Investigation of growth kinetics of Ni0.855Co0.145(OH)2 particles in continuous co-precipitation process

Continuous co-precipitation is a powder-making method in which the injection of the reaction materials and the discharge of the product powder are performed simultaneously. This method enables the mass production of powder by a continued long-term reaction in comparison with batch-type methods. However, systematic investigation of particle growth kinetics is lacking because of the complexity of the method. In this study, the kinetics of the development of the particle size distribution in continuous co-precipitation is analyzed as a function of reaction operation time. From a steady-state approximation based on the sustainability requirements of the continuous-type reactor, equations for determining the particle size, growth rate, number of particles in the reactor, and total particle surface area are proposed, and the time profiles of these properties are quantitatively analyzed. On this basis, a strategy for controlling the processing conditions is discussed according to the intended particle size distribution, with particular focus on the frequency of massive nucleation and the time gap between generations. The analysis is supported by experimental results showing good agreement.