Embodiments relate to methods for generating selected materials from a natural brine. A natural brine comprising at least a portion of a selected material is heated. CO.sub.2 is added and mixes with the natural brine forming a mixture such that the CO.sub.2/P is a first predetermined value. The mixture is held so that impurities in the natural brine precipitate as solids leaving a second brine substantially comprising the selected material. The second brine is heated. CO.sub.2 gas is injected into the second brine, mixing so that the CO.sub.2/P is a second predetermined value. The mixture is held so that the selected material precipitates out and are removed.

Embodiments relate to methods for generating selected materials from a natural brine. A natural brine comprising at least a portion of a selected material is heated. CO.sub.2 is added and mixes with the natural brine forming a mixture such that the CO.sub.2/P is a first predetermined value. The mixture is held so that impurities in the natural brine precipitate as solids leaving a second brine substantially comprising the selected material. The second brine is heated. CO.sub.2 gas is injected into the second brine, mixing so that the CO.sub.2/P is a second predetermined value. The mixture is held so that the selected material precipitates out and are removed.

In a method for recovering active metals of a lithium secondary battery according to an embodiment, a cathode active material mixture is collected from the cathode of the lithium secondary battery, the cathode active material mixture is reduced by a reducing reaction to prepare a preliminary precursor mixture, an aqueous lithium precursor solution is formed from the preliminary precursor mixture, and an aluminum-containing material is removed from the aqueous lithium precursor solution with an aluminum removing resin.

In a method for recovering active metals of a lithium secondary battery according to an embodiment, a cathode active material mixture is collected from the cathode of the lithium secondary battery, the cathode active material mixture is reduced by a reducing reaction to prepare a preliminary precursor mixture, an aqueous lithium precursor solution is formed from the preliminary precursor mixture, and an aluminum-containing material is removed from the aqueous lithium precursor solution with an aluminum removing resin.

Proposed is a method of preparing high-purity lithium carbonate through reduction calcining of waste cathode materials without using a carbonate such as sodium carbonate. The method reduces the amount of water required for lithium carbonate recovery, thereby reducing energy consumption for evaporation of water. The method includes (a) preparing scrap powder, (b) reducing and calcining the scrap powder using activated carbon, (c) preparing a lithium hydrogen carbonate solution by adding carbon dioxide gas and the reduced and calcined scrap powder to 8° C. to 12° C. soft water, (d) separating the lithium hydrogen carbonate solution into solid and liquid; (e) converting lithium hydrogen carbonate into lithium carbonate by heating, evaporating, and concentrating the lithium hydrogen carbonate solution, and (f) obtaining the lithium carbonate through filtration.

Proposed is a method of preparing high-purity lithium carbonate through reduction calcining of waste cathode materials without using a carbonate such as sodium carbonate. The method reduces the amount of water required for lithium carbonate recovery, thereby reducing energy consumption for evaporation of water. The method includes (a) preparing scrap powder, (b) reducing and calcining the scrap powder using activated carbon, (c) preparing a lithium hydrogen carbonate solution by adding carbon dioxide gas and the reduced and calcined scrap powder to 8° C. to 12° C. soft water, (d) separating the lithium hydrogen carbonate solution into solid and liquid; (e) converting lithium hydrogen carbonate into lithium carbonate by heating, evaporating, and concentrating the lithium hydrogen carbonate solution, and (f) obtaining the lithium carbonate through filtration.

A process for the recovery of lithium carbonate from a solution (1) containing a mixture of lithium sulfate and lithium hydroxide, the process comprising the precipitation of lithium carbonate (3) from the solution (1) containing a mixture of lithium sulfate and lithium hydroxide through the addition of carbon dioxide (2).

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.

An improved method of lithium recovery from borax dilute solution is provided. In this method, boron in the borax dilute solution is removed from the medium as borax decahydrate and while this removal process is carried out, liquid-liquid extraction with organic sedimentary chemicals or ion exchange resins are not used.