US 2014/0231555 A1 · METHOD FOR GRINDING MILL MATERIAL AND ROLLER MILL

Abstract

The invention relates to a method for grinding mill material and to a roller mill and is suited in particular to a finest grinding of relatively hard and dry materials, for example cement clinker and granulated blast furnace slag and also for relatively large roller mills. In order to avoid mill vibrations due to over-grinding of the mill material and to reduce the specific work requirement as well as increasing the throughput a fine material nozzle is arranged after each grinding roller, from which fine material nozzle an air jet with defined impulse is directed from above onto a fine material concentration zone. The fine material concentration zone is formed directly after the grinding zone of each grinding roller and is virtually free of supplied material to be ground and accumulated on a retention rim region. The fine material blown outwards and upwards is fed to a rising conveying air flow and subsequent classifying process.

Claims23

Dependent claims

Method for grinding mill material in a roller mill,

wherein mill material to be ground (5) is fed to a rotating grinding pan (2) provided with a retention rim (3) and is ground by means of stationary grinding rollers (4), which roll in a force impacted way on a grinding bed (6) formed by the supplied mill material (5), in a grinding zone (7) and
the ground material (5) is impacted after each grinding roller (4) with air from a nozzle-like device and fine material is blown out and fed to a conveying air flow (9) rising from a louvre ring (8) between grinding pan (2) and mill housing (19) and to a classifying process,
characterised in that
a fine material nozzle (10) is used as nozzle-like device and an air jet (11) with defined impulse is directed from above onto a fine material concentration zone (12) which is formed directly after the grinding zone (7) of each grinding roller (4) extensively free of supplied mill material (5) to be ground and accumulated on a retention rim region (13), and
the fine material (15) is blown out of the fine material concentration zone (12) with the aid of the air jet (11) from the fine material nozzle (10) and upwards into the rising conveying air flow (9).

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