Abstract: A method and apparatus are provided for maintaining a predetermined energy balance in a device, such as an aluminum reduction cell. The apparatus includes a relatively short and thin heat flow sensor having a first and second thermocouple located within opposite closed ends of a hollow thermally conductive body. Each thermocouple is composed of two wires of the same dissimilar metals. The sensor is secured by one closed end of the sensor body to an outside surface of the wall member to extend substantially perpendicular to the location on the wall without significantly affecting the heat flow from the wall surface being measured. A first wire of each thermocouple is of the same metal for electrically connecting the junctions of each thermocouple. The second wire of each thermocouple extends to a location intermediate the closed ends of the sensor body and is electrically connected to an instrument responsive to the electrical potential between the first and second thermocouples.

Abstract: A method of operating an electrolytic cell having a corrosive environment. For electrolytic operation, the cell is supplied with DC current from current carrying buses or leads located externally of the cell. AC voltage is applied between the shell and at least one of the buses, and an AC meter is electrically connected between the bus and the shell for continuously monitoring the level of electrical resistance existing between the bus and the shell. The resistance monitoring determines the existence of any leakage current flowing between the bus and the shell, which is, in turn, an indication of the quality of the insulating wall of the cell.

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: A calorimetric transducer comprising spaced parallel metallic plates sandwiching an open region of high thermal resistivity. A plurality of wires of high thermal conductivity bridge the open space to reduce the thermal resistivity thereof to a predetermined level and further function to structurally support the plates as well as to form a plurality of differential thermocouples therewith. Means are provided to serially connect the differential thermocouple to provide an amplified response and a flux meter is provided to pesent a visual indication of the flux rate measured by the calorimetric transducer.

Abstract: A method for producing aluminum chloride comprises contacting Al.sub.2 O.sub.3 with a reducing agent and chlorine in a bath of molten metal halides to form aluminum chloride and recovering the aluminum chloride by vaporization.

Abstract: A thermocouple assembly having a thermocouple encased in a tube having an outer carbon permeable layer and an inner carbon reactive layer. The assembly provides extended life for thermocouples used in a carbonaceous environment such as in the carbon liner of a furnace or in carbon bodies during baking thereof.

Abstract: A process for producing aluminum in which alumina is decomposed electrolytically to aluminum metal in an electrolyte bath between an anode and a cathodic interface formed between aluminum metal and the electrolyte bath. The bath consists essentially of Al.sub.2 O.sub.3, NaF, and AlF.sub.3, and has a weight ratio NaF to AlF.sub.3 up to 1.1:1. During decomposition, the bath is maintained at an operating temperature greater than 40.degree.C above the cryolite liquidus temperature of the bath and effective for preventing bath crusting in interfacial areas between bath and aluminum metal.