Non-Ferrous Metal Ions Removal from Metallurgical Waste and Acid Mine Drainage Waters

摘要

Sulphide weathering in mining, beneficiation and metallurgical wastes often generates drainage waters with low pH and high concentration of potentially hazardous metals. To meet the increased environmental concerns in Iranian mining industry, this project was initiated. Using contaminated water samples from mining disposal sites, different methods were applied to reduce non-ferrous metal contamination of mining and metallurgical waste waters. The use of different locally available sorbents for the removal of some heavy metals such as copper, nickel, and zinc from strongly contaminated waters has been investigated. It was found that under certain condition some naturally occurring clay minerals may be used as cost-effective adsorbents for the separation of heavy metals from contaminated mining waters. It was found that the combination of adsorption and precipitation can lead to effective removal of heavy metals. Such combined process can be performed in 2 steps: (1) adsorption of heavy metals on clay minerals and (2) gradual precipitation of the residual heavy metal compounds. The 2-steps processing of contaminated wastes results in a significant ecological and economical improvement of waters. However, the prevention of acid mine drainage generation is a more economical way to avoid water contamination. This can be achieved by altering the chemical and physical properties of the wastes prior to disposal and by restricting the transport of oxygen and water into the waste dumps.