Abstract: A method of producing aluminum in an electrolytic cell containing alumina dissolved in an electrolyte, the method comprising the steps of providing a molten salt electrolyte at a temperature of less than 900° C. having alumina dissolved therein in an electrolytic cell having a liner for containing the electrolyte, the liner having a bottom and walls extending upwardly from said bottom. A plurality of non-consumable Cu—Ni—Fe—Sn anodes and cathodes are disposed in a vertical direction in the electrolyte, the cathodes having a plate configuration and the anodes having a flat configuration to compliment the cathodes. The anodes contain apertures therethrough to permit flow of electrolyte through the apertures to provide alumina-enriched electrolyte between the anodes and the cathodes. Electrical current is passed through the anodes and through the electrolyte to the cathodes, depositing aluminum at the cathodes and producing gas at the anodes.

Abstract: A method of producing aluminum in an electrolytic cell containing alumina dissolved in an electrolyte, the method comprising the steps of providing a molten salt electrolyte at a temperature of less than 900° C. having alumina dissolved therein in an electrolytic cell having a liner for containing the electrolyte, the liner having a bottom and walls extending upwardly from said bottom. A plurality of non-consumable Cu—Ni—Fe anodes and cathodes are disposed in a vertical direction in the electrolyte, the cathodes having a plate configuration and the anodes having a flat configuration to compliment the cathodes. The anodes contain apertures therethrough to permit flow of electrolyte through the apertures to provide alumina-enriched electrolyte between the anodes and the cathodes. Electrical current is passed through the anodes and through the electrolyte to the cathodes, depositing aluminum at the cathodes and producing gas at the anodes.

Abstract: Electrolysis of alumina dissolved in a molten salt electrolyte employing inert anode and cathodes, the anode having a box shape with slots for the cathodes.

Abstract: A method of maintaining molten salt concentration in a low temperature electrolytic cell used for production of aluminum from alumina dissolved in a molten salt electrolyte contained in a cell free of frozen crust wherein volatile material is vented from the cell and contacted and captured on alumina being added to the cell. The captured volatile material is returned with alumina to cell to maintain the concentration of the molten salt.

Abstract: An electrolytic cell for producing aluminum from alumina having a reservoir for collecting molten aluminum remote from the electrolysis.

Abstract: A method of producing aluminum in an electrolytic cell containing alumina dissolved in an electrolyte, the method comprising providing a molten salt electrolyte having alumina dissolved therein in an electrolytic cell. A plurality of anodes and cathodes having planar surfaces are disposed in a generally vertical orientation in the electrolyte, the anodes and cathodes arranged in alternating or interleaving relationship to provide anode planar surfaces disposed opposite cathode planar surfaces, the anode comprised of carbon. Electric current is passed through anodes and through the electrolyte to the cathodes depositing aluminum at the cathodes and forming carbon containing gas at the anodes.

Abstract: Electrolysis of alumina dissolved in a molten salt electrolyte employing inert anode and cathodes, the anode having a box shape with slots for the cathodes.

Abstract: An electrolytic cell for producing aluminum from alumina having a reservoir for collecting molten aluminum remote from the electrolysis.

Abstract: A method of producing aluminum in an electrolytic cell containing alumina dissolved in an electrolyte, the method comprising the steps of providing a molten salt electrolyte at a temperature of less than 900° C. having alumina dissolved therein in an electrolytic cell having a liner for containing the electrolyte, the liner having a bottom and walls extending upwardly from said bottom. A plurality of non-consumable Cu—Ni—Fe anodes and cathodes are disposed in a vertical direction in the electrolyte, the cathodes having a plate configuration and the anodes having a flat configuration to compliment the cathodes. The anodes contain apertures therethrough to permit flow of electrolyte through the apertures to provide alumina-enriched electrolyte between the anodes and the cathodes. Electrical current is passed through the anodes and through the electrolyte to the cathodes, depositing aluminum at the cathodes and producing gas at the anodes.

Abstract: A method of producing aluminum in an electrolytic cell containing alumina dissolved in an electrolyte, the method comprising providing a molten salt electrolyte having alumina dissolved therein in an electrolytic cell. A plurality of anodes and cathodes having planar surfaces are disposed in a generally vertical orientation in the electrolyte, the anodes and cathodes arranged in alternating or interleaving relationship to provide anode planar surfaces disposed opposite cathode planar surfaces, the anode comprised of carbon. Electric current is passed through anodes and through the electrolyte to the cathodes depositing aluminum at the cathodes and forming carbon containing gas at the anodes.

Abstract: A method of maintaining molten salt concentration in a low temperature electrolytic cell used for production of aluminum from alumina dissolved in a molten salt electrolyte contained in a cell free of frozen crust wherein volatile material is vented from the cell and contacted and captured on alumina being added to the cell. The captured volatile material is returned with alumina to cell to maintain the concentration of the molten salt.

