US 7,452,520 B2Granted

Process for the production of calcium bromide by liquid-liquid extraction

AssigneeBromine Compounds Ltd.

InventorsBaruch Grinbaum, Leni Kogan, Eli Barnea, Gideon Harel, Rafael Semiat, Samuel Wahrmann

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Abstract

A process for the production of calcium bromide from feed brines, particularly from Dead Sea End Brine (EB), is described. The process comprises extracting the feed brine in countercurrent with a composite organic solvent; optionally, purifying the extract to increase the ratio Br:Cl by contacting it with a part of the product; and washing the purified extract with water to yield the product, that is an aqueous solution of CaBr2. The composite solvent comprises an anionic extractant, such as an amine or a mixture of amines; a cationic extractant, such as a carboxylic phosphoric or sulphonic acid or a mixtures of said acids; and diluent/modifier, which is an organic solvent. An apparatus for the production of calcium bromide is also described, which comprises: an extraction battery; optionally, a purification battery; and a washing battery, wherein at least one of the batteries comprises a plurality of stages.

Claims16

Dependent claims

A process for the production of a calcium bromide solution comprising the steps of:

a) extracting a feed brine comprising Cl−, Br−, Ca++ and Mg++ countercurrently with a composite organic solvent in a first plurality of stages, thereby obtaining an extract and a depleted brine;
and
b) washing said extract with water to yield a product of an aqueous solution of CaBr2 and a refluxed solvent, wherein said composite organic solvent comprises (1) an anionic extractant selected from the group consisting of primary, secondary, tertiary, and quaternary amines, and mixtures thereof having long, straight, or branched aliphatic chains (2) a cationic extractant selected from the group consisting of carboxylic acids, alkyl- or aryl-phosphoric acids, and alkyl- or aryl-sulphonic acids, and mixtures thereof having long, straight, or branched aliphatic chains and (3) a diluent-modifier selected from the group consisting of aromatic solvents having short aliphatic chains, nitro- or halo-aromatic solvents, and cycloaliphatic solvents.

Dependencies are inferred from the claim text.