A process for preparing a metal hydroxide comprising (i) at least one metal chosen from nickel and cobalt and optionally (ii) at least one metal chosen from manganese, lithium and aluminum. The process comprises: reacting a metal sulfate comprising (i) at least one metal chosen from nickel and cobalt and optionally (iii) at least one metal chosen from manganese and aluminum with sodium hydroxide and optionally a chelating agent in order to obtain a solid comprising the metal hydroxide and a liquid comprising sodium sulfate; separating the liquid and the solid from one another to obtain the metal hydroxide; submitting the liquid comprising sodium sulfate to an electromembrane process for converting the sodium sulfate into sodium hydroxide; and reusing the sodium hydroxide obtained by the electromembrane process for reacting with the metal sulfate.

A wastewater treatment equipment and a treatment method of a wastewater are provided. The wastewater treatment equipment includes: a microfiltration unit, configured to receive and filter a wastewater to obtain a solution; a membrane salt separation unit, configured to receive the solution and separate monovalent ions and multivalent ions from the solution to obtain a first solution including the monovalent ions and a second solution including the multivalent ions; a first evaporative crystallization unit, configured to crystallize the first solution to form a monovalent salt; and a second evaporative crystallization unit, configured to crystallize the second solution to form a mixed salt; the microfiltration unit is connected to the membrane salt separation unit, and the first evaporative crystallization unit and the second evaporative crystallization unit are both directly connected to the membrane salt separation unit, the wastewater treatment equipment can achieve the standard discharge of wastewater.

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.

Embodiments provide methods and strictures for purification or volume reduction of a brine by an advanced vacuum distillation process (AVMD) to achieve higher flux by passage of vapors through an AVMD distillation unit. In one example, brine is circulated in a tank. The tank may include one or more membrane pouches that are submerged in the circulating brine or placed above the water level of the hot circulating brine. In other embodiments the membrane pouches are outside of the tank that includes the hot circulating brine but still in communication with it. The circulating brine is heated, allowing creation of water vapor. Using a vacuum, the water vapor is drawn through the membrane, where it may be condensed and subjected to further beneficial use. This process can concentrate to levels to generate crystals or solids, which can be separated and utilized.

A forward osmosis system is provided. The system includes forward osmosis container having a semipermeable membrane dividing the forward osmosis chamber into a first chamber and a second chamber, a draw solution water removal unit including a quantity of draw solution solvent and water, wherein the draw solution solvent includes a nonaqueous liquid and a condenser configured to receive either water vapor or draw solution solvent vapor from the draw solution water removal unit and provide condensed draw solution solvent to the second chamber. The second chamber provides a water diluted draw solution solvent to the draw solution water removal unit. The first chamber takes in received water including a dissolved solute at an input mass per unit of volume and provides a fluid output having an output mass per unit of volume greater than the input mass per unit of volume.

A filtration system suitable for recovering base stock from used lubricating oil and other applications pass feedstock over nano-filtration membranes assembled as a stack of membranes all experiencing parallel flow. On exiting a first stack of membranes the feedstock passes through an opening in a pressure-sustaining separator plate to flow in the reverse direction past a second stack of membranes and subsequently establish a serpentine flow of feedstock through multiple stacks of membranes. The stacks of membranes all share a common pressure containment vessel. Pressure boosters installed in the flow-through openings of separator plates separating consecutive stacks can serve to restore lost pressure of the feedstock and maintain effective permeation of permeate through the membranes. A pressure control valve at the outlet to the permeate-receiving cavities of a stack can be used to adjust the trans-membrane pressure.

A filtration system suitable for recovering base stock from used lubricating oil and other applications pass feedstock over nano-filtration membranes assembled as a stack of membranes all experiencing parallel flow. On exiting a first stack of membranes the feedstock passes through an opening in a pressure-sustaining separator plate to flow in the reverse direction past a second stack of membranes and subsequently establish a serpentine flow of feedstock through multiple stacks of membranes. The stacks of membranes all share a common pressure containment vessel. Pressure boosters installed in the flow-through openings of separator plates separating consecutive stacks can serve to restore lost pressure of the feedstock and maintain effective permeation of permeate through the membranes. A pressure control valve at the outlet to the permeate-receiving cavities of a stack can be used to adjust the trans-membrane pressure.

A water mass transfer process providing a method and system to benefit conversion of poor quality water to attain high quality feed water or make-up water for a boiler. Wherein a low volatile solute is imbued within the water of a boiler, sufficiently so the elevated osmotic pressure of the boiler water can serve as a draw solution for forward osmosis based extraction of clean, high quality make-up water from poor quality water sources.

This document describes systems and methods for treating and recovering water from feed solutions using a membrane module that has a plurality of hollow fiber membranes encapsulated in a collection chamber and an expansion chamber that is connected to the outlet of the membrane module.

A preparation method of lithium hydroxide includes the following steps: A. coprecipitating a lithium extraction mother solution of salt lake brine with an aluminum salt solution and a sodium hydroxide solution, aging and then performing solid-liquid separation, washing and drying to obtain lithium aluminum hydrotalcite; B. acidifying the lithium aluminum hydrotalcite to obtain a lithium aluminate solution; C. performing nanofiltration on the lithium aluminate solution for lithium-aluminum separation, and sequentially performing primary concentration by reverse osmosis to obtain a primary concentrated lithium-rich solution; D. deeply removing aluminum from the lithium-rich solution to obtain an aluminum-removed lithium-rich solution; E. performing bipolar membrane electrodialysis on the aluminum-removed lithium-rich solution to obtain a secondary concentrated lithium-rich solution; F. evaporating the secondary concentrated lithium-rich solution for concentration to obtain lithium hydroxide.