Separation and Characteristics of Colloid in Leaching Residual Ores Column of a Hard Uranium Ores

This paper aims to investigate the mass and characteristics of colloid in leaching process to provide useful information for assessing the effects of colloid on leach at vertical and safety assessment of the disposal of (ultra-) low uraniferous radioactive waste. The variation of pH, colloid mass and effects on leach were studied at ambient conditions. The experimental results showed that the formation of colloid was strongly influenced by the pH value, it increased with time from 24 h to 96 h, and mass of colloid showed the opposite trend. The mass of colloid increased by the thick of uranium residual ores from 0.2 m to 0.8 m, but the pH showed opposite trend. The colloid morphology was identified using S-4800 scanning electron microscopy (SEM/EDS), and confirmed Al, Fe, Mg, Cs, U, Pr, O, and C as main composition. It implies that the existence of colloids would retard uranium leaching process. The residue grade of different thick nicely verified this point.