Recovery of boric acid from boronic wastes by leaching with water, carbon dioxide- or sulfur dioxide-saturated water and leaching kinetics

• Published in: Resources, conservation and recycling conservation and recycling, 2000, Vol.28 (1), p.135-146
• Main Authors: Demirbaş, Ayhan, Yüksek, Haydar, Çakmak, İsmail, Küçük, Mehmet M., Cengiz, Mustafa, Alkan, Muzaffer
• Format: Article
• Language: English
• Subjects: Applied sciences; Boric acid; Boronic wastes; Carbon dioxide; Exact sciences and technology; Leaching kinetics; Other industrial wastes. Sewage sludge; Pollution; Solubility; Sulfur dioxide; Wastes
• ISSN: 0921-3449; 1879-0658
• DOI: 10.1016/S0921-3449(99)00039-7

B 2O 3 was recovered from waste samples such as borogypsum, reactor waste, boronic sludges, waste mud and concentrator waste by leaching processes using distilled water, sulfur dioxide- and carbon dioxide-saturated water. In the leaching processes, temperature, stirring time and solid-to-liquid ratio were taken as parameters. The amount of B 2O 3 leached increased with increasing temperature and stirring time and it also increased with decreasing solid-to-liquid ratio, but the increase was less than that recorded for the leaching temperature and the stirring time. SO 2 saturated water is a more effective leaching solvent than CO 2 saturated water for boronic wastes. By the end of the experiments, more than 90% of B 2O 3 recovery was found as boric acid. In the leaching of boric acid from boronic wastes in water saturated with sulfur dioxide, it was observed that the leaching rate increases with increasing temperature and leaching time. The overall average values of the kinetic parameters were: apparent activation energy ( E) 33.2 kJ mol −1, pre-exponential factor ( A) 8.2×10 9 min −1, reaction order ( n) 0.97 and rate constant ( k) 3.37×10 3 min −1 for the leaching processes of the boronic wastes.