An Experimental Design Study for crystallization of boric acid by Central composite design

Boric acid find a diverge range of application in industry, e.g. in borosilicate glasses, ointments, cream, detergents, agriculture and as dusting powder. Aqueous or alcoholic solutions of commercial grade boric acid appear hazy due to the presence of sulfate, chloride, arsenic and heavy metals. Such impurities impairs the divergent applications of boric acid especially for pharmaceutial and glass industry. In this study physical refining and purification method was used to obtain high purity boric acid. Three level full factorial design and central composite design were applied to select the most amount recovery of boric acid and the least amount of impurities. The effect of boric acid concentration, dissolution temperature, crystallization temperature, their binary interaction and quadratic effects on total impurities and also recovery of boric acid was investigated to realize the optimal conditions leading to reduce the total impurities and enhancement of boric acid recovery. The significant effect of the parameters was analyzed using Minitab software (Version 16) by analysis of the responses variance (ANOVA). The results showed that the increase of the crystallization temperature is effective on the recovery enhancement and reducing total impurities.

Keywords:

boric acid , crystallization , experimental design , Optimization , CCD