The present invention refers to the field of flue gas purification, which discloses a method and apparatus for capturing carbon dioxide and producing sulfuric acid by sodium bisulfate; using a three-format electrodialysis apparatus to convert the desulfurized by-product NaHSO.sub.4 into H.sub.2SO.sub.4 while capturing CO.sub.2 in the flue gas in the cathode chamber. Under the action of electric field drive and ion exchange membrane, HSO.sub.4.sup.− enters the anode chamber to generate H.sub.2SO.sub.4 and is concentrated, and Na.sup.+ enters the cathode chamber to generate NaOH; the flue gas containing CO.sub.2 to be treated is introduced from the cathode chamber and absorbed by NaOH. The invention provides a simple, green, and economic proceeding method to capture the carbon dioxide in the flue gas during the comprehensive utilization of sodium bisulfate solution, which is of better environmental benefits and improvement of the flue gas treatment technology and reducing the pressure of desulfurization gypsum treatment.

Provided are methods of extracting lithium from a lithium containing solution, as well as the resulting compositions. The method includes supplying a lithium containing solution to a lithium capture step, the lithium capture step being operable to capture lithium from the lithium salt containing solution. The method further includes recovering lithium from the lithium capture step to produce a lithium rich stream. In especially preferred methods, the lithium capture step is performed to increase the lithium to sodium ratio above at least 1:1. Optionally, the lithium rich stream can be purified to remove divalent ions and borate ions. The lithium rich stream is then concentrated by supplying the lithium rich stream to a reverse osmosis step to produce a concentrated lithium rich stream.

The present invention relates to an apparatus and method for bio-assisted treatment of spent caustic obtained from hydrocarbon and gas processing installations. The present invention also relates to method for recovery of caustic and recovery of sulfur from spent caustic. According to present invention, the sulfide removal is about 96% and the sulphur formation and deposition on the electrode lies in range of 72±8%.

The present invention relates to an apparatus and method for bio-assisted treatment of spent caustic obtained from hydrocarbon and gas processing installations. The present invention also relates to method for recovery of caustic and recovery of sulfur from spent caustic. According to present invention, the sulfide removal is about 96% and the sulphur formation and deposition on the electrode lies in range of 72±8%.

Provided are methods of extracting lithium from a lithium containing solution, as well as the resulting compositions. The method includes supplying a lithium containing solution to a lithium capture step, the lithium capture step being operable to capture lithium from the lithium salt containing solution. The method further includes recovering lithium from the lithium capture step to produce a lithium rich stream. In especially preferred methods, the lithium capture step is performed to increase the lithium to sodium ratio above at least 1:1. Optionally, the lithium rich stream can be purified to remove divalent ions and borate ions. The lithium rich stream is then concentrated by supplying the lithium rich stream to a reverse osmosis step to produce a concentrated lithium rich stream.

There are provided system for preparing lithium hydroxide from an aqueous composition comprising a lithium compound and use of the system thereof to prepare lithium hydroxide, the system comprising an electrochemical cell, a pH probe and at least one inlet for receiving acid or base for maintaining pH. For example, the lithium compound can be lithium sulphate and the aqueous composition can be at least substantially maintained at a pH having a value of about 2 to about 4.

There are provided system for preparing lithium hydroxide from an aqueous composition comprising a lithium compound and use of the system thereof to prepare lithium hydroxide, the system comprising an electrochemical cell, a pH probe and at least one inlet for receiving acid or base for maintaining pH. For example, the lithium compound can be lithium sulphate and the aqueous composition can be at least substantially maintained at a pH having a value of about 2 to about 4.

A method (10) for the processing of lithium containing brines, the method comprising the method steps of: (i) Passing a lithium containing brine (12) to a filtration step (14) to remove sulphates; (ii) Passing a product (16) of step (i) to a first ion exchange step (18) to remove divalent impurities; (iii) Passing a product (20) of step (ii) to a second ion exchange step (22) to remove boron impurities; (iv) Passing a product (24) of step (iii) to an electrolysis step (26) to produce lithium hydroxide (28); and (v) Passing a product (30) of step (iv) to a crystallisation step (32) that in turn provides a lithium hydroxide monohydrate product (34).

A method (10) for the processing of lithium containing brines, the method comprising the method steps of: (i) Passing a lithium containing brine (12) to a filtration step (14) to remove sulphates; (ii) Passing a product (16) of step (i) to a first ion exchange step (18) to remove divalent impurities; (iii) Passing a product (20) of step (ii) to a second ion exchange step (22) to remove boron impurities; (iv) Passing a product (24) of step (iii) to an electrolysis step (26) to produce lithium hydroxide (28); and (v) Passing a product (30) of step (iv) to a crystallisation step (32) that in turn provides a lithium hydroxide monohydrate product (34).

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.