ULTRAFINE METAL OXIDE PRODUCTION

摘要

An ultrafine metal oxide powder consisting of non agglomerated ultrafine particles having a shape of given aspect ratio, of high density corresponding to at least 90% of the intrinsic density of a large crystal of the metal oxide and a narrow particle size distribution, is prepared by a first stage rapid crystallization of a small volume, typically in a Segmented Flow Tubular Reactor (SFTR), to produce low-density ultrafine powder of narrow particle size distribution, followed by subjecting a quantity of the ultrafine powder produced by repeating the first step to a second stage solvothermal post treatment at a temperature less than 400°C to convert the particles of low density to ultrafine particles of increased density while maintaining the particles' aspect ratio and narrow particle size distribution, allowing easy scale up of the process.