Abstract
Hundreds of grams of calcined cerium dioxide (CeO2) microspheres with the smallest possible diameters were produced using the internal gelation process for crush strength studies. To achieve the small sizes required, a modified internal gelation system was employed, which utilized a two-fluid nozzle, two static mixers for turbulent flow, and 2-ethyl-1-hexanol as the medium for gel formation at 333338 K. This effort generated over 400 g of 75−150 µm and 300 g of <75 µm CeO2 microspheres. The typical product yields for the 75−150 µm and <75 µm microspheres were 70 and 99 %, respectively, with a typical throughput of 65−72 g of CeO2 microspheres per test. In comparison, the uranium microspheres produced from the same system had a much wider size distribution, which is more typical of two-fluid nozzle system based on previous experience. The fraction of air-dried uranium microspheres smaller than 150 µm was typically 50% or less. The higher yield of very small cerium spheres lead to challenges and modifications, which are discussed in detail.
