Synthetic faujasite based on coal by-products for the treatment of acid mine drainage (AMD).

Abstract

Acid mine drainage (AMD) has long been a significant environmental problem associated to mining operations at the Parys Mountain copper-lead-zinc deposit of Anglesey (North Wales), a volcanogenic massive sulphide district of major metallogenic importance. AMD is a natural occurrence resulting from the microbial oxidation of sulphide minerals, especially pyrite (FeS2), pyrite in presence of water and air, which produces polluted waters strongly acidic containing high concentrations of Fe, sulphate and toxic metals. The treatment of AMD has traditionally been conducted by neutralization with lime or similar materials. However, liming is often temporary and produces secondary wastes, such as metal hydroxide sludges and gypsum, which are highly regulated and have costly disposal requirements. Several methods for AMD treatment have been developed, although adsorption being the preferred method for heavy metal removal due to its effectiveness. AMD remediation can be very costly and difficult, due to the high costs of activated carbon production and regeneration for water treatment. Therefore, alternative low-cost liming materials are constantly sought. Such adsorbents should be readily available, economically viable and easily regenerated. The aim of this study is to investigate the efficiency of synthetic faujasite obtained from coal by-products as adsorbent in removing heavy metals from AMD generated at the Parys Mountain copper-lead-zinc deposit.