阅读说明：本技术 用于提纯铝的系统和方法 (System and method for purifying aluminum ) 是由 D·H·德尤恩格 刘兴华 B·L·拜得兰德 J·韦斯维尔 于 2016-02-11 设计创作，主要内容包括：本申请涉及用于提纯铝的系统和方法。方法包括：(a)将铝原料进料到槽中；(b)引导电流到阳极中,穿过电解液并导入阴极,其中阳极包含细长立式阳极,并且其中阴极包含细长立式阴极,其中该阳极和阴极配置为延伸到电解液区域中,以使在电解液区域中该阳极和阴极配置为具有阳极-阴极重叠和阳极-阴极距离；并由铝原料制造一些提纯的铝产品。(The present application relates to systems and methods for purifying aluminum. The method comprises the following steps: (a) feeding aluminum feedstock to a tank; (b) directing an electric current into the anode, through the electrolyte and into the cathode, wherein the anode comprises an elongated vertical anode, and wherein the cathode comprises an elongated vertical cathode, wherein the anode and the cathode are configured to extend into the electrolyte zone such that the anode and the cathode are configured to have an anode-cathode overlap and an anode-cathode distance in the electrolyte zone; and producing some purified aluminum product from the aluminum feedstock.)

1. An aluminum electrolysis cell comprising:

(a) a base;

(b) a bottom portion positioned adjacent the base, wherein the bottom portion has an upper surface and a lower surface, wherein the upper surface of the bottom portion has a slope;

(c) an anode connector in electrical communication with a lower surface of the base, wherein the anode connector comprises an outer end configured to be connected to an external power source;

(d) at least one elongated vertical anode extending upwardly from the upper surface of the base;

(e) a cathode connector adjacent the top cover, the cathode connector having: an upper connecting bar and a lower surface, wherein the upper connecting bar is configured to be connected to an external power source;

(f) at least one elongated vertical cathode extending downwardly from a lower surface of the cathode connector, wherein at least some of the elongated vertical cathodes overlap the elongated vertical anodes such that the distal ends of the elongated vertical cathodes are proximate a middle portion of the respective elongated vertical anodes.

2. The electrolytic cell of claim 1 comprising a side wall, wherein the side wall, roof and bottom define a cell chamber.

3. An electrolysis cell according to claim 2, comprising a cell inlet passage through the cell chamber, wherein the cell inlet passage has an inlet aperture.

4. The electrolytic cell of claim 2 comprising aluminum extraction holes through one of the side walls.

5. An electrolysis cell according to claim 2, comprising an inert gas inlet in the top cover, wherein the inert gas inlet is configured to provide an inert atmosphere to the cell chamber.

6. The electrolytic cell of claim 1 wherein the slope has an angle of less than 10 degrees.

7. The electrolytic cell of claim 6 wherein the slope has an angle from 3 to 5 degrees.

Technical Field

In general, the present application relates to different configurations and processes that utilize an electrolysis cell to provide a purified aluminum product from a feedstock containing aluminum metal. More particularly, the present application relates to utilizing vertically oriented, spaced apart anode and cathode configurations wherein the anodes and cathodes are constructed of aluminum wettable materials in order to reduce the inter-electrode distance and increase the electrode surface area (e.g., purification area) of the operating electrolysis cell to produce purified aluminum metal products from aluminum feedstock (e.g., feedstock comprising aluminum metal and/or alloys thereof) with much lower energy consumption and higher productivity.

Background

The hopus (hopes) process is an electrolytic process that has been used to obtain aluminum metal with extremely high purity.

Disclosure of Invention

In one aspect, there is provided a method comprising: (a) feeding aluminum feedstock into a cell inlet channel of an aluminum reduction cell, wherein the aluminum reduction cell is configured to have at least two zones, including a molten metal pad zone and an electrolyte zone (e.g., a reaction/purification zone), further wherein the aluminum feedstock remains in the molten metal pad zone; (b) directing an electrical current into an anode through the electrolyte and into a cathode, wherein the anode comprises an elongated vertical anode, and wherein the cathode comprises an elongated vertical cathode, wherein the anode and cathode are configured to extend into the electrolyte region (e.g., in an opposing, spaced-apart configuration) such that in the electrolyte region, the anode and cathode are configured to have an anode-cathode overlap and an anode-cathode distance [ wherein the anode, cathode, and electrolyte are (electrically and mechanically) configured to be contained in an aluminum electrolysis cell ]; (c) wetting at least a portion of a surface of the elongated vertical anode with molten material from a molten metal pad layer, wherein the molten material comprises aluminum metal; (d) generating at least a portion of aluminum ions in the electrolyte from the aluminum metal on the surface of the elongated vertical anode, concomitant with the directing step; and (e) concomitantly with the directing step, reducing at least a portion of the aluminum ions in the bath to the surface of the elongated vertical cathode to produce a molten purified aluminum product.

In some embodiments, the method comprises: the raw materials are melted prior to the feeding step.

In some embodiments, the method comprises: collecting at least a portion of the upper layer of the purified aluminum product, wherein the upper layer comprises molten purified aluminum product.

In some embodiments, the method comprises: removing the purified aluminum product from the aluminum reduction cell.

In some embodiments, the removing step comprises tapping (tapping) the tank.

In some embodiments, the removing step comprises: casting the purified aluminum product into an ingot to provide an aluminum product having an aluminum purity of at least 99.5 wt.%.

