nearby unloading hatch to shut it off. Switch plate edges have shaped cutouts. In compliance with the other version, said flow switch represents a chute with its lower edge fitted on rotary axle nearby unloading hatch lower edge, while chute top edge can engage with common branch pipe edge when chute turn about rotational axis. Top parts of the chutes are jointed to the cover.

EFFECT: higher quality of enrichment and efficiency.

4 cl, 3 dwg, 2 ex