Growth of Aragonite CaCO3 Whiskers in a Microreactor with Calcium Dodecyl Benzenesulfonate as a Control Agent

This study presents a novel technique for the controllable preparation of aragonite CaCO3 whiskers using a microdispersion process. Calcium dodecyl benzenesulfonate [Ca(Ar–SO3)2] was first used as an additive for controlling the crystalline form. A homogeneous concentration distribution in the system was achieved due to the efficient micromixing. The effects of various operation parameters on the whiskers were determined, and the reaction conditions were optimized. The mechanism of the additive was discussed. The dynamic adsorption of Ca(Ar–SO3)2 on the surface of whiskers was experimentally demonstrated to be in charge of maintaining the one-dimensional growth and the high purity of the crystals. Aragonite CaCO3 with a crystalline purity of 98–99.5% was controllably synthesized at room temperature. The whiskers were approximately 27 μm in length and had an aspect ratio of about 58.