Verfahren zum Sintern,insbesondere von Dolomit

摘要

A material, such as dolomite or magnesite, is sintered in an oil- or gas- fired shaft furnace by passing the material down the furnace through a calcining zone, a sintering zone and a cooling zone. The material is subjected to the action of gases flowing in counter-current to the material in the calcining zone, is sintered in the sintering zone by gases flowing in co-current, and is cooled in the cooling zone by gases flowing in counter-current. The exhaust gases are discharged from the lower end of the sintering zone while cooling air discharged from the upper end of the cooling zone is extracted from the furnace and is reintroduced therein together with fuel at the lower end of the calcining zone to provide the gases required to calcine the material. A fuel gas-air mixture containing substantially no exhaust gas is introduced into the upper end of the sintering zone and, depending on whether the fuel gas-air mixture contains an excess of oxygen or fuel, additional fuel or air is introduced into the material in the sintering zone so as to increase the combustion therein and heat the calcined material to the sintering temperature.