Chemistry: physical processes – Physical processes – Crystallization
Patent
1994-03-18
1995-12-12
Straub, Gary P.
Chemistry: physical processes
Physical processes
Crystallization
423240R, 4234995, 588205, C01D 308, C01B 700, A67D 300
Patent
active
054745810
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The invention relates to a method for producing an aqueous sodium chloride solutions for use in industrial methods.
TECHNOLOGY REVIEW
Aqueous sodium chloride solutions have important applications in industry. This is especially the case in industries producing sodium carbonate by the ammonium-soda method, and by the electrolytic processing method for chlorine and aqueous sodium hydroxide solutions.
These industrial methods usually require very pure aqueous sodium chloride solutions, notably not containing polyvalent metals such as, for example, calcium, magnesium, aluminum, iron, lead and zinc. This requirement is especially strict in case of electrolysis methods involving membranes which are selectively permeable to cations, such as perfluoropolymers comprising functional groups derived from carboxylic acid (GB 1,375,126). For these electrolysis methods, sodium chloride solutions are usually recommended whose polyvalent cation contents, notably, calcium cations, does not exceed 0.1 ppm (GB 2,005,723).
These aqueous solutions intended for electrolysis cells are usually obtained by dissolving common salt in water (Chlorine, Its Manufacture, Properties and Uses. J. S. Sconce, Reinhold Publishing Corporation, New York, 1962, Pages 119 and 123). However, the raw brines obtained by dissolving common salt in water have a polyvalent cation content which is generally too high to allow them to be used in electrolysis methods. Due to this fact, it was proposed to treat them on Na-type chelating resins, with the intention of extracting polyvalent cations. (The American Institute of Chemical Engineers, No. 219, Vol. 78, 1982, Pages 46-53; J. J. Wolff and R. E. Anderson, Ion-Exchange Purification of Feed Brine for Chlor-Alkali Electrolysis Cells; The Role of Duolite ES-467).
The document, JP-B-6038197, describes a method for recovering heavy metals present in residual waters from washing fumes. According to this method, the residual waters are alkalinized to precipitate heavy metals which are subsequently separated by decanting and filtering, and the aqueous solution collected from the filtration is treated successively on a chelating resin comprising sulfur ligands in order to recover the mercury, and on a chelating resin containing nitrogen ligands in order to recover the calcium and the other heavy metals. The aqueous solution collected at the end of this known method contains a high level of sodium chloride and its content of heavy metals is sufficiently low for it to be discharged in a stream of water. In the known method which was described above, the chelating resin having nitrogen ligands may be of the Na-type, Ca-type or H-type. However, H-type resins are preferable, because their regeneration by means of an aqueous solution of hydrochloric or sulfuric acid is facilitated. However, the aqueous sodium chloride solutions obtained at the end of the method using H-type resins, has a calcium level which is too high to allow them to be used in an industrial method such as, for example, electrolysis.
The present invention remedies this drawback by providing a valuable industrial method for aqueous sodium chloride solution as a result of washing fumes.
SUMMARY OF THE INVENTION
Consequently, the invention relates to a manufacturing method of an industrial sodium chloride solution wherein an industrial aqueous solution of sodium chloride containing metals having a valency greater than 1 is treated on a chelating Na-type resin. The process is characterized in that in order to obtain the aqueous sodium chloride solution containing metal having a valency greater than 1, the fumes containing hydrogen chloride and metal having a valency greater than 1 and resulting from the oxidation of chlorinated products are subjected to washing with acidified water; an aqueous solution of hydrochloric acid is collected from the wash, and the hydrochloric acid solution is alkalinized in order to precipitate metal having a valency greater than 1 to a state of hydroxides which are separated chloride and resulti
REFERENCES:
patent: 2829095 (1958-04-01), Oda et al.
patent: 3988415 (1976-10-01), Barr
patent: 4002564 (1977-01-01), Carbonel et al.
patent: 4115531 (1978-09-01), Optiz et al.
patent: 4617180 (1986-10-01), Voss
patent: 4747917 (1988-05-01), Reynolds et al.
patent: 5126019 (1992-06-01), Rutherford et al.
patent: 5213778 (1993-05-01), Sato
patent: 5257588 (1993-11-01), Kollmann
Chlorine, Its Manufacture, Properties And Uses. J. S. Sconce, Reinhold Publishing Corporation, New York, 1962, pp. 119-199.
Sodium Chloride, The Production and Properties of Salt and Brine. Dale W. Kaufmann, Reinhold Publishing Corporation, New York, 1960, pp. 204-275.
Ion-Exchange Purification of Feed Brine for Chlor-Alkali Electrolysis Cells; The Role of Duolite. The American Institute of Chemical Engineers, No. 219, vol. 78, 1982, pp. 46-53; J. J. Wolff and R. E. Anderson.
Adam Jean-Francois
Ninane Leon
Solvay ( Societe Anonyme)
Straub Gary P.
LandOfFree
Method for producing an aqueous sodium chloride solution and use does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for producing an aqueous sodium chloride solution and use, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for producing an aqueous sodium chloride solution and use will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1357149