Present situation and future outlook for burning fine-grained limestone

The pressure for continuous improvement in productivity has made the burnin g of fine-grained limestone a major challenge for kiln systems. Traditional ly the rotary kiln is at an advantage here, but the parallel-flow regenerat ive (PFR) kiln operated with small-sized limestone is now winning a share o f the market because of its substantially better heat consumption. Future r equirements, however are aimed at kiln throughputs of 1000 t/d or more comb ined with greater flexibility with respect to the lime reactivity which can be produced. This poses the question of the development potential of the k iln systems with respect to throughput, heat consumption, availability, and flexible adjustment of lime reactivity. In addition to the above-mentioned rotary and PFR kiln systems it is also necessary to consider annular shaft kilns, multi-chamber shaft kilns, Chisaki kilns, travelling grates and fla sh calciners. Furthermore, combined kiln systems, like flash calciner - rot ary kiln fluidized bed cooler; could offer the most attractive features. Th is article deals with the technological and economic implications of such d evelopments, including the required product mix.