New In-situ Sampling and Analysis of the Production of CeO2 Powders from Liquid Precursors using a Novel Wet Collection System in a rf Inductively Coupled Thermal Plasma Reactor. Part 1: Reactor System and Sampling Probe

摘要

A new reactor and a novel in-situ sampling technique were developed for the study of the synthesis of CeO2 powders produced from dissolved cerium nitrate salts. The conical reactor minimized particle recirculation and provided a highly symmetrical and undisturbed plasma flow suitable for the analysis of the phenomena affecting the formation of CeO2 powders. Both a calorimetric study of the reactor and a thermodynamic analysis of CeO2 formation were conducted. The sampling probe is described and near-isokinetic sampling was achieved. The sampled particles were collected using a miniature wet collection system, i.e. a mist atomizer and a custom-made spray chamber. A numerical simulation of the velocity and temperature fields of the plasma gas in the reactor was done using Fluent. A comprehensive droplet-to-particle formation mechanism presented elsewhere is revisited and expanded based on calorimetry, thermodynamics of CeO2 formation, numerical simulations and collected particles. No traces of other oxidation states other than CeO2 were found.