Optimization and kinetic of boric acid from colemanite using sulphur dioxide gas

In this study, optimization and kinetics of boric acid production in aqueous medium were investigated by using SO2 gas from colemanite ore. The aim of optimization studies is to optimize the optimum production conditions of pure boric acid with less energy and cost compared to today's technology. In addition, the kinetic model of boric acid dissolution and reactions from the collemanit ore was obtained and it was determined which model is suitable for this system. In optimization studies, time, reaction temperature and pH were taken as parameters. Three levels have been applied for each parameter. As a result of optimization studies, it was observed that PH was the most effective parameter of parameters and reaction temperature and duration were not very effective. After the application of the cycle trials, it is determined that the best dissolution occurs in the conditions where the pH is 4, the reaction temperature is 70 ° C and the duration is 60 min. It has been observed that boric acid, although it is dissolved at approximately 99% level under these conditions, contains impurities. It has been observed that boric acid should be treated with washing and catalyst should be used with increasing time to eliminate these impurities. As a result of the application of washing process, the use of catalysts and the increase of time to 120 min, it was determined that Fe3+, SO42-, Ca2+ and Mg2+ impurities in boric acid were lower than the commercially available boric acid values. In kinetic studies, solid-liquid ratio, particle size, reaction temperature and mixing speed were chosen as parameters. In the kinetic model derivation, the conversion rates calculated from the amount of B2O3 passed to the solution were used. A kinetic model was derived based on heterogeneous reaction models with the help of transformation-time graphs drawn using the resulting conversion ratios. Since the mixing speed is not effective, it is not used in model derivation. The 10.0 version of the Statistica program was used to perform the calculations of the model. Using these data, the results of the calculations made with the help of the computer program yielded the following equation with the use of quasi and Newton models from non-linear prediction models.: 1-3(1-X)2/3+2(1-X) = 2.10-8.(K/S)-0,7.(TB)-2,2.e(18183,4/RT).t According to this equation, it is understood that the system is suitable for the ash or product film diffusion model. In this equation, S/L: solid to liquid ratio (g ore/mL water), P.S: particle size (mm), T: reaction temperature (K), t: reaction time (min). In the obtained equation, the activation energy of 18183,4 Joule/mol.K and the particle size of the base is 2.2 (≈ 2) confirms the idea of ash or product film diffusion model. It also supports this view that the mixing speed does not affect the B2O3 conversion.