Abstract: A process for treatment of aluminum chloride production offgas containing Cl.sub.2, CO, CO.sub.2, HCl, COCl.sub.2, COS, SO.sub.2, N.sub.2, SiCl.sub.4 and metal chlorides by reaction with water vapor in the presence of an alumina or low iron sand catalyst to convert SiCl.sub.4 and metal chlorides to the corresponding oxides and HCl; subsequent reaction of COCl.sub.2 with water vapor in the presence of an activated carbon catalyst to form CO.sub.2 and HCl; and removal of HCl by contacting the offgas with liquid water. Reaction with steam in the presence of alumina catalyst prior to reaction with steam in the presence of an activated carbon catalyst prolongs the useful life of the activated carbon catalyst and avoids the necessity of removing SiCl.sub.4 and metal chlorides from the offgas by adsorption onto dry activated carbon prior to contacting the activated carbon catalyst with offgas.

Abstract: A method is provided for removing aluminum or compounds thereof causing a short circuit in an electrolytic cell containing aluminum chloride dissolved in a molten solvent of higher decomposition potential, the cell used for the production of aluminum from aluminum chloride and having a terminal anode and cathode providing an inter-electrode space therebetween. The method comprises removing aluminum chloride and molten solvent from the cell to an extent which exposes the materials in the inter-electrode space causing the short circuit, introducing a source of chlorinating agent to the cell and contacting the materials causing the short circuit with the chlorinating agent to form aluminum chloride, the contacting being for a time sufficient to remove the short circuit thereby permitting the addition of the aluminum chloride and solvent and the electrolysis thereof for the production of aluminum.

Abstract: A method is disclosed for preparing for operation a cell, having an outer shell and an inner lining, which is employed to produce metal by electrolysis of a compound of the metal in a molten production bath. The method includes placing in the cell an initial bath having a solidus temperature higher than the solidus temperature of the production bath, and higher than the temperature maintained on the inside surface of the shell. Because of this higher solidus temperature, a freeze-line barrier for the initial bath is established within the lining of the cell. Subsequently, electrolysis is carried out in the production bath.

Abstract: An improved lining for an electrolytic furnace for producing aluminum is disclosed having sufficient thickness that heat flow therethrough is such that an insulative coating provided on the inside surface of a perimetric metal shell around the electrolytic furnace is not exposed to temperatures above an upper temperature limit at which the coating is impenetrable by molten salt. Such improved lining includes an inner layer of high-fired refractory, penetrable by the molten salt and resistant to chemical corrosion by such penetration. The inner layer is of sufficient thickness that a salt freeze line is located therein. Within the inner layer and outside the freeze line is a layer of material impenetrable by molten aluminum. In at least the bottom portion of the furnace and outside the inner layer is at least one layer of glass refractory impermeable to the molten salt.

Abstract: Waste gases containing 15% or less vaporized chlorides are processed to recover chlorine values as HCl by filtration of particulate material followed by the adsorption of metal chlorides on carbon beds and subsequent hydrolyzing of the metal chlorides at a temperature of 100.degree.-150.degree. C. to form metal oxides and HCl. The remaining gases such as COCl.sub.2 are further hydrolyzed to recover aqueous HCl and then the gases are scrubbed and finally incinerated to provide a discharge to the atmosphere containing CO.sub.2, N.sub.2, H.sub.2 O, O.sub.2 and about 5ppm HCl.

Abstract: A process is provided for producing aluminum in an electrolytic cell containing aluminum chloride dissolved in a molten solvent of higher decomposition potential. The cell has a terminal anode, a terminal cathode and a bipolar electrode arranged to operate with the anode and the cathode, providing interelectrode spaces therebetween. On electrolyzing the cell chlorine is produced on each anode surface thereof and aluminum on each cathode surface, the aluminum being swept from the cathode surface by bath material. In the process, carbonaceous material is provided for use as the electrode. The direction of grain flow constituting the carbonaceous material is determined and the electrode is arranged in the cell such that the direction of electrolysis current flow through the cell is in a direction substantially perpendicular to the direction of grain flow in the electrode.

Abstract: A method and apparatus for producing metal by electrolysis in a molten bath of salt. The apparatus includes an electrolytic cell containing a molten bath of salt and a vertical stack of electrodes located within the bath of salt, with the uppermost electrode being located beneath the upper level of the bath. A baffle extends vertically above the uppermost electrode, the baffle being effective to direct a flow of the bath laterally and beneath the upper level of the bath, and to increase the velocity of the flow of the bath and metal between vertically adjacent electrodes of the vertical stack.

Abstract: Activated carbon having adsorbed materials thereon is regenerated by passing a mixture of gases and/or vapors capable of exothermically reacting through the bed. The heat of reaction liberated by the reaction heats the carbon bed sufficiently to permit removal of the adsorbed materials thereon. The bed may then be further purged with an inert gas to complete the removal of the adsorbed materials.

Abstract: A molten mixture containing magnesium oxide, magnesium chloride and a reducing agent is chlorinated in a furnace having a refractory lining, at least a portion of which adjacent the surface of the molten mixture therein is formed from a nitride-based refractory.

Abstract: Magnesium is produced by decomposition of magnesium chloride contained in an electrolyte. The magnesium chloride containing electrolyte is provided in a refractory lined electrolytic cell having an anode and a cathode wherein magnesium is produced at the cathode and chlorine at the anode, the magnesium accumulating in a layer on the surface of the electrolyte. A shroud having a skirt portion therein formed from a nitride-based refractory projects into the electrolyte such that chlorine produced at the anode is removed from the cell without contacting the molten magnesium layer, the shroud being resistant to attack by molten magnesium, electrolyte and gases emanating therefrom.

Abstract: Use of Co, Ni, Cu or Ca catalyst to decompose hypochlorite contained in the product resulting from scrubbing of chlorine-containing gas.