This electrodialysis device comprises: an electrodialyzer stack having a cathode, an anode, and a membrane unit including at least three membranes provided at intervals between the cathode and the anode, wherein a dilution chamber and a concentration chamber is formed between adjacent membranes; a liquid-to-be-treated feed device that causes a liquid to be treated to flow through the dilution chamber to obtain a diluted liquid; a concentrate liquid circulation device for causing a concentrate liquid to be concentrated to circulate through the concentration chamber, a circulation line through which the concentrate liquid flows to return to the concentration chamber after flowing out from the concentration chamber; a drainage line through which the diluted liquid flowing out from the dilution chamber flows; a concentrated solution line for extracting a part of the concentrate liquid circulating through the circulation line from the circulation line; and a narrowing member provided on the circulation line between the branch point at which the concentrated solution line branches from the circulation line and the outlet of the concentration chamber, and which narrows the flow of the concentrate liquid, and/or a narrowing member provided on the drainage line and which narrows the flow of the diluted liquid.

A method of processing brine comprising lithium. The method may include providing a feed brine and a draw brine to a first forward osmosis (FO) module, the feed brine and/or the draw brine comprising lithium, and forming a feed brine concentrate and a dilute draw brine; and providing the dilute draw brine to a first nanofiltration (NF) module, and forming a first NF retentate, at least a portion of which is optionally recycled to the FO module, and forming a first NF permeate comprising at least a portion of the lithium. The method may additionally include providing a first brine to an initial NF module that is upstream of the first FO module, and forming the feed brine that is provided to the FO module, and forming an initial NF retentate, at least a portion of which is optionally recycled to the first FO module and/or the first NF module.

A method of separating and recovering a cobalt salt and a nickel salt includes a separation step of separating, by using a nanofiltration membrane, a cobalt salt and a nickel salt from a rare metal-containing aqueous solution containing at least both the cobalt salt and the nickel salt as rare metals, in which the nanofiltration membrane has a glucose permeability of 3 times or more a sucrose permeability, the sucrose permeability of 10% or less, and an isopropyl alcohol permeability of 50% or more when a 1,000 mg/L glucose aqueous solution, a 1,000 mg/L sucrose aqueous solution, and a 1,000 mg/L isopropyl alcohol aqueous solution, each having a pH of 6.5 and a temperature of 25 C., individually permeate through the nanofiltration membrane at an operating pressure of 0.5 MPa.

A system and method to increase a ratio of multivalent ions to monovalent ions in a retentate of a multistage nanofiltration system from saline source water. Multiple nanofiltration units can be arranged in a series to selectively remove monovalent ions from the water fed into each nanofiltration stage in the nanofiltration permeate stream while retaining multivalent ions in the nanofiltration reject stream. The methods and systems may produce the concentrated multivalent ion product is suitable for many applications, which includes fertilizer for plants and remineralization of desalinated water.

A method for determining mixing parameters for preparing a phosphoric acid solution having a controlled content of at least one of its chemical constituents, by mixing at least two phosphoric acid solutions, each having a different content of the chemical constituent, of which at least one is a permeate resulting from the filtration of a crude phosphoric acid solution through at least one nanofiltration membrane. The method includes: (1) providing a desired content (Tm) of the chemical constituent in the phosphoric acid solution to be prepared, and a desired volume (Vm) of the phosphoric acid solution to be prepared; (2) determining, using a computer, on the basis of the desired content (Tm) and the desired volume (Vm): at least one combination of at least two phosphoric acid solutions among the phosphoric acid solutions to be mixed; volumes of each of the phosphoric acid solutions to be mixed of the combination, such that the mixing of the phosphoric acid solutions of the combination leads to the phosphoric acid solution to be prepared.

A system and method for producing minerals from divalent ion-containing brine stream includes rejecting sulfate from a divalent-ion rich reject stream in a first nanofiltration seawater reverse osmosis (NF-SWRO) unit, producing solid calcium sulfate dihydrate and a magnesium-rich brine stream in a first concentration unit, concentrating the magnesium-rich brine stream to a saturation point of sodium chloride in a second concentration unit, producing solid sodium chloride and a supernatant product stream in a first crystallizing unit, produce a concentrated magnesium-rich bittern stream from the supernatant product stream in a third concentration unit, and at least one of producing hydrated magnesium chloride from the concentrated magnesium-rich bittern stream in a second crystallizing unit and producing anhydrous magnesium chloride by prilling the concentrated magnesium-rich bitterns stream under a hydrogen chloride atmosphere in a dry air process unit.

A saline water pre-treatment or treatment system using nanofiltration and hybrid forward osmosis: the system comprising: a feed solution, a pressure pump, a nanofiltration module, and a hybrid forward osmosis module.

A method for producing an injection water for a reservoir includes receiving a brine that is produced based on a reverse osmosis of water, performing a separation of the brine, producing a concentrated brine based on the separation of the brine, and producing, based on the concentrated brine, the injection water suitable for use in maintaining a reservoir pressure. Performing the separation of the brine includes performing at least one of a filtration, a membrane distillation, or a forward osmosis. The concentrated brine has a lower sulfate level and NaCl level and a higher total dissolved solids (TDS) level than the brine.

A method of concentrating lithium containing solutions includes inputting a feed brine solution to an initial separation stage, the feed brine solution including lithium sulfate and one or more of sodium sulfate, potassium sulfate, calcium sulfate, and sodium chloride dissolved in water. In the initial separation stage, the feed brine solution is introduced to a pre-treatment membrane at a pressure that is less than the osmotic pressure of the feed brine solution. An initial permeate that passes through the pre-treatment membrane becomes the feed to a final separation stage, and an initial retentate that does not pass through the pre-treatment membrane includes a precipitate of at least one of the salts other than lithium sulfate. In the final separation stage, the initial permeate is introduced to a nanofiltration membrane at a pressure that is less than the osmotic pressure of the initial permeate. A final retentate that does not pass through the nanofiltration membrane is combined with the initial retentate to obtain a product solution having a higher concentration of dissolved lithium sulfate than the feed brine solution.

This electrodialysis device comprises: an electrodialyzer stack having a cathode, an anode, and a membrane unit including at least three membranes provided at intervals between the cathode and the anode, wherein a dilution chamber and a concentration chamber is formed between adjacent membranes; a liquid-to-be-treated feed device that causes a liquid to be treated to flow through the dilution chamber to obtain a diluted liquid; a concentrate liquid circulation device for causing a concentrate liquid to be concentrated to circulate through the concentration chamber, a circulation line through which the concentrate liquid flows to return to the concentration chamber after flowing out from the concentration chamber; a drainage line through which the diluted liquid flowing out from the dilution chamber flows; a concentrated solution line for extracting a part of the concentrate liquid circulating through the circulation line from the circulation line; and a narrowing member provided on the circulation line between the branch point at which the concentrated solution line branches from the circulation line and the outlet of the concentration chamber, and which narrows the flow of the concentrate liquid, and/or a narrowing member provided on the drainage line and which narrows the flow of the diluted liquid.