Sulfuric acid concentration with an electro-electrodialysis process

Framatome, Tour Fiat, Place de la Coupole, 92084 Paris la Défense France
Hydrometallurgy (Impact Factor: 1.93). 12/1988; 21(2):191-201. DOI: 10.1016/0304-386X(88)90004-7

ABSTRACT Commercial anion-exchange membranes exhibit a strong proton leakage which makes them unsuitable for use in the recovery of sulphuric acid from sulphate containing solutions resulting from some hydrometallurgy processes. Experiments are reported which compare membrane permeabilities under electro-electrodialysis conditions. With most commercial membranes, the permeability to sulphate ions decreases rapidly when the acid concentration increases in the anolyte. The highest sulphuric acid concentration is obtained with a prototype membrane which will be shortly produced on an industrial scale.

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    • "This is widely used for desalination of water (Metcalf and Hunt, 1989) and separation and concentration of heavy metals (Hanra and Ramchandhran, 1996) and is regarded as a cheap method for concentrating solute concentrations in solutions. Similarly electro-dialysis/electroelectrodialysis is another technique for concentrating/ separating acid and salt solutions or various cations and anions (Cherif et al., 1988; Norton and Buehler 1994; Pfromm, 1997; Rockstraw and Scamehoron, 1997; Shah et al., 1999; Luo and Wu, 2000). Electrolytic decomposition of salt could be another option as it has been investigated for sodium sulphate (Jorissen and Simmrock, 1991; Jorissen and Simmrock, 1996). "
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    ABSTRACT: Oxidative ammonia leaching of sulphidic ores and reductive leaching of oxidic ores with sulphur based reductants in ammoniacal medium produce effluent streams containing ammonium sulphate. The various options for treating such solutions are: (a) concentration of ammonium sulphate by reverse osmosis or electro-dialysis (b) electrolytic decomposition of ammonium sulphate for ammonia and sulphuric acid recovery and (c) lime boil for ammonia recovery. Experimental data generated for concentrating synthetically prepared ammonium sulphate by reverse osmosis and by electro-dialysis gave maximum concentrations of ~40 and 270g/l respectively. Electro-decomposition studies showed that current efficiency depended on various factors such as initial ammonium sulphate concentration, current density and presence of metal ion impurities. A maximum of 87% current efficiency was achieved with initial ammonium sulphate concentration > 70g/l while keeping the current density as 100mA/cm 2 . The energy requirement during electro-decomposition of ammonium sulphate for producing ammonia was found to be less as compared to other processes used for its production. Ammonia recovery through lime boil gave ~93% efficiency but the process suffers due to disposal problem of calcium sulphate. A combination of electrochemical decomposition and electro-dialysis operations has been suggested as a viable approach for ammonia and sulphuric acid recovery. © 2004 SDU. All rights reserved.
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    • "Solvay, France, Raipore 5035 and Raipore 6030 from Pall, UK, and ACS and AFN7 from Tokuyama, Japan. The AW, ARA, ACS and AFN7 membranes have been used in several ED studies and their characteristics such as ionic exchange capacity, water content, transport number and nature of ionic sites can be found in the literature [25] [26] [27] [28] [29]. The Raipore membranes 5035 and 6030 are for the separation of acids with low proton leakage. "
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    ABSTRACT: The electrolysis of concentrated nitric acid solutions was carried out in an electrochemical cell with parallel plates (FM01-LC ICI). An anionic membrane that permits the migration of nitrate ions under the influence of an electrical field separated the anodic and cathodic compartments. The current efficiency for the transported nitrate ions was evaluated for several membranes, at a constant current. All the membranes allowed the transport of nitrate ions at different current efficiencies, following the increase in acid concentration in the anodic compartment. This electroseparation membrane process concentrated nitric acid from 25% up to 90% in successive stages. A special case to be noted was when the acid concentration was near the azeotropic value. In this case, the acid concentration in the anodic compartment rose above the azeotropic value of 68.5%, thus breaking the azeotrope mixture. It is expected that, for some niche applications, this process could be competitive with extractive distillation.
    Journal of Membrane Science 06/2000; 171(1-171):67-77. DOI:10.1016/S0376-7388(99)00383-X · 5.06 Impact Factor
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    • "Recently electrodialysis has been successfully employed in the purification of many food products such as milk, sugar and wine (El khatabi, 2001; Bonnin, 1988; Cherif et al., 1988; Meyer, 1990) "
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    ABSTRACT: Morocco is characterised by a semi-arid climate and by unlimited conventional fresh water especially underground water. Electrodialysis experiment to desalinise water for irrigation was conduced on underground water from the north of Morocco. The effects of the use of desalted water on the germination and growth and seed yield of wheat were monitored to determine the best yield from use of desalted water for irrigation of wheat.
    African journal of agricultural research 2(2). · 0.26 Impact Factor
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