From coal ash to the nuclear fuel cycle: A new method of uranium extraction with membranes

Abstract

This study presents results from experiments on uranium leaching from coal combustion through theproducts by use of a membrane system. The aim of the study was to develop a basic operational model for a novel system dedicated to dusty materials that form colloids and are difficult to separate. Experiments were conducted to evaluate the efficiency and rate, along with the dynamics of uranium diffusion through the membrane. The results indicate that the proposed method allows efficient uranium leaching, with an average yield of 96.7 %. To describe the process, kinetic models were applied: second-order reaction kinetics for the leaching step and simple diffusion for uranium transport through the membrane. This membrane-assisted approach effectively addresses the challenges posed by the complex physical nature of ash residues, and its further refinement may enhance the efficiency of the process and support the principles of circular economy within the nuclear fuel cycle. Key experimental parameters, including the permeability coefficient and the leaching rate constant, were determined and will serve as the basis for the design of operations in subsequent stages of industrial application. The proposed membrane approach solves the problematic issues related to the difficult form of ashes, and further development can lead to optimisation of the fuel cycle in modern power generation.