A method for transforming a crystal form of an electrolyte containing lithium for aluminum electrolysis includes the following steps: S1, pulverizing the electrolyte containing lithium; S2, uniformly mixing an additive with the electrolyte powder to obtain a mixture, wherein the additive is one or more selected from the group consisting of an oxide of an alkali metal other than lithium, an oxo acid salt of an alkali metal other than lithium, and a halide of an alkali metal other than lithium; a molar ratio of a sum of alkali metal fluoride contained in the electrolyte, alkali metal fluoride directly added from the additive, and alkali metal fluoride to which the additive is converted under the high-temperature calcination condition in the mixture to aluminum fluoride is greater than 3; S3, calcining the mixture at a high temperature.

A method for transforming a crystal form of an electrolyte containing lithium for aluminum electrolysis includes the following steps: S1, pulverizing the electrolyte containing lithium; S2, uniformly mixing an additive with the electrolyte powder to obtain a mixture, wherein the additive is one or more selected from the group consisting of an oxide of an alkali metal other than lithium, an oxo acid salt of an alkali metal other than lithium, and a halide of an alkali metal other than lithium; a molar ratio of a sum of alkali metal fluoride contained in the electrolyte, alkali metal fluoride directly added from the additive, and alkali metal fluoride to which the additive is converted under the high-temperature calcination condition in the mixture to aluminum fluoride is greater than 3; S3, calcining the mixture at a high temperature.

The method for producing an electrolytic aluminum foil of the present disclosure is a method for producing an electrolytic aluminum foil, the method including supplying an electrolytic solution in an electrolytic cell provided with a diaphragm between an anode and a cathode and depositing an aluminum foil on a surface of the cathode by electrolysis, wherein the diaphragm is made of aluminum having a purity of 85.0% or more and has a plurality of pores having an average pore diameter of 100 to 1000 μm.

The method for producing an electrolytic aluminum foil of the present disclosure is a method for producing an electrolytic aluminum foil, the method including supplying an electrolytic solution in an electrolytic cell provided with a diaphragm between an anode and a cathode and depositing an aluminum foil on a surface of the cathode by electrolysis, wherein the diaphragm is made of aluminum having a purity of 85.0% or more and has a plurality of pores having an average pore diameter of 100 to 1000 μm.

New methods of producing aluminum fluoride from cryolite are disclosed. A method may include a step of reacting cryolite bath materials with aluminum sulfate, thereby producing a reactant product, the reactant product comprising aluminum fluoride. The method may further include a step of removing impurities from the reactant product, thereby creating a purified product comprising the aluminum fluoride. The removed impurities may comprise at least one of sodium (Na), magnesium (Mg), and calcium (Ca). In one embodiment, due to the removing step, the purified product contains not greater than 0.2 wt. % of calcium.

New methods of producing aluminum fluoride from cryolite are disclosed. A method may include a step of reacting cryolite bath materials with aluminum sulfate, thereby producing a reactant product, the reactant product comprising aluminum fluoride. The method may further include a step of removing impurities from the reactant product, thereby creating a purified product comprising the aluminum fluoride. The removed impurities may comprise at least one of sodium (Na), magnesium (Mg), and calcium (Ca). In one embodiment, due to the removing step, the purified product contains not greater than 0.2 wt. % of calcium.

Disclosed herein are systems and methods for obtaining efficient aluminum smelters. More specifically disclosed herein is a method comprising: applying an alternating current (AC) comprising an oscillatory current waveform to an electrolytic cell comprising an electrolyte for a first predetermined time, wherein waveform comprises an amplitude, frequency and/or phase that are predetermined to stabilize the electrolytic cell such that substantially no change in a current oscillation is observed in the electrolyte during electrolysis. Also disclosed herein is a system comprising an electrolytic cell, direct current and alternating current sources. The disclosed electrolytic cell exhibits substantially no change in oscillations present in the molten salt electrolyte over a predetermined period of time when the AC is provided to the electrolytic cell.

Disclosed herein are systems and methods for obtaining efficient aluminum smelters. More specifically disclosed herein is a method comprising: applying an alternating current (AC) comprising an oscillatory current waveform to an electrolytic cell comprising an electrolyte for a first predetermined time, wherein waveform comprises an amplitude, frequency and/or phase that are predetermined to stabilize the electrolytic cell such that substantially no change in a current oscillation is observed in the electrolyte during electrolysis. Also disclosed herein is a system comprising an electrolytic cell, direct current and alternating current sources. The disclosed electrolytic cell exhibits substantially no change in oscillations present in the molten salt electrolyte over a predetermined period of time when the AC is provided to the electrolytic cell.

The invention relates to vertical or inclined electrodes of an electrolyzer for electrolytically producing aluminum from aluminum oxide. An electrode contains an electrode base and a surface coating based on refractory ceramics. According to a first variant of the invention, the electrode base is made of a composite material containing between 5% and 90% by mass of refractory ceramics, and of at least one metal having a melting temperature exceeding 1000° C., which forms refractory intermetallic compounds upon interaction with aluminum, and/or containing at least one alloy of such a metal. According to a second variant of the invention, the electrode base is made of a metal alloy, for example structural steel or another alloy, and the surface of the electrode base has applied thereto an intermediary layer consisting of a composite material having the composition described above.

The invention relates to vertical or inclined electrodes of an electrolyzer for electrolytically producing aluminum from aluminum oxide. An electrode contains an electrode base and a surface coating based on refractory ceramics. According to a first variant of the invention, the electrode base is made of a composite material containing between 5% and 90% by mass of refractory ceramics, and of at least one metal having a melting temperature exceeding 1000° C., which forms refractory intermetallic compounds upon interaction with aluminum, and/or containing at least one alloy of such a metal. According to a second variant of the invention, the electrode base is made of a metal alloy, for example structural steel or another alloy, and the surface of the electrode base has applied thereto an intermediary layer consisting of a composite material having the composition described above.