GB1102153A - Pellet manufacture and apparatus therefor - Google Patents

Abstract

1,102,153. Moulding pellets. F. O. WIENERT. 29 March, 1966 [2 April, 1965], No. 13722/66. Heading B5A. Rounded pellets are produced from a mixture of particulate material e.g. hematite ore, chromite ore, magnetite ore and ore concentrates, ilmenite, alumina, silica-alumina mixtures, iron oxide-silica-carbon mixtures, limestone, and magnesia, with a liquid e.g. oils, thin tars, resins or water, which may contain a binder e.g. sodium silicate, clay, bentonite, starch, glue or cellulose derivatives, which mixture is deposited from a hopper 24 on to an endless continuously moving horizontal rubber belt 11 which is backed, under the upper span 14 thereof, by spring plates 26, 27, vibrated by electromechanical devices 33, 35, which assist compaction of the mixture in a plurality of die holes 23 provided in the belt 11 and into which the mixture is forced by mechanical fingers or pins (not shown) or a die filling means comprising a pair of blades 38 extending transversely to the belt 11 between side plates 40; the belt 11 with filled die holes 23 passes on the lower span 15 thereof, over a resiliently mounted and vibrated supporting grid 61 which is provided with longitudinally extending slots (64) (Fig. 2, not shown), over the area of the die holes so that air, steam, nitrogen or CO 2 pressure, which is independently maintained in a series of transversely extending compartments in a head 46 maintained in sealing contact on the upper side of the belt 11, forces the moulded pellets through the grid 61 on to an inclined table 67 which is longitudinally reciprocated and is provided with a series of longitudinally extending grooves 71 which register with the slots (64) and into one end of which the same or a different dry particulate material is distributed from means (83) whereby the pellets which are still in a plastic condition are rounded in passing along the table to a receptacle (73) at the other end thereof and may also pick up a coating of the particulate material. A lighter coating results if warm air is blown across the table (67) through a nozzle (75) and, where a thicker coating is desired, a liquid is sprayed on to the table through a nozzle (76) on to which finely divided material is also deposited from a vibrating screen (77). Excess liquid exuding from the material compacted in the die holes may be removed by means (not shown). The reciprocated table (86) (Fig. 3, not shown) may be disposed at 90 degrees to the belt with gas pressure hood (88) angularly disposed. The die holes may be tapered (Fig. 4, not shown) or may be lined with silicone rubber or a fluorocarbon polymer (Fig. 5, not shown) to facilitate release of the pellet. The pellets may be rounded in an inclined rotating drum or disc pelletizer instead of on the reciprocating table.