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 invention describes an integrated process for carbon dioxide capture, sequestration and utilisation, which comprises: a) providing an aqueous slurry comprising an aqueous solution and a particulate solid comprising an activated magnesium silicate mineral; b) in a dissolution stage, contacting a CO.sub.2-containing gas stream with the aqueous slurry to dissolve magnesium from the mineral to provide a magnesium ion enriched aqueous solution and a magnesium depleted solid residue; c) recovering at least a portion of the magnesium depleted solid residue; d) in a separate acid treatment stage, reacting the recovered portion of the magnesium depleted solid residue with a solution comprising a mineral acid or acid salt to further dissolve magnesium and other metals and to provide an acid-treated solid residue; e) recovering the acid-treated solid residue; and f) in a separate precipitation stage, precipitating magnesium carbonate from the magnesium ion enriched aqueous solution.

The present invention describes an integrated process for carbon dioxide capture, sequestration and utilisation, which comprises: a) providing an aqueous slurry comprising an aqueous solution and a particulate solid comprising an activated magnesium silicate mineral; b) in a dissolution stage, contacting a CO.sub.2-containing gas stream with the aqueous slurry to dissolve magnesium from the mineral to provide a magnesium ion enriched aqueous solution and a magnesium depleted solid residue; c) recovering at least a portion of the magnesium depleted solid residue; d) in a separate acid treatment stage, reacting the recovered portion of the magnesium depleted solid residue with a solution comprising a mineral acid or acid salt to further dissolve magnesium and other metals and to provide an acid-treated solid residue; e) recovering the acid-treated solid residue; and f) in a separate precipitation stage, precipitating magnesium carbonate from the magnesium ion enriched aqueous solution.

Embodiments of the present disclosure are directed to systems and methods of removing carbon dioxide from a gaseous stream using magnesium hydroxide and then regenerating the magnesium hydroxide. In some embodiments, the systems and methods can further comprise using the waste heat from one or more gas streams to provide some or all of the heat needed to drive the reactions. In some embodiments, magnesium chloride is primarily in the form of magnesium chloride dihydrate and is fed to a decomposition reactor to generate magnesium hydroxychloride, which is in turn fed to a second decomposition reactor to generate magnesium hydroxide.

Embodiments of the present disclosure are directed to systems and methods of removing carbon dioxide from a gaseous stream using magnesium hydroxide and then regenerating the magnesium hydroxide. In some embodiments, the systems and methods can further comprise using the waste heat from one or more gas streams to provide some or all of the heat needed to drive the reactions. In some embodiments, magnesium chloride is primarily in the form of magnesium chloride dihydrate and is fed to a decomposition reactor to generate magnesium hydroxychloride, which is in turn fed to a second decomposition reactor to generate magnesium hydroxide.

The present invention aims to provide techniques for efficiently synthesizing inorganic microparticles. According to the present invention, inorganic carbonate microparticles can be synthesized by generating ultrafine bubbles containing carbonic acid gas by injecting a gas containing carbonic acid gas and a liquid into a reaction vessel through a nozzle to deposit an inorganic carbonate having an average primary particle size of 300 nm or less in the presence of the ultrafine bubbles.

A platform for sequestering carbon dioxide using a body of water is described. The platform has a vessel for holding solid metal hydroxide and for exposing the solid metal hydroxide to a flow of water to create a solution of a metal hydroxide having a pH level. The solution containing metal hydroxide is released into the body of water, causing a reaction with the carbon dioxide present in the body of water, thereby producing metal carbonate/bicarbonate, thus sequestering the carbon dioxide. A choice of the metal in the metal hydroxide, a rate of the releasing the solution containing the metal hydroxide into the body of water, and a flow rate of the flow of water so that to substantially maintain the solution containing the metal hydroxide at the pH level that is defined as environmentally safe and not changing chemistry of seawater. A corresponding method is also provided.

A platform for sequestering carbon dioxide using a body of water is described. The platform has a vessel for holding solid metal hydroxide and for exposing the solid metal hydroxide to a flow of water to create a solution of a metal hydroxide having a pH level. The solution containing metal hydroxide is released into the body of water, causing a reaction with the carbon dioxide present in the body of water, thereby producing metal carbonate/bicarbonate, thus sequestering the carbon dioxide. A choice of the metal in the metal hydroxide, a rate of the releasing the solution containing the metal hydroxide into the body of water, and a flow rate of the flow of water so that to substantially maintain the solution containing the metal hydroxide at the pH level that is defined as environmentally safe and not changing chemistry of seawater. A corresponding method is also provided.

This invention provides a method for efficiently separating magnesium and lithium from salt lake brine, and simultaneously preparing high-purity magnesium oxide and battery-grade lithium carbonate. The detailed processing steps are as follows: (1) adding urea into the brine to dissolve, (2) placing the solution into the reactor for hydrothermal reaction, the magnesium ion will precipitate and enter the solid phase; (3) filtering and drying the production to get the magnesium carbonate solid, while the lithium ion remains in the liquid phase; (4) after directly concentration and precipitation, the battery-grade lithium carbonate can be obtained, while the calcination of solid-phase product results in the high-purity magnesium oxide. In this method, urea is used as the precipitant to separate magnesium and lithium in salt lake without introducing any new metal ion, and the brine solution is not diluted. The solid product is white and fluffy powder, which is easy to filter and separate. The extraction rate of lithium is high than 94%, and the purity of MgO obtained by calcination is higher than 99.5%.

This invention provides a method for efficiently separating magnesium and lithium from salt lake brine, and simultaneously preparing high-purity magnesium oxide and battery-grade lithium carbonate. The detailed processing steps are as follows: (1) adding urea into the brine to dissolve, (2) placing the solution into the reactor for hydrothermal reaction, the magnesium ion will precipitate and enter the solid phase; (3) filtering and drying the production to get the magnesium carbonate solid, while the lithium ion remains in the liquid phase; (4) after directly concentration and precipitation, the battery-grade lithium carbonate can be obtained, while the calcination of solid-phase product results in the high-purity magnesium oxide. In this method, urea is used as the precipitant to separate magnesium and lithium in salt lake without introducing any new metal ion, and the brine solution is not diluted. The solid product is white and fluffy powder, which is easy to filter and separate. The extraction rate of lithium is high than 94%, and the purity of MgO obtained by calcination is higher than 99.5%.