Determination of optimum conditions for boric acid production from colemanite by using co2 in high-pressure reactor

The purpose of this research is to produce boric acid from colemanite (2CaO center dot 3B(2)O(3)center dot 5H(2)O) by using CO2 instead of sulfuric acid through an eco-friendly method. CO2 which is known as a greenhouse gas has thermodynamically turned into stable CaCO3 after having been used for leaching of boric acid (H3BO3). Optimization of dissolution of colemanite obtianed from Bursa Kestelek under CO2 pressure has been investigated by using Taguchi Method. The parameters and their ranges used in the experiments were chosen as in the following: solid-to-liquid ratio (0.24-0.171 g/ml), gas pressure (15-30 bar), temperature (80-140 degrees C), time (90-150 min) and particle size (0.250-0.125 mm). The optimum conditions were found to be solid-to-liquid ratio 0171 g/ml, gas pressure 30 bar, temperature 120 degrees C, time 130 min. and the particle size 0.125 mm. The derived boric acid product has been characterized through the use of XRD, XPS, SEM, TGA and BET instruments. Dissolution rate under optimum conditions has been found to be 95.33%. The use of CO2 in boric acid production from colemanite is a contribution in the reduction of CO2 emission which causes greenhouse effect.