Processing of fine size minerals : Studies on some Indian uranium ores

Abstract

Conventionally uranium ores are processed by direct chemical leaching techniques. However, the application of chemical leaching for lean tenor and high tonnage uranium- ores is being desisted due to obvious environmental concerns. It is in this context that the physical benefi-ciation methods for the pre-concentration of uranium ores, if feasible, are gaining importance. Adoption of physical beneficiation helps in containing uranium and daughter nuclides in a smaller mass of pre-concentrate, which can be further subjected to conventional chemical processing, leaving bulk of the ore safe for disposal. In the application of physical beneficiation techniques, particle size plays a significant role. Both the economic mineral of uranium - uraninite and pitchblend, are brittle and report in very fine sizes during comminution, an oper-ation meant for their liberation.It is well established fact that concentration of particles finer than 25um by conventional physical beneficiation methods is very difficult due to the low mass and high surface area. However with the advent of new fine particle concentrators and techniques the situation has shown tremendous impr-ovement. This paper highlights the studies carried out on the use of both physical (gravity and magnetic) and physico-chemical beneficiation methods for recovering fine size uranium values from some low grade uranium bearing ores of India.