Abstract: A method of producing aluminum in an electrolytic cell containing alumina dissolved in an electrolyte, the method comprising the steps of providing a molten salt electrolyte at a temperature of less than 900° C. having alumina dissolved therein in an electrolytic cell having a liner for containing the electrolyte, the liner having a bottom and walls extending upwardly from said bottom. A plurality of non-consumable anodes and cathodes are disposed in a vertical direction in the electrolyte, the cathodes having a plate configuration and the anodes having a flat configuration to compliment the cathodes. The anodes contain apertures therethrough to permit flow of electrolyte through the apertures to provide alumina-enriched electrolyte between the anodes and the cathodes. Electrical current is passed through the anodes and through the electrolyte to the cathodes, depositing aluminum at the cathodes and producing gas at the anodes.

Abstract: A method for processing alumina-bearing ores such as bauxite to recover iron, aluminum, silicon and titanium metal values therefrom the method comprising the steps of adding the alumina-bearing ores to a digester containing an acid to provide a mixture of acid and alumina-bearing ores and heating the mixture to dissolve soluble compounds of at least one of iron, aluminum, silicon and titanium to provide a digest containing dissolved salts of the soluble compounds and to provide a gas component. Thereafter, the digest is treated with water to dissolve water soluble salts therein to provide a slurry comprised of a liquid containing water and the dissolved soluble salts and a solid component comprised of silica. The solid component is separated from the liquid and the pH of the liquid is adjusted to form an aluminate and an iron-containing precipitate.

Abstract: A method for processing alumina-bearing ores such as bauxite to recover iron, aluminum, silicon and titanium metal values therefrom the method comprising the steps of adding the alumina-bearing ores to a digester containing an acid to provide a mixture of acid and alumina-bearing ores and heating the mixture to dissolve soluble compounds of at least one of iron, aluminum, silicon and titanium to provide a digest containing dissolved salts of the soluble compounds and to provide a gas component. Thereafter, the digest is treated with water to dissolve water soluble salts therein to provide a slurry comprised of a liquid containing water and the dissolved soluble salts and a solid component comprised of silica. The solid component is separated from the liquid and the pH of the liquid is adjusted to form an aluminate and an iron-containing precipitate.

Abstract: A method for processing red mud to recover iron, aluminum, silicon and titanium metal values therefrom the method comprising the steps of adding the red mud to a digester containing an acid to provide a mixture of acid and red mud and heating the mixture to dissolve soluble compounds of at least one of iron, aluminum, silicon and titanium to provide a digest containing dissolved salts of the soluble compounds and to provide a gas component. Thereafter, the digest is treated with water to dissolve water soluble salts therein to provide a slurry comprised of a liquid containing water and the dissolved soluble salts and a solid component comprised of silica. The solid component is separated from the liquid and the pH of the liquid is adjusted to form an aluminate and an iron-containing precipitate.

Abstract: A method of recovering chloride and sulfate salts from spent potliner using acid digestion.

Abstract: Spent potliner from aluminum reduction cells is treated, for example, with sulfuric acid to recover carbon, silica and alumina or to recover a vitrified product of silca and alumina.

Abstract: A method for producing fumed silica and a fluorine-containing product from a source of silica in solid form and a solid material containing fluorine, the solid material selected from the group consisting of sodium aluminum tetrafluoride, cryolite, aluminum fluosilicate ammonium bifluoride, sodium aluminum silicofluoride, and sodium fluosilicate. The method comprises the steps of digesting the silica in solid form and the solid material selected from the group consisting of sodium aluminum tetrafluoride, cryolite, aluminum fluosilicate, ammonium bifluoride, sodium aluminum silicofluoride, and sodium flurosilicate in a sulfuric acid digester. The digestion step produces a first gas component comprised of silicon tetrafluoride, hydrogen fluoride and water vapor. The first gas component is removed from the digester.

Abstract: Spent potliner from an aluminum reduction cell is subject to an acid digest and the digest may be adjusted to produce a first gas component comprised of at least one material selected from the group consisting of silicon tetrafluoride, hydrogen fluoride, hydrogen cyanide gas and water vapor, and a slurry component comprised of at least one material selected from the group consisting of carbon, silica, alumina, and sodium, iron, calcium and magnesium compounds. The first gas component is removed from the digester and heated to a temperature sufficiently high to convert said silicon tetrafluoride to fumed silica and hydrogen fluoride. Thereafter, the fumed silica is separated from the hydrogen fluoride to recover fumed silica from spent potliner material.

Abstract: A method of recovering AlF3 from spent potliner using an acid digest to form gaseous HF which is converted to hydrofluoric acid and reacted with alumina trihydrate to form AlF3.