Improvements in or relating to the production of quicklime

摘要

Alkaline earth (including magnesium) oxides are produced in granular form by drying and calcining without briquetting a mixture of alkaline earth carbonate and hydrated oxide and water. The process is described with reference to quicklime and is especially suitable for the treatment of finely-divided calcium carbonate from water-softening plants and chemical works. Between 4 and 40 per cent. by weight of the output of lime is slaked and mixed with the carbonate and water, and the resultant mixture may be granulated or extruded, with or without admixture with a solid fuel, such as coal, coke &c. before being dried and calcined. The extruded cylinders may be mixed with a dry powder containing the carbonate to prevent sticking, the powder being removed by screening before drying. Rotary or shaft kilns may be employed. The sludge from a water-softening plant may be mixed with quicklime and be run directly to a rotary kiln.