PROCESS FOR CALCINING SLUDGES OF CALCIUM MATERIALS AND APPARATUS FOR CARRYING OUT THE PROCESS

摘要

A process and apparatus for thermal processing material especially sludges of calcium bearing material such as the recovery of lime sludge formed in causticizing of alkaline digestion liquors employed in the pulping of wood fibers. The process includes a suspension preheater and a suspension cooler and an apparatus for flash drying and calcining the material while in suspension in hot combustion gases. The calcining furnace itself includes a lower inlet for fuel to allow the material to be exposed to high temperature flame additional thermal energy supplied to the calcining vessel by separate combustion chambers close coupled at the upper levels of the calcining furnace. The gas flow in the calciner is helical. Various points for introduction of fuel and material to be processed ace described. 2993S/bir-5