Dry grinding system for preparing iron ore for an agglomerating process

Abstract

Abstract A dry grinding system is disclosed for preparing iron ore for a process in which the ore is formed into waterbound agglomerates and then dried and heat hardened to provide agglomerates with sufficient degradation resistance to withstand handling and shipment. The system includes a separator for receiving about minus 3/8 inch iron ore particles which may be at ambient temperature and dividing it into a fraction containing fines and dust of about minus 325 mesh and a fraction of plus 325 mesh and minus 3/8 inch material. The system also includes a rotary dryer and conveying means that deliver the plus 325 mesh-minus 3/8 in fraction of material from the separator to the dryer where such material is dried to a moisture content of about 0.5%. A dry operating grinding mill is provided and a second conveying means delivers the ore from the dryer to the mill where such material is reduced to about minus 325 mesh and discharged into a third conveying means for delivery to agglomerating apparatus. A fourth conveying means is connected to separator to receive the dust and fines fraction and bypass the dryer and mill, and discharge such material into the third conveyor means to mix with and cool the discharge from the mill to reduce a tendency of the mill discharge to steam and evaporate water therefrom when water is added thereto for making the waterbound agglomerates. The second conveying means may include in series flow relation a second conveying means may include in series flow relation a second separator followed by a concentrator with the concentrator separating iron values from tailings which are discharged from the second conveying means. The second separator removes dust and fines generated in the dryer and has an outlet for such material connected to a fifth conveying means, discharging such fines and dust from the second separator directly into the fourth and mill bypassing conveying means for later remixing in the third conveying means with concentrate discharged from the mill.

Inventors

• 👤 Chester A Rowland Jr

Bibliographic Details