Method and system are disclosed for the production and use of a chemical compound, where a given amount of CO.sub.2 is emitted in the production and the use, including producing a second chemical compound that is required for the production or the use of the first compound, where the production of the second compound consumes CO.sub.2 and sequesters it from the atmosphere so that the total net CO.sub.2 emitted in the production and use of the first compound is now reduced. In one embodiment, the second chemical compound is a negative-CO.sub.2-emissions hydrogen, oxygen or chlorine gas produced in an electrolytic cell.

Systems and methods for processing slag produced by iron and steel making processes are disclosed. The slag is treated produce a series of valued industrial products, such as metal oxides, metal carbonates, rare-earth metals, and water glass. The systems and methods also integrate slag processing with CO.sub.2 sequestration and flue gas desulphurization. Processing slag minimizes the land use for stockpiling or landfilling wastes produced from iron and steel making processes and protects the ground water underneath. Overall, the solid and gaseous emissions of an energy-intensive and highly polluted industrial process have been largely reduced, recycled and valorized in order to achieve a near zero-emission goal.

Systems and methods for processing slag produced by iron and steel making processes are disclosed. The slag is treated produce a series of valued industrial products, such as metal oxides, metal carbonates, rare-earth metals, and water glass. The systems and methods also integrate slag processing with CO.sub.2 sequestration and flue gas desulphurization. Processing slag minimizes the land use for stockpiling or landfilling wastes produced from iron and steel making processes and protects the ground water underneath. Overall, the solid and gaseous emissions of an energy-intensive and highly polluted industrial process have been largely reduced, recycled and valorized in order to achieve a near zero-emission goal.

An electrochemical cell comprising a membrane electrode assembly and a selectively permeable barrier layer comprising sulfonated polymer is disclosed. The selectively permeable barrier layer is arranged facing at least one electrocatalyst layer, e.g., anode or cathode. The sulfonated polymer layer aids in controlling the movement of fluids and/or their constituents into and out of the electrochemical cell assembly for separation or capture for subsequent use.

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.

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.

A dual-membrane on-line generator for an acid or alkali solution is provided, including an upper electrolytic cell body (3), a middle electrolytic cell body (4) and a lower electrolytic cell body (5) which are clamped by an upper fastening steel plate (1) and a lower fastening steel plate (2), an upper regeneration liquid channel (A), a middle eluent channel (B) and a lower regeneration liquid channel (C) being provided on the middle electrolytic cell body (4).

A dual-membrane on-line generator for an acid or alkali solution is provided, including an upper electrolytic cell body (3), a middle electrolytic cell body (4) and a lower electrolytic cell body (5) which are clamped by an upper fastening steel plate (1) and a lower fastening steel plate (2), an upper regeneration liquid channel (A), a middle eluent channel (B) and a lower regeneration liquid channel (C) being provided on the middle electrolytic cell body (4).