A system for controlling an electrochemical production process includes a variable controllable power circuit and an electrolytic cell. The cell includes two electrodes and operates in different states dependent on the potential difference across the electrodes. The system includes a power circuit controller that causes the power circuit to apply a given potential difference across the electrodes to initiate operation of the cell in the one of multiple possible states associated with the given potential difference. The possible states include a production state associated with a first non-zero potential difference in which a product of interest is produced, and an idle state associated with a second non-zero potential difference in which the product of interest is not produced. A monitoring and control subsystem maintains a predefined set of production process conditions, including a predefined operating temperature range, while the cell operates in both the production state and the idle state.

A system for controlling an electrochemical production process includes a variable controllable power circuit and an electrolytic cell. The cell includes two electrodes and operates in different states dependent on the potential difference across the electrodes. The system includes a power circuit controller that causes the power circuit to apply a given potential difference across the electrodes to initiate operation of the cell in the one of multiple possible states associated with the given potential difference. The possible states include a production state associated with a first non-zero potential difference in which a product of interest is produced, and an idle state associated with a second non-zero potential difference in which the product of interest is not produced. A monitoring and control subsystem maintains a predefined set of production process conditions, including a predefined operating temperature range, while the cell operates in both the production state and the idle state.

A method and system for electrochemically regenerating hydroxide (MOH) and carbon dioxide (CO.sub.2) from an alkali metal carbonate (M.sub.2CO.sub.3) via an electrochemical reactor that can replace a conventional thermochemical causticizing operation in a DAC system. The electrochemical reactor comprises: a cathode having an inlet for receiving an electrolyte feed stream comprising MOH, M.sub.2CO.sub.3 and H.sub.2O, and an outlet for discharging an electrolyte product stream comprising MOH, M.sub.2CO.sub.3, H.sub.2O and H.sub.2; a porous hydrophilic transport barrier in adjacent contact with the cathode; a porous hydrophilic anode in adjacent contact with the transport barrier configured and operable to generate CO.sub.2 in the presence of MOH while suppressing their recombination; a porous hydrophobic CO.sub.2 and O.sub.2 separation barrier in adjacent contact with the anode; and a product gas exit channel in adjacent contact with the CO.sub.2 and O.sub.2 separation barrier and for discharging an anode product stream comprising at least CO.sub.2.

A method and system for electrochemically regenerating hydroxide (MOH) and carbon dioxide (CO.sub.2) from an alkali metal carbonate (M.sub.2CO.sub.3) via an electrochemical reactor that can replace a conventional thermochemical causticizing operation in a DAC system. The electrochemical reactor comprises: a cathode having an inlet for receiving an electrolyte feed stream comprising MOH, M.sub.2CO.sub.3 and H.sub.2O, and an outlet for discharging an electrolyte product stream comprising MOH, M.sub.2CO.sub.3, H.sub.2O and H.sub.2; a porous hydrophilic transport barrier in adjacent contact with the cathode; a porous hydrophilic anode in adjacent contact with the transport barrier configured and operable to generate CO.sub.2 in the presence of MOH while suppressing their recombination; a porous hydrophobic CO.sub.2 and O.sub.2 separation barrier in adjacent contact with the anode; and a product gas exit channel in adjacent contact with the CO.sub.2 and O.sub.2 separation barrier and for discharging an anode product stream comprising at least CO.sub.2.

An electrochemical method for producing calcium hydroxide includes dissolving a calcium precursor in a first solution in contact with a first electrode to produce Ca.sup.2+ ions, transporting the Ca.sup.2+ ions across a first membrane from the first solution into a second solution using a first electrochemical potential, producing hydroxide ions at a second electrode, transporting the hydroxide ions across a second membrane into the second solution using a second electrochemical potential, and precipitating calcium hydroxide from the second solution.

An electrochemical method for producing calcium hydroxide includes dissolving a calcium precursor in a first solution in contact with a first electrode to produce Ca.sup.2+ ions, transporting the Ca.sup.2+ ions across a first membrane from the first solution into a second solution using a first electrochemical potential, producing hydroxide ions at a second electrode, transporting the hydroxide ions across a second membrane into the second solution using a second electrochemical potential, and precipitating calcium hydroxide from the second solution.

In this disclosure, a process of recycling acid, base and the salt reagents required in the Li recovery process is introduced. A membrane electrolysis cell which incorporates an oxygen depolarized cathode is implemented to generate the required chemicals onsite. The system can utilize a portion of the salar brine or other lithium-containing brine or solid waste to generate hydrochloric or sulfuric acid, sodium hydroxide and carbonate salts. Simultaneous generation of acid and base allows for taking advantage of both chemicals during the conventional Li recovery from brines and mineral rocks. The desalinated water can also be used for the washing steps on the recovery process or returned into the evaporation ponds. The method also can be used for the direct conversion of lithium salts to the high value LiOH product. The method does not produce any solid effluent which makes it easy-to-adopt for use in existing industrial Li recovery plants.

In this disclosure, a process of recycling acid, base and the salt reagents required in the Li recovery process is introduced. A membrane electrolysis cell which incorporates an oxygen depolarized cathode is implemented to generate the required chemicals onsite. The system can utilize a portion of the salar brine or other lithium-containing brine or solid waste to generate hydrochloric or sulfuric acid, sodium hydroxide and carbonate salts. Simultaneous generation of acid and base allows for taking advantage of both chemicals during the conventional Li recovery from brines and mineral rocks. The desalinated water can also be used for the washing steps on the recovery process or returned into the evaporation ponds. The method also can be used for the direct conversion of lithium salts to the high value LiOH product. The method does not produce any solid effluent which makes it easy-to-adopt for use in existing industrial Li recovery plants.

The present disclosure relates to a method for extracting lithium from a lithium-containing material. For example, the method can comprise leaching a roasted lithium-containing material under conditions suitable to obtain an aqueous composition comprising a lithium compound such as lithium sulfate and/or lithium bisulfate. The aqueous composition comprising lithium sulfate and/or lithium bisulfate can optionally be used, for example, in a method for preparing lithium hydroxide comprising an electromembrane process. The roasted lithium-containing material can be prepared, for example by a method which uses an aqueous composition comprising optionally lithium sulfate and/or lithium bisulfate which can be obtained from a method for preparing lithium hydroxide comprising an electromembrane process such as a two-compartment monopolar or bipolar electrolysis process.

The present disclosure relates to a method for extracting lithium from a lithium-containing material. For example, the method can comprise leaching a roasted lithium-containing material under conditions suitable to obtain an aqueous composition comprising a lithium compound such as lithium sulfate and/or lithium bisulfate. The aqueous composition comprising lithium sulfate and/or lithium bisulfate can optionally be used, for example, in a method for preparing lithium hydroxide comprising an electromembrane process. The roasted lithium-containing material can be prepared, for example by a method which uses an aqueous composition comprising optionally lithium sulfate and/or lithium bisulfate which can be obtained from a method for preparing lithium hydroxide comprising an electromembrane process such as a two-compartment monopolar or bipolar electrolysis process.