An apparatus for electro-polishing an object that has a complex shape that defines a cavity. The apparatus includes an electrode that is configured to closely engage a predetermined location of the object. The electrode is configured to be electrically connected to a power supply.

A geothermally powered aluminum production subsystem includes a geothermal system with a wellbore extending from a surface into an underground magma reservoir. A hopper receives a bauxite ore that is crushed and provided to a digestor. The digestor is heated by a heat transfer fluid heated by the geothermal system, and a product of the digestor is used to prepare aluminum.

A geothermally powered aluminum production subsystem includes a geothermal system with a wellbore extending from a surface into an underground magma reservoir. A hopper receives a bauxite ore that is crushed and provided to a digestor. The digestor is heated by a heat transfer fluid heated by the geothermal system, and a product of the digestor is used to prepare aluminum.

Spent potlining material contains spent potliner from aluminium electrolysis cells, and at least one hydrophobic binder. The hydrophobic binder being selected from wax, a waxlike compound or mixtures thereof. A method for producing a spent potlining material includes the steps of (a) providing spent potliner from aluminium electrolysis cells, (b) comminuting the spent potliner in at least one comminuting apparatus, (c) fractionating the spent potliner through a separating apparatus, (d) mixing the spent potliner with at least one hydrophobic binder, selected from wax, a waxlike compound or mixtures thereof, in a mixing apparatus, (e) portioning the mixture obtained in step (d), (f) withdrawing the spent potlining material The steps (b) to (d) are carried out in an inert gas atmosphere. Also, spent potlining material is used as fuel in power stations and also in connection with the production of mineral wool, cement and steel.

The present disclosure includes a method for purifying aluminum. The method includes producing purified aluminum from an aluminum feedstock in an aluminum purification cell and flowing the purified aluminum from a cell chamber of the aluminum purification cell to a purified metal reservoir via an overflow passage, wherein the purified metal reservoir is located internal to the aluminum purification cell. In some embodiments, a feeding reservoir is located internal to the aluminum purification cell and can be accessed via a feeding port located in a refractory top cover of the cell chamber. In some embodiments, the method includes removing the purified aluminum from the purified metal reservoir via a tapping port located in a refractory top cover of the cell chamber. In some embodiments, concomitant with the removing step, the method includes restricting or preventing oxidation of the purified aluminum.

This invention relates to producing aluminum by electrolysis of a melt and can be used in the process control of an electrolyte composition by quantitative X-ray phase analysis (XRD) of potassium-containing electrolyte with calcium or calcium and magnesium additives. A quantitative XRD method is employed for analyzing doped samples of crystallized bath samples taken from baths. A weighted ground bath sample is mixed with a weighted quantity of sodium fluoride at a ratio, for example, 1:2 by weight. The weighted quantities are mixed and placed in a furnace (650-750 C. for 20-40 minutes) to dissolve sodium fluoride in the sample and recrystallize the sample with the desired phase composition. The doped sample is placed in a furnace (420-450 C) and held for 15-30 minutes. The doped sample is removed from the furnace and allowed to air cool. The phase composition of the doped sample is analyzed by any quantitative X-ray phase method.

System, method and apparatus for measuring electrolysis cell operating conditions and communicating the same are disclosed. The system includes a selectively positionable member coupled to an analytical apparatus, wherein the selectively positionable is configured to move the analytical apparatus into and out of physical communication with a bath. The system may also include a crust breaker for breaking the surface of a bath and an electronic device for measuring bath level.

In a method for removing a substance from a feedstock comprising a solid metal or a solid metal compound, the feedstock is contacted with a fused-salt melt. The fused-salt melt contains a fused salt, a reactive-metal compound, and a reactive metal. The fused salt comprises an anion species which is different from the substance, the reactive-metal compound comprises the reactive metal and the substance, and the reactive metal is capable of reaction to remove at least some of the substance from the feedstock. A cathode and an anode contact the melt, and the feedstock contacts the cathode. An electrical current is applied between the cathode and the anode such that at least a portion of the substance is removed from the feedstock. During the application of the current, a quantity of the reactive metal in the melt is maintained sufficient to prevent oxidation of the anion species of the fused salt at the anode. The method may advantageously be usable for removing the substance from successive batches of the feedstock, where the applied current is controlled such that the fused-salt melt after processing a batch contains the quantity of the reactive metal sufficient to prevent oxidation of the anion species at the anode.

In a method for removing a substance from a feedstock comprising a solid metal or a solid metal compound, the feedstock is contacted with a fused-salt melt. The fused-salt melt contains a fused salt, a reactive-metal compound, and a reactive metal. The fused salt comprises an anion species which is different from the substance, the reactive-metal compound comprises the reactive metal and the substance, and the reactive metal is capable of reaction to remove at least some of the substance from the feedstock. A cathode and an anode contact the melt, and the feedstock contacts the cathode. An electrical current is applied between the cathode and the anode such that at least a portion of the substance is removed from the feedstock. During the application of the current, a quantity of the reactive metal in the melt is maintained sufficient to prevent oxidation of the anion species of the fused salt at the anode. The method may advantageously be usable for removing the substance from successive batches of the feedstock, where the applied current is controlled such that the fused-salt melt after processing a batch contains the quantity of the reactive metal sufficient to prevent oxidation of the anion species at the anode.

The present invention relates to nonferrous metallurgy, in particular to the electrolytic production of aluminum, more particularly to a structure of a cathode assembly of a reduction cell for production of aluminum. A lining of a cathode assembly of an aluminum reduction cell is provided which comprises a thermal insulation layer and a fire-resistant layer consisting of no less than two sub-layers, wherein the porosity of the thermal insulation layer and the fire-resistant layer increases from an upper sub-layer to a bottom sub-layer and the thickness ratio of the fire-resistant layer and the thermal insulation layer is no less than 1/3. Also, the present invention provides a method for lining a cathode assembly of a reduction cell and a reduction cell having the claimed cathode assembly lining. The invention is aimed at the reduction of the cyanide content in upper thermal insulation layers and to provision of conditions for material reuse in the thermal insulation layer, waste reduction and improvement of the environmental situation on aluminum production facilities.