METHOD AND SHAFT FURNACE FOR ROASTING OF LUMP MATERIALS Russian patent published in 1997 - IPC

FIELD: metallurgy, chemical and construction material industry. SUBSTANCE: method involves charging, heating, roasting and cooling lump material supplied in dense layer in countercurrency with fuel and air combustion product flow; intaking and supplying exhaust gases to lower level of fuel combustion devices. Cooling zone air is fed to upper level of combustion devices. Amount of supplied air is 0.2-0.4 of air supplied for cooling purposes. Amount of waste furnace gases supplied to lower level of combustion devices is 0.5-1.0 of air flow supplied for cooling purposes. Ratio of gas pressure in roasting zone at upper level of combustion devices and of air in cooling zone is (5-5-):1, and in roasting zone at lower level of combustion devices and downstream of exhaust fan is (2-10):1. Arcs 5,6 and 8 are mounted above combustion devices 7 and in lower part of furnace along its diameter. Arcs 6 are positioned adjacent to opposite furnace walls at distance of (0.35-0.45)D, where D is diameter of furnace shaft. Arc 5 is mounted along diameter of furnace at distance of (1.0-1.5)D from lower arcs 6. Width of arc 5 is (0.2-0.35)D. Arc 8 is positioned below arcs 6 at distance of (0.5-1.0)D from them. Upper combustion devices 7 and space below arc 8 are communicated through pipelines with branch pipes. EFFECT: increased efficiency, simplified method and improved quality of roasted product. 3 cl, 2 dwg, 1 tbl