Abstract:
The invention provides partially purified EPS that was purified from Thauera sp. Strain MZ1T. This partially purified EPS comprises rhamnose, xylose, galacturonic acid, galactose, glucose, N-acetylfucosamine. The invention further provides methods of producing the partially purified EPS and of utilizing the partially purified EPS in methods of chelating metals. Further provided by this invention is an exopolysaccharide termed "thaueran" that was purified from Thauera sp. Strain MZ1T. This exopolysaccharide has a molecular weight of about 250 kDa and comprises rhamnose, galacturonic acid, N-acetylfucosamine and N-acetylglucosamine. The invention also provides methods of producing the exopolysaccharide and of utilizing the exopolysaccharide in methods of chelating metals.
Abstract:
A process for selectively separating a metallic constituent from other metals and other materials accompanying the metallic constituent in a mixture is described. The process comprises the step of providing the mixture in an aqueous solution such that the metallic constituent forms a complex anion in the solution. One or more of the other metals forms a cation or a complex cation in the solution. Another step includes contacting the solution with one or more additives to form layered double hydroxide (LDH) material in situ such that the complex anion is intercalated within interlayers of the LDH material and wherein one or more of the other metals are incorporated into the LDH material's crystal structure or matrix. Another step involves the addition of an LDH to an aqueous solution. The process involves selectively recovering the metallic constituent from the interlayer of the LDH by subjecting the LDH to a recovery treatment step(s) and as required, methods to modify the LDH to facilitate metal separation and recovery or contaminant stabilisation.
Abstract:
L'invention se rapporte à l'utilisation d'un matériau hybride organique-inorganique, comprenant un support solide inorganique sur lequel sont greffées des molécules organiques de formule générale (I) ci-après : dans laquelle : x, y et z = 0 ou 1, avec l'un au moins de x, y et z différent de 0; m = 1 à 6; v et w = 0 ou 1, avec v = 1 quand w = 0, et v = 0 quand w = 1; si x = 0, R 1 = H ou un groupe hydrocarboné, saturé ou insaturé, linéaire ou ramifié, en C 1 à C 12 , tandis que, si x = 1, R 1 = un groupe lié au support solide inorganique par au moins une liaison covalente; si y = 0, R 2 = H ou un groupe hydrocarboné, saturé ou insaturé, linéaire ou ramifié, en C 1 à C 12 , tandis que, si y = 1, R 2 = un groupe lié au support solide inorganique par au moins une liaison covalente; si z = 0, R 3 = H ou un groupe hydrocarboné, saturé ou insaturé, linéaire ou ramifié, en C 1 à C 12 , tandis que, si z = 1, R 3 = un groupe lié au support solide inorganique par au moins une liaison covalente; R 4 et R 5 = H, un groupe hydrocarboné, saturé ou insaturé, linéaire ou ramifié, en C 2 à C 8 , ou un groupe aromatique monocyclique; pour extraire l'uranium(VI) d'une solution aqueuse d'acide sulfurique. L'invention se rapporte aussi à un procédé qui permet de récupérer l'uranium(VI) présent dans une solution aqueuse d'acide sulfurique, sélectivement vis-à-vis des autres cations métalliques susceptibles d'être également présents dans cette solution.
Abstract:
L'invention se rapporte à l'utilisation de composés de formule générale (I) ci-après dans laquelle: R 1 et R 2 représentent un groupe hydrocarboné, saturé ou insaturé, linéaire ou ramifié, en C 6 à C 12 ; R 3 représente H, un groupe hydrocarboné, saturé ou insaturé, linéaire ou ramifié, en C 1 à C 12 et comprenant éventuellement un ou plusieurs hétéroatomes, ou un groupe hydrocarboné, saturé ou insaturé, monocyclique, en C 3 à C 8 et comprenant éventuellement un ou plusieurs hétéroatomes; tandis que R 4 représente un groupe hydrocarboné, saturé ou insaturé, linéaire ou ramifié, en C 2 à C 8 , ou un groupe aromatique monocyclique; en tant qu'extractants, pour extraire l'uranium(VI) d'une solution aqueuse d'acide sulfurique. Elle se rapporte également à un procédé qui permet de récupérer l'uranium présent dans une solution aqueuse d'acide sulfurique issue de la lixiviation d'un minerai uranifère par l'acide sulfurique et qui met en œuvre lesdits composés en tant qu'extractants. Applications: traitement des minerais uranifères en vue de valoriser l'uranium présent dans ces minerais.
