A cassette type electrodialysis unit includes an accommodating box, a filter membrane group and a cover member disposed on the accommodating box. The accommodating box includes a membrane support, a membrane limiting wall and an accommodating opening. The membrane limiting wall is disposed on and surrounds the membrane support to form the accommodation opening. The filter membrane group is disposed on the membrane support and abuts an inner side of the membrane limiting wall, and includes a first ion exchange membrane, a second ion exchange membrane and a spacer disposed therebetween. The cover member includes a main body, an opening penetrating the main body, and a pressing portion. A first side of the main body adjacent to the filter membrane group has a peripheral area and an inner area closer to the opening than the outer area, and the pressing portion is formed on the inner area.

The present invention relates to a lithium compound manufacturing method comprising the steps of heat treatment of lithium-containing ore; roasting the heat-treated ore with sulfuric acid to prepare an acid product; mixing the acid product with leaching water to prepare a leachate; purifying the leachate; and adding a phosphorus supply material and a basic material to the purified leachate to obtain a solid lithium phosphate.

An apparatus for the treatment of acid mine drainage and selective recovery of at least one of metals, critical elements, sulphuric acid and water is disclosed. The apparatus includes at least one electrochemical reactor, at least one catholyte reservoir and at least one anolyte reservoir for containing the acid mine drainage and a buffer, respectively. The reservoirs are in fluid communication with the at least one electrochemical reactor. The apparatus also includes at least one sensor for monitoring a pH of a contents of the reactor; and a power source for supplying an electrical current to the at least one electrochemical reactor. The electrical current is supplied until a predetermined pH is reached for the selective recovery of the at least one of metals, critical elements, sulphuric acid and water. A process for the treatment of acid mine drainage is also disclosed.

The present invention provides a strong polymer electrolyte membrane which can provide a water electrolyzer operable at low electrolysis voltage. The polymer electrolyte membrane of the present invention comprises a fluorinated polymer and a woven fabric, wherein the weight of the woven fabric is from 20 to 95 g/m.sup.2, and the warp and weft of the woven fabric independently have a denier of from 30 to 100.

A system comprises an electrodialysis apparatus, which includes first and second reservoirs, wherein a salt concentration in the first reservoir reduces below a threshold concentration and salt concentration in the second reservoir increases during an operation mode. A first electrode comprises a first solution of a first redox-active electrolyte material, and a second electrode comprises a second solution of a second redox-active electrolyte material. In a first reversible redox reaction between the first electrode and first electrolyte material at least one ion is accepted from the first reservoir, and in a second reversible redox reaction between the second electrode and second electrolyte material at least one ion is driven into the second reservoir. A first type of membrane is disposed between the first and second reservoirs, and a second type of membrane, different from the first type, is disposed between the respective electrodes and reservoirs.

The present invention relates to methods for selective binding, selective membrane transport and storage of carbon dioxide (CO.sub.2) in aqueous media. The method of the present invention comprises providing an aqueous acceptor solution containing at least one acceptor compound having a free guanidino and/or amidino group, which is contacted with a gas containing carbon dioxide to bind the carbon dioxide in the acceptor solution. The acceptor solutions containing bound carbon dioxide obtained thereby are useful for storing carbon dioxide in aqueous media, for again releasing the carbon dioxide, and for use in electrochemical processes, such as electrodialysis, to selectively transport bound carbon dioxide through separation membranes into aqueous media. The present invention further relates to the preparation of carbonates starting from acceptor solutions containing bound carbon dioxide.

An ultrapure water manufacturing facility includes: a first tank; a plurality of reverse osmosis membranes sequentially arranged downstream of the first tank; an electrodeionization device arranged downstream of the plurality of reverse osmosis membranes; an ion exchange resin tower arranged downstream of the electrodeionization device and filled with a boron selective resin; and a chemical supplier arranged between the plurality of reverse osmosis membranes and configured to supply a pH regulator to treatment-target water.

A concentrated spent dialysate is produced for by reducing electrolytes in a spent dialysate by electrodialysis and de-watering the spent dialysate by a forward osmosis operation.

A hemodialysis treatment apparatus has an ultrafiltration unit for exchange of solutes of a patient's blood plasma and a dialysate, resulting in a stream of cleaned blood for returning to the patient and a stream of spent dialysate. An electrodialysis device reduces electrolytes in the spent dialysate. A forward osmosis unit with a membrane having a feed side and a draw side that is allows only water to permeate. A stream of spent dialysate from the ultrafiltration unit is in fluid communication with the feed side and a stream of concentrated dialysate is in fluid communication with the draw side. A stream of dialysate results. Blood plasma is pumped from the patient to the ultrafiltration unit.

A method is disclosed for concentrating and purifying an eluate brine and producing a purified lithium compound. An extraction eluate, rich in lithium, is directed to a nanofiltration unit or a softening process that removes sulfate and/or calcium and magnesium. Permeate from the nanofiltration unit or the effluent from the softening process is directed through an electrodialysis unit. As the lithium-rich solution moves through the electrodialysis unit, lithium, sodium and chloride ions pass from the solution through a cation-transfer membrane and an anion-transfer membrane to concentrate compartments. A dilute stream is directed through the concentrate compartments and collects the lithium, sodium and chloride ions. The electrodialysis unit also produces a product stream which contains non-ionized impurities, such as silica and/or boron. Concentrate from the electrodialysis unit is subject to a precipitation process that produces a lithium compound that is subsequently subjected to a purification process.

The invention relates to a capacitive electrode comprising: an electrode housing comprising: ˜a number of housing walls that enclose a housing space; and ˜an opening that is operatively connected to the housing space, and wherein the opening is configured to be positioned adjacent an end membrane of a membrane stack; —a capacitive layer that is positioned in the housing space; —a current feeder that is positioned in the housing space and that is in electrical contact with the capacitive layer; —a gel layer that is positioned in contact with the capacitive layer; wherein the gel layer is provided in or adjacent to the opening such that the gel layer seals the opening, or wherein the gel layer is positioned near a bottom housing wall of the housing and the current feeder is positioned in or near the opening.