Kinetic studies on lime causticization using locally sourced soda ash and hydrated lime

Lime causticization was studied to develop the governing rate equation for the reaction. Under heterogeneous reaction conditions, the reaction was found to be limited by mass transfer. With thorough mixing (pseudo-homogeneous reaction) a rate equation was developed at optimized reaction time. The determining of initial rates method gave the order of reaction with respect to lime and soda ash to be 1.4 and 1.2 respectively. The overall rate equation was however found to follow a shift-order model; which indicates product inhibition characteristics of the reaction: _ rA = K^CA 1+KM^CA