Extraction of elements and/or compounds from iron-containing materials, such as iron-containing tailings, and related systems and products are generally described. The systems and methods described herein can provide, in accordance with certain embodiments, the ability to efficiently process iron-containing (e.g., iron-rich) tailings even in the presence of aluminosilicates and/or other impurities. In addition, in accordance with some embodiments, the systems and methods described herein can provide the ability to efficiently extract different minerals and/or other compounds (e.g., metal(s), salt(s), etc.) from complex tailings structures. Furthermore, reactors and methods for recovery of a reaction product with a relatively high magnetic susceptibility are generally described. Certain reactors are configured such that, during operation, the reaction products are selectively transported to the magnetic field source, relative to the reactants.

A selective membrane for selectively removing a metal ion from a solution. The selective membrane comprises a substrate, a polyethyleneimine layer comprising a crown ether and a cross-linker, and a polydopamine layer. A method for manufacturing a selective membrane. The method comprises contacting a substrate with polydopamine, forming a polydopamine layer on the surface of the substrate, contacting the polydopamine layer with polyethyleneimine, a cross-linker, and a crown ether, forming a polyethyleneimine layer comprising the crown ether and the cross-linker, and forming an ion channel with the crown ether. A method for selectively removing a metal ion from a solution. The method comprises contacting the solution comprising a metal with a selective membrane, applying an electric field to the selective membrane, and passing the metal ion through an ion channel.

A selective membrane for selectively removing a metal ion from a solution. The selective membrane comprises a substrate, a polyethyleneimine layer comprising a crown ether and a cross-linker, and a polydopamine layer. A method for manufacturing a selective membrane. The method comprises contacting a substrate with polydopamine, forming a polydopamine layer on the surface of the substrate, contacting the polydopamine layer with polyethyleneimine, a cross-linker, and a crown ether, forming a polyethyleneimine layer comprising the crown ether and the cross-linker, and forming an ion channel with the crown ether. A method for selectively removing a metal ion from a solution. The method comprises contacting the solution comprising a metal with a selective membrane, applying an electric field to the selective membrane, and passing the metal ion through an ion channel.

A method for producing a concentrated aqueous sodium hydroxide solution from a purge stream deriving from a sodium carbonate, or sesqui-carbonate, or wegsheiderite crystallizer, or sodium bicarbonate crystallizer, said purge stream comprising sodium carbonate and/or bicarbonate, and at least 1% of sodium chloride or sodium sulfate and a soluble impurity from an ore deposit comprising at least one of the following elements: As, Ba, B, Ca, Co, K, Li, Mo, P, Pb, Se, Sn, Sr, Te, Tl, Ti, V, and W, to be purified, the method comprising: causticizing at least 50 mol. % of the sodium carbonate into a caustic solution and into a calcium carbonate mud with lime and water; separating the mud from the caustic solution; concentrating the caustic solution by removing part of the water to obtain a concentrated caustic solution comprising at least 25% NaOH, and a crystallized solid comprising sodium carbonate and sodium chloride and/or sulfate; and separating the crystallized solid from the concentrated caustic solution, said crystallized solid to be disposed of or to be further valorized.

A method for producing a concentrated aqueous sodium hydroxide solution from a purge stream deriving from a sodium carbonate, or sesqui-carbonate, or wegsheiderite crystallizer, or sodium bicarbonate crystallizer, said purge stream comprising sodium carbonate and/or bicarbonate, and at least 1% of sodium chloride or sodium sulfate and a soluble impurity from an ore deposit comprising at least one of the following elements: As, Ba, B, Ca, Co, K, Li, Mo, P, Pb, Se, Sn, Sr, Te, Tl, Ti, V, and W, to be purified, the method comprising: causticizing at least 50 mol. % of the sodium carbonate into a caustic solution and into a calcium carbonate mud with lime and water; separating the mud from the caustic solution; concentrating the caustic solution by removing part of the water to obtain a concentrated caustic solution comprising at least 25% NaOH, and a crystallized solid comprising sodium carbonate and sodium chloride and/or sulfate; and separating the crystallized solid from the concentrated caustic solution, said crystallized solid to be disposed of or to be further valorized.

This invention relates to treated geothermal brine compositions containing reduced concentrations of iron, silica, and manganese compared to the untreated brines. Exemplary compositions contain a concentration of manganese less than 10 mg/kg, a concentration of silica ranging from less than 10 mg/kg, and a concentration of iron less than 10 mg/kg, and the treated geothermal brine is derived from a Saltern Sea geothermal reservoir.

This invention relates to treated geothermal brine compositions containing reduced concentrations of iron, silica, and manganese compared to the untreated brines. Exemplary compositions contain a concentration of manganese less than 10 mg/kg, a concentration of silica ranging from less than 10 mg/kg, and a concentration of iron less than 10 mg/kg, and the treated geothermal brine is derived from a Saltern Sea geothermal reservoir.

A method of making a material for capturing carbon dioxide from the earth's atmosphere, comprises producing an acid and a base with an electrochemical acid-base generator; dissolving a mineral in the acid to produce a mineral rich solution, separating silica from the mineral rich solution to form a silica depleted solution; adding a first portion of the base to the silica depleted solution to remove impurities by precipitation, adding a second portion of the base until ferrous hydroxide (Fe(OH).sub.2) precipitates, then pausing base addition and removing the ferrous hydroxide precipitate from the solution. Then adding a third portion of the base to the iron-depleted solution to precipitate magnesium hydroxide (Mg(OH).sub.2) and/or calcium hydroxide (Ca(OH).sub.2). Then recovering a salt solution and directing the recovered salt solution to the electrochemical acid-base generator to produce a new acid and a new base. The magnesium hydroxide and/or calcium hydroxide may be used to capture and sequester carbon dioxide from a CO.sub.2-containing gas (e.g., air) by forming a carbonate or from the ocean by forming bicarbonate.

A method of making a material for capturing carbon dioxide from the earth's atmosphere, comprises producing an acid and a base with an electrochemical acid-base generator; dissolving a mineral in the acid to produce a mineral rich solution, separating silica from the mineral rich solution to form a silica depleted solution; adding a first portion of the base to the silica depleted solution to remove impurities by precipitation, adding a second portion of the base until ferrous hydroxide (Fe(OH).sub.2) precipitates, then pausing base addition and removing the ferrous hydroxide precipitate from the solution. Then adding a third portion of the base to the iron-depleted solution to precipitate magnesium hydroxide (Mg(OH).sub.2) and/or calcium hydroxide (Ca(OH).sub.2). Then recovering a salt solution and directing the recovered salt solution to the electrochemical acid-base generator to produce a new acid and a new base. The magnesium hydroxide and/or calcium hydroxide may be used to capture and sequester carbon dioxide from a CO.sub.2-containing gas (e.g., air) by forming a carbonate or from the ocean by forming bicarbonate.

A method of extracting lithium from a lithium-containing solution according to an exemplary embodiment of the present invention includes: obtaining a lithium chloride solution from the lithium-containing solution; and crystallizing and removing sodium chloride in the obtained lithium chloride solution.