In some embodiments, the method comprises: collecting at least a portion of the purified aluminum upper layer, wherein the upper layer comprises a purified aluminum product.

In some embodiments, the method comprises: the raffinate and/or residue from the molten metal pad layer in the aluminium electrolysis cell is removed via the cell inlet channel.

In some embodiments, the anode and cathode are constructed of aluminum wettable material.

In some embodiments, the directing step further comprises supplying an electric current to the elongated vertical anode.

In some embodiments, the anode and cathode are immersed in the electrolyte.

In some embodiments, the method comprises: the purified aluminum product comprises an aluminum purity of at least 99.5 wt.% up to 99.999 wt.% Al.

In some embodiments, the method comprises: the purified aluminum product comprises an aluminum purity of at least 99.8 wt.% up to 99.999 wt.% Al.

In some embodiments, the purified aluminum product comprises an aluminum purity of at least 99.9 wt.% up to 99.999 wt.% Al.

In some embodiments, the method comprises: the purified aluminum product comprises an aluminum purity of at least 99.98 wt.% up to 99.999 wt.% Al.

In another aspect, a method is provided, comprising: (a) providing an aluminum electrolysis cell comprising at least two zones, including an electrolyte zone (e.g., a reaction/purification zone) and a molten metal pad zone (e.g., a feed zone) comprising an aluminum feed material; (b) directing an electric current into an anode through an electrolyte and into a cathode, wherein the anode comprises an elongated vertical anode, and wherein the cathode comprises an elongated vertical cathode, wherein the anode and cathode are in electrical communication with the electrolyte and are configured to extend into an electrolyte area (e.g., in an opposing, spaced-apart configuration) such that the anode and cathode are configured to have an anode-cathode overlap and an anode-cathode distance; wherein the anode, cathode and electrolyte are configured to be contained in an aluminum electrolysis cell; (c) wetting at least a portion of a surface of the elongated vertical anode with a region of molten material from a molten metal pad, wherein the molten material comprises aluminum metal; (d) generating at least a portion of aluminum ions in the electrolyte from the aluminum metal on the surface of the elongated vertical anode, concomitant with the directing step; and (e) concomitantly with the directing step, reducing at least a portion of the aluminum ions in the bath to the surface of the elongated vertical cathode to produce a molten purified aluminum product.

In some embodiments, the method comprises: forming a third region comprising the purified aluminum product, wherein the third region is disposed above the electrolyte region to define an upper layer.

In some embodiments, the method comprises: at least a portion of the purified aluminum product is removed from the aluminum electrolysis cell via a tapping operation.

In some embodiments, the method comprises: the purified aluminum product is cast into a cast form (e.g., ingot).

In some embodiments, the method comprises: (a) aluminum feedstock is fed into the cell inlet channel of an aluminum electrolysis cell.

In some embodiments, the method comprises purifying the aluminum such that a purified aluminum product is produced via the electrolysis cell at an energy efficiency of 1 to 15kWh/kg of purified aluminum product.

In some embodiments, purified aluminum is produced via the electrolysis cell at an energy efficiency of 2 to 10kWh/kg of purified aluminum product.

In some embodiments, purified aluminum is produced via the electrolysis cell at an energy efficiency of 2 to 6kWh/kg of purified aluminum product.

In some embodiments, the method comprises: the chamber is purged with an inert gas.

In some embodiments, the method comprises: an inert gas is flowed into the aluminum electrolysis cell via an inert gas inlet disposed within a refractory top cover of the aluminum electrolysis cell, wherein the inert gas is configured to provide an inert atmosphere in a gas phase space defined in the cell chamber (e.g., above the electrolyte and/or the purified aluminum product).

In some embodiments, the method comprises: a densification aid is added to the aluminum feedstock to configure the density of the aluminum feedstock so as to remain in the molten metal liquid layer region prior to the wetting step.

In some embodiments, the method comprises: bath components are added to the aluminium electrolysis cell via the cell inlet channel.

In some embodiments, the bath components are configured to replenish the electrolyte and facilitate the production and reduction steps.

In some embodiments, the elongated vertical anode comprises TiB₂、ZrB₂、HfB₂、SrB₂At least one of carbonaceous material, W, Mo, steel, and combinations thereof, the elongated vertical cathode comprising TiB₂、ZrB₂、HfB₂、SrB₂At least one of carbonaceous materials, and combinations thereof.

In another aspect, there is provided an aluminum electrolysis cell comprising: (a) a base, refractory sidewalls and a refractory top cover; (b) a base located adjacent the base, the base having an upper surface; (c) an anode connector in electrical communication with the base, the anode connector having an outer end configured to be connected to an external power source; (d) an elongated vertical anode extending upwardly from the upper surface of the base, the elongated vertical anode having: (i) a proximal end connected to the upper surface of the base; (ii) a free distal end extending upwardly toward the refractory top cover; and (iii) an intermediate portion; (e) a cathode connector adjacent the refractory top cover, the cathode connector having: (i) an upper connecting rod configured to be connected to an external power source; and (ii) a lower surface; (f) an elongated vertical cathode extending downwardly from a lower surface of the cathode connector, the elongated vertical cathode having: (i) a proximal end connected to the upper surface of the cathode connector; (ii) a free distal end extending downwardly toward the base; and (iii) an intermediate portion; wherein the elongated vertical cathode overlaps the elongated vertical anode such that the distal end of the elongated vertical cathode is proximate the middle portion of the elongated vertical anode and the distal end of the elongated vertical anode is proximate the middle portion of the elongated vertical cathode.

