Apparatus for reclaiming limestone mud

Abstract

Apparatus and process for reclaiming limestone mud wherein a supply of the mud in a wet condition is passed to a spray type dryer and dried to a bone dry free-flowing powder by the use of hot drying air from a calciner furnace. The dry powder together with the exhaust gases are then passed to a dust collector for removing substantially all of the fines from the gases. The spent lime powder may then be back-mixed with some of the original spent mud in proportions designed to yield a calciner feed having the desired moisture content for optimum physical condition of both feed and calcined product. The pugged mixture is then conveyed to the top of the calciner furnace and passed downwardly through successive zones including a heating zone, a drying zone, a decomposition zone wherein the spent lime is decomposed into calcined lime and gaseous carbon dioxide, and a second heating zone to increase the density without loss of activity thereof, while passing hot gases upwardly in countercurrent flow with respect to the downwardly flowing spent lime. The calcined lime is discharged at the bottom of the furnace and conveyed to a cooler wherein the temperature is reduced to usable levels for recycling in the system.