Abstract: The invention discloses a direct-current shunt preheating start method for an inert electrode aluminum electrolysis cell, comprising: (1) forming multiple groups of direct-current shunt elements by using conductors with preset resistance values and geometric sizes; (2) laying in a hearth of the electrolysis cell electrical heating element groups of the same number as/a different number from electrode groups; (3) drying the hearth, smelting electrolyte and establishing a thermal balance and a hearth inner profile by using the electrical heating element groups according to a set heating curve or set steps; (4) changing the number of groups/a series or parallel connection state of the direct-current shunt elements; and (5) gradually replacing inert electrodes and gradually adjusting the number of the groups of/the series or parallel connection state of the shunt elements.

Abstract: A method for starting up an electrolytic cell (20) for aluminum production having a cathode block (26) with an upper surface (32), the method comprising: disposing contact resistance material (46) over the upper surface (32) of the cathode block (26); lowering a plurality of anodes (28) to abut the contact resistance material (46); filling the electrolytic cell (20) and covering the anodes (28) with solid electrolyte material (72) comprising crushed electrolytic bath material, cryolite, or mixtures thereof; delivering electrical current to the anodes (28) to at least partially melt the solid electrolyte material (72) and raising the anodes (28) when a predetermined depth of molten electrolyte material has been reached.

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 has a cavity for containing electrolyte (20) and one or more non emerging active anode bodies (5) that are suspended in the electrolyte. The electrolyte's surface (21,21?) has an expanse extending over the cavity and is substantially covered by a self-formed crust (25) of frozen electrolyte. The crust is mechanically reinforced by at least one preformed refractory body (30, 30?,30?). The electrolyte crust is formed against the preformed refractory body and bonded thereto so as to inhibit mechanical failure of the crust and collapse of the crust into the cavity.

Abstract: The method of process control is for a Hall-Héroult process of aluminum production from alumina ore in an industrial potline. The method includes measuring an array of sampled potline data including a plurality of cell voltages (V) and a plurality of line amperages (A) at a plurality of time points. The method also includes calculating a predicted voltage (PV) for each cell voltage and line amperage in the array. The method further includes controlling a plurality of alumina ore feed rates and a plurality of pot voltage settings based upon the predicted voltages. The method also includes calculating a plurality of bath temperatures based upon the predicted voltages. The PV variable is preferably used in an automated control environment. The PV variable is also preferably used to monitor cell noise levels, operating temperature, metal pad roll, and oscillatory electrical shorting events.

Abstract: A slurry comprises suspended aluminum particles in a colloid having dispersed colloidal particles of a metal oxide such as a hydroxide. The metal oxide is reducible by metallic aluminum. The slurry has such a basic pH that dissolution of the aluminum particles in the slurry is inhibited so that when the slurry is subjected to a heat treatment, the undissolved aluminum particles are reactable with the colloidal particles to form an aluminum-based mixture resistant to chemical attack made of aluminum oxide, metal aluminum and the metal of the colloidal particles. The slurry can be used to form an aluminum-based protective coating on a component, in particular of an aluminum electrowinning cell or an apparatus for treating molten aluminum.

Abstract: The present invention relates to a method of pre-heating a pot provided with anodes and cathodes for the production of aluminium by electrolysis, said method including a first step, prior to the pot being supplied with current, during which a layer of a granular conductive material is deposited then crushed between the anodes and the cathodes, characterized in that the granular conductive material is graphite-based and in that the layer of granular conductive material only extends, after crushing, over a part of a lower surface of each anode and takes the form of contact blocks.

Abstract: A process for preheating an electrolytic cell, which involves disposing at least one sheet of compressed particles of exfoliated graphite across at least a portion of the surface of cathode blocks in the cell.

Abstract: A method for protecting anode assemblies in an electrolytic cell from thermal shock is disclosed. The method generally involves applying a thermal insulating layer (8, 16) to the anode (2) prior to preheating the anode assembly in a furnace, where the layer (8, 16) protects the anode (2) from thermal shock during transfer from the preheat furnace to the electrolytic cell. In a preferred embodiment the anode (2) is attached to a castable plate (4) that is also protected from thermal shock by an insulating layer.

