INTERNATIONAL JOURNAL OF CHEMICAL REACTOR ENGINEERING, cilt.10, 2012 (SCI-Expanded)
In this study, the recovery of boron from the clay waste of boron industry by leaching with sulfuric acid solution was studied in a batch reactor and the subsequent production of boric acid (H3BO3) was investigated. The effects of acid concentration, solid-to-liquid ratio and reaction temperature on the leaching process were examined. Experimental studies were carried out in the ranges of 0.1-1.0 M for acid concentration, 1-10 g/120 mL for solid-to-liquid ratio and 25-75 degrees C for reaction temperature. The analysis of the experimental data showed that the kinetics of the leaching process fitted the Avrami model in the form of X = 1 -exp (-k t (n)). For the production of boric acid, the optimum leaching conditions were determined as follows: acid concentration, 0.1 M; solid-to-liquid ratio, 6 g/120 mL; reaction temperature, 50 degrees C and reaction time, 60 min. Finally, boric acid was produced in the purity of more than 95% by crystallization of the leach solution.