Abstract: The present invention provides an apparatus for preparing a metal based on solar energy thermal reduction. The apparatus includes a solar energy collection and photothermal conversion system and a thermal reduction system. The solar energy collection and photothermal conversion system includes: a solar energy collection device (1), a solar energy concentration device (2), and a solar energy transfer device (3) or a photothermal conversion and transfer device. The thermal reduction system includes: a metal reduction chamber (15), an electric field and/or magnetic field generation device (15-3), and a separation and cooling device (15-4). The solar energy collection and photothermal conversion system transfers sunlight or heat to the metal reduction chamber to decompose a metal oxide, and a product resulted from the decomposition is dissociated under the effect of an electric field/magnetic field, and a liquid metal is obtained upon cooling.

Abstract: A process for shutting down an operating electrolytic cell for the production of aluminium is described. The process includes: lowering anodes until a lower portion of the anodes is immersed in an aluminium layer; allowing the aluminium layer and an electrolyte bath to cool down with the lower portion of the anodes immersed in the aluminium layer; determining if the electrolyte bath is solidified, and if the electrolyte bath is solidified, raising the anodes before solidification of the aluminium layer to create a space between the solidified electrolyte bath and the anodes and the aluminium layer.

Abstract: A cell for the electrowinning of aluminium by the electrolysis from an aluminium compound dissolved in a molten electrolyte (50), comprises: (I) a plurality of non-carbon anodes (10), each anode being suspended in operating in the molten electrolyte by an anode stem (11) that connects the anode (10) to a positive current source; and (II) a thermic insulating cover (60,60?) which covers the electrolyte (50) and through which each anode stem (11) extends from the positive current source to an anode (10). The insulating cover (60,60?) comprises a plurality of movable sections (60) that together cover a substantial part of the electrolyte (50). Each movable section (60) covers a corresponding portion of the electrolyte (50) that is located therebelow and that can be uncovered by moving the corresponding movable section (60).

Abstract: Object of the invention is an anodic structure for mercury cathode cells for the industrial electrolysis of sodium chloride. The new structure is constituted by a grid array comprising a multiplicity of vertically disposed and mutually parallel titanium blades, covered by an electrocatalytic coating specific for the discharge of chlorine. The ratio between the thickness and the height of the blades is comprised between 1:16 and 1:100 and the ratio between the surface of free passage between the blades and the projected surface is comprised between 15:17 and 25:30. The new grid array is perpendicularly fixed to new or existing frames having the function of mechanical support and current conduction to the grid array. Scope of the invention is simultaneously reducing the energetic consumption of the cell and the costs for restoring the exhausted electrocatalytic coating.

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: The invention is relative to an electrolytic cell comprising electrodes spaced apart from the back-wall by means of ribs, wherein a portion of the contact surface between the electrodes and the ribs is free from constraints in order to permit the complete removal of the electrodes once they have to be replaced by removing only partially the original contact surface, so that positioning of the substitute electrodes is allowed on the residual portion. A method for substituting the electrodes of the cell which leaves the distance between the electrode surface and the back-wall unvaried is also disclosed.

Abstract: A cell for the electrowinning of aluminium comprises at least one non-carbon metal-based anode (10) having an electrically conductive metallic structure (12, 13, 15) which is suspended substantially parallel to a facing cathode (20, 21, 22). Such metallic structure (12, 13, 15) comprises a series of parallel horizontal anode members (15), each having an electrochemically active surface (16) on which during electrolysis oxygen is anodically evolved. The electrochemically active surfaces (16) are in a generally coplanar arrangement to form the active anode surface. The anode members are spaced apart from one another by inter-member gaps forming flow-through openings (17) for the circulation of electrolyte (30) driven by the escape of anodically-evolved oxygen. The electrolyte (30) may circulate upwardly and/or downwardly in the flow-through openings (17) and possibly around the anode structure (12, 13, 15).

Abstract: A method of producing aluminum in an electrolytic cell containing alumina dissolved in an electrolyte. A plurality of non-consumable anodes are disposed substantially vertically in the electrolyte along with a plurality of monolithic hollow cathodes. Each cathode has a top and bottom and the cathodes are disposed vertically in the electrolyte and the anodes and the cathodes are arranged in alternating relationship. Each of the cathodes is comprised of a first side facing a first opposing anode and a second side facing a second opposing anode. The first and second sides are joined by ends to form a reservoir in the hollow cathode for collecting aluminum therein deposited at the cathode.

Abstract: Cathode connector means for low temperature aluminum smelting cell for connecting titanium diboride cathode or the like to bus bars.

Abstract: A method of producing aluminum in an electrolytic cell containing alumina dissolved in an electrolyte. The method comprises the steps of providing a molten salt electrolyte in an electrolytic cell having an anodic liner for containing the electrolyte, the liner having an anodic bottom and walls including at least one end wall extending upwardly from the anodic bottom, the anodic liner being substantially inert with respect to the molten electrolyte. A plurality of non-consumable anodes is provided and disposed vertically in the electrolyte. A plurality of cathodes is disposed vertically in the electrolyte in alternating relationship with the anodes. The anodes are electrically connected to the anodic liner. An electric current is passed through the anodic liner to the anodes, through the electrolyte to the cathodes, and aluminum is deposited on said cathodes. Oxygen bubbles are generated at the anodes and the anodic liner, the bubbles stirring the electrolyte.

Abstract: A device for adjusting the distance between the anode and the cathode of an electrolytic cell having a compartment, at least one anode partially disposed in a molten metal producing salt bath and a layer of molten metal above a cathode. The device includes a displacement device partially disposed within the layer of molten metal, and an actuator to move the displacement device generally vertically.

Abstract: Carbon-containing components of cells for the production of aluminium by the electrolysis of alumina dissolved in a cryolite-based molten electrolyte are protected from attack by liquid and/or gaseous components of the electrolyte in the form of elements, ions or compounds, by a refractory boride coating applied from a slurry composed of pre-formed particulate refractory boride in a colloidal carrier which is dried and heated to consolidate the coating.

Abstract: The smelting of aluminum from alumina in the Hall-Heroult process can be dramatically improved by lowering power consumption and in the use of carbon free anodes by using a feed of positively charged alumina. Laboratory experiments have shown that the apparent solubility and reactivity of alumina in molten fluoride baths is surprisingly increased by altering the negatively charged aluminum hydroxide Al(OH)4− particles, at about pH of nine, to positively charged particles containing Al+++ with a pH of less than two, by using acid solutions. The alumina thus produced is referred to as Al+++ alumina, or positively charged alumina. In particular, sulfuric acid is used to convert aluminum hydroxide using the Bayer process to a family of basic aluminum sulfates, 3Al2O3.4SO3.9H2O, which are dehydrated and calcined to produce Al+++ alumina.

Abstract: An electrolytic cell and electrolytic process for producing a metal by reduction of a metal oxide dissolved in a molten salt bath containing at least one chloride and at least one fluoride. A solid conductor of oxide ions is interposed between the anode and the cathode. The solid conductor preferably comprises zirconia, stabilized in cubic form by addition of a divalent or trivalent metal oxide such as yttria.