GB994588A - Process and apparatus for fire-hardening pellets - Google Patents

Abstract

994,588. Sintering apparatus. METALLGESELLSCHAFT A.G. Feb. 7, 1963 [Feb. 12, 1962], No. 5073/63. Heading F4B. In apparatus of the Dwight-Lloyd type for burning cement or hardening ore pellets comprising the travelling grate 2 moving between windboxes 3 and a hood structure 4 arranged to produce an updraught drying zone 7, a downdraught drying zone 12, a preheating zone 21, a firing zone 24, an after-firing zone 28, an initial cooling zone 32 and a final cooling zone 33, a fan 40 supplies air to manifold 39 and windboxes in groups 34 and 35 and thence upwardly through zones 32 and 33, air from zone 32 passing along duct 17 and through ports 18 into zones 21, 24 and 28 to be utilized as secondary air, and another fan 52 exhausts hot gases from zone 28 and part of zone 24 through windboxes 26 and manifold 37b passing them along duct 54 to fan 55 which supplies them through manifold 36 and windboxes 11 upwardly into drying zone 7. Air from the final cooling zone 33, which may be diluted with cold air controllably supplied by pipe 49, is driven by fan 42 through pipe 44, first being diverted along pipe 45 and used as primary air in burners 16, 23 and 27 respectively disposed in drying zone 12, preheating zone 21 and firing zone 24. The remainder is supplied either to drying zone 12 along with diluting air supplied by fan 70, or to the inlet or outlet of an extractor fan 9 under control of one of valves 48. Waste gases from zones 21 and 24 are extracted by fan 60 through windboxes 15 and 22 and manifold 37a and discharged to flue 10 by pipe 62. The extent of manifolds 37a and 37b may be controlled by sliding dampers 38 and individual control of certain windboxes is afforded by valves 65. Some atmospheric air may be supplied by fan 57 to manifold 36 to cool the grate. In a modification, Fig. 2 (not shown), part of the air from zone 33 is re-circulated as cooling air below zone 32.