Hydrotalcite, which is an anionic clay, has been prepared by precipitation reaction in a conventional stirred semibatch reactor and a novel narrow-channel reactor. For the stirred batch reactor, the effects of various parameters such as feed point location, stirring rate, impeller type, supersaturation ratio, and temperature on particle size (PS) and particle size distribution (PSD) have been studied. For the narrow-channel reactor, the effects of the channel cross-sectional area (two square channels with cross sections of 1 and 2 mm(2)), the Reynolds number, the type of mixer (Y and cross mixers), and the supersaturation ratio were studied. Modeling for agglomeration was performed to predict the PSD. Comparison of the mean PS of the two reactors, on a power consumption basis, clearly indicates the superiority of the narrow-channel reactor. The results also clearly show that the narrow-channel reactor is composed of much more compact process equipment, which has significantly lower capital and operating costs, as compared to a conventional stirred reactor, yielding, simultaneously, a better product. All these advantages lead to an intensified process.