Process for pelletizing limestone fines

摘要

A process for pelletizing limestone or other fines into pellets, having controlled properties of hardness and liquid dispersion, by the addition of a suitable binder and water to form a cohesive plastic mix and by extrusion at relatively low pressures through a plurality of orifices in a specially designed die plate. The orifices in the plate are of a predetermined length relative to the thickness of the die plate. Each orifice in the die plate is formed at the inlet end thereof with a compacting zone in which the mix is compacted as it enters the orifice, a zone in which the mix is subjected to a damped flow and high longitudinal stresses, and a zone on leaving the orifice so as to effect microstructure cracks in the surface of the extruded product. The product is vibrated or tumbled for breaking at the surface cracks therein into pellets of a substantially uniform size and is subsequently dried under controlled temperature and time conditions in order to enhance hardness and dispersibility characteristics.