Sulphurs are present in different rocks. During min ing activities and the sulphur removal processes Ac id Mine Drainage (AMD) may be produced, by sulphate ions (SO 4 2- ) in solution. AMDs are the main source of pollutio n from mining operations and in Colombia their discharge into natural bodies of water must comply with national environmental regulations (pH between 5 and 9). Cement Kiln Dust (CKD), with calcium carbonate as its main component, from a Cementos Argos S.A. plant was used to neut ralize an AMD generated through a coal bio-desulphurization process. Neutra lized AMDs had pH values between 7.72 ‐ 8.05 and the sulphates removal ranged from 67% to 70%. Precipitated sludge was dried and analyzed in order to determine its chemical and min eralogical composition. Moisture content was between 69% and 81%; this precipitated material was composed of gypsum with approximately 50% purity, as well as calcium carbonate. This composition makes i t suitable for use in cement production.