Patent GB-824732-A (GB)
Title: Ion retardation method for fractionating brines
IPC: B01J43/00
Filed: 1957-06-25
Abstract: Alkali-metal salt brine containing alkaline-earth metal impurities are fractionated by contacting the brine with an insoluble composite anion-cation exchange resin, thereby absorbing at least some of the salts, removing the resin and eluting it with wash water thereby removing the absorbed salts in fractions and regenerating the resin. The resin consists of one or more normally water-soluble members of the group consisting of a polymeric form of an ionizable cationic monomer, and of a polymeric form of acrylic acid, methacrylic acid or maleic acid, which water-soluble polymer has been polymerized with the porous structure of, and has thereby been rendered insoluble by, an insoluble resin component, consisting of, or in admixture with, an ion exchange resin which exchanges ions opposite in charge to those of the insolubilized normally water-soluble polymer.  The process may be repeated in alternating absorption and regeneration cycles. Suitable resins are those of Specification 795,624, [Group IV (a)]. The resin usually contains 0.3 to 3, preferably 0.5 to 2, and especially about 1 chemical equivalents on anion-exchanging component per chemical equivalent of cation exchanging component.  Examples of suitable ingredients for the component ion-exchange resins are: polyacrylic acid; polymethacrylic acid; copolymers of styrene and maleic anhydride; copolymers of styrene, ethyl vinylbenzene, and divinylbenzene; copolymers of styrene, alpha-methylstyrene, ethyl vinylbenzene, and divinyl benzene; copolymers of vinylxylene and divinyl benzene; copolymers of vinyltoluene and divinylbenzene; copolymers of acrylic acid, ethylvinylbenzene and divinylbenzene; copolymers of methacrylic acid, ethylvinyl benzene and divinyl benzene, copolymers of styrene, ethylvinyl benzene and divinyl benzene, having quaternary ammonium radicals or polyalkylpolyamine groups (e.g. -CH2NHCH2CH2NH2) as nuclear substituents.  Preferred composite ion exchange resins are those which comprise copolymers of a major proportion of one or more alkenyl aromatic hydrocarbons and a minor proportion of one or more polyvinyl aromatic hydrocarbons, which copolymers preferably contain ionizable groups as substituents and are of themselves effective as ion exchange agents.  These copolymers and derivatives are useful as the insoluble cross-linked ingredients of the agents.  In an example, the resin employed consisted of polyacrylic acid and a polymer formed by reaching trimethylamine with a nuclearly chloromethylated copolymer of styrene, ethylvinyl benzene, and divinyl benzene.ALSO:An insoluble composite anion-cation exchange resin suitable for fractionating brines comprises one or more normally water-soluble members of the group consisting of a polymeric form of an ionisable cationic monomer and of a polymeric form of a carboxylic acid member of the group consisting of acrylic acid, methacrylic acid, and maleic acid, which water-soluble polymer has been polymerized within the porous structure of, and has thereby been rendered insoluble by, an insoluble resin component consisting of or in admixture with an ion exchange resin which exchanges ions opposite in charge to those of the thereby insolubilized normally water-soluble polymer.  Suitable composite resins are those of Specification 795,624, and are preferably prepared by absorbing a liquid monomeric material consisting of one or more polymerizable vinylidene compounds having groups or radicals that are ionizable or that can be readily converted to ionizable groups, in an insoluble cross-linked polymer containing ionizable groups.  The monomer may contain various additives such as plasticizers, lubricants or polymerization catalysts, such as peroxides.  Unabsorbed monomeric material is removed and the mass is then maintained at a temperature at which the monomer readily polymerizes.  This may be carried out with the granules immersed in an inert liquid.  In an example an anion exchange resin formed by reacting trimethylamine with a nuclearly chrloromethylated copolymer of styrene, ethylvinyl benzene, and divinyl benzene, is mixed with water cooled to 0-10 DEG  C. and glacial acrylic acid added with stirring.  After 12 hours potassium persulphate was added, the temperature was maintained at 12 DEG  C. for 5 1/2 hours, all air was swept out of the mixture by nitrogen, and sodium sulphite was added.  The mixture was stored for 19 hours and then heated to 75-85 DEG  C. for two hours to complete the polymerization of the acrylic acid.  The product was washed with water.