Abstract
The worldwide known treatment processes of acid mine drainage result into the
formation of hydrous ferric oxides that is amorphous, poorly crystalline and into the generation
of hazardous voluminous sludge posing threat to the environment. Applicable treatment technologies
to treat hazardous solid material and produce useful products are limited and in most cases
nonexistence. A chemical treatment process utilizing different reagents was developed to treat
hazardous acid mine drainage (AMD) sludge with the objectives to conduct radioactivity assessment
of the sludge generated from lime treatment process and determine the reagent that provides the
best results. Leaching with 0.5 M citric acid, 0.4 M oxalic acid, 0.5 M sodium carbonate and 0.5 M
sodium bicarbonate was investigated. The leaching time applied was 24 hours at 25 oC. The
characterization of the raw AMD revealed that the AMD sludge from lime treatment process is
radioactive. The sludge was laden with radioactive elements namely, 238U, 214Pb, 226Ra, 232Th, 40K
and 214Bi. 0.5 M citric acid provided the best results and the hazardous contaminants were
significantly reduced. The constituents in the sludge after treatment revealed that there is a
great potential for the sludge to be used for other applications
such as building and construction.