| 摘要 |
<p>Limestone is burnt in an air-fluidised bed together with a bituminous shale, substantially all the particles of the charge having a grain size between 0.1 and 6.0 millimetres, and the burning temperature being so chosen between 1,000 DEG C. and 1,150 DEG C. for so limited a period of time that the particles of the burnt limestone do not react with the shale particles. The product may be used in the manufacture of building materials. The fluidising air may be preheated, preferably to at least 100 DEG C. especially to at least 400 DEG C., and, prior to the fluidising, the fluidising chamber and contents may be preheated to at least 700 DEG C. The fluidising air is preferably supplied in such amount that the oxygen content of the flue gases is at least 5%, preferably at least 8%. If desired, only part of the air necessary for complete combustion of the charge need be supplied as fluidising air, the remainder being introduced above the bed. Cooling, either direct or indirect, may be applied above the bed, for example by the addition of cooled flue gases or water, or by circulating water through tubes above the bed, which latter may be employed for the generation of steam. Solids recovered from the flue gases may be returned to the bed, preferably after agglomeration.</p> |
