Recovering iron and sulfate in the form of mineral from acid mine drainage by a bacteria-driven cyclic biomineralization system.

Acid mine drainage (AMD) is recognized as a challenge encountered by mining industries globally. Cyclic mineralization method, namely Fe oxidation/mineralization-residual Fe reduction-resultant Fe oxidation/mineralization, could precipitate Fe and SO present in AMD into iron hydroxysulfate minerals and greatly improve the efficiency of subsequent lime neutralization, but the current Fe-mediated reduction approach increased the mineralization cycles. This study constructed a bacteria-driven biomineralization system based on the reactions of Acidithiobacillus ferrooxidans-mediated Fe oxidation and Acidiphilium multivorum-controlled Fe reduction, and utilized water-dropping aeration and biofilm technology to satisfy the requirement of practical application.

A novel approach to rapidly purify acid mine drainage through chemically forming schwertmannite followed by lime neutralization.

Acid mine drainage (AMD) has been recognized as a major challenge to the global mining industry due to its environmental consequences. Lime neutralization has been a traditional treatment for AMD, but the abundance of iron and sulfate in AMD usually renders it ineffective by forming iron hydroxide and gypsum precipitate coating on the surface of lime. In light of ubiquitous biological mineralization phenomena present at AMD sites, a rapid chemical mineralization was developed to reduce iron and sulfate and recovery of iron from AMD prior to lime neutralization.