Synthesis of nanoparticles with novel technology: High-gravity reactive precipitation

On the basis of the analysis of key engineering factors predominating in a reactive precipitation process, a new method called high-gravity reactive p recipitation (HGRP), which means that reactive precipitation takes place in high-gravity conditions, is presented here for the massive production of n anoparticles. A rotating packed-bed reactor was designed to generate accele ration higher than the gravitational acceleration on Earth. The syntheses o f nanoparticles of CaCO3, aluminum hydroxide, and SrCO3 were employed to de monstrate the advantages and industrial potentials of this technology, wher e the typical gas-liquid-solid, gas-liquid, and liquid-liquid multiphase re action systems were involved. Experimental results show that the mean size of CaCO3 particles can be controlled and adjusted in the range of 17-36 nm through the change of operation conditions such as high-gravity levels, flu id flow rates, and reactant concentrations. Nanofibrils of aluminum hydroxi de of 1-10 nm in diameter and 50-300 nm in length as well as nanoparticles of SrCO3 with a mean size of 40 nm were synthesized. The crystal structures of these compounds synthesized in high-gravity conditions were the same as those in gravitational conditions. HGRP technology is believed to be capab le of the preparation of nanoparticles with low-cost and high-volume produc tion and therefore to have potential applications in industry.