Abstract: A thermal treatment system for thermally treating a sterile medium is controlled via a foot actuated switch to thermally treat the sterile medium to a desired temperature and/or form (e.g., slush). The thermal treatment system includes a basin recessed in a system top surface, while a surgical sterile drape is placed over the system and within the basin to form a drape container for containing the sterile medium. The basin may be configured to cool the sterile medium and form sterile surgical slush, or heat the sterile medium to provide warm sterile liquid. A dislodgment mechanism may be employed within a cooling basin to manipulate the drape and dislodge frozen pieces of sterile medium adhered to the drape. Information pertaining to the sterile medium and system operation may be displayed on a system display that has dimensions sufficient to provide visibility of the information to users located within extended ranges from the system.

Abstract: The present invention is directed to methods for preheating a molten salt electrolysis cell having inert anodes (24) using recuperative gas heating by combusting a first gas outside the cell chamber (20) in a combustion chamber (2) and using to heat a second gas in recuperator (8) which second gas us passed to the cell chamber (20). The inert anode can be a cermet inert anode.

Abstract: A cermet anode of an electrolytic cell is protected from thermal shock during cell start-up by coating an outer surface portion of the anode with a coating composition comprising carbon or aluminum or a mixture thereof. A particularly preferred coating composition includes an aluminum underlayer adjacent the outer surface portion of the anode, and a carbon overlayer overlying the underlayer. A support structure assembly supporting the cermet anode includes a high alumina ceramic material. In a preferred embodiment, the high alumina ceramic material is protected from thermal shock and corrosion by the coating composition of the invention.

Abstract: A method of protecting during the start-up procedure a cathode (1) of a cell for the electrowinning of aluminium where the cathode (1) is optionally coated with an aluminium-wettable refractory material (2) and on which cathode, in use, aluminium is produced. The start-up procedure comprises applying before preheating the cell one or more start-up layers (3) on the aluminium-wettable refractory coating (2). The start-up layer(s) form(s) a temporary protection (3) against damage of chemical and/or mechanical origin to the aluminium-wettable coating (2), this temporary protection (3) being in intimate contact with the aluminium-wettable coating (2) and being eliminated before or during the initial normal operation of the cell. The layers of the temporary protection (3) may be obtained from at least one pliable foil of aluminium having a thickness of less than 0.

Abstract: A cell of advanced design for production aluminum by the electrolysis of an aluminum compound dissolve in a molten ectrolyte, has a cathode (30) of drained configuration, and at least one non-carbon anode (10) facing the cathode both covered by the electrolyte (54). The upper part of the cell contains a removable thermic insulating cover (60) placed just above the level of the electrolyte (54). Preferably, the cathode (30) comprises a cathode mass (32) supported by a cathode carrier (31) made of electrically conductive material which serves also for the uniform distribution of electric current feeders (42) which connect the cathode carrier (31) to the negative busbars.

Abstract: A cell for the production of aluminium by the electrolysis of an aluminium compound dissolved in a molten electrolyte, in which an outer mechanical structure forming an outer shell (21) houses therein one or more inner electrically-conductive cathode holder shells or plates (31) which contain a cathode mass (32) and is/are connected electrically to the busbar. The cathode mass (32) has an aluminium-wettable top surface (37), preferably at a slope forming a drained cathode. The inner cathode holder shell or shells (31) is/are separated from the outer shell (21) by an electric and thermic insulation (40), the cathode holder shell(s) (31) also serving to distribute current uniformly to the cathode mass (32). The or each cathode (30) formed by the cathode holder shell (31) and cathode mass (32) is removable from the cell as a unit.

Abstract: A method of protecting a cathode during the start-up procedure of an aluminum electrowinning cell where the cathode is optionally coated with an aluminium-wettable refractory material and when in use, aluminium is produced thereon. The start-up procedure comprises applying, before preheating the cell, one or more start-up layers in intimate contact on the aluminium-wettable refractory coating which form(s) a temporary protection against damage of chemical and/or mechanical origin to the aluminium-wettable coating; this temporary protection being eliminated before or during the initial normal cell operation. The temporary protection layers may be obtained from at least one pliable aluminium foil having a thickness of less than 0.1 mm and/or an applied aluminium-containing metallization, optionally in combination with inter alia a boron-containing solution, a polymer, a phosphates of aluminium-containing solution, or a colloid that gels while preheating the cell, or combinations thereof.

Abstract: Roller clamps provide an economical and effective means to achieve steady and uniform current distribution through the anodes and cathode of an Hall-Heroult electrolytic cell during the pre-heat cycle. The roller clamps, which replace conventional bar clamps that are used in normal operation, have rollers adapted to bias anode support rods against electrical contacts on an anode bus bar with sufficient pressure to maintain desired electrical contact between the anode and contact; and to permit the anode supports to move to accommodate thermal expansion or deflections of cell components as the cell is heated.