Dimensionally stable drained aluminum electrowinning cathode method and apparatus
AssigneeEltech Systems Corporation
InventorsAjit Y. Sane, Douglas J. Wheeler, Charles S. Kuivila
Life of this patent
Estimating the term…
Abstract
A method and apparatus for making a drained aluminum electrowinning cathode dimensionally stable. A thin, 1/2 to 10 millimeter coating of substantially stagnant molten aluminum is maintained upon the cathode surface by an openly porous sheath or membrane closely conforming to contours of the electrowinning cathode. The sheath or membrane is made from a material substantially resistant to corrosives present in the aluminum electrowinning; it may be only slightly aluminum wettable, but should be relatively electrically nonconductive.
Claims17
In an electrolysis cell for electrowinning aluminum having a cathode presenting a drained electrically conductive electrowinning surface to contents of the cell, the improvement comprising:
- a sheath closely conforming to contours of the presented surface at least where the presented surface contacts aluminum being electrowon;
- the sheath having a plurality of apertures traversing a sheath thickness, the apertures being of a size and configuration whereby molten aluminum is retained within the apertures during electrolysis remaining substantially stagnant and in contact with the presented surface;
- the sheath being made of a material substantially resistant to corrosion by contents of the electrolysis cell.
A method for making a drained aluminum electrowinning cathode surface dimensionally stable comprising the steps of:
- sheathing said surface in close conformance to contours of the cathode surface at least where such surface contacts aluminum being electrowon, said sheath having a plurality of apertures traversing the sheath thickness, the apertures being of size and configuration whereby molten aluminum is retained within the apertures during electrolysis;
- and
- electrolyzing a composition for electrowinning aluminum in contact with the resulting sheath surface;
- thereby
- providing a coating including substantially stagnant molten aluminum upon the cathode.
A method for making a drained aluminum electrowinning cathode surface made from one of carbon, and refractory metal carbides, nitrides and borides dimensionally stable, comprising the steps of:
- sheathing said surface in close conformance to contours of the cathode surface at least where such surface contacts aluminum being electrowon, said sheath having a plurality of apertures traversing the sheath thickness, the apertures being of size and configuration whereby molten aluminum is retained within the apertures during electrolysis;
- and
- electrolyzing a composition for electrowinning aluminum in contact with the resulting sheath surface;
- thereby
- providing a coating including substantially stagnant molten aluminum upon the cathode surface of at least about 0.5 millimeter in thickness, but not more than 10.0 millimeters.
A method for making an aluminum electrowinning cathode surface made from TiB.sub.2 dimensionally stable, comprising the steps of:
- sheathing said surface in close conformance to contours of the cathode surface at least where such surface contacts aluminum being electrowon, said sheath having a plurality of apertures traversing the sheath thickness, the apertures being of size and configuration whereby molten aluminum is retained within the apertures during electrolysis;
- and
- electrolizing a composition for electrowinning aluminum in contact with the resulting sheath surface;
- thereby
- providing a coating including essentially stagnant molten aluminum upon the cathode surface of at least about 0.5 millimeter in thickness, and not more than 10.0 millimeters in thickness.
In an electrode presenting a drained electrically conductive electrowinning surface for use in an electrolysis cell used to electrowin aluminum, the improvement comprising:
- an openly porous membrane closely conforming to contours of the presented surface at least where the presented surface is in contact with aluminum being electrowon, pores within the membrane being of a size and shape whereby molten aluminum is retained in the pores during electrolysis substantially stagnant and in contact with the presented surface, the membrane being substantially resistant to corrosive effects of contents of the electrolysis cell.
An aluminum electrowinning cell having a drained electrowinning surface of a refractory hard metal boride, nitride, carbide or mixtures or combinations thereof, the electrowinning surface having molten aluminum retained in substantially stagnant contact therewith by at least one piece of a substantially non-electrically conductive material selected from Si.sub.3 N.sub.4, BN, AlON, SiAlON, AlN and AlB.sub.12.
Dependencies are inferred from the claim text.