Thermal denitration of uranyl nitrate in a fluidised bed reactor.

Commissioning and operating experience are described for the thermal denitration of uranyl nitrate in a 0.1 m diameter fluidised bed reactor. The effects of operating temperature, uranyl nitrate concentration and feed rate, nozzle air to liquid flow ratio, and the addition of sulphate to the feed, on the characteristics of the product and equipment performance were examined. Particle growth was a predominant feature which was strongly influenced by operating temperature. Changes in the main process variables exerted a minor influence on other properties of the product. The addition of sulphate to the uranyl nitrate feed solution produced an increase in surface area, and a decrease in pour and tap density. The wall-to-bed heat transfer coefficient was in the range 190 to 265W nf 2K-1, and shown to be an inverse function of the average particle size