Hyphae and organic acids of Aspergillus Niger promote uranium recovery by destroying the ore surface and increasing the porosity and permeability of ores

Abstract

To elucidate the mechanism of damage caused by hyphae and organic acids produced by Aspergillus Niger on the surface and internal structure of uranium ore, direct uranium leaching, indirect uranium leaching and semi-direct uranium leaching were conducted, and the surface morphology, strength, mineral crystallinity, porosity, and permeability of the ore were analyzed. The results demonstrated that the combination of biomechanical forces exerted by hyphae and the complexation effects of organic acids led to the dissolution of SiO2 and other substances on the surface of ore, resulting in exfoliation from the exterior to the interior, thereby promoting uranium recovery. Furthermore, the proton exchange involving H+ and the complexation of organic acids resulted in the dissolution of cations within the ore, causing destruction to the crystal lattice structure of minerals and increasing the porosity and permeability inside the ore. The dominant factor contributing to ore damage during recovery was organic acids.