Abstract: The specification describes a process for pelletising particles of an alkali metal ferrite with an aqueous binder such as a black liquor derived from pulping wood chips. The particles are ground and fed to a microgranulator in measured quantities together with measured quantities of aqueous binder. The particles are ground such that they have an even size distribution about a mean in the range from 25 to 50 microns. The particles are mixed with the binder in the microgranulator to form microgranules which are fed to a pelletising pan. The temperature of the microgranules on the pelletising pan is controlled by cooling either or both the alkali metal ferrite or aqueous binder prior to measuring them into the microgranulator. A pan temperature of less than 70.degree. C. is disclosed.

Abstract: The specification describes a process for recovering alkali metal hydroxides from an organic liquor such as black liquors derived from pulping wood chips. The organic liquor is burned in a fluidised bed combustion furnace containing fluidised particles of an iron rich mixed oxide of an alkali metal and iron. Particles of alkali metal ferrite are extracted from the furnace and dissolved in a solution of alkali metal hydroxide to form a more concentrated solution of alkali metal hydroxide and a precipitate of the iron rich mixed oxides of alkali metal and iron. A mixed oxide disclosed in the specification generally has the following formula: NaFe.sub.5 O.sub.8.4H.sub.2 O.