Recycling calcium- and-or magnesium-rich used brine, e.g. from water softeners, involves recovering used brine to form a stock and precipitating bivalent ions by adding an inositol phosphate compound

摘要

#CMT# #/CMT# A method for recycling used brines rich in bivalent ions, especially calcium and/or magnesium, involves (A) recovery of used brine to form a stock (UB) (B) treatment of the stock with a precipitating reagent (PR) containing at least one inositol phosphate so as to precipitate the bivalent ions as above . #CMT# : #/CMT# An independent claim is also included for a treatment system for the above method, comprising (A) a container (4) holding the stock of UB to be treated (B) a vessel (5) filled with the PR (C) a reactor (6) for mixing the UB with the PR (D) a filtration tank (7) (E) a vessel (8) containing regenerated brine (F) a vessel (9) containing the sludge from the process (G) pumps for the moving the various liquids between the various vessels in the system (1) . #CMT#USE : #/CMT# Especially for recycling brine from the regeneration of water softeners or calcium chloride-rich brine from the manufacture of sodium carbonate. #CMT#ADVANTAGE : #/CMT# A simple method enabling the recycling of used brine on a large scale at reasonable cost and with the formation of precipitates which are environmentally-neutral and easily handled. Prior-art methods may be unsuitable for large-scale application or dependent on expensive techniques such as reverse osmosis. #CMT#DESCRIPTION OF DRAWINGS : #/CMT# The drawing shows a diagram of an installation (1) for recycling used brine. 2 : water softener(s) 3 : recuperator 4 : used brine stock 5 : tank for precipitating reagent 6 : reactor 7 : filtration tank 8 : regenerated brine 9 : sludge tank. #CMT#ENVIRONMENT : #/CMT# Preferred Precipitants: Salts of inositol hexaphosphoric acid, especially the sodium salt. Preferred Starting Materials: Used brine from the regeneration of water-softener resins, or calcium chloride-rich brine from the manufacture of sodium carbonate. Preferred Method: The brine stock (UB) is adjusted to pH ca. 7 after adding the PR. The method also includes separation of the reaction product (preferably by filtration) to give a regenerated brine with a sodium chloride content of ca. 110 g/l plus an environmentally-neutral calcium- and magnesium-rich sludge.