Abstract:
The present disclosure relates to a process and system for recovery of one or more metal values using solution extraction techniques and to a system for metal value recovery. In an exemplary embodiment, the solution extraction system comprises a first solution extraction circuit and a second solution extraction circuit. A first metal-bearing solution is provided to the first and second circuit, and a second metal-bearing solution is provided to the first circuit. The first circuit produces a first rich electrolyte solution, which can be forwarded to primary metal value recovery, and a low-grade raffinate, which is forwarded to secondary metal value recovery. The second circuit produces a second rich electrolyte solution, which is also forwarded to primary metal value recovery. The first and second solution extraction circuits have independent organic phases and each circuit can operate independently of the other circuit.
Abstract:
A process to recover a target metal from hydrometallurgical solutions comprising the method steps of: i. Adding a calcium based neutralising agent such as lime or limestone to a solution containing aluminium sulphate at moderate temperature thereby forming an amount of soluble basic aluminium sulphate; and precipitating excess sulphate as gypsum, ii. After removing gypsum, passing the solution formed in step i to a target metal recovery step in which the target metal, that is complexed to an amine functionality, is stripped from the amine functional group by the soluble basic aluminium sulphate in the aqueous solution, and iii. precipitating the target metal from the aqueous solution, which contains the target metal and basic aluminium sulphate by the addition of hydrogen peroxide. whereby the target metal enters the aqueous solution in step ii without substanial precipitation or pH control.
Abstract:
The present invention provides a process for the production of a uranium trioxide yellowcake from a uranium peroxide precipitate, the peroxide precipitate being in the form of a low solids content, uranium rich feed slurry, the process including the stages of: a. thickening the feed slurry to produce a thickener underflow with a solids content in the range of 15 to 50% w/w and a thickener overflow; b. dewatering the thickener underflow to produce a solids cake with a solids content of at least 50% w/w and a dewater overflow; and c. calcining the solids cake at a temperature in the range of 450°C to 480°C to produce a calcined uranium trioxide yellowcake.
Abstract:
The invention concerns a process for separating uranium, radium and arsenic from solutions of their compounds, uranium being bonded and separated by means of anion exchangers, radium being separated by physical and/or chemical bonding to alkaline earth sulphate, and arsenic being separated by precipitation by the addition of a ferric salt. The separated materials containing uranium, radium and arsenic can be immobilized by inclusion in hydraulic binders.
Abstract:
A process for recovering metal (17) and acid values (48) from a source material (22) containing metallic fluorides comprises digesting (10) the source material in sulfuric acid (20) to form a slurry, separating (12) a fluoride containing solid phase (39) and a metal containing first liquid phase (26). The solid phase is subjected to pyrohydrolysis (14), sulfuric (40) and hydrofluoric acids (42) are recovered, and the first liquid phase is processed to recover the metal values by solvent extraction (16) or ion exchanges (18). The tantalum values are extracted from the first liquid aqueous phase by a water immiscible organic extractant such as methylisobutyl ketone to form a first liquid organic phase containing tantalum and a second liquid aqueous phase. The tantalum is stripped from the first organic phase using water (33). The process includes the additional steps of heating the separated solid phase from about ambient temperature to an elevated temperature in the presence of water vapor to evolve sulfuric acid (44) and render the gangue chemically inert (52). When the source material contains uranium the digestion step reduces the amount of gangue present in the radioactive source. The process can include the additional steps of removing uranium (34) from the second liquid aqueous phase by either an ion exchange resin or by solvent extraction using a water immiscible organic extractant to yield a uranium depleted aqueous phase (50) which can be treated with an aqueous solution of calcium oxide (66). Sulfuric acid and the organic extractant for extracting uranium can be recycled if desired (20).
Abstract:
Disclosed herein is a method for recovering an acid or a base during a metal extraction process. The method comprises contacting a feed stream comprising the acid or base and the metal with an ultrafiltration membrane to produce an ultrafiltration retentate and an ultrafiltration permeate, and contacting the ultrafiltration permeate with a nanofiltration membrane. The nanofiltration retentate produced comprises a majority of the metal from the feed stream, and the nanofiltration permeate produced comprises a majority of the acid or base from the feed stream. Also disclosed herein is a recovery apparatus for recovering an acid or a base during a metal extraction process.