Abstract: A method of making fine particulate aluminum nitride, including the steps of reacting gaseous aluminum trichloride with aluminum-containing metallic material at elevated temperature to convert some of the trichloride to monochloride gas; introducing a gaseous nitrogen source to the monochloride-containing gas for reacting nitrogen with the monochloride to form fine particulate aluminum nitride; conducting a flow of gas comprising aluminum trichloride having the particulate nitride entrained therein to a cooling locality; there condensing the trichoride and accumulating the condensed trichloride and particulate nitride; and periodically reevaporating and removing the trichloride from the cooling locality for separating out and recovering the accumulated nitride.

Abstract: An electrolytic reduction cell for the production of molten metal by electrolysis of a molten electrolyte, which is less dense than the molten metal includes a generally rectangular shell, one or more suspended anodes and a floor structure which supports a body of the molten metal. At least one essentially linear baffle member extends transversely of the cell and is formed with restricted flow channels for absorbing energy from the molten metal and to reduce the amplitude of the wave motion in the molten metal. The baffle may be in the form of a single member formed with apertures for metal flow restriction or may be constituted by a number of separate aligned members with metal flow channels between them.

Abstract: In a process for the treatment of fume-laden carbon monoxide evolved in carbothermic reduction of alumina the fume-laden gas is contacted with particulate carbon in a fluidized bed maintained at a temperature, preferably in the range 2010.degree.-2050.degree. C. and above that at which sticky aluminium oxycarbide forms. The temperature of the bed is most conveniently controlled by the rate at which fresh carbon feed material is added to the bed. The hot gas emerging from the bed is rapidly chilled to a temperature below the solidification point of aluminium oxycarbide. This is most conveniently achieved by contact with a large excess of cool alumina/carbon mix in a stream which is continuously circulated through a heat exchange stage.

Abstract: In a process for production of aluminium metal described in U.S. Pat. No. 4,099,959 carbon monoxide gas is evolved at very high temperature through reaction of aluminium carbide and alumina in a high temperature zone of the system. This gas is cooled by contact with a molten alumina slag at a lower temperature to cause back reaction of contained aluminium suboxide and Al vapor and consequent heat transfer to the contacted molten alumina slag.A body of molten alumina slag is maintained in a pretreatment zone, to which carbon and alumina feed are introduced and the carbon monoxide gas is led into the pretreatment zone. Excess slag, resulting from such introduction of feed and from gaseous back reaction, spills over into a low temperature zone of the system to augment the circulating slag stream.

Abstract: In a apparatus for the production of aluminium a molten alumina slag, containing combined carbon is circulated through one or more alternately arranged relatively low temperature zones where carbon is added to increase the combined carbon content of the slag by reaction with the alumina slag and high temperature zones where aluminium metal is released by reaction of aluminium carbide and alumina in the slag with consequent depletion of the combined carbon content. Alumina is supplied to the slag at one or more locations. The energy to drive the reactions is preferably supplied by resistance heating of the slag particularly in transit from a low temperature zone to a high temperature zone although usually additional energy is supplied to the slag in the return from a high temperature zone to the next low temperature zone.In most instances the aluminium-liberating reaction is carried out in an upwardly inclined passage and the gas evolved is employed to achieve the circulatory movement of the slag.