Uranium recovery as a byproduct from radioactive coal

The coal in the Calaf area, Barcelona, deposit is characterized by its uranium content and high sulphur and ash grade. Reasonably assured resources are about 200 Mt of coal containing 40,000 t U3O8. Some studies have been carried out at a pilot plant aimed at both thermal exploitation and uranium recovery. Prior coal washing is necessary. Design and operation parameters for a heavy media separation plant have been determined. The fluid-bed combustion technology was selected, followed by uranium recovery from the ash. This combustion technology involves close temperature control and a very short residence time. In this way an acceptable uranium solubilization has been obtained. At the same time, limestone additions have been considered to keep most of the sulphur in the combustion bed and, in this way, reduce the environmental damage otherwise produced by SO2 emissions. The uranium distribution in the fly ash and bed overflow has been studied to find out the necessary conditions for concentrating the uranium in a single product. Leaching conditions for uranium solubilization with sulphuric acid have been established. A flowsheet with the global benefit of this coal is included. (author)