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.

There are provided methods for preparing lithium carbonate. For example, such methods can comprise reacting an aqueous composition comprising lithium hydroxide with CO.sub.2 by sparging the CO.sub.2 the said composition, thereby obtaining a precipitate comprising the lithium carbonate. The methods can also comprise inserting at least a portion of the precipitate into a clarifier and obtaining a supernatant comprising lithium bicarbonate and a solid comprising the lithium carbonate, separating the solid from the supernatant; and heating the supernatant at a desired temperature so as to at least partially convert the lithium bicarbonate into lithium carbonate.

There are provided methods for preparing lithium carbonate. For example, such methods can comprise reacting an aqueous composition comprising lithium hydroxide with CO.sub.2 by sparging the CO.sub.2 the said composition, thereby obtaining a precipitate comprising the lithium carbonate. The methods can also comprise inserting at least a portion of the precipitate into a clarifier and obtaining a supernatant comprising lithium bicarbonate and a solid comprising the lithium carbonate, separating the solid from the supernatant; and heating the supernatant at a desired temperature so as to at least partially convert the lithium bicarbonate into lithium carbonate.

An electrochemical reactor includes positive and negative electrodes. A conductive and/or dielectric liquid is provided between the positive and negative electrodes. A first isolation member provided on the positive electrode isolates the positive electrode from the liquid, and a second isolation member provided on the negative electrode isolates the negative electrode from the liquid. The first and second isolation member each includes a liquid-repellent porous membrane. The reactor further includes a pressure-applying member which pressurizes the liquid to fill the pores of the first and second liquid-repellent porous membranes with the liquid, thereby causing an electrochemical reaction involving the positive and negative electrodes.

An electrochemical reactor includes positive and negative electrodes. A conductive and/or dielectric liquid is provided between the positive and negative electrodes. A first isolation member provided on the positive electrode isolates the positive electrode from the liquid, and a second isolation member provided on the negative electrode isolates the negative electrode from the liquid. The first and second isolation member each includes a liquid-repellent porous membrane. The reactor further includes a pressure-applying member which pressurizes the liquid to fill the pores of the first and second liquid-repellent porous membranes with the liquid, thereby causing an electrochemical reaction involving the positive and negative electrodes.

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 system for an electrochemical process includes an electrochemical reactor, a converter bridge for supplying direct current to electrodes of the electrochemical reactor, and serial inductors connected to alternating voltage terminals of the converter bridge. The converter bridge includes bi-directional controllable switches between the alternating voltage terminals and direct voltage terminals of the converter bridge. Forced commutation of the bi-directional controllable switches enables reduction of current ripple in the direct current supplied to the electrochemical reactor. The forced commutation enables also to control a power factor of an alternating voltage supply of the system.

An ion source and ion recycle module includes an electrolyte reservoir, an eluent recovery chamber, and an ion exchange connector. The electrolyte reservoir includes a chamber containing an aqueous electrolyte solution including an electrolyte having a chamber inlet and a chamber outlet, and a first electrode. The chamber inlet is fluidically connected to a source chamber of an electrolytic eluent generator and configured to receive depleted electrolyte solution from the source chamber of the electrolytic eluent generator. The chamber outlet is fluidically connected to the source chamber of the electrolytic eluent generator and configured to provide recycled electrolyte solution to the electrolytic eluent generator source chamber. The eluent recovery chamber including a second electrode and configured to receive an eluent solution including eluent counter ions from the eluent generator; and the ion exchange connector including an ion exchange membrane stack.