Procédé pour obtenir un produit pratiquement dépourvu d'alcali à la sortie d'un four utilisé pour la cuisson de minéraux contenant des alcalis difficilement volatils

摘要

Minerals containing alkali metal compounds which are difficult to volatilize, in particular raw powdered cement, are burned in a kiln by a method in which the kiln discharge is passed through a cooler through which air flows, the heated cooling air then at least partially being supplied to the kiln, and which also contains water which is evaporated therein in such quantities that the combined action of the steam thus produced and the heated cooling air when introduced into the kiln is sufficient to convert a substantial proportion of the difficultly-volatilizable alkali metal compounds into the hydroxides, which are then removed in the waste gases, so that a kiln discharge substantially free of alkali metal compounds is obtained.