Prepare for U<inf>3</inf>0<inf>8</inf> from ammonium uranyl carbonate using microwave calcination

The novel technology of calcination to prepare triuranium octaoxide (U<inf>3</inf>O<inf>8</inf>) from ammonium uranyl carbonate in microwave fields was investigated on the basis of the temperature rising characteristics of ammonium uranyl carbonate, triuranium octaoxide (U<inf>3</inf>O<inf>8</inf>), and their mixture. The result of experiments show that ammonium uranyl carbonate had weak capability to absorb microwave energy, while triuranium octaoxide has the very strong capability to absorb microwave energy and the sample temperature increased rapidly with an increase mixture ratio of triuranium octaoxide. The optimal calcination conditions were as follows: microwave power 700 W, calcination time 10 min and 60 g in this experiments range, respectively. Under these conditions the value of total uranium and U4+ of triuranium octaoxide was 84.28% and 31.02%, respectively. It is feasible to prepare triuranium octaoxide by calcination from ammonium uranyl carbonate, which mixed with small amounts of triuranium octaoxide under microwave fields. Copyright © 2015 by The Minerals, Metals & Materials Society. All rights reserved