In some embodiments, the slot comprises: a trough chamber defined by refractory sidewalls, a refractory roof, and a bottom; a trough inlet channel is thus provided through the lower portion of the refractory side wall to a passage to the lower portion of the trough chamber, the trough inlet channel having an inlet aperture.

In some embodiments, the slot comprises: an aluminum extraction hole through the upper portion of the refractory sidewall thereby providing access to the upper portion of the cell.

In some embodiments, the slot comprises: an inert gas inlet formed in the refractory top cover configured to provide an inert atmosphere to the cell.

In some embodiments, the slot comprises: a housing, wherein the housing comprises: a housing floor located below the base; and a shell sidewall spaced from and surrounding the refractory sidewall.

In some embodiments, the slot comprises: thermal insulators, wherein the thermal insulators are positioned between the shell floor and the base, and between the shell side walls and the refractory side walls.

In some embodiments, the elongated vertical anode is aluminum wettable.

In some embodiments, the anode is selected from: TiB₂、ZrB₂、HfB₂、SrB₂At least one of carbonaceous material, W, Mo, steel, and combinations thereof.

In some embodiments, the elongated vertical cathode is aluminum wettable.

In some embodiments, the cathode is selected from: TiB₂、ZrB₂、HfB₂、SrB₂At least one of carbonaceous materials, and combinations thereof.

In another aspect, a method is provided, comprising: (a) supplying current to an elongated vertical anode in an aluminium electrolysis cell comprising: (i) a base, refractory sidewalls and a refractory top cover; (ii) a base located adjacent the base; (iii) a trough chamber defined by refractory sidewalls, a refractory roof, and a bottom; (iv) a molten metal liquid layer contained in the chamber above the bottom; wherein the molten metal pad comprises aluminum and impurities; (v) an upper layer of purified aluminum contained in the cell chamber above the molten metal liquid layer; (vi) an electrolyte contained in the cell chamber and separating the upper layer from a bottom layer of the molten metal pad layer; (vii) an elongated vertical anode extending upwardly from the bottom, through the molten metal pad and terminating in the electrolyte; (viii) a cathode connector adjacent the refractory cap; (ix) an elongated vertical cathode extending downwardly from the cathode connector and terminating in the electrolyte so that the elongated vertical cathode overlaps the elongated vertical anode in the electrolyte; (b) wetting at least a portion of a surface of the elongated vertical anode with molten material from a molten metal pad; (c) producing aluminum ions from the molten metal pad via the elongated vertical anode; (d) reducing at least a portion of the aluminum ions via the elongated vertical cathode, thereby producing purified aluminum; (e) at least a portion of the purified aluminum in the upper layer is collected.

In some embodiments, the method includes providing purified aluminum having at least 99.5 wt.% up to 99.999 wt.% Al.

In some embodiments, the method includes providing purified aluminum having at least 99.8 wt.% up to 99.999 wt.% Al.

In some embodiments, the method includes providing purified aluminum having at least 99.9 wt.% up to 99.999 wt.% Al.

In some embodiments, the method includes providing purified aluminum having at least 99.98 wt.% to 99.999 wt.% Al.

In some embodiments, the method includes adding aluminum feedstock to the cell chamber via the cell inlet aperture.

In some embodiments, the adding step comprises metering the aluminum feedstock into the cell chamber at a first feed rate.

In some embodiments, the method includes removing purified aluminum from the cell chamber at a second removal rate.

In some embodiments, the first feed rate is controlled based at least in part on the second removal rate.

In some embodiments, the adding step comprises periodically adding the aluminum feedstock to the cell chamber.

In some embodiments, the method includes periodically removing purified aluminum from the chamber.

In some embodiments, the method comprises producing purified aluminum such that the purified aluminum is produced via the electrolytic cell at an energy efficiency of 1 to 15kWh/kg of purified aluminum.

In some embodiments, the method provides purified aluminum produced via the electrolytic cell with an energy efficiency of 2 to 10kWh/kg of purified aluminum.

In some embodiments, the method provides for producing purified aluminum via the electrolytic cell with an energy efficiency of 2 to 6kWh/kg of purified aluminum.

In some embodiments, the method comprises purging the chamber with an inert gas.

Brief description of the drawings

Fig. 1 is a schematic cross-sectional side view of an embodiment of an electrolytic cell for purifying aluminum of the present disclosure.

Fig. 2 is a schematic cross-sectional side view of an embodiment of an electrolytic cell for purifying aluminum of the present disclosure.

Fig. 3 is a schematic side view (elevation view) of an electrolytic purification cell for laboratory scale testing.

Fig. 4 is a top down schematic (plan view) of an electrolytic purification cell (cathode assembly not shown) for laboratory scale testing.

Fig. 5 is a graph depicting experimental data obtained, shown as Fe (% by weight) in metal determined by ICP, shown for each cell.

Detailed Description

The present invention will be further explained with reference to the attached figures, wherein like structure is referred to by like numerals throughout the several views. The drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention. Furthermore, some features may be exaggerated to show details of particular components.

