Evaluation of Factors Affecting Sludge Volume in Mine Drainage Neutralization

Abstract

In this study, the effect of neutralizer type and concentration, target pH, and elapsed time on sludge volume were evaluated using Ilkwang mine drainage. A higher neutralizer concentration produced more sludge when the pH 7 was neutralized with 5%, 10%, and 20% lime slurry. Neutralization with the same pH with 20% lime and NaOH resulted in less sludge when using lime. The type of neutralizer affected the amount of sludge produced. However, regardless of the type of neutralizer, the volume of the sludge rapidly shrank within one hour and slowly declined thereafter. The control of pH 7 and 10 with 20% lime resulted in considerable sludge at a high pH. A comparison of sludge with 1 L and 1 m3 neutralized mine drainage showed 9% and 10% sludge volume, respectively, as compared to raw mine water. A beaker neutralization experiment was also able to estimate reliable sludge generation.