STUDY OF THE NEUTRALIZATION RATE IN A COAGULATION PARTICLE MADE BY THE SEED COAGULATION METHOD FROM POLYMER LATEX

The neutralization rate of fatty acid to calcium fatty acid in a coagulation particle using calcium hydroxide solution was studied. The coagulation particles were made by the seed coagulation method, using hydrochloric acid solution as the coagulant. The following results were obtained. (1) A model of the neutralization rate in a particle was proposed, based upon the unreacted core model in which the rate-controlling step was the diffusion of the hydroxyl ion in a particle. (2) To design the neutralization reactor, relation between the conversion X[-] and time t[s] can be simulated when the hydroxyl ion diffusion coefficient D[m2.s-1] is obtained in neutralizing experiments, using the following equation provided that the model density of fatty acid rho[mol.kg-1], radius of particle R[m] and neutralizing condition pOH are given. t = rho-R2.{3-3(1-X)2/3-2X}/6.10pOH.D In this study, the hydroxyl ion diffusion coefficient D was 2.91 x 10(-8)m2.s-1 at 358 K.