GB114180A - Improved Method for the Utilization of Nitre Cake. - Google Patents

Abstract

114,180. Grossmann, J. March 19, 1917. Nitrogen oxides and oxy-acids.-An intimate mixture of nitre-cake and sodium nitrate, both finely ground, for instance so as to pass through a sieve having 60 meshes per linear inch, is heated and the resulting gases are mixed with air, which is drawn or blown through the retort or through other ports of the apparatus. Atmospheric or reduced or increased pressure may be employed. The reaction begins at 150‹ C. and is complete at 250‹ C., and a practically quantitative yield of nitrogen oxides other than nitrous oxide is obtained. The solid mixture, containing a slight excess of acid, may be conveyed through a retort heated to less than 150‹ C. at the charging end and to about 250‹ C. at discharging end. Agitation is unnecessary. The mixture may be placed on trucks 0 previously covered with salt cake or. the like to facilitate removal of the product. The trucks may be fed singly by a screw or other pusher N from an antechamber provided with sliding doors K, M. At the other end of the furnace is a. similar chamber but with a sloping floor S to facilitate the separation of the front truck. Flues Q, R from the end chambers may be connected to separate condensers or to the main flue P. Muffle furnaces like those used for salt cake or apparatus like baking-ovens may be employed. Heating may be effected by combustion, waste gas, steam, superheated steam, or superheated water. The nitrogen oxides produced may be passed directly into a vitriol chamber, or may be mixed with steam or a water spray, and the nitric acid condensed, the residual gases being either utilized in a vitriol chamber or further oxidized and condensed. Oxidation and condensation may be done as in the Birkeland-Eyde process.