Hydrometallurgical treatment of metal‐containing solid waste using anaerobic processes

Abstract

The potential to damage the environment is the major motive to treat solid wastes. One main group of pollutants comprises metals such as cadmium, chromium, copper, mercury, nickel, lead, and zinc. This paper is a synthesis of five elsewhere published investigations focusing on the possibilities and limits to control the flux of metals from solid wastes using anaerobic processes. In particular, the treatment of sulfide forming elements and hexavalent chromium (Cr(VI)) were studied at both bench‐, pilot‐, and full‐scale. It was found that two‐step processes have the potential to significantly improve the quality of solid wastes. In a first step, metals were leached and transferred to the process water. In a second step, the metal‐enriched process water was treated under methanogenic conditions facilitating metal trapping through precipitation as sulfides or hydroxides. Anaerobic hydrometallurgy is judged to be a promising technique that has the potential to gain wide acceptance in the treatment of metal‐containing solid wastes from a wide variety of sources.

Keywords:

• Anaerobic hydrometallurgy
• metals
• solid waste
• leaching
• precipitation