Roasting fine grained limestone to produce roasted lime - by hot compacting roasted fine grains before tempering to complete roasting

摘要

Heat treatment of fine grained material, esp. for producing roasted lime from fine grained limestone, consists of preheating the fine grained material in a cyclone type heat exchanger using the off-gases of a fluidised bed calcinator, roasting in the calcinator, cooling in a first stage, hot compacting the fine material, and then holding in a tempering stage in the gas permeable but compacted form for an adjustable time period. Pref., the temp. at the tempering stage corresponds to that in the fluidised bed calcinator. After compaction the agglomerate is subjected to mechanical working and the fine particles sieved off returned to the hot compacting stage. After tempering a second cooling stage is carried out. ADVANTAGE - The product is converted from a soft roasted highly reactive phase to a hard roasted material which has a low reactivity corresp. to a T60 value of 4-8 min. The fusal product is homogeneous over the total grain spectrum.