The drawings constitute a part of this specification and include an illustrative embodiment of the present invention and illustrate various objects and features thereof. Furthermore, the figures are not necessarily to scale, some features may be exaggerated to show details of particular components. Furthermore, any measurements, specifications, etc. shown in the figures are intended to be illustrative, and not restrictive. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.

Among the benefits and improvements that have been disclosed, other objects and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings. Detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely illustrative of the invention that may be embodied in various forms. Furthermore, the examples given in connection with the various embodiments of the invention are intended to be illustrative, not limiting.

Throughout the specification and claims, the following terms take the meanings explicitly associated herein, unless the context clearly dictates otherwise. The phrases "in one embodiment" and "in some embodiments" as used herein do not necessarily refer to the same embodiment, although they may. Moreover, the phrases "in another embodiment" and "in other embodiments" as used herein do not necessarily refer to a different embodiment, although they may. Thus, as described below, various embodiments of the invention may be readily combined without departing from the scope or spirit of the invention.

Furthermore, the term "or" as used herein is an inclusive "or" operator, and is equivalent to the term "and/or," unless the context clearly dictates otherwise. The term "based on" is not exclusive and allows for being based on additional factors not described, unless the context clearly dictates otherwise. Furthermore, throughout this specification, the meaning of "a", "an" and "the" includes plural references. The meaning of "in … …" includes "in … …" and "on … …".

As used herein, "aluminum feedstock" refers to a material having at least 80 weight percent aluminum.

As used herein, "purified molten aluminum" refers to a molten material having at least 99.5 weight percent aluminum.

As used herein, "molten metal pad" refers to a reservoir of molten material located below the electrolyte, wherein the molten material comprises aluminum.

As used herein, "residue" refers to waste material precipitated during the purification of aluminum. In some embodiments, the residue comprises solid material.

As used herein, "raffinate" refers to aluminum containing a very high level of impurities.

As used herein, "aluminum wettability" means having a contact angle with molten aluminum of no greater than 90 °.

As used herein, "electrolyte" refers to a medium in which a current flows by the movement of ions/ionic substances. In one embodiment, the electrolyte may comprise a molten salt.

As used herein, "energy efficiency" refers to the amount of energy (in kilowatt-hours) consumed by an aluminum electrolysis cell per kilogram of purified aluminum produced by the cell. Thus, energy efficiency can be expressed as kWh/kg of aluminum produced (kWh/kg).

As used herein, "anode-cathode overlap" (ACO) refers to the vertical distance from the distal end of an elongated vertical anode to the distal end of a corresponding elongated vertical cathode.

As used herein, "anode-cathode distance" (ACD) refers to the horizontal distance separating an elongated vertical anode from a corresponding elongated vertical cathode.

In one embodiment, the invention includes an aluminum electrolysis cell. The trough may include a base, refractory sidewalls, and a refractory roof. The trough may include a bottom portion located adjacent the base, wherein the bottom portion has an upper surface. The tank may include an anode connector in electrical communication with the bottom, the anode connector having an outer end configured to be connected to an external power source. The tank may include an elongate vertical anode extending upwardly from the upper surface of the base. The elongated vertical anode can have a proximal end connected to the upper surface of the bottom, a free distal end extending upwardly toward the refractory top cover, and a middle portion. The cell may include a cathode connector proximate the refractory cap. The cathode connector may have an upper connecting bar configured to be connected to an external power source, and a lower surface. The cell may have an elongated vertical cathode extending downwardly from a lower surface of the cathode connector. The elongated vertical cathode may have a proximal end connected to the upper surface of the cathode connector, a free distal end extending downward toward the base, and a middle portion. In one embodiment, the elongated vertical cathode overlaps the elongated vertical anode such that the distal end of the elongated vertical cathode is proximate the middle portion of the elongated vertical anode and the distal end of the elongated vertical anode is proximate the middle portion of the elongated vertical cathode.

In one embodiment, the aluminum reduction cell includes a cell chamber defined by refractory sidewalls, a refractory roof, and a bottom. The trough may include an inlet passage through a lower portion of the refractory side wall thereby providing access to a lower portion of the trough chamber. The tank inlet channel may have an inlet aperture.

In one embodiment, the aluminum electrolysis cell includes aluminum extraction holes through the upper portion of the refractory side wall, thereby providing access to the upper portion of the cell chamber. In one embodiment, the aluminum electrolysis cell includes an inert gas inlet formed in the refractory top cover configured to provide an inert atmosphere to the cell chamber.

In one embodiment, the aluminum electrolysis cell comprises a housing, wherein the housing comprises: a housing floor located below the base; and a shell sidewall spaced from and surrounding the refractory sidewall. The aluminum reduction cell may include thermal insulation, wherein the thermal insulation is between the shell floor and the base, and between the shell side wall and the refractory side wall.

In one embodiment, the elongated vertical anode is aluminum wettable. In this regard, the elongated vertical anode can comprise TiB₂、ZrB₂、HfB₂、SrB₂At least one of carbonaceous material, W, Mo, steel, and combinations thereof.

In one embodiment, the elongated vertical cathode is aluminum wettable. In this regard, the elongated vertical cathode may comprise TiB₂、ZrB₂、HfB₂、SrB₂At least one of carbonaceous materials, and combinations thereof.

Without being bound by any particular mechanism or theory, it is believed that the anode is configured to undergo an electrochemical reaction such that the aluminum metal containing impurities is anodized to aluminum ions Al³⁺(delivered to the electrolyte) to leave impurities on the anode. Subsequently, the ions are reduced onto the cathode surface and aluminum metal is formed, wherein the metal is in a purified form as impurities remain on the anode surface and/or collect in the metal pad (e.g. a given density vs. electrolyte/bath composition of the impurities).

In one embodiment, the invention includes a method. The method may comprise supplying electrical current to an elongate vertical anode in an aluminium electrolysis cell. The aluminum electrolysis cell may include a base, refractory sidewalls, and a refractory roof. The aluminum reduction cell may include a base located adjacent to the base. The aluminum reduction cell may include a cell chamber defined by refractory sidewalls, a refractory roof, and a bottom. The aluminum reduction cell may include a molten metal pad contained in the cell chamber above the bottom. The molten metal pad may include aluminum and impurities. The aluminum reduction cell may include an upper layer of purified aluminum contained in the cell chamber above the molten metal tapping layer. The aluminum reduction cell may include an electrolyte contained in the cell chamber and separating the upper layer from a molten metal pad layer. The elongated vertical anode may extend upwardly from the bottom, through the molten metal pad and terminate in the electrolyte. The aluminum electrolysis cell may include a cathode connector proximate the refractory top cover. The aluminum electrolysis cell may include an elongated vertical cathode extending downwardly from a cathode connector and terminating in an electrolyte such that the elongated vertical cathode overlaps the elongated vertical anode in the electrolyte. The method may include wetting at least a portion of a surface of the elongated vertical anode with molten material from a molten metal pad. The method may comprise producing aluminium ions from the molten metal pad via the elongate vertical anode. The method can include reducing at least a portion of the aluminum ions via the elongated vertical cathode, thereby producing purified aluminum. The method can include collecting at least a portion of the purified aluminum in the upper layer.

In some embodiments of the method, the purified aluminum comprises 99.5 wt.% to 99.999 wt.% Al. In some embodiments of the method, the purified aluminum comprises at least 99.8 wt.% to 99.999 wt.% Al. In some embodiments of the method, the purified aluminum comprises at least 99.9 wt.% to 99.999 wt.% Al. In some embodiments of the method, the purified aluminum comprises at least 99.98 wt.% to 99.999 wt.% Al.

In some embodiments, the method includes adding aluminum feedstock to the cell chamber via the cell inlet aperture. In some embodiments of the method, the adding step comprises metering the aluminum feedstock into the cell chamber at a first feed rate. In some embodiments, the method includes removing purified aluminum from the cell chamber at a second removal rate. In some embodiments of the method, the first feed rate is controlled based at least in part on the second removal rate. In some embodiments of the method, the adding step comprises periodically adding the aluminum feedstock to the cell chamber. In some embodiments, the method includes periodically removing purified aluminum from the chamber.

In some embodiments of the method, purified aluminum is produced via the electrolytic cell with an energy efficiency of 1 to 15kWh/kg of purified aluminum. In some embodiments of the method, purified aluminum is produced via the electrolytic cell with an energy efficiency of 2 to 10kWh/kg of purified aluminum. In some embodiments of the method, purified aluminum is produced via the electrolytic cell with an energy efficiency of 2 to 6kWh/kg of purified aluminum.

In some embodiments, the method includes purging the chamber (19) with an inert gas.

Figures 1 and 2 are schematic views of an electrolytic cell for purifying aluminum. In the embodiment shown, the electrolytic cell (1) comprises a base (7), refractory side walls (15) and a refractory roof (17). The aluminium electrolysis cell (1) comprises a bottom (30) located adjacent to the base (7). The base (30) has an upper surface (32) and a lower surface (34). In some embodiments, the upper surface (32) of the base (30) is sloped. In some embodiments, the slope comprises an angle of less than 10 °. In some embodiments, the slope comprises an angle of about 3 to 5 °. The aluminium electrolysis cell (1) comprises an anode connector (20). The anode connector (20) is in electrical communication with the lower surface (34) of the base (30). In some embodiments, the base includes at least one slot configured to receive the anode connector. The anode connector (20) has an outer end (22) configured to be connected to an external power source.

The aluminium electrolysis cell (1) comprises at least one elongate vertical anode (40) extending upwardly from the upper surface (32) of the base. The elongated vertical anode (40) has a proximal end (42), a free distal end (44), and an intermediate portion (46). The proximal end (42) of the elongated vertical anode is attached to the upper surface (32) of the base. The free distal end (44) of the elongate vertical anode extends upwardly towards the refractory roof (17). In some embodiments, the elongated vertical anode (40) is aluminum wettable. For example, the elongated vertical anode (40) may comprise TiB₂、ZrB₂、HfB₂、SrB₂One or more of carbonaceous material, W, Mo, steel, and combinations thereof.

In some embodiments, the aluminum electrolysis cell (1) includes a cathode connector (50) proximate the refractory top cover (17). The cathode connector (50) has an upper connecting rod (54) and a lower surface (52). The upper connecting rod (54) is configured to be connected to an external power source.

The aluminium electrolysis cell (1) comprises at least one elongated vertical cathode (60). The elongated vertical cathode (60) extends downwardly from the lower surface (52) of the cathode connector (50). The elongated vertical cathode (60) has a proximal end (62), a free distal end (64), and an intermediate portion (66). The proximal end (62) of the elongated vertical cathode is connected to the upper surface (52) of the cathode connector (40). The free distal end (64) of the vertical cathode extends downwardly towards the base (7) of the aluminium electrolysis cell. In some embodiments, the elongated vertical cathode (60) is aluminum wettable. For example, the elongated vertical cathode (60) may comprise TiB₂、ZrB₂、HfB₂、SrB₂One or more of carbonaceous materials, and combinations thereof.

In the embodiment shown in fig. 1 and 2, the elongated vertical cathode (60) overlaps the elongated vertical anode (40) such that the distal end (64) of the elongated vertical cathode (60) is proximate the middle portion (46) of the elongated vertical anode (40). Further, in the illustrated embodiment, the distal end (44) of the elongated vertical anode (40) is proximate the middle portion (66) of the elongated vertical cathode (60). In some embodiments, the anode-cathode overlap is configured to balance the voltage requirements of the cell and/or the energy consumption of the cell. In some embodiments, the anode-cathode overlap (ACO) is 0 to 50 inches. In some embodiments, the anode-cathode overlap (ACO) is 1 to 50 inches. In some embodiments, the anode-cathode overlap (ACO) is 5 to 50 inches. In some embodiments, the anode-cathode overlap (ACO) is 10 to 50 inches. In some embodiments, the anode-cathode overlap (ACO) is 20 to 50 inches. In some embodiments, the anode-cathode overlap (ACO) is 25 to 50 inches. In some embodiments, the anode-cathode overlap (ACO) is at least some overlap up to 12 inches of overlap. In some embodiments, the anode-cathode overlap (ACO) is at least 2 inches of overlap to 10 inches of overlap. In some embodiments, the anode-cathode overlap (ACO) is at least 3 inches of overlap to 8 inches of overlap. In some embodiments, the anode-cathode overlap (ACO) is at least 3 inches of overlap to 6 inches of overlap.

One or more inert spacers (100) may be located between the elongated vertical cathode (60) and the elongated vertical anode (40) to maintain a desired anode-to-cathode distance (ACD). In some embodiments, the ACD may be 1/8 inches to 3 inches. In some embodiments, the ACD may be 1/8 inches to 2 inches. In some embodiments, the ACD may be 1/8 inches to 1 inch. In some embodiments, the ACD may be 1/8 inches to 1/4 inches. In some embodiments, the ACD may be 1/4 inches to 1/2 inches. In some embodiments, the ACD may be 1/8 inches to 3/4 inches. In some embodiments, the ACD may be 1/8 inches to 1 inch. In some embodiments, the ACD may be 1/8 inches to 1/2 inches.

The refractory side wall (15), refractory top cover (17) and bottom (30) define a cell chamber (19) in the aluminium electrolysis cell (1). In some embodiments, the chamber (19) contains: a molten metal pad (250), an upper layer (400) of purified molten aluminum, and an electrolyte (300). The molten metal pad (250) is in contact with the bottom (30). The electrolyte (300) separates the upper layer (400) from the molten metal pad (250). The elongated vertical anode (40) extends upwardly from the bottom (30), through the molten metal pad (250) and terminates in the electrolyte (300). The elongated vertical cathode (60) extends downwardly from the cathode connector (50) and terminates in the electrolyte (300) such that the elongated vertical cathode (60) overlaps the elongated vertical anode (40) in the electrolyte (300). Thereby, the elongated vertical cathode (60) is separated from the elongated vertical anode (40) by the electrolyte (300).

As described above, the electrolyte (300) separates the upper layer (400) of purified aluminum from the molten metal pad (250). In this regard, the composition of the electrolyte (300) may be selected such that the electrolyte (300) has a density lower than the molten metal pad (250) and a density higher than the upper layer (400) of purified aluminum. In some embodiments, the electrolyte (300) may include at least one of fluorides and/or chlorides of Na, K, Al, Ba, Ca, Ce, La, Cs, Rb, and combinations thereof, among others.

The molten metal pad (250) may comprise at least one alloy comprising one or more of Al, Si, Cu, Fe, Sb, Gd, Cd, Sn, Pb, and impurities.

In some embodiments, the purified molten aluminum has 99.5 wt.% to 99.999 wt.% aluminum. In some embodiments, the purified molten aluminum has 99.6 wt.% to 99.999 wt.% aluminum. In some embodiments, the purified molten aluminum has 99.7 wt.% to 99.999 wt.% aluminum. In some embodiments, the purified molten aluminum has 99.8 wt.% to 99.999 wt.% aluminum. In some embodiments, the purified molten aluminum has 99.9 wt.% to 99.999 wt.% aluminum. In some embodiments, the purified molten aluminum has 99.95 wt.% to 99.999 wt.% aluminum. In some embodiments, the purified molten aluminum has 99.98 wt.% to 99.999 wt.% aluminum.

In some embodiments, the purified molten aluminum has 99.5 wt.% to 99.99 wt.% aluminum. In some embodiments, the purified molten aluminum has 99.5 wt.% to 99.95 wt.% aluminum. In some embodiments, the purified molten aluminum has 99.5 wt.% to 99.9 wt.% aluminum. In some embodiments, the purified molten aluminum has 99.5 wt.% to 99.8 wt.% aluminum. In some embodiments, the purified molten aluminum has 99.5 wt.% to 99.7 wt.% aluminum.

In some embodiments, the aluminum electrolysis cell (1) comprises a plurality of elongated vertical anodes (40). In some embodiments, the aluminum electrolysis cell (1) comprises a plurality of elongated vertical cathodes (60). The plurality of elongated vertical anodes (40) may be interleaved with the plurality of elongated vertical cathodes (60).

In some embodiments, the aluminum electrolysis cell (1) includes a cell inlet channel (70) that passes through the cell chamber (19) thereby providing access to a lower portion of the cell chamber. The tank inlet passage (70) may have an inlet aperture (72). Aluminium raw material (200) may be added to the aluminium electrolysis cell (1) via the inlet aperture (72).

In some embodiments, the aluminum electrolysis cell (1) includes aluminum extraction holes (80) through the refractory side wall (15), thereby providing access to the upper portion of the cell chamber (19). Purified aluminum (400) can be extracted from the aluminum electrolysis cell (1) via the extraction aperture (80).

In some embodiments, the aluminum electrolysis cell (1) includes an inert gas inlet formed in the refractory top cover (17). The inert gas inlet is configured to provide an inert atmosphere (500) to the chamber (19).

In some embodiments, the aluminum electrolysis cell (1) comprises an outer shell (5). The housing may comprise steel or other suitable material. In some embodiments, the housing (5) may include a housing floor (6) located below the base. In some embodiments, the outer shell (5) may include a shell sidewall (9) spaced from the refractory sidewall (15) and surrounding the refractory sidewall (15).

In some embodiments, the aluminum electrolysis cell (1) may include a thermal insulator (11). The thermal insulation may be located between the shell floor (6) and the base (7), and between the shell side wall (9) and the refractory side wall (15). The thermal insulation may promote a high electrical efficiency of the aluminium electrolysis cell (1).

One embodiment of a method of purifying aluminum includes supplying an electric current to the elongated vertical anode (40). Molten material (comprising molten aluminum) from the molten metal pad (250) may creep up the vertical surfaces of the elongated vertical anodes (40). In some embodiments, upward creep of molten material from the molten metal pad may occur continuously during operation of the trough (1). In some embodiments, the elongated vertical anode may cover substantially all of the exposed surface of the elongated vertical anode (40). Molten aluminum on the surface of the elongated vertical anode (40) may be anodized through the elongated vertical anode (40), thereby generating aluminum ions. At least a portion of the aluminum ions may be transferred to the surface of the elongated vertical cathode (60) via the electrolyte. At least a portion of the aluminum ions may be reduced via the elongated vertical cathode (60), thereby producing purified aluminum on the surface of the elongated vertical cathode (60). Without being bound by a particular mechanism or theory, one possible explanation is that the purified aluminum then creeps up along the surface of the elongated vertical cathode (60) due to the buoyancy of the purified aluminum in the electrolyte (300). Thus, the purified aluminum tends to collect as a layer (400) above the electrolyte (300). For example, the molten metal pad layer is below the electrolyte region based on a density difference between the purified aluminum product and the electrolyte (e.g., bath components in the electrolyte) molten metal pad layer (e.g., including a feedstock containing aluminum metal, impurities, and/or densification aids (additives that increase density to configure the metal pad layer to have a density greater than the electrolyte).

In some embodiments, purified aluminum (400) is produced via the electrolytic cell (1) with an energy efficiency of 1 to 15kWh/kg of purified aluminum. In some embodiments, purified aluminum (400) is produced via the electrolytic cell (1) with an energy efficiency of 1 to 10kWh/kg of purified aluminum. In some embodiments, purified aluminum (400) is produced via the electrolytic cell (1) with an energy efficiency of 1 to 8kWh/kg of purified aluminum. In some embodiments, purified aluminum (400) is produced via the electrolytic cell (1) with an energy efficiency of 1 to 6kWh/kg of purified aluminum. In some embodiments, purified aluminum (400) is produced via the electrolytic cell (1) with an energy efficiency of 1 to 4kWh/kg of purified aluminum.

In some embodiments, purified aluminum (400) is produced via the electrolytic cell (1) with an energy efficiency of 5 to 15kWh/kg of purified aluminum. In some embodiments, purified aluminum (400) is produced via the electrolytic cell (1) with an energy efficiency of 10 to 15kWh/kg of purified aluminum. In some embodiments, purified aluminum (400) is produced via the electrolytic cell (1) with an energy efficiency of 12 to 15kWh/kg of purified aluminum.

In some embodiments, purified aluminum (400) is produced via the electrolytic cell (1) with an energy efficiency of 2 to 10kWh/kg of purified aluminum. In some embodiments, purified aluminum (400) is produced via the electrolytic cell (1) with an energy efficiency of 2 to 8kWh/kg of purified aluminum. In some embodiments, purified aluminum (400) is produced via the electrolytic cell (1) with an energy efficiency of 2 to 6kWh/kg of purified aluminum.

In some embodiments, the method may include adding aluminum feedstock (200) to the tank chamber (19) via the tank inlet aperture (72). In some embodiments, the aluminum feedstock (200) may be added substantially continuously during operation of the cell (1). In some embodiments, the aluminum feedstock (200) may be added by metering the aluminum feedstock (200) at a first feed rate. In some embodiments, the aluminum source (200) may be added periodically.

In some embodiments, the method can include removing at least a portion of the upper layer of purified aluminum (400) from the cell (1) via an aluminum extraction aperture (80). In some embodiments, the aluminum feedstock (200) may be removed substantially continuously during operation of the cell (1). In some embodiments, for example, the first removal rate may be controlled based at least in part on the second removal rate. In some embodiments, the aluminum feedstock (200) may be periodically removed during operation of the cell (1). In some embodiments, equipment (e.g., alumina, graphite, and/or TiB) configured to remove the purified aluminum product without contaminating the product is used₂Tapping device) completes the removal step.

In some embodiments, the method may include providing an inert atmosphere to the chamber (19) via an inert gas inlet (90). In this regard, the chamber may be isolated from the ambient atmosphere. Examples of inert gases include helium, argon and nitrogen, among others.

In some embodiments, a residue (220) may be produced at least in part as a result of the passing step. The residue (220) may have a density higher than the molten metal liquid layer (250). As mentioned above, the upper surface (32) of the base (30) may be sloped. In some embodiments, the ramp may run from the refractory sidewall (15) down to the trough inlet channel (70). Thereby, the residue (220) can be discharged along the upper surface (32) towards the tank inlet channel (70). In some embodiments, the residue may be removed from the sump chamber (19) via a sump inlet channel (70). In some embodiments, impurities may tend to collect in the molten metal pad (250). The trough inlet channel (70) may thereby facilitate removal of at least a portion of the molten metal pad (250).

Examples

The following examples are intended to illustrate the invention and should not be construed as limiting the invention in any way.

Laboratory scale electrolytic purification tank

Schematic diagrams of cells used to perform laboratory scale experiments of electrolytic purification cells are shown in fig. 3 and 4 (not to scale). Fig. 3 is a side view (elevation view) of an electrolytic purification cell for laboratory scale testing. Fig. 4 is a top down schematic (plan view) of an electrolytic purification cell (cathode assembly not shown) for laboratory scale testing. Fig. 5 is a graph depicting experimental data obtained, shown as Fe (% by weight) in metal determined by ICP, shown for each cell.

Four tests with different electrolyte and anode plate configurations were performed using the cell configurations shown in figures 3 and 4. The cell is placed in an electric furnace (101) to heat and control the cell temperature. Inside the furnace, the cell is contained in an Inconel retort (102) in which a graphite crucible (103) is placed. The graphite crucible provides an electrical connection to the anodic aluminum pad at the bottom of the cell. An alumina liner (104) is placed in the graphite retort to provide electrical insulation between the graphite retort walls and the electrolyte and between the graphite retort walls and the cathodic aluminum.

Impure aluminum (feed) alloyed with copper (e.g., 15-60% target 35 wt% as a densification aid) is added to the cell as anodic aluminum. Copper is added to the impure aluminum to increase the melt density to greater than the electrolyte. Mounting two vertical anodes (TiB) in an anodic aluminium pad₂Plates (105)) with their ends extending vertically into the electrolyte.

The cathode electrical connection is constructed from a graphite block (106). Vertical cathode (TiB)₂Plate (108)) is secured to the graphite cathode electrical connection and placed between the two anode plates. The cathode electrical connection is secured through a superstructure not shown in fig. 3. For test 1, the cathode plate had the same dimensions as the respective anode plate. For test 2, the anode plate area was doubled, while the cathode plate area was the same as for test 1. The anode plate area is doubled by doubling the width, which is the long dimension on the anode plate in the top-down view of fig. 4. Two other runs (runs 3 and 4) are described in table 1 and the results of all four runs are shown in figure 5. When pure aluminum is in TiB₂The graphite blocks have cavities to collect pure aluminum when made on the plates and flowing upwards due to buoyancy. The anode aluminum plate (109) fills the bottom of the graphite crucible and is lowered while the cell is running.

The electrolyte used in the test was AlF₃NaF, KF and BaF₂A mixture of salts. The electrolyte level (107) is maintained near the top of the graphite retort. The electrolyte mixture composition is selected to have a density (when molten) between that of the anodic and cathodic aluminum. The electrolyte composition of experiment 1 contained BaF₂、AlF₃And KF. The electrolyte composition of experiment 2 contained BaF₂、AlF₃And NaF. Other useful electrolyte compositions include those having at least 5% BaF₂And at least 5% AlF₃Those of (a).

The cell containing the anode aluminum alloy and electrolyte mixture was heated and maintained at a temperature of 700 to 900 c by the electric furnace. Once the electrolyte mixture is at this temperature, a direct current of 0 to 150 amps is provided between the anode and cathode.

Cell voltage, current and temperature were recorded during each experiment using a data acquisition system. The purified aluminum is collected in a cathode collection chamber. Iron impurities in aluminum were measured in order to quantify the purification performance from samples taken from feeding aluminum and purifying molten aluminum. The elemental impurity concentration from the molten aluminum was measured using inductively coupled plasma mass spectrometry (ICP).

The results of both tests are shown in table 1 below.

TABLE 1 summary of results of two electrolytic purification cell tests

While a number of embodiments of the present invention have been described, it is to be understood that these examples are illustrative only and not limiting, and that many modifications may become apparent to those of ordinary skill in the art. Further, the various steps may be performed in any desired order (and any desired steps may be added and/or any desired steps may be eliminated).