GB819219A - Sintering process and apparatus - Google Patents

Abstract

819,219. Sintering ores. HUNTINGDON HEBERLEIN & CO. Ltd. March 10, 1958 [Dec. 10, 1956], No. 37658/56. Class 82(1) In a process of sintering ores comprising depositing on a hearth a first layer of raw ore mixed with fuel, depositing on it a second layer of return fines mixed with fuel, igniting the layers anc drawing air downwardly through them, the layers be ing of substantially equal depth, the first layer em bodies such a smaller proportion of fuel than the second layer that the ignition of the layers and the drawing of air downwardly there through causes substantially complete sintering of the second layer and either substantially complete calcining of the first layer or partial sintering and partial calcining of such layer and the treated materials from both layers are subsequently screened together to give sintered ore on the screen and a finer product of substantially calcined ore and sinter fines through the screen which constitute return fines for the second layer. The proportion of fuel in the first and second layers is preferably 1 and 4 per cent, respectively, the depth being preferably approximately 15 cm. The raw ore of the first layer may include particles larger than the screen mesh to form an oversize fraction on the screen and in the upper portion of this layer the ore may be sintered. Suitable sintering apparatus comprises a straight-line sintering machine 10 with an endless travelling sinter-band, a first bin system 27, 28 for containing raw ore and solid fuel, a second bin system 29, 30 for containing return fines and solid fuel, conveyers 32 for delivering raw ore and fuel from the bin system 27, 28 and return fines and fuel from the bin system 29, 30 through mixers 12, 13, having spouts 16 and 17, to the upper run 11 of the sinter band constituting the hearth to form first and second layers 14, 15, respectively, means 31 for apportioning less fuel to the layer 14 than the layer 15, feed gates 18, 19 to ensure substantially equal depth of the layers a screen 35 to receive the treated materials therefrom, conveyers 36, 37 to deliver material thereoff and therethrough, respectively to a blast furnace (for example) and to the bin 29 for return fines. Between the band and the screen 35 is a crashdeck 33 and a sinter breaker 34 A hood 21 may be used, after an igniter 20, to apply hot or flaming gaseous medium to the materials on the hearth beneath which is one or more suction boxes 22 connected by a duct 23 to one or more exhaust fans 24. Instead of a straight line sintering machine use may be made of pan sintering apparatus or a rotatable table sintering machine, the latter of which has means for lateral discharge of the materials to a crash deck and screen. In pan sintering the pan is tipped to discharge the materials, so that the treatment is not continuous. The mixers deliver by conveyers to elevated hoppers periodically emptied into two travelling feed hoppers embodied in a wheeled charging car therebeneath to feed the pan to form two layers, through roll feeders by moving the car in opposite directions. After the charging car is moved away a travelling igniter is brought over the pan for ignition of the materials on the hearth under the suction of a fan. On completing the process, the sinter is tipped through a breaker and screen and dealt